usr/src/uts/common/vm/seg_vn.c
changeset 0 68f95e015346
child 63 25e4c130753b
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/usr/src/uts/common/vm/seg_vn.c	Tue Jun 14 00:00:00 2005 -0700
@@ -0,0 +1,7745 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
+/*	  All Rights Reserved  	*/
+
+/*
+ * University Copyright- Copyright (c) 1982, 1986, 1988
+ * The Regents of the University of California
+ * All Rights Reserved
+ *
+ * University Acknowledgment- Portions of this document are derived from
+ * software developed by the University of California, Berkeley, and its
+ * contributors.
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+/*
+ * VM - shared or copy-on-write from a vnode/anonymous memory.
+ */
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/t_lock.h>
+#include <sys/errno.h>
+#include <sys/systm.h>
+#include <sys/mman.h>
+#include <sys/debug.h>
+#include <sys/cred.h>
+#include <sys/vmsystm.h>
+#include <sys/tuneable.h>
+#include <sys/bitmap.h>
+#include <sys/swap.h>
+#include <sys/kmem.h>
+#include <sys/sysmacros.h>
+#include <sys/vtrace.h>
+#include <sys/cmn_err.h>
+#include <sys/vm.h>
+#include <sys/dumphdr.h>
+#include <sys/lgrp.h>
+
+#include <vm/hat.h>
+#include <vm/as.h>
+#include <vm/seg.h>
+#include <vm/seg_vn.h>
+#include <vm/pvn.h>
+#include <vm/anon.h>
+#include <vm/page.h>
+#include <vm/vpage.h>
+
+/*
+ * Private seg op routines.
+ */
+static int	segvn_dup(struct seg *seg, struct seg *newseg);
+static int	segvn_unmap(struct seg *seg, caddr_t addr, size_t len);
+static void	segvn_free(struct seg *seg);
+static faultcode_t segvn_fault(struct hat *hat, struct seg *seg,
+		    caddr_t addr, size_t len, enum fault_type type,
+		    enum seg_rw rw);
+static faultcode_t segvn_faulta(struct seg *seg, caddr_t addr);
+static int	segvn_setprot(struct seg *seg, caddr_t addr,
+		    size_t len, uint_t prot);
+static int	segvn_checkprot(struct seg *seg, caddr_t addr,
+		    size_t len, uint_t prot);
+static int	segvn_kluster(struct seg *seg, caddr_t addr, ssize_t delta);
+static size_t	segvn_swapout(struct seg *seg);
+static int	segvn_sync(struct seg *seg, caddr_t addr, size_t len,
+		    int attr, uint_t flags);
+static size_t	segvn_incore(struct seg *seg, caddr_t addr, size_t len,
+		    char *vec);
+static int	segvn_lockop(struct seg *seg, caddr_t addr, size_t len,
+		    int attr, int op, ulong_t *lockmap, size_t pos);
+static int	segvn_getprot(struct seg *seg, caddr_t addr, size_t len,
+		    uint_t *protv);
+static u_offset_t	segvn_getoffset(struct seg *seg, caddr_t addr);
+static int	segvn_gettype(struct seg *seg, caddr_t addr);
+static int	segvn_getvp(struct seg *seg, caddr_t addr,
+		    struct vnode **vpp);
+static int	segvn_advise(struct seg *seg, caddr_t addr, size_t len,
+		    uint_t behav);
+static void	segvn_dump(struct seg *seg);
+static int	segvn_pagelock(struct seg *seg, caddr_t addr, size_t len,
+		    struct page ***ppp, enum lock_type type, enum seg_rw rw);
+static int	segvn_setpagesize(struct seg *seg, caddr_t addr, size_t len,
+		    uint_t szc);
+static int	segvn_getmemid(struct seg *seg, caddr_t addr,
+		    memid_t *memidp);
+static lgrp_mem_policy_info_t	*segvn_getpolicy(struct seg *, caddr_t);
+
+struct	seg_ops segvn_ops = {
+	segvn_dup,
+	segvn_unmap,
+	segvn_free,
+	segvn_fault,
+	segvn_faulta,
+	segvn_setprot,
+	segvn_checkprot,
+	segvn_kluster,
+	segvn_swapout,
+	segvn_sync,
+	segvn_incore,
+	segvn_lockop,
+	segvn_getprot,
+	segvn_getoffset,
+	segvn_gettype,
+	segvn_getvp,
+	segvn_advise,
+	segvn_dump,
+	segvn_pagelock,
+	segvn_setpagesize,
+	segvn_getmemid,
+	segvn_getpolicy,
+};
+
+/*
+ * Common zfod structures, provided as a shorthand for others to use.
+ */
+static segvn_crargs_t zfod_segvn_crargs =
+	SEGVN_ZFOD_ARGS(PROT_ZFOD, PROT_ALL);
+static segvn_crargs_t kzfod_segvn_crargs =
+	SEGVN_ZFOD_ARGS(PROT_ZFOD & ~PROT_USER,
+	PROT_ALL & ~PROT_USER);
+static segvn_crargs_t stack_noexec_crargs =
+	SEGVN_ZFOD_ARGS(PROT_ZFOD & ~PROT_EXEC, PROT_ALL);
+
+caddr_t	zfod_argsp = (caddr_t)&zfod_segvn_crargs;	/* user zfod argsp */
+caddr_t	kzfod_argsp = (caddr_t)&kzfod_segvn_crargs;	/* kernel zfod argsp */
+caddr_t	stack_exec_argsp = (caddr_t)&zfod_segvn_crargs;	/* executable stack */
+caddr_t	stack_noexec_argsp = (caddr_t)&stack_noexec_crargs; /* noexec stack */
+
+#define	vpgtob(n)	((n) * sizeof (struct vpage))	/* For brevity */
+
+size_t	segvn_comb_thrshld = UINT_MAX;	/* patchable -- see 1196681 */
+
+static int	segvn_concat(struct seg *, struct seg *, int);
+static int	segvn_extend_prev(struct seg *, struct seg *,
+		    struct segvn_crargs *, size_t);
+static int	segvn_extend_next(struct seg *, struct seg *,
+		    struct segvn_crargs *, size_t);
+static void	segvn_softunlock(struct seg *, caddr_t, size_t, enum seg_rw);
+static void	segvn_pagelist_rele(page_t **);
+static void	segvn_setvnode_mpss(vnode_t *);
+static void	segvn_relocate_pages(page_t **, page_t *);
+static int	segvn_full_szcpages(page_t **, uint_t, int *, uint_t *);
+static int	segvn_fill_vp_pages(struct segvn_data *, vnode_t *, u_offset_t,
+    uint_t, page_t **, page_t **, uint_t *, int *);
+static faultcode_t segvn_fault_vnodepages(struct hat *, struct seg *, caddr_t,
+    caddr_t, enum fault_type, enum seg_rw, caddr_t, caddr_t, int);
+static faultcode_t segvn_fault_anonpages(struct hat *, struct seg *, caddr_t,
+    caddr_t, enum fault_type, enum seg_rw, caddr_t, caddr_t, int);
+static faultcode_t segvn_faultpage(struct hat *, struct seg *, caddr_t,
+    u_offset_t, struct vpage *, page_t **, uint_t,
+    enum fault_type, enum seg_rw, int);
+static void	segvn_vpage(struct seg *);
+
+static void segvn_purge(struct seg *seg);
+static int segvn_reclaim(struct seg *, caddr_t, size_t, struct page **,
+    enum seg_rw);
+
+static int sameprot(struct seg *, caddr_t, size_t);
+
+static int segvn_demote_range(struct seg *, caddr_t, size_t, int);
+static int segvn_clrszc(struct seg *);
+static struct seg *segvn_split_seg(struct seg *, caddr_t);
+static int segvn_claim_pages(struct seg *, struct vpage *, u_offset_t,
+    ulong_t, uint_t);
+
+static struct kmem_cache *segvn_cache;
+
+#ifdef VM_STATS
+static struct segvnvmstats_str {
+	ulong_t	fill_vp_pages[31];
+	ulong_t fltvnpages[49];
+	ulong_t	fullszcpages[10];
+	ulong_t	relocatepages[3];
+	ulong_t	fltanpages[17];
+	ulong_t pagelock[3];
+	ulong_t	demoterange[3];
+} segvnvmstats;
+#endif /* VM_STATS */
+
+#define	SDR_RANGE	1		/* demote entire range */
+#define	SDR_END		2		/* demote non aligned ends only */
+
+#define	CALC_LPG_REGION(pgsz, seg, addr, len, lpgaddr, lpgeaddr) {            \
+		if ((len) != 0) { 		      	      		      \
+			lpgaddr = (caddr_t)P2ALIGN((uintptr_t)(addr), pgsz);  \
+			ASSERT(lpgaddr >= (seg)->s_base);	      	      \
+			lpgeaddr = (caddr_t)P2ROUNDUP((uintptr_t)((addr) +    \
+			    (len)), pgsz);				      \
+			ASSERT(lpgeaddr > lpgaddr);		      	      \
+			ASSERT(lpgeaddr <= (seg)->s_base + (seg)->s_size);    \
+		} else {					      	      \
+			lpgeaddr = lpgaddr = (addr);	      		      \
+		}							      \
+	}
+
+/*ARGSUSED*/
+static int
+segvn_cache_constructor(void *buf, void *cdrarg, int kmflags)
+{
+	struct segvn_data *svd = buf;
+
+	rw_init(&svd->lock, NULL, RW_DEFAULT, NULL);
+	mutex_init(&svd->segp_slock, NULL, MUTEX_DEFAULT, NULL);
+	return (0);
+}
+
+/*ARGSUSED1*/
+static void
+segvn_cache_destructor(void *buf, void *cdrarg)
+{
+	struct segvn_data *svd = buf;
+
+	rw_destroy(&svd->lock);
+	mutex_destroy(&svd->segp_slock);
+}
+
+/*
+ * Patching this variable to non-zero allows the system to run with
+ * stacks marked as "not executable".  It's a bit of a kludge, but is
+ * provided as a tweakable for platforms that export those ABIs
+ * (e.g. sparc V8) that have executable stacks enabled by default.
+ * There are also some restrictions for platforms that don't actually
+ * implement 'noexec' protections.
+ *
+ * Once enabled, the system is (therefore) unable to provide a fully
+ * ABI-compliant execution environment, though practically speaking,
+ * most everything works.  The exceptions are generally some interpreters
+ * and debuggers that create executable code on the stack and jump
+ * into it (without explicitly mprotecting the address range to include
+ * PROT_EXEC).
+ *
+ * One important class of applications that are disabled are those
+ * that have been transformed into malicious agents using one of the
+ * numerous "buffer overflow" attacks.  See 4007890.
+ */
+int noexec_user_stack = 0;
+int noexec_user_stack_log = 1;
+
+int segvn_lpg_disable = 0;
+uint_t segvn_maxpgszc = 0;
+
+ulong_t segvn_fltvnpages_clrszc_err;
+ulong_t segvn_setpgsz_align_err;
+ulong_t segvn_setpgsz_getattr_err;
+ulong_t segvn_setpgsz_eof_err;
+ulong_t segvn_faultvnmpss_align_err1;
+ulong_t segvn_faultvnmpss_align_err2;
+ulong_t segvn_faultvnmpss_align_err3;
+ulong_t segvn_faultvnmpss_align_err4;
+ulong_t segvn_faultvnmpss_align_err5;
+ulong_t	segvn_vmpss_pageio_deadlk_err;
+
+/*
+ * Initialize segvn data structures
+ */
+void
+segvn_init(void)
+{
+	uint_t maxszc;
+	uint_t szc;
+	size_t pgsz;
+
+	segvn_cache = kmem_cache_create("segvn_cache",
+		sizeof (struct segvn_data), 0,
+		segvn_cache_constructor, segvn_cache_destructor, NULL,
+		NULL, NULL, 0);
+
+	if (segvn_lpg_disable != 0)
+		return;
+	szc = maxszc = page_num_pagesizes() - 1;
+	if (szc == 0) {
+		segvn_lpg_disable = 1;
+		return;
+	}
+	if (page_get_pagesize(0) != PAGESIZE) {
+		panic("segvn_init: bad szc 0");
+		/*NOTREACHED*/
+	}
+	while (szc != 0) {
+		pgsz = page_get_pagesize(szc);
+		if (pgsz <= PAGESIZE || !IS_P2ALIGNED(pgsz, pgsz)) {
+			panic("segvn_init: bad szc %d", szc);
+			/*NOTREACHED*/
+		}
+		szc--;
+	}
+	if (segvn_maxpgszc == 0 || segvn_maxpgszc > maxszc)
+		segvn_maxpgszc = maxszc;
+}
+
+#define	SEGVN_PAGEIO	((void *)0x1)
+#define	SEGVN_NOPAGEIO	((void *)0x2)
+
+static void
+segvn_setvnode_mpss(vnode_t *vp)
+{
+	int err;
+
+	ASSERT(vp->v_mpssdata == NULL ||
+	    vp->v_mpssdata == SEGVN_PAGEIO ||
+	    vp->v_mpssdata == SEGVN_NOPAGEIO);
+
+	if (vp->v_mpssdata == NULL) {
+		if (vn_vmpss_usepageio(vp)) {
+			err = VOP_PAGEIO(vp, (page_t *)NULL,
+			    (u_offset_t)0, 0, 0, CRED());
+		} else {
+			err = ENOSYS;
+		}
+		/*
+		 * set v_mpssdata just once per vnode life
+		 * so that it never changes.
+		 */
+		mutex_enter(&vp->v_lock);
+		if (vp->v_mpssdata == NULL) {
+			if (err == EINVAL) {
+				vp->v_mpssdata = SEGVN_PAGEIO;
+			} else {
+				vp->v_mpssdata = SEGVN_NOPAGEIO;
+			}
+		}
+		mutex_exit(&vp->v_lock);
+	}
+}
+
+int
+segvn_create(struct seg *seg, void *argsp)
+{
+	struct segvn_crargs *a = (struct segvn_crargs *)argsp;
+	struct segvn_data *svd;
+	size_t swresv = 0;
+	struct cred *cred;
+	struct anon_map *amp;
+	int error = 0;
+	size_t pgsz;
+	lgrp_mem_policy_t mpolicy = LGRP_MEM_POLICY_DEFAULT;
+
+
+	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	if (a->type != MAP_PRIVATE && a->type != MAP_SHARED) {
+		panic("segvn_create type");
+		/*NOTREACHED*/
+	}
+
+	/*
+	 * Check arguments.  If a shared anon structure is given then
+	 * it is illegal to also specify a vp.
+	 */
+	if (a->amp != NULL && a->vp != NULL) {
+		panic("segvn_create anon_map");
+		/*NOTREACHED*/
+	}
+
+	/* MAP_NORESERVE on a MAP_SHARED segment is meaningless. */
+	if (a->type == MAP_SHARED)
+		a->flags &= ~MAP_NORESERVE;
+
+	if (a->szc != 0) {
+		if (segvn_lpg_disable != 0 || a->amp != NULL ||
+		    (a->type == MAP_SHARED && a->vp == NULL) ||
+		    (a->flags & MAP_NORESERVE) || seg->s_as == &kas) {
+			a->szc = 0;
+		} else {
+			if (a->szc > segvn_maxpgszc)
+				a->szc = segvn_maxpgszc;
+			pgsz = page_get_pagesize(a->szc);
+			if (!IS_P2ALIGNED(seg->s_base, pgsz) ||
+			    !IS_P2ALIGNED(seg->s_size, pgsz)) {
+				a->szc = 0;
+			} else if (a->vp != NULL) {
+				extern struct vnode kvp;
+				if (IS_SWAPFSVP(a->vp) || a->vp == &kvp) {
+					/*
+					 * paranoid check.
+					 * hat_page_demote() is not supported
+					 * on swapfs pages.
+					 */
+					a->szc = 0;
+				} else if (map_addr_vacalign_check(seg->s_base,
+				    a->offset & PAGEMASK)) {
+					a->szc = 0;
+				}
+			}
+		}
+	}
+
+	/*
+	 * If segment may need private pages, reserve them now.
+	 */
+	if (!(a->flags & MAP_NORESERVE) && ((a->vp == NULL && a->amp == NULL) ||
+	    (a->type == MAP_PRIVATE && (a->prot & PROT_WRITE)))) {
+		if (anon_resv(seg->s_size) == 0)
+			return (EAGAIN);
+		swresv = seg->s_size;
+		TRACE_3(TR_FAC_VM, TR_ANON_PROC, "anon proc:%p %lu %u",
+			seg, swresv, 1);
+	}
+
+	/*
+	 * Reserve any mapping structures that may be required.
+	 */
+	hat_map(seg->s_as->a_hat, seg->s_base, seg->s_size, HAT_MAP);
+
+	if (a->cred) {
+		cred = a->cred;
+		crhold(cred);
+	} else {
+		crhold(cred = CRED());
+	}
+
+	/* Inform the vnode of the new mapping */
+	if (a->vp) {
+		error = VOP_ADDMAP(a->vp, a->offset & PAGEMASK,
+		    seg->s_as, seg->s_base, seg->s_size, a->prot,
+		    a->maxprot, a->type, cred);
+		if (error) {
+			if (swresv != 0) {
+				anon_unresv(swresv);
+				TRACE_3(TR_FAC_VM, TR_ANON_PROC,
+					"anon proc:%p %lu %u",
+					seg, swresv, 0);
+			}
+			crfree(cred);
+			hat_unload(seg->s_as->a_hat, seg->s_base,
+				seg->s_size, HAT_UNLOAD_UNMAP);
+			return (error);
+		}
+	}
+
+	/*
+	 * If more than one segment in the address space, and
+	 * they're adjacent virtually, try to concatenate them.
+	 * Don't concatenate if an explicit anon_map structure
+	 * was supplied (e.g., SystemV shared memory).
+	 */
+	if (a->amp == NULL) {
+		struct seg *pseg, *nseg;
+		struct segvn_data *psvd, *nsvd;
+		lgrp_mem_policy_t ppolicy, npolicy;
+		uint_t	lgrp_mem_policy_flags = 0;
+		extern lgrp_mem_policy_t lgrp_mem_default_policy;
+
+		/*
+		 * Memory policy flags (lgrp_mem_policy_flags) is valid when
+		 * extending stack/heap segments.
+		 */
+		if ((a->vp == NULL) && (a->type == MAP_PRIVATE) &&
+			!(a->flags & MAP_NORESERVE) && (seg->s_as != &kas)) {
+			lgrp_mem_policy_flags = a->lgrp_mem_policy_flags;
+		} else {
+			/*
+			 * Get policy when not extending it from another segment
+			 */
+			mpolicy = lgrp_mem_policy_default(seg->s_size, a->type);
+		}
+
+		/*
+		 * First, try to concatenate the previous and new segments
+		 */
+		pseg = AS_SEGPREV(seg->s_as, seg);
+		if (pseg != NULL &&
+		    pseg->s_base + pseg->s_size == seg->s_base &&
+		    pseg->s_ops == &segvn_ops) {
+			/*
+			 * Get memory allocation policy from previous segment.
+			 * When extension is specified (e.g. for heap) apply
+			 * this policy to the new segment regardless of the
+			 * outcome of segment concatenation.  Extension occurs
+			 * for non-default policy otherwise default policy is
+			 * used and is based on extended segment size.
+			 */
+			psvd = (struct segvn_data *)pseg->s_data;
+			ppolicy = psvd->policy_info.mem_policy;
+			if (lgrp_mem_policy_flags ==
+			    LGRP_MP_FLAG_EXTEND_UP) {
+				if (ppolicy != lgrp_mem_default_policy) {
+					mpolicy = ppolicy;
+				} else {
+					mpolicy = lgrp_mem_policy_default(
+					    pseg->s_size + seg->s_size,
+					    a->type);
+				}
+			}
+
+			if (mpolicy == ppolicy &&
+			    (pseg->s_size + seg->s_size <=
+			    segvn_comb_thrshld || psvd->amp == NULL) &&
+			    segvn_extend_prev(pseg, seg, a, swresv) == 0) {
+				/*
+				 * success! now try to concatenate
+				 * with following seg
+				 */
+				crfree(cred);
+				nseg = AS_SEGNEXT(pseg->s_as, pseg);
+				if (nseg != NULL &&
+				    nseg != pseg &&
+				    nseg->s_ops == &segvn_ops &&
+				    pseg->s_base + pseg->s_size ==
+				    nseg->s_base)
+					(void) segvn_concat(pseg, nseg, 0);
+				ASSERT(pseg->s_szc == 0 ||
+				    (a->szc == pseg->s_szc &&
+				    IS_P2ALIGNED(pseg->s_base, pgsz) &&
+				    IS_P2ALIGNED(pseg->s_size, pgsz)));
+				return (0);
+			}
+		}
+
+		/*
+		 * Failed, so try to concatenate with following seg
+		 */
+		nseg = AS_SEGNEXT(seg->s_as, seg);
+		if (nseg != NULL &&
+		    seg->s_base + seg->s_size == nseg->s_base &&
+		    nseg->s_ops == &segvn_ops) {
+			/*
+			 * Get memory allocation policy from next segment.
+			 * When extension is specified (e.g. for stack) apply
+			 * this policy to the new segment regardless of the
+			 * outcome of segment concatenation.  Extension occurs
+			 * for non-default policy otherwise default policy is
+			 * used and is based on extended segment size.
+			 */
+			nsvd = (struct segvn_data *)nseg->s_data;
+			npolicy = nsvd->policy_info.mem_policy;
+			if (lgrp_mem_policy_flags ==
+			    LGRP_MP_FLAG_EXTEND_DOWN) {
+				if (npolicy != lgrp_mem_default_policy) {
+					mpolicy = npolicy;
+				} else {
+					mpolicy = lgrp_mem_policy_default(
+					    nseg->s_size + seg->s_size,
+					    a->type);
+				}
+			}
+
+			if (mpolicy == npolicy &&
+			    segvn_extend_next(seg, nseg, a, swresv) == 0) {
+				crfree(cred);
+				ASSERT(nseg->s_szc == 0 ||
+				    (a->szc == nseg->s_szc &&
+				    IS_P2ALIGNED(nseg->s_base, pgsz) &&
+				    IS_P2ALIGNED(nseg->s_size, pgsz)));
+				return (0);
+			}
+		}
+	}
+
+	if (a->vp != NULL) {
+		VN_HOLD(a->vp);
+		if (a->type == MAP_SHARED)
+			lgrp_shm_policy_init(NULL, a->vp);
+	}
+	svd = kmem_cache_alloc(segvn_cache, KM_SLEEP);
+
+	seg->s_ops = &segvn_ops;
+	seg->s_data = (void *)svd;
+	seg->s_szc = a->szc;
+
+	svd->vp = a->vp;
+	/*
+	 * Anonymous mappings have no backing file so the offset is meaningless.
+	 */
+	svd->offset = a->vp ? (a->offset & PAGEMASK) : 0;
+	svd->prot = a->prot;
+	svd->maxprot = a->maxprot;
+	svd->pageprot = 0;
+	svd->type = a->type;
+	svd->vpage = NULL;
+	svd->cred = cred;
+	svd->advice = MADV_NORMAL;
+	svd->pageadvice = 0;
+	svd->flags = (ushort_t)a->flags;
+	svd->softlockcnt = 0;
+	if (a->szc != 0 && a->vp != NULL) {
+		segvn_setvnode_mpss(a->vp);
+	}
+
+	amp = a->amp;
+	if ((svd->amp = amp) == NULL) {
+		svd->anon_index = 0;
+		if (svd->type == MAP_SHARED) {
+			svd->swresv = 0;
+			/*
+			 * Shared mappings to a vp need no other setup.
+			 * If we have a shared mapping to an anon_map object
+			 * which hasn't been allocated yet,  allocate the
+			 * struct now so that it will be properly shared
+			 * by remembering the swap reservation there.
+			 */
+			if (a->vp == NULL) {
+				svd->amp = anonmap_alloc(seg->s_size, swresv);
+				svd->amp->a_szc = seg->s_szc;
+			}
+		} else {
+			/*
+			 * Private mapping (with or without a vp).
+			 * Allocate anon_map when needed.
+			 */
+			svd->swresv = swresv;
+		}
+	} else {
+		pgcnt_t anon_num;
+
+		/*
+		 * Mapping to an existing anon_map structure without a vp.
+		 * For now we will insure that the segment size isn't larger
+		 * than the size - offset gives us.  Later on we may wish to
+		 * have the anon array dynamically allocated itself so that
+		 * we don't always have to allocate all the anon pointer slots.
+		 * This of course involves adding extra code to check that we
+		 * aren't trying to use an anon pointer slot beyond the end
+		 * of the currently allocated anon array.
+		 */
+		if ((amp->size - a->offset) < seg->s_size) {
+			panic("segvn_create anon_map size");
+			/*NOTREACHED*/
+		}
+
+		anon_num = btopr(a->offset);
+
+		if (a->type == MAP_SHARED) {
+			/*
+			 * SHARED mapping to a given anon_map.
+			 */
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
+			amp->refcnt++;
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+			svd->anon_index = anon_num;
+			svd->swresv = 0;
+		} else {
+			/*
+			 * PRIVATE mapping to a given anon_map.
+			 * Make sure that all the needed anon
+			 * structures are created (so that we will
+			 * share the underlying pages if nothing
+			 * is written by this mapping) and then
+			 * duplicate the anon array as is done
+			 * when a privately mapped segment is dup'ed.
+			 */
+			struct anon *ap;
+			caddr_t addr;
+			caddr_t eaddr;
+			ulong_t	anon_idx;
+			int hat_flag = HAT_LOAD;
+
+			if (svd->flags & MAP_TEXT) {
+				hat_flag |= HAT_LOAD_TEXT;
+			}
+
+			svd->amp = anonmap_alloc(seg->s_size, 0);
+			svd->amp->a_szc = seg->s_szc;
+			svd->anon_index = 0;
+			svd->swresv = swresv;
+
+			/*
+			 * Prevent 2 threads from allocating anon
+			 * slots simultaneously.
+			 */
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
+			eaddr = seg->s_base + seg->s_size;
+
+			for (anon_idx = anon_num, addr = seg->s_base;
+			    addr < eaddr; addr += PAGESIZE, anon_idx++) {
+				page_t *pp;
+
+				if ((ap = anon_get_ptr(amp->ahp,
+				    anon_idx)) != NULL)
+					continue;
+
+				/*
+				 * Allocate the anon struct now.
+				 * Might as well load up translation
+				 * to the page while we're at it...
+				 */
+				pp = anon_zero(seg, addr, &ap, cred);
+				if (ap == NULL || pp == NULL) {
+					panic("segvn_create anon_zero");
+					/*NOTREACHED*/
+				}
+
+				/*
+				 * Re-acquire the anon_map lock and
+				 * initialize the anon array entry.
+				 */
+				ASSERT(anon_get_ptr(amp->ahp,
+				    anon_idx) == NULL);
+				(void) anon_set_ptr(amp->ahp, anon_idx, ap,
+				    ANON_SLEEP);
+
+				ASSERT(seg->s_szc == 0);
+				ASSERT(!IS_VMODSORT(pp->p_vnode));
+
+				hat_memload(seg->s_as->a_hat, addr, pp,
+					svd->prot & ~PROT_WRITE, hat_flag);
+
+				page_unlock(pp);
+			}
+			ASSERT(seg->s_szc == 0);
+			anon_dup(amp->ahp, anon_num, svd->amp->ahp,
+			    0, seg->s_size);
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+		}
+	}
+
+	/*
+	 * Set default memory allocation policy for segment
+	 *
+	 * Always set policy for private memory at least for initialization
+	 * even if this is a shared memory segment
+	 */
+	(void) lgrp_privm_policy_set(mpolicy, &svd->policy_info, seg->s_size);
+
+	if (svd->type == MAP_SHARED)
+		(void) lgrp_shm_policy_set(mpolicy, svd->amp, svd->anon_index,
+		    svd->vp, svd->offset, seg->s_size);
+
+	return (0);
+}
+
+/*
+ * Concatenate two existing segments, if possible.
+ * Return 0 on success, -1 if two segments are not compatible
+ * or -2 on memory allocation failure.
+ * If private == 1 then try and concat segments with private pages.
+ */
+static int
+segvn_concat(struct seg *seg1, struct seg *seg2, int private)
+{
+	struct segvn_data *svd1 = seg1->s_data;
+	struct segvn_data *svd2 = seg2->s_data;
+	struct anon_map *amp1 = svd1->amp;
+	struct anon_map *amp2 = svd2->amp;
+	struct vpage *vpage1 = svd1->vpage;
+	struct vpage *vpage2 = svd2->vpage, *nvpage = NULL;
+	size_t size, nvpsize;
+	pgcnt_t npages1, npages2;
+
+	ASSERT(seg1->s_as && seg2->s_as && seg1->s_as == seg2->s_as);
+	ASSERT(AS_WRITE_HELD(seg1->s_as, &seg1->s_as->a_lock));
+	ASSERT(seg1->s_ops == seg2->s_ops);
+
+	/* both segments exist, try to merge them */
+#define	incompat(x)	(svd1->x != svd2->x)
+	if (incompat(vp) || incompat(maxprot) ||
+	    (!svd1->pageadvice && !svd2->pageadvice && incompat(advice)) ||
+	    (!svd1->pageprot && !svd2->pageprot && incompat(prot)) ||
+	    incompat(type) || incompat(cred) || incompat(flags) ||
+	    seg1->s_szc != seg2->s_szc || incompat(policy_info.mem_policy) ||
+	    (svd2->softlockcnt > 0))
+		return (-1);
+#undef incompat
+
+	/*
+	 * vp == NULL implies zfod, offset doesn't matter
+	 */
+	if (svd1->vp != NULL &&
+	    svd1->offset + seg1->s_size != svd2->offset) {
+		return (-1);
+	}
+
+	/*
+	 * Fail early if we're not supposed to concatenate
+	 * private pages.
+	 */
+	if ((private == 0 || svd1->type != MAP_PRIVATE) &&
+	    (amp1 != NULL || amp2 != NULL)) {
+		return (-1);
+	}
+
+	/*
+	 * If either seg has vpages, create a new merged vpage array.
+	 */
+	if (vpage1 != NULL || vpage2 != NULL) {
+		struct vpage *vp;
+
+		npages1 = seg_pages(seg1);
+		npages2 = seg_pages(seg2);
+		nvpsize = vpgtob(npages1 + npages2);
+
+		if ((nvpage = kmem_zalloc(nvpsize, KM_NOSLEEP)) == NULL) {
+			return (-2);
+		}
+		if (vpage1 != NULL) {
+			bcopy(vpage1, nvpage, vpgtob(npages1));
+		}
+		if (vpage2 != NULL) {
+			bcopy(vpage2, nvpage + npages1, vpgtob(npages2));
+		}
+		for (vp = nvpage; vp < nvpage + npages1; vp++) {
+			if (svd2->pageprot && !svd1->pageprot) {
+				VPP_SETPROT(vp, svd1->prot);
+			}
+			if (svd2->pageadvice && !svd1->pageadvice) {
+				VPP_SETADVICE(vp, svd1->advice);
+			}
+		}
+		for (vp = nvpage + npages1;
+		    vp < nvpage + npages1 + npages2; vp++) {
+			if (svd1->pageprot && !svd2->pageprot) {
+				VPP_SETPROT(vp, svd2->prot);
+			}
+			if (svd1->pageadvice && !svd2->pageadvice) {
+				VPP_SETADVICE(vp, svd2->advice);
+			}
+		}
+	}
+
+	/*
+	 * If either segment has private pages, create a new merged anon
+	 * array.
+	 */
+	if (amp1 != NULL || amp2 != NULL) {
+		struct anon_hdr *nahp;
+		struct anon_map *namp = NULL;
+		size_t asize = seg1->s_size + seg2->s_size;
+
+		if ((nahp = anon_create(btop(asize), ANON_NOSLEEP)) == NULL) {
+			if (nvpage != NULL) {
+				kmem_free(nvpage, nvpsize);
+			}
+			return (-2);
+		}
+		if (amp1 != NULL) {
+			/*
+			 * XXX anon rwlock is not really needed because
+			 * this is a private segment and we are writers.
+			 */
+			ANON_LOCK_ENTER(&amp1->a_rwlock, RW_WRITER);
+			ASSERT(amp1->refcnt == 1);
+			if (anon_copy_ptr(amp1->ahp, svd1->anon_index,
+			    nahp, 0, btop(seg1->s_size), ANON_NOSLEEP)) {
+				anon_release(nahp, btop(asize));
+				ANON_LOCK_EXIT(&amp1->a_rwlock);
+				if (nvpage != NULL) {
+					kmem_free(nvpage, nvpsize);
+				}
+				return (-2);
+			}
+		}
+		if (amp2 != NULL) {
+			ANON_LOCK_ENTER(&amp2->a_rwlock, RW_WRITER);
+			ASSERT(amp2->refcnt == 1);
+			if (anon_copy_ptr(amp2->ahp, svd2->anon_index,
+			    nahp, btop(seg1->s_size), btop(seg2->s_size),
+			    ANON_NOSLEEP)) {
+				anon_release(nahp, btop(asize));
+				ANON_LOCK_EXIT(&amp2->a_rwlock);
+				if (amp1 != NULL) {
+					ANON_LOCK_EXIT(&amp1->a_rwlock);
+				}
+				if (nvpage != NULL) {
+					kmem_free(nvpage, nvpsize);
+				}
+				return (-2);
+			}
+		}
+		if (amp1 != NULL) {
+			namp = amp1;
+			anon_release(amp1->ahp, btop(amp1->size));
+		}
+		if (amp2 != NULL) {
+			if (namp == NULL) {
+				ASSERT(amp1 == NULL);
+				namp = amp2;
+				anon_release(amp2->ahp, btop(amp2->size));
+			} else {
+				amp2->refcnt--;
+				ANON_LOCK_EXIT(&amp2->a_rwlock);
+				anonmap_free(amp2);
+			}
+			svd2->amp = NULL; /* needed for seg_free */
+		}
+		namp->ahp = nahp;
+		namp->size = asize;
+		svd1->amp = namp;
+		svd1->anon_index = 0;
+		ANON_LOCK_EXIT(&namp->a_rwlock);
+	}
+	/*
+	 * Now free the old vpage structures.
+	 */
+	if (nvpage != NULL) {
+		if (vpage1 != NULL) {
+			kmem_free(vpage1, vpgtob(npages1));
+		}
+		if (vpage2 != NULL) {
+			svd2->vpage = NULL;
+			kmem_free(vpage2, vpgtob(npages2));
+		}
+		if (svd2->pageprot) {
+			svd1->pageprot = 1;
+		}
+		if (svd2->pageadvice) {
+			svd1->pageadvice = 1;
+		}
+		svd1->vpage = nvpage;
+	}
+
+	/* all looks ok, merge segments */
+	svd1->swresv += svd2->swresv;
+	svd2->swresv = 0;  /* so seg_free doesn't release swap space */
+	size = seg2->s_size;
+	seg_free(seg2);
+	seg1->s_size += size;
+	return (0);
+}
+
+/*
+ * Extend the previous segment (seg1) to include the
+ * new segment (seg2 + a), if possible.
+ * Return 0 on success.
+ */
+static int
+segvn_extend_prev(seg1, seg2, a, swresv)
+	struct seg *seg1, *seg2;
+	struct segvn_crargs *a;
+	size_t swresv;
+{
+	struct segvn_data *svd1 = (struct segvn_data *)seg1->s_data;
+	size_t size;
+	struct anon_map *amp1;
+	struct vpage *new_vpage;
+
+	/*
+	 * We don't need any segment level locks for "segvn" data
+	 * since the address space is "write" locked.
+	 */
+	ASSERT(seg1->s_as && AS_WRITE_HELD(seg1->s_as, &seg1->s_as->a_lock));
+
+	/* second segment is new, try to extend first */
+	/* XXX - should also check cred */
+	if (svd1->vp != a->vp || svd1->maxprot != a->maxprot ||
+	    (!svd1->pageprot && (svd1->prot != a->prot)) ||
+	    svd1->type != a->type || svd1->flags != a->flags ||
+	    seg1->s_szc != a->szc)
+		return (-1);
+
+	/* vp == NULL implies zfod, offset doesn't matter */
+	if (svd1->vp != NULL &&
+	    svd1->offset + seg1->s_size != (a->offset & PAGEMASK))
+		return (-1);
+
+	amp1 = svd1->amp;
+	if (amp1) {
+		pgcnt_t newpgs;
+
+		/*
+		 * Segment has private pages, can data structures
+		 * be expanded?
+		 *
+		 * Acquire the anon_map lock to prevent it from changing,
+		 * if it is shared.  This ensures that the anon_map
+		 * will not change while a thread which has a read/write
+		 * lock on an address space references it.
+		 * XXX - Don't need the anon_map lock at all if "refcnt"
+		 * is 1.
+		 *
+		 * Can't grow a MAP_SHARED segment with an anonmap because
+		 * there may be existing anon slots where we want to extend
+		 * the segment and we wouldn't know what to do with them
+		 * (e.g., for tmpfs right thing is to just leave them there,
+		 * for /dev/zero they should be cleared out).
+		 */
+		if (svd1->type == MAP_SHARED)
+			return (-1);
+
+		ANON_LOCK_ENTER(&amp1->a_rwlock, RW_WRITER);
+		if (amp1->refcnt > 1) {
+			ANON_LOCK_EXIT(&amp1->a_rwlock);
+			return (-1);
+		}
+		newpgs = anon_grow(amp1->ahp, &svd1->anon_index,
+		    btop(seg1->s_size), btop(seg2->s_size), ANON_NOSLEEP);
+
+		if (newpgs == 0) {
+			ANON_LOCK_EXIT(&amp1->a_rwlock);
+			return (-1);
+		}
+		amp1->size = ptob(newpgs);
+		ANON_LOCK_EXIT(&amp1->a_rwlock);
+	}
+	if (svd1->vpage != NULL) {
+		new_vpage =
+		    kmem_zalloc(vpgtob(seg_pages(seg1) + seg_pages(seg2)),
+			KM_NOSLEEP);
+		if (new_vpage == NULL)
+			return (-1);
+		bcopy(svd1->vpage, new_vpage, vpgtob(seg_pages(seg1)));
+		kmem_free(svd1->vpage, vpgtob(seg_pages(seg1)));
+		svd1->vpage = new_vpage;
+		if (svd1->pageprot) {
+			struct vpage *vp, *evp;
+
+			vp = new_vpage + seg_pages(seg1);
+			evp = vp + seg_pages(seg2);
+			for (; vp < evp; vp++)
+				VPP_SETPROT(vp, a->prot);
+		}
+	}
+	size = seg2->s_size;
+	seg_free(seg2);
+	seg1->s_size += size;
+	svd1->swresv += swresv;
+	return (0);
+}
+
+/*
+ * Extend the next segment (seg2) to include the
+ * new segment (seg1 + a), if possible.
+ * Return 0 on success.
+ */
+static int
+segvn_extend_next(
+	struct seg *seg1,
+	struct seg *seg2,
+	struct segvn_crargs *a,
+	size_t swresv)
+{
+	struct segvn_data *svd2 = (struct segvn_data *)seg2->s_data;
+	size_t size;
+	struct anon_map *amp2;
+	struct vpage *new_vpage;
+
+	/*
+	 * We don't need any segment level locks for "segvn" data
+	 * since the address space is "write" locked.
+	 */
+	ASSERT(seg2->s_as && AS_WRITE_HELD(seg2->s_as, &seg2->s_as->a_lock));
+
+	/* first segment is new, try to extend second */
+	/* XXX - should also check cred */
+	if (svd2->vp != a->vp || svd2->maxprot != a->maxprot ||
+	    (!svd2->pageprot && (svd2->prot != a->prot)) ||
+	    svd2->type != a->type || svd2->flags != a->flags ||
+	    seg2->s_szc != a->szc)
+		return (-1);
+	/* vp == NULL implies zfod, offset doesn't matter */
+	if (svd2->vp != NULL &&
+	    (a->offset & PAGEMASK) + seg1->s_size != svd2->offset)
+		return (-1);
+
+	amp2 = svd2->amp;
+	if (amp2) {
+		pgcnt_t newpgs;
+
+		/*
+		 * Segment has private pages, can data structures
+		 * be expanded?
+		 *
+		 * Acquire the anon_map lock to prevent it from changing,
+		 * if it is shared.  This ensures that the anon_map
+		 * will not change while a thread which has a read/write
+		 * lock on an address space references it.
+		 *
+		 * XXX - Don't need the anon_map lock at all if "refcnt"
+		 * is 1.
+		 */
+		if (svd2->type == MAP_SHARED)
+			return (-1);
+
+		ANON_LOCK_ENTER(&amp2->a_rwlock, RW_WRITER);
+		if (amp2->refcnt > 1) {
+			ANON_LOCK_EXIT(&amp2->a_rwlock);
+			return (-1);
+		}
+		newpgs = anon_grow(amp2->ahp, &svd2->anon_index,
+		    btop(seg2->s_size), btop(seg1->s_size),
+		    ANON_NOSLEEP | ANON_GROWDOWN);
+
+		if (newpgs == 0) {
+			ANON_LOCK_EXIT(&amp2->a_rwlock);
+			return (-1);
+		}
+		amp2->size = ptob(newpgs);
+		ANON_LOCK_EXIT(&amp2->a_rwlock);
+	}
+	if (svd2->vpage != NULL) {
+		new_vpage =
+		    kmem_zalloc(vpgtob(seg_pages(seg1) + seg_pages(seg2)),
+			KM_NOSLEEP);
+		if (new_vpage == NULL) {
+			/* Not merging segments so adjust anon_index back */
+			if (amp2)
+				svd2->anon_index += seg_pages(seg1);
+			return (-1);
+		}
+		bcopy(svd2->vpage, new_vpage + seg_pages(seg1),
+		    vpgtob(seg_pages(seg2)));
+		kmem_free(svd2->vpage, vpgtob(seg_pages(seg2)));
+		svd2->vpage = new_vpage;
+		if (svd2->pageprot) {
+			struct vpage *vp, *evp;
+
+			vp = new_vpage;
+			evp = vp + seg_pages(seg1);
+			for (; vp < evp; vp++)
+				VPP_SETPROT(vp, a->prot);
+		}
+	}
+	size = seg1->s_size;
+	seg_free(seg1);
+	seg2->s_size += size;
+	seg2->s_base -= size;
+	svd2->offset -= size;
+	svd2->swresv += swresv;
+	return (0);
+}
+
+static int
+segvn_dup(struct seg *seg, struct seg *newseg)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct segvn_data *newsvd;
+	pgcnt_t npages = seg_pages(seg);
+	int error = 0;
+	uint_t prot;
+	size_t len;
+
+	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	/*
+	 * If segment has anon reserved, reserve more for the new seg.
+	 * For a MAP_NORESERVE segment swresv will be a count of all the
+	 * allocated anon slots; thus we reserve for the child as many slots
+	 * as the parent has allocated. This semantic prevents the child or
+	 * parent from dieing during a copy-on-write fault caused by trying
+	 * to write a shared pre-existing anon page.
+	 */
+	if ((len = svd->swresv) != 0) {
+		if (anon_resv(svd->swresv) == 0)
+			return (ENOMEM);
+
+		TRACE_3(TR_FAC_VM, TR_ANON_PROC, "anon proc:%p %lu %u",
+			seg, len, 0);
+	}
+
+	newsvd = kmem_cache_alloc(segvn_cache, KM_SLEEP);
+
+	newseg->s_ops = &segvn_ops;
+	newseg->s_data = (void *)newsvd;
+	newseg->s_szc = seg->s_szc;
+
+	if ((newsvd->vp = svd->vp) != NULL) {
+		VN_HOLD(svd->vp);
+		if (svd->type == MAP_SHARED)
+			lgrp_shm_policy_init(NULL, svd->vp);
+	}
+	newsvd->offset = svd->offset;
+	newsvd->prot = svd->prot;
+	newsvd->maxprot = svd->maxprot;
+	newsvd->pageprot = svd->pageprot;
+	newsvd->type = svd->type;
+	newsvd->cred = svd->cred;
+	crhold(newsvd->cred);
+	newsvd->advice = svd->advice;
+	newsvd->pageadvice = svd->pageadvice;
+	newsvd->swresv = svd->swresv;
+	newsvd->flags = svd->flags;
+	newsvd->softlockcnt = 0;
+	newsvd->policy_info = svd->policy_info;
+	if ((newsvd->amp = svd->amp) == NULL) {
+		/*
+		 * Not attaching to a shared anon object.
+		 */
+		newsvd->anon_index = 0;
+	} else {
+		struct anon_map *amp;
+
+		amp = svd->amp;
+		if (svd->type == MAP_SHARED) {
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
+			amp->refcnt++;
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+			newsvd->anon_index = svd->anon_index;
+		} else {
+			int reclaim = 1;
+
+			/*
+			 * Allocate and initialize new anon_map structure.
+			 */
+			newsvd->amp = anonmap_alloc(newseg->s_size, 0);
+			newsvd->amp->a_szc = newseg->s_szc;
+			newsvd->anon_index = 0;
+
+			/*
+			 * We don't have to acquire the anon_map lock
+			 * for the new segment (since it belongs to an
+			 * address space that is still not associated
+			 * with any process), or the segment in the old
+			 * address space (since all threads in it
+			 * are stopped while duplicating the address space).
+			 */
+
+			/*
+			 * The goal of the following code is to make sure that
+			 * softlocked pages do not end up as copy on write
+			 * pages.  This would cause problems where one
+			 * thread writes to a page that is COW and a different
+			 * thread in the same process has softlocked it.  The
+			 * softlock lock would move away from this process
+			 * because the write would cause this process to get
+			 * a copy (without the softlock).
+			 *
+			 * The strategy here is to just break the
+			 * sharing on pages that could possibly be
+			 * softlocked.
+			 */
+retry:
+			if (svd->softlockcnt) {
+				struct anon *ap, *newap;
+				size_t i;
+				uint_t vpprot;
+				page_t *anon_pl[1+1], *pp;
+				caddr_t addr;
+				ulong_t anon_idx = 0;
+
+				/*
+				 * The softlock count might be non zero
+				 * because some pages are still stuck in the
+				 * cache for lazy reclaim. Flush the cache
+				 * now. This should drop the count to zero.
+				 * [or there is really I/O going on to these
+				 * pages]. Note, we have the writers lock so
+				 * nothing gets inserted during the flush.
+				 */
+				if (reclaim == 1) {
+					segvn_purge(seg);
+					reclaim = 0;
+					goto retry;
+				}
+				i = btopr(seg->s_size);
+				addr = seg->s_base;
+				/*
+				 * XXX break cow sharing using PAGESIZE
+				 * pages. They will be relocated into larger
+				 * pages at fault time.
+				 */
+				while (i-- > 0) {
+					if (ap = anon_get_ptr(amp->ahp,
+					    anon_idx)) {
+						error = anon_getpage(&ap,
+						    &vpprot, anon_pl, PAGESIZE,
+						    seg, addr, S_READ,
+						    svd->cred);
+						if (error) {
+							newsvd->vpage = NULL;
+							goto out;
+						}
+						/*
+						 * prot need not be computed
+						 * below 'cause anon_private is
+						 * going to ignore it anyway
+						 * as child doesn't inherit
+						 * pagelock from parent.
+						 */
+						prot = svd->pageprot ?
+						    VPP_PROT(
+						    &svd->vpage[
+						    seg_page(seg, addr)])
+						    : svd->prot;
+						pp = anon_private(&newap,
+						    newseg, addr, prot,
+						    anon_pl[0],	0,
+						    newsvd->cred);
+						if (pp == NULL) {
+							/* no mem abort */
+							newsvd->vpage = NULL;
+							error = ENOMEM;
+							goto out;
+						}
+						(void) anon_set_ptr(
+						    newsvd->amp->ahp, anon_idx,
+						    newap, ANON_SLEEP);
+						page_unlock(pp);
+					}
+					addr += PAGESIZE;
+					anon_idx++;
+				}
+			} else {	/* common case */
+				if (seg->s_szc != 0) {
+					/*
+					 * If at least one of anon slots of a
+					 * large page exists then make sure
+					 * all anon slots of a large page
+					 * exist to avoid partial cow sharing
+					 * of a large page in the future.
+					 */
+					anon_dup_fill_holes(amp->ahp,
+					    svd->anon_index, newsvd->amp->ahp,
+					    0, seg->s_size, seg->s_szc,
+					    svd->vp != NULL);
+				} else {
+					anon_dup(amp->ahp, svd->anon_index,
+					    newsvd->amp->ahp, 0, seg->s_size);
+				}
+
+				hat_clrattr(seg->s_as->a_hat, seg->s_base,
+				    seg->s_size, PROT_WRITE);
+			}
+		}
+	}
+	/*
+	 * If necessary, create a vpage structure for the new segment.
+	 * Do not copy any page lock indications.
+	 */
+	if (svd->vpage != NULL) {
+		uint_t i;
+		struct vpage *ovp = svd->vpage;
+		struct vpage *nvp;
+
+		nvp = newsvd->vpage =
+		    kmem_alloc(vpgtob(npages), KM_SLEEP);
+		for (i = 0; i < npages; i++) {
+			*nvp = *ovp++;
+			VPP_CLRPPLOCK(nvp++);
+		}
+	} else
+		newsvd->vpage = NULL;
+
+	/* Inform the vnode of the new mapping */
+	if (newsvd->vp != NULL) {
+		error = VOP_ADDMAP(newsvd->vp, (offset_t)newsvd->offset,
+		    newseg->s_as, newseg->s_base, newseg->s_size, newsvd->prot,
+		    newsvd->maxprot, newsvd->type, newsvd->cred);
+	}
+out:
+	return (error);
+}
+
+
+/*
+ * callback function used by segvn_unmap to invoke free_vp_pages() for only
+ * those pages actually processed by the HAT
+ */
+extern int free_pages;
+
+static void
+segvn_hat_unload_callback(hat_callback_t *cb)
+{
+	struct seg		*seg = cb->hcb_data;
+	struct segvn_data	*svd = (struct segvn_data *)seg->s_data;
+	size_t			len;
+	u_offset_t		off;
+
+	ASSERT(svd->vp != NULL);
+	ASSERT(cb->hcb_end_addr > cb->hcb_start_addr);
+	ASSERT(cb->hcb_start_addr >= seg->s_base);
+
+	len = cb->hcb_end_addr - cb->hcb_start_addr;
+	off = cb->hcb_start_addr - seg->s_base;
+	free_vp_pages(svd->vp, svd->offset + off, len);
+}
+
+
+static int
+segvn_unmap(struct seg *seg, caddr_t addr, size_t len)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct segvn_data *nsvd;
+	struct seg *nseg;
+	struct anon_map *amp;
+	pgcnt_t	opages;		/* old segment size in pages */
+	pgcnt_t	npages;		/* new segment size in pages */
+	pgcnt_t	dpages;		/* pages being deleted (unmapped) */
+	hat_callback_t callback;	/* used for free_vp_pages() */
+	hat_callback_t *cbp = NULL;
+	caddr_t nbase;
+	size_t nsize;
+	size_t oswresv;
+	int reclaim = 1;
+
+	/*
+	 * We don't need any segment level locks for "segvn" data
+	 * since the address space is "write" locked.
+	 */
+	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	/*
+	 * Fail the unmap if pages are SOFTLOCKed through this mapping.
+	 * softlockcnt is protected from change by the as write lock.
+	 */
+retry:
+	if (svd->softlockcnt > 0) {
+		/*
+		 * since we do have the writers lock nobody can fill
+		 * the cache during the purge. The flush either succeeds
+		 * or we still have pending I/Os.
+		 */
+		if (reclaim == 1) {
+			segvn_purge(seg);
+			reclaim = 0;
+			goto retry;
+		}
+		return (EAGAIN);
+	}
+
+	/*
+	 * Check for bad sizes
+	 */
+	if (addr < seg->s_base || addr + len > seg->s_base + seg->s_size ||
+	    (len & PAGEOFFSET) || ((uintptr_t)addr & PAGEOFFSET)) {
+		panic("segvn_unmap");
+		/*NOTREACHED*/
+	}
+
+	if (seg->s_szc != 0) {
+		size_t pgsz = page_get_pagesize(seg->s_szc);
+		int err;
+		if (!IS_P2ALIGNED(addr, pgsz) || !IS_P2ALIGNED(len, pgsz)) {
+			ASSERT(seg->s_base != addr || seg->s_size != len);
+			VM_STAT_ADD(segvnvmstats.demoterange[0]);
+			err = segvn_demote_range(seg, addr, len, SDR_END);
+			if (err == 0) {
+				return (IE_RETRY);
+			}
+			return (err);
+		}
+	}
+
+	/* Inform the vnode of the unmapping. */
+	if (svd->vp) {
+		int error;
+
+		error = VOP_DELMAP(svd->vp,
+			(offset_t)svd->offset + (uintptr_t)(addr - seg->s_base),
+			seg->s_as, addr, len, svd->prot, svd->maxprot,
+			svd->type, svd->cred);
+
+		if (error == EAGAIN)
+			return (error);
+	}
+	/*
+	 * Remove any page locks set through this mapping.
+	 */
+	(void) segvn_lockop(seg, addr, len, 0, MC_UNLOCK, NULL, 0);
+
+	/*
+	 * Unload any hardware translations in the range to be taken out.
+	 * Use a callback to invoke free_vp_pages() effectively.
+	 */
+	if (svd->vp != NULL && free_pages != 0) {
+		callback.hcb_data = seg;
+		callback.hcb_function = segvn_hat_unload_callback;
+		cbp = &callback;
+	}
+	hat_unload_callback(seg->s_as->a_hat, addr, len, HAT_UNLOAD_UNMAP, cbp);
+
+	/*
+	 * Check for entire segment
+	 */
+	if (addr == seg->s_base && len == seg->s_size) {
+		seg_free(seg);
+		return (0);
+	}
+
+	opages = seg_pages(seg);
+	dpages = btop(len);
+	npages = opages - dpages;
+	amp = svd->amp;
+
+	/*
+	 * Check for beginning of segment
+	 */
+	if (addr == seg->s_base) {
+		if (svd->vpage != NULL) {
+			size_t nbytes;
+			struct vpage *ovpage;
+
+			ovpage = svd->vpage;	/* keep pointer to vpage */
+
+			nbytes = vpgtob(npages);
+			svd->vpage = kmem_alloc(nbytes, KM_SLEEP);
+			bcopy(&ovpage[dpages], svd->vpage, nbytes);
+
+			/* free up old vpage */
+			kmem_free(ovpage, vpgtob(opages));
+		}
+		if (amp != NULL) {
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
+			if (amp->refcnt == 1 || svd->type == MAP_PRIVATE) {
+				/*
+				 * Free up now unused parts of anon_map array.
+				 */
+				if (seg->s_szc != 0) {
+					anon_free_pages(amp->ahp,
+					    svd->anon_index, len, seg->s_szc);
+				} else {
+					anon_free(amp->ahp, svd->anon_index,
+					    len);
+				}
+
+				/*
+				 * Unreserve swap space for the unmapped chunk
+				 * of this segment in case it's MAP_SHARED
+				 */
+				if (svd->type == MAP_SHARED) {
+					anon_unresv(len);
+					amp->swresv -= len;
+				}
+			}
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+			svd->anon_index += dpages;
+		}
+		if (svd->vp != NULL)
+			svd->offset += len;
+
+		if (svd->swresv) {
+			if (svd->flags & MAP_NORESERVE) {
+				ASSERT(amp);
+				oswresv = svd->swresv;
+
+				svd->swresv = ptob(anon_pages(amp->ahp,
+				    svd->anon_index, npages));
+				anon_unresv(oswresv - svd->swresv);
+			} else {
+				anon_unresv(len);
+				svd->swresv -= len;
+			}
+			TRACE_3(TR_FAC_VM, TR_ANON_PROC, "anon proc:%p %lu %u",
+				seg, len, 0);
+		}
+
+		seg->s_base += len;
+		seg->s_size -= len;
+		return (0);
+	}
+
+	/*
+	 * Check for end of segment
+	 */
+	if (addr + len == seg->s_base + seg->s_size) {
+		if (svd->vpage != NULL) {
+			size_t nbytes;
+			struct vpage *ovpage;
+
+			ovpage = svd->vpage;	/* keep pointer to vpage */
+
+			nbytes = vpgtob(npages);
+			svd->vpage = kmem_alloc(nbytes, KM_SLEEP);
+			bcopy(ovpage, svd->vpage, nbytes);
+
+			/* free up old vpage */
+			kmem_free(ovpage, vpgtob(opages));
+
+		}
+		if (amp != NULL) {
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
+			if (amp->refcnt == 1 || svd->type == MAP_PRIVATE) {
+				/*
+				 * Free up now unused parts of anon_map array
+				 */
+				if (seg->s_szc != 0) {
+					ulong_t an_idx = svd->anon_index +
+					    npages;
+					anon_free_pages(amp->ahp, an_idx,
+					    len, seg->s_szc);
+				} else {
+					anon_free(amp->ahp,
+					    svd->anon_index + npages, len);
+				}
+				/*
+				 * Unreserve swap space for the unmapped chunk
+				 * of this segment in case it's MAP_SHARED
+				 */
+				if (svd->type == MAP_SHARED) {
+					anon_unresv(len);
+					amp->swresv -= len;
+				}
+			}
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+		}
+
+		if (svd->swresv) {
+			if (svd->flags & MAP_NORESERVE) {
+				ASSERT(amp);
+				oswresv = svd->swresv;
+				svd->swresv = ptob(anon_pages(amp->ahp,
+					svd->anon_index, npages));
+				anon_unresv(oswresv - svd->swresv);
+			} else {
+				anon_unresv(len);
+				svd->swresv -= len;
+			}
+			TRACE_3(TR_FAC_VM, TR_ANON_PROC,
+				"anon proc:%p %lu %u", seg, len, 0);
+		}
+
+		seg->s_size -= len;
+		return (0);
+	}
+
+	/*
+	 * The section to go is in the middle of the segment,
+	 * have to make it into two segments.  nseg is made for
+	 * the high end while seg is cut down at the low end.
+	 */
+	nbase = addr + len;				/* new seg base */
+	nsize = (seg->s_base + seg->s_size) - nbase;	/* new seg size */
+	seg->s_size = addr - seg->s_base;		/* shrink old seg */
+	nseg = seg_alloc(seg->s_as, nbase, nsize);
+	if (nseg == NULL) {
+		panic("segvn_unmap seg_alloc");
+		/*NOTREACHED*/
+	}
+	nseg->s_ops = seg->s_ops;
+	nsvd = kmem_cache_alloc(segvn_cache, KM_SLEEP);
+	nseg->s_data = (void *)nsvd;
+	nseg->s_szc = seg->s_szc;
+	*nsvd = *svd;
+	nsvd->offset = svd->offset + (uintptr_t)(nseg->s_base - seg->s_base);
+	nsvd->swresv = 0;
+	nsvd->softlockcnt = 0;
+
+	if (svd->vp != NULL) {
+		VN_HOLD(nsvd->vp);
+		if (nsvd->type == MAP_SHARED)
+			lgrp_shm_policy_init(NULL, nsvd->vp);
+	}
+	crhold(svd->cred);
+
+	if (svd->vpage == NULL) {
+		nsvd->vpage = NULL;
+	} else {
+		/* need to split vpage into two arrays */
+		size_t nbytes;
+		struct vpage *ovpage;
+
+		ovpage = svd->vpage;		/* keep pointer to vpage */
+
+		npages = seg_pages(seg);	/* seg has shrunk */
+		nbytes = vpgtob(npages);
+		svd->vpage = kmem_alloc(nbytes, KM_SLEEP);
+
+		bcopy(ovpage, svd->vpage, nbytes);
+
+		npages = seg_pages(nseg);
+		nbytes = vpgtob(npages);
+		nsvd->vpage = kmem_alloc(nbytes, KM_SLEEP);
+
+		bcopy(&ovpage[opages - npages], nsvd->vpage, nbytes);
+
+		/* free up old vpage */
+		kmem_free(ovpage, vpgtob(opages));
+	}
+
+	if (amp == NULL) {
+		nsvd->amp = NULL;
+		nsvd->anon_index = 0;
+	} else {
+		/*
+		 * Need to create a new anon map for the new segment.
+		 * We'll also allocate a new smaller array for the old
+		 * smaller segment to save space.
+		 */
+		opages = btop((uintptr_t)(addr - seg->s_base));
+		ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
+		if (amp->refcnt == 1 || svd->type == MAP_PRIVATE) {
+			/*
+			 * Free up now unused parts of anon_map array
+			 */
+			if (seg->s_szc != 0) {
+				ulong_t an_idx = svd->anon_index + opages;
+				anon_free_pages(amp->ahp, an_idx, len,
+				    seg->s_szc);
+			} else {
+				anon_free(amp->ahp, svd->anon_index + opages,
+				    len);
+			}
+
+			/*
+			 * Unreserve swap space for the unmapped chunk
+			 * of this segment in case it's MAP_SHARED
+			 */
+			if (svd->type == MAP_SHARED) {
+				anon_unresv(len);
+				amp->swresv -= len;
+			}
+		}
+
+		nsvd->anon_index = svd->anon_index +
+		    btop((uintptr_t)(nseg->s_base - seg->s_base));
+		if (svd->type == MAP_SHARED) {
+			ASSERT(seg->s_szc == 0);
+			amp->refcnt++;
+			nsvd->amp = amp;
+		} else {
+			struct anon_map *namp;
+			struct anon_hdr *nahp;
+
+			ASSERT(svd->type == MAP_PRIVATE);
+			nahp = anon_create(btop(seg->s_size), ANON_SLEEP);
+			namp = anonmap_alloc(nseg->s_size, 0);
+			namp->a_szc = seg->s_szc;
+			(void) anon_copy_ptr(amp->ahp, svd->anon_index, nahp,
+			    0, btop(seg->s_size), ANON_SLEEP);
+			(void) anon_copy_ptr(amp->ahp, nsvd->anon_index,
+			    namp->ahp, 0, btop(nseg->s_size), ANON_SLEEP);
+			anon_release(amp->ahp, btop(amp->size));
+			svd->anon_index = 0;
+			nsvd->anon_index = 0;
+			amp->ahp = nahp;
+			amp->size = seg->s_size;
+			nsvd->amp = namp;
+		}
+		ANON_LOCK_EXIT(&amp->a_rwlock);
+	}
+	if (svd->swresv) {
+		if (svd->flags & MAP_NORESERVE) {
+			ASSERT(amp);
+			oswresv = svd->swresv;
+			svd->swresv = ptob(anon_pages(amp->ahp,
+				svd->anon_index, btop(seg->s_size)));
+			nsvd->swresv = ptob(anon_pages(nsvd->amp->ahp,
+				nsvd->anon_index, btop(nseg->s_size)));
+			ASSERT(oswresv >= (svd->swresv + nsvd->swresv));
+			anon_unresv(oswresv - (svd->swresv + nsvd->swresv));
+		} else {
+			if (seg->s_size + nseg->s_size + len != svd->swresv) {
+				panic("segvn_unmap: "
+				    "cannot split swap reservation");
+				/*NOTREACHED*/
+			}
+			anon_unresv(len);
+			svd->swresv = seg->s_size;
+			nsvd->swresv = nseg->s_size;
+		}
+		TRACE_3(TR_FAC_VM, TR_ANON_PROC, "anon proc:%p %lu %u",
+			seg, len, 0);
+	}
+
+	return (0);			/* I'm glad that's all over with! */
+}
+
+static void
+segvn_free(struct seg *seg)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	pgcnt_t npages = seg_pages(seg);
+	struct anon_map *amp;
+	size_t len;
+
+	/*
+	 * We don't need any segment level locks for "segvn" data
+	 * since the address space is "write" locked.
+	 */
+	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	/*
+	 * Be sure to unlock pages. XXX Why do things get free'ed instead
+	 * of unmapped? XXX
+	 */
+	(void) segvn_lockop(seg, seg->s_base, seg->s_size,
+	    0, MC_UNLOCK, NULL, 0);
+
+	/*
+	 * Deallocate the vpage and anon pointers if necessary and possible.
+	 */
+	if (svd->vpage != NULL) {
+		kmem_free(svd->vpage, vpgtob(npages));
+		svd->vpage = NULL;
+	}
+	if ((amp = svd->amp) != NULL) {
+		/*
+		 * If there are no more references to this anon_map
+		 * structure, then deallocate the structure after freeing
+		 * up all the anon slot pointers that we can.
+		 */
+		ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
+		if (--amp->refcnt == 0) {
+			if (svd->type == MAP_PRIVATE) {
+				/*
+				 * Private - we only need to anon_free
+				 * the part that this segment refers to.
+				 */
+				if (seg->s_szc != 0) {
+					anon_free_pages(amp->ahp,
+					    svd->anon_index, seg->s_size,
+					    seg->s_szc);
+				} else {
+					anon_free(amp->ahp, svd->anon_index,
+					    seg->s_size);
+				}
+			} else {
+				/*
+				 * Shared - anon_free the entire
+				 * anon_map's worth of stuff and
+				 * release any swap reservation.
+				 */
+				ASSERT(seg->s_szc == 0);
+				anon_free(amp->ahp, 0, amp->size);
+				if ((len = amp->swresv) != 0) {
+					anon_unresv(len);
+					TRACE_3(TR_FAC_VM, TR_ANON_PROC,
+						"anon proc:%p %lu %u",
+						seg, len, 0);
+				}
+			}
+			svd->amp = NULL;
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+			anonmap_free(amp);
+		} else if (svd->type == MAP_PRIVATE) {
+			/*
+			 * We had a private mapping which still has
+			 * a held anon_map so just free up all the
+			 * anon slot pointers that we were using.
+			 */
+			if (seg->s_szc != 0) {
+				anon_free_pages(amp->ahp, svd->anon_index,
+				    seg->s_size, seg->s_szc);
+			} else {
+				anon_free(amp->ahp, svd->anon_index,
+				    seg->s_size);
+			}
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+		} else {
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+		}
+	}
+
+	/*
+	 * Release swap reservation.
+	 */
+	if ((len = svd->swresv) != 0) {
+		anon_unresv(svd->swresv);
+		TRACE_3(TR_FAC_VM, TR_ANON_PROC, "anon proc:%p %lu %u",
+			seg, len, 0);
+		svd->swresv = 0;
+	}
+	/*
+	 * Release claim on vnode, credentials, and finally free the
+	 * private data.
+	 */
+	if (svd->vp != NULL) {
+		if (svd->type == MAP_SHARED)
+			lgrp_shm_policy_fini(NULL, svd->vp);
+		VN_RELE(svd->vp);
+		svd->vp = NULL;
+	}
+	crfree(svd->cred);
+	svd->cred = NULL;
+
+	seg->s_data = NULL;
+	kmem_cache_free(segvn_cache, svd);
+}
+
+/*
+ * Do a F_SOFTUNLOCK call over the range requested.  The range must have
+ * already been F_SOFTLOCK'ed.
+ * Caller must always match addr and len of a softunlock with a previous
+ * softlock with exactly the same addr and len.
+ */
+static void
+segvn_softunlock(struct seg *seg, caddr_t addr, size_t len, enum seg_rw rw)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	page_t *pp;
+	caddr_t adr;
+	struct vnode *vp;
+	u_offset_t offset;
+	ulong_t anon_index;
+	struct anon_map *amp;
+	struct anon *ap = NULL;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+	ASSERT(SEGVN_LOCK_HELD(seg->s_as, &svd->lock));
+
+	if ((amp = svd->amp) != NULL)
+		anon_index = svd->anon_index + seg_page(seg, addr);
+
+	hat_unlock(seg->s_as->a_hat, addr, len);
+	for (adr = addr; adr < addr + len; adr += PAGESIZE) {
+		if (amp != NULL) {
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+			if ((ap = anon_get_ptr(amp->ahp, anon_index++))
+								!= NULL) {
+				swap_xlate(ap, &vp, &offset);
+			} else {
+				vp = svd->vp;
+				offset = svd->offset +
+				    (uintptr_t)(adr - seg->s_base);
+			}
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+		} else {
+			vp = svd->vp;
+			offset = svd->offset +
+			    (uintptr_t)(adr - seg->s_base);
+		}
+
+		/*
+		 * Use page_find() instead of page_lookup() to
+		 * find the page since we know that it is locked.
+		 */
+		pp = page_find(vp, offset);
+		if (pp == NULL) {
+			panic(
+			    "segvn_softunlock: addr %p, ap %p, vp %p, off %llx",
+			    (void *)adr, (void *)ap, (void *)vp, offset);
+			/*NOTREACHED*/
+		}
+
+		if (rw == S_WRITE) {
+			hat_setrefmod(pp);
+			if (seg->s_as->a_vbits)
+				hat_setstat(seg->s_as, adr, PAGESIZE,
+				    P_REF | P_MOD);
+		} else if (rw != S_OTHER) {
+			hat_setref(pp);
+			if (seg->s_as->a_vbits)
+				hat_setstat(seg->s_as, adr, PAGESIZE, P_REF);
+		}
+		TRACE_3(TR_FAC_VM, TR_SEGVN_FAULT,
+			"segvn_fault:pp %p vp %p offset %llx", pp, vp, offset);
+		page_unlock(pp);
+	}
+	mutex_enter(&freemem_lock); /* for availrmem */
+	availrmem += btop(len);
+	segvn_pages_locked -= btop(len);
+	svd->softlockcnt -= btop(len);
+	mutex_exit(&freemem_lock);
+	if (svd->softlockcnt == 0) {
+		/*
+		 * All SOFTLOCKS are gone. Wakeup any waiting
+		 * unmappers so they can try again to unmap.
+		 * Check for waiters first without the mutex
+		 * held so we don't always grab the mutex on
+		 * softunlocks.
+		 */
+		if (AS_ISUNMAPWAIT(seg->s_as)) {
+			mutex_enter(&seg->s_as->a_contents);
+			if (AS_ISUNMAPWAIT(seg->s_as)) {
+				AS_CLRUNMAPWAIT(seg->s_as);
+				cv_broadcast(&seg->s_as->a_cv);
+			}
+			mutex_exit(&seg->s_as->a_contents);
+		}
+	}
+}
+
+#define	PAGE_HANDLED	((page_t *)-1)
+
+/*
+ * Release all the pages in the NULL terminated ppp list
+ * which haven't already been converted to PAGE_HANDLED.
+ */
+static void
+segvn_pagelist_rele(page_t **ppp)
+{
+	for (; *ppp != NULL; ppp++) {
+		if (*ppp != PAGE_HANDLED)
+			page_unlock(*ppp);
+	}
+}
+
+static int stealcow = 1;
+
+/*
+ * Workaround for viking chip bug.  See bug id 1220902.
+ * To fix this down in pagefault() would require importing so
+ * much as and segvn code as to be unmaintainable.
+ */
+int enable_mbit_wa = 0;
+
+/*
+ * Handles all the dirty work of getting the right
+ * anonymous pages and loading up the translations.
+ * This routine is called only from segvn_fault()
+ * when looping over the range of addresses requested.
+ *
+ * The basic algorithm here is:
+ * 	If this is an anon_zero case
+ *		Call anon_zero to allocate page
+ *		Load up translation
+ *		Return
+ *	endif
+ *	If this is an anon page
+ *		Use anon_getpage to get the page
+ *	else
+ *		Find page in pl[] list passed in
+ *	endif
+ *	If not a cow
+ *		Load up the translation to the page
+ *		return
+ *	endif
+ *	Call anon_private to handle cow
+ *	Load up (writable) translation to new page
+ */
+static faultcode_t
+segvn_faultpage(
+	struct hat *hat,		/* the hat to use for mapping */
+	struct seg *seg,		/* seg_vn of interest */
+	caddr_t addr,			/* address in as */
+	u_offset_t off,			/* offset in vp */
+	struct vpage *vpage,		/* pointer to vpage for vp, off */
+	page_t *pl[],			/* object source page pointer */
+	uint_t vpprot,			/* access allowed to object pages */
+	enum fault_type type,		/* type of fault */
+	enum seg_rw rw,			/* type of access at fault */
+	int brkcow)			/* we may need to break cow */
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	page_t *pp, **ppp;
+	uint_t pageflags = 0;
+	page_t *anon_pl[1 + 1];
+	page_t *opp = NULL;		/* original page */
+	uint_t prot;
+	int err;
+	int cow;
+	int claim;
+	int steal = 0;
+	ulong_t anon_index;
+	struct anon *ap, *oldap;
+	struct anon_map *amp;
+	int hat_flag = (type == F_SOFTLOCK) ? HAT_LOAD_LOCK : HAT_LOAD;
+	int anon_lock = 0;
+	anon_sync_obj_t cookie;
+
+	if (svd->flags & MAP_TEXT) {
+		hat_flag |= HAT_LOAD_TEXT;
+	}
+
+	ASSERT(SEGVN_READ_HELD(seg->s_as, &svd->lock));
+	ASSERT(seg->s_szc == 0);
+
+	/*
+	 * Initialize protection value for this page.
+	 * If we have per page protection values check it now.
+	 */
+	if (svd->pageprot) {
+		uint_t protchk;
+
+		switch (rw) {
+		case S_READ:
+			protchk = PROT_READ;
+			break;
+		case S_WRITE:
+			protchk = PROT_WRITE;
+			break;
+		case S_EXEC:
+			protchk = PROT_EXEC;
+			break;
+		case S_OTHER:
+		default:
+			protchk = PROT_READ | PROT_WRITE | PROT_EXEC;
+			break;
+		}
+
+		prot = VPP_PROT(vpage);
+		if ((prot & protchk) == 0)
+			return (FC_PROT);	/* illegal access type */
+	} else {
+		prot = svd->prot;
+	}
+
+	if (type == F_SOFTLOCK) {
+		mutex_enter(&freemem_lock);
+		if (availrmem <= tune.t_minarmem) {
+			mutex_exit(&freemem_lock);
+			return (FC_MAKE_ERR(ENOMEM));	/* out of real memory */
+		} else {
+			svd->softlockcnt++;
+			availrmem--;
+			segvn_pages_locked++;
+		}
+		mutex_exit(&freemem_lock);
+	}
+
+	/*
+	 * Always acquire the anon array lock to prevent 2 threads from
+	 * allocating separate anon slots for the same "addr".
+	 */
+
+	if ((amp = svd->amp) != NULL) {
+		ASSERT(RW_READ_HELD(&amp->a_rwlock));
+		anon_index = svd->anon_index + seg_page(seg, addr);
+		anon_array_enter(amp, anon_index, &cookie);
+		anon_lock = 1;
+	}
+
+	if (svd->vp == NULL && amp != NULL) {
+		if ((ap = anon_get_ptr(amp->ahp, anon_index)) == NULL) {
+			/*
+			 * Allocate a (normally) writable anonymous page of
+			 * zeroes. If no advance reservations, reserve now.
+			 */
+			if (svd->flags & MAP_NORESERVE) {
+				if (anon_resv(ptob(1))) {
+					svd->swresv += ptob(1);
+				} else {
+					err = ENOMEM;
+					goto out;
+				}
+			}
+			if ((pp = anon_zero(seg, addr, &ap,
+			    svd->cred)) == NULL) {
+				err = ENOMEM;
+				goto out;	/* out of swap space */
+			}
+			/*
+			 * Re-acquire the anon_map lock and
+			 * initialize the anon array entry.
+			 */
+			(void) anon_set_ptr(amp->ahp, anon_index, ap,
+				ANON_SLEEP);
+			if (enable_mbit_wa) {
+				if (rw == S_WRITE)
+					hat_setmod(pp);
+				else if (!hat_ismod(pp))
+					prot &= ~PROT_WRITE;
+			}
+			/*
+			 * If AS_PAGLCK is set in a_flags (via memcntl(2)
+			 * with MC_LOCKAS, MCL_FUTURE) and this is a
+			 * MAP_NORESERVE segment, we may need to
+			 * permanently lock the page as it is being faulted
+			 * for the first time. The following text applies
+			 * only to MAP_NORESERVE segments:
+			 *
+			 * As per memcntl(2), if this segment was created
+			 * after MCL_FUTURE was applied (a "future"
+			 * segment), its pages must be locked.  If this
+			 * segment existed at MCL_FUTURE application (a
+			 * "past" segment), the interface is unclear.
+			 *
+			 * We decide to lock only if vpage is present:
+			 *
+			 * - "future" segments will have a vpage array (see
+			 *    as_map), and so will be locked as required
+			 *
+			 * - "past" segments may not have a vpage array,
+			 *    depending on whether events (such as
+			 *    mprotect) have occurred. Locking if vpage
+			 *    exists will preserve legacy behavior.  Not
+			 *    locking if vpage is absent, will not break
+			 *    the interface or legacy behavior.  Note that
+			 *    allocating vpage here if it's absent requires
+			 *    upgrading the segvn reader lock, the cost of
+			 *    which does not seem worthwhile.
+			 */
+			if (AS_ISPGLCK(seg->s_as) && vpage != NULL &&
+			    (svd->flags & MAP_NORESERVE)) {
+				claim = VPP_PROT(vpage) & PROT_WRITE;
+				ASSERT(svd->type == MAP_PRIVATE);
+				if (page_pp_lock(pp, claim, 0))
+					VPP_SETPPLOCK(vpage);
+			}
+
+
+			/*
+			 * Handle pages that have been marked for migration
+			 */
+			if (lgrp_optimizations())
+				page_migrate(seg, addr, &pp, 1);
+			hat_memload(hat, addr, pp, prot, hat_flag);
+
+			if (!(hat_flag & HAT_LOAD_LOCK))
+				page_unlock(pp);
+
+			anon_array_exit(&cookie);
+			return (0);
+		}
+	}
+
+	/*
+	 * Obtain the page structure via anon_getpage() if it is
+	 * a private copy of an object (the result of a previous
+	 * copy-on-write).
+	 */
+	if (amp != NULL) {
+		if ((ap = anon_get_ptr(amp->ahp, anon_index)) != NULL) {
+			err = anon_getpage(&ap, &vpprot, anon_pl, PAGESIZE,
+			    seg, addr, rw, svd->cred);
+			if (err)
+				goto out;
+
+			if (svd->type == MAP_SHARED) {
+				/*
+				 * If this is a shared mapping to an
+				 * anon_map, then ignore the write
+				 * permissions returned by anon_getpage().
+				 * They apply to the private mappings
+				 * of this anon_map.
+				 */
+				vpprot |= PROT_WRITE;
+			}
+			opp = anon_pl[0];
+		}
+	}
+
+	/*
+	 * Search the pl[] list passed in if it is from the
+	 * original object (i.e., not a private copy).
+	 */
+	if (opp == NULL) {
+		/*
+		 * Find original page.  We must be bringing it in
+		 * from the list in pl[].
+		 */
+		for (ppp = pl; (opp = *ppp) != NULL; ppp++) {
+			if (opp == PAGE_HANDLED)
+				continue;
+			ASSERT(opp->p_vnode == svd->vp); /* XXX */
+			if (opp->p_offset == off)
+				break;
+		}
+		if (opp == NULL) {
+			panic("segvn_faultpage not found");
+			/*NOTREACHED*/
+		}
+		*ppp = PAGE_HANDLED;
+
+	}
+
+	ASSERT(PAGE_LOCKED(opp));
+
+	TRACE_3(TR_FAC_VM, TR_SEGVN_FAULT,
+		"segvn_fault:pp %p vp %p offset %llx",
+		opp, NULL, 0);
+
+	/*
+	 * The fault is treated as a copy-on-write fault if a
+	 * write occurs on a private segment and the object
+	 * page (i.e., mapping) is write protected.  We assume
+	 * that fatal protection checks have already been made.
+	 */
+
+	cow = brkcow && ((vpprot & PROT_WRITE) == 0);
+
+	/*
+	 * If not a copy-on-write case load the translation
+	 * and return.
+	 */
+	if (cow == 0) {
+		if (IS_VMODSORT(opp->p_vnode) || enable_mbit_wa) {
+			if (rw == S_WRITE)
+				hat_setmod(opp);
+			else if (rw != S_OTHER && !hat_ismod(opp))
+				prot &= ~PROT_WRITE;
+		}
+
+		/*
+		 * Handle pages that have been marked for migration
+		 */
+		if (lgrp_optimizations())
+			page_migrate(seg, addr, &opp, 1);
+
+		hat_memload(hat, addr, opp, prot & vpprot, hat_flag);
+
+		if (!(hat_flag & HAT_LOAD_LOCK))
+			page_unlock(opp);
+
+		if (anon_lock) {
+			anon_array_exit(&cookie);
+		}
+		return (0);
+	}
+
+	hat_setref(opp);
+
+	ASSERT(amp != NULL && anon_lock);
+
+	/*
+	 * Steal the page only if it isn't a private page
+	 * since stealing a private page is not worth the effort.
+	 */
+	if ((ap = anon_get_ptr(amp->ahp, anon_index)) == NULL)
+		steal = 1;
+
+	/*
+	 * Steal the original page if the following conditions are true:
+	 *
+	 * We are low on memory, the page is not private, page is not
+	 * shared, not modified, not `locked' or if we have it `locked'
+	 * (i.e., p_cowcnt == 1 and p_lckcnt == 0, which also implies
+	 * that the page is not shared) and if it doesn't have any
+	 * translations. page_struct_lock isn't needed to look at p_cowcnt
+	 * and p_lckcnt because we first get exclusive lock on page.
+	 */
+	(void) hat_pagesync(opp, HAT_SYNC_DONTZERO | HAT_SYNC_STOPON_MOD);
+
+	if (stealcow && freemem < minfree && steal &&
+	    page_tryupgrade(opp) && !hat_ismod(opp) &&
+	    ((opp->p_lckcnt == 0 && opp->p_cowcnt == 0) ||
+	    (opp->p_lckcnt == 0 && opp->p_cowcnt == 1 &&
+	    vpage != NULL && VPP_ISPPLOCK(vpage)))) {
+		/*
+		 * Check if this page has other translations
+		 * after unloading our translation.
+		 */
+		if (hat_page_is_mapped(opp)) {
+			hat_unload(seg->s_as->a_hat, addr, PAGESIZE,
+				HAT_UNLOAD);
+		}
+
+		/*
+		 * hat_unload() might sync back someone else's recent
+		 * modification, so check again.
+		 */
+		if (!hat_ismod(opp) && !hat_page_is_mapped(opp))
+			pageflags |= STEAL_PAGE;
+	}
+
+	/*
+	 * If we have a vpage pointer, see if it indicates that we have
+	 * ``locked'' the page we map -- if so, tell anon_private to
+	 * transfer the locking resource to the new page.
+	 *
+	 * See Statement at the beginning of segvn_lockop regarding
+	 * the way lockcnts/cowcnts are handled during COW.
+	 *
+	 */
+	if (vpage != NULL && VPP_ISPPLOCK(vpage))
+		pageflags |= LOCK_PAGE;
+
+	/*
+	 * Allocate a private page and perform the copy.
+	 * For MAP_NORESERVE reserve swap space now, unless this
+	 * is a cow fault on an existing anon page in which case
+	 * MAP_NORESERVE will have made advance reservations.
+	 */
+	if ((svd->flags & MAP_NORESERVE) && (ap == NULL)) {
+		if (anon_resv(ptob(1))) {
+			svd->swresv += ptob(1);
+		} else {
+			page_unlock(opp);
+			err = ENOMEM;
+			goto out;
+		}
+	}
+	oldap = ap;
+	pp = anon_private(&ap, seg, addr, prot, opp, pageflags, svd->cred);
+	if (pp == NULL) {
+		err = ENOMEM;	/* out of swap space */
+		goto out;
+	}
+
+	/*
+	 * If we copied away from an anonymous page, then
+	 * we are one step closer to freeing up an anon slot.
+	 *
+	 * NOTE:  The original anon slot must be released while
+	 * holding the "anon_map" lock.  This is necessary to prevent
+	 * other threads from obtaining a pointer to the anon slot
+	 * which may be freed if its "refcnt" is 1.
+	 */
+	if (oldap != NULL)
+		anon_decref(oldap);
+
+	(void) anon_set_ptr(amp->ahp, anon_index, ap, ANON_SLEEP);
+
+	ASSERT(!IS_VMODSORT(pp->p_vnode));
+	if (enable_mbit_wa) {
+		if (rw == S_WRITE)
+			hat_setmod(pp);
+		else if (!hat_ismod(pp))
+			prot &= ~PROT_WRITE;
+	}
+
+
+	/*
+	 * Handle pages that have been marked for migration
+	 */
+	if (lgrp_optimizations())
+		page_migrate(seg, addr, &pp, 1);
+	hat_memload(hat, addr, pp, prot, hat_flag);
+
+	if (!(hat_flag & HAT_LOAD_LOCK))
+		page_unlock(pp);
+
+	ASSERT(anon_lock);
+	anon_array_exit(&cookie);
+	return (0);
+out:
+	if (anon_lock)
+		anon_array_exit(&cookie);
+
+	if (type == F_SOFTLOCK) {
+		mutex_enter(&freemem_lock);
+		availrmem++;
+		segvn_pages_locked--;
+		svd->softlockcnt--;
+		mutex_exit(&freemem_lock);
+	}
+	return (FC_MAKE_ERR(err));
+}
+
+/*
+ * relocate a bunch of smaller targ pages into one large repl page. all targ
+ * pages must be complete pages smaller than replacement pages.
+ * it's assumed that no page's szc can change since they are all PAGESIZE or
+ * complete large pages locked SHARED.
+ */
+static void
+segvn_relocate_pages(page_t **targ, page_t *replacement)
+{
+	page_t *pp;
+	pgcnt_t repl_npgs, curnpgs;
+	pgcnt_t i;
+	uint_t repl_szc = replacement->p_szc;
+	page_t *first_repl = replacement;
+	page_t *repl;
+	spgcnt_t npgs;
+
+	VM_STAT_ADD(segvnvmstats.relocatepages[0]);
+
+	ASSERT(repl_szc != 0);
+	npgs = repl_npgs = page_get_pagecnt(repl_szc);
+
+	i = 0;
+	while (repl_npgs) {
+		spgcnt_t nreloc;
+		int err;
+		ASSERT(replacement != NULL);
+		pp = targ[i];
+		ASSERT(pp->p_szc < repl_szc);
+		ASSERT(PAGE_EXCL(pp));
+		ASSERT(!PP_ISFREE(pp));
+		curnpgs = page_get_pagecnt(pp->p_szc);
+		if (curnpgs == 1) {
+			VM_STAT_ADD(segvnvmstats.relocatepages[1]);
+			repl = replacement;
+			page_sub(&replacement, repl);
+			ASSERT(PAGE_EXCL(repl));
+			ASSERT(!PP_ISFREE(repl));
+			ASSERT(repl->p_szc == repl_szc);
+		} else {
+			page_t *repl_savepp;
+			int j;
+			VM_STAT_ADD(segvnvmstats.relocatepages[2]);
+			repl_savepp = replacement;
+			for (j = 0; j < curnpgs; j++) {
+				repl = replacement;
+				page_sub(&replacement, repl);
+				ASSERT(PAGE_EXCL(repl));
+				ASSERT(!PP_ISFREE(repl));
+				ASSERT(repl->p_szc == repl_szc);
+				ASSERT(page_pptonum(targ[i + j]) ==
+				    page_pptonum(targ[i]) + j);
+			}
+			repl = repl_savepp;
+			ASSERT(IS_P2ALIGNED(page_pptonum(repl), curnpgs));
+		}
+		err = page_relocate(&pp, &repl, 0, 1, &nreloc, NULL);
+		if (err || nreloc != curnpgs) {
+			panic("segvn_relocate_pages: "
+			    "page_relocate failed err=%d curnpgs=%ld "
+			    "nreloc=%ld", err, curnpgs, nreloc);
+		}
+		ASSERT(curnpgs <= repl_npgs);
+		repl_npgs -= curnpgs;
+		i += curnpgs;
+	}
+	ASSERT(replacement == NULL);
+
+	repl = first_repl;
+	repl_npgs = npgs;
+	for (i = 0; i < repl_npgs; i++) {
+		ASSERT(PAGE_EXCL(repl));
+		ASSERT(!PP_ISFREE(repl));
+		targ[i] = repl;
+		page_downgrade(targ[i]);
+		repl = page_next(repl);
+	}
+}
+
+/*
+ * Check if all pages in ppa array are complete smaller than szc pages and
+ * their roots will still be aligned relative to their current size if the
+ * entire ppa array is relocated into one szc page. If these conditions are
+ * not met return 0.
+ *
+ * If all pages are properly aligned attempt to upgrade their locks
+ * to exclusive mode. If it fails set *upgrdfail to 1 and return 0.
+ * upgrdfail was set to 0 by caller.
+ *
+ * Return 1 if all pages are aligned and locked exclusively.
+ *
+ * If all pages in ppa array happen to be physically contiguous to make one
+ * szc page and all exclusive locks are successfully obtained promote the page
+ * size to szc and set *pszc to szc. Return 1 with pages locked shared.
+ */
+static int
+segvn_full_szcpages(page_t **ppa, uint_t szc, int *upgrdfail, uint_t *pszc)
+{
+	page_t *pp;
+	pfn_t pfn;
+	pgcnt_t totnpgs = page_get_pagecnt(szc);
+	pfn_t first_pfn;
+	int contig = 1;
+	pgcnt_t i;
+	pgcnt_t j;
+	uint_t curszc;
+	pgcnt_t curnpgs;
+	int root = 0;
+
+	ASSERT(szc > 0);
+
+	VM_STAT_ADD(segvnvmstats.fullszcpages[0]);
+
+	for (i = 0; i < totnpgs; i++) {
+		pp = ppa[i];
+		ASSERT(PAGE_SHARED(pp));
+		ASSERT(!PP_ISFREE(pp));
+		pfn = page_pptonum(pp);
+		if (i == 0) {
+			if (!IS_P2ALIGNED(pfn, totnpgs)) {
+				contig = 0;
+			} else {
+				first_pfn = pfn;
+			}
+		} else if (contig && pfn != first_pfn + i) {
+			contig = 0;
+		}
+		if (pp->p_szc == 0) {
+			if (root) {
+				VM_STAT_ADD(segvnvmstats.fullszcpages[1]);
+				return (0);
+			}
+		} else if (!root) {
+			if ((curszc = pp->p_szc) >= szc) {
+				VM_STAT_ADD(segvnvmstats.fullszcpages[2]);
+				return (0);
+			}
+			if (curszc == 0) {
+				/*
+				 * p_szc changed means we don't have all pages
+				 * locked. return failure.
+				 */
+				VM_STAT_ADD(segvnvmstats.fullszcpages[3]);
+				return (0);
+			}
+			curnpgs = page_get_pagecnt(curszc);
+			if (!IS_P2ALIGNED(pfn, curnpgs) ||
+			    !IS_P2ALIGNED(i, curnpgs)) {
+				VM_STAT_ADD(segvnvmstats.fullszcpages[4]);
+				return (0);
+			}
+			root = 1;
+		} else {
+			ASSERT(i > 0);
+			VM_STAT_ADD(segvnvmstats.fullszcpages[5]);
+			if (pp->p_szc != curszc) {
+				VM_STAT_ADD(segvnvmstats.fullszcpages[6]);
+				return (0);
+			}
+			if (pfn - 1 != page_pptonum(ppa[i - 1])) {
+				panic("segvn_full_szcpages: "
+				    "large page not physically contiguous");
+			}
+			if (P2PHASE(pfn, curnpgs) == curnpgs - 1) {
+				root = 0;
+			}
+		}
+	}
+
+	for (i = 0; i < totnpgs; i++) {
+		ASSERT(ppa[i]->p_szc < szc);
+		if (!page_tryupgrade(ppa[i])) {
+			for (j = 0; j < i; j++) {
+				page_downgrade(ppa[j]);
+			}
+			*pszc = ppa[i]->p_szc;
+			*upgrdfail = 1;
+			VM_STAT_ADD(segvnvmstats.fullszcpages[7]);
+			return (0);
+		}
+	}
+
+	/*
+	 * When a page is put a free cachelist its szc is set to 0.  if file
+	 * system reclaimed pages from cachelist targ pages will be physically
+	 * contiguous with 0 p_szc.  in this case just upgrade szc of targ
+	 * pages without any relocations.
+	 * To avoid any hat issues with previous small mappings
+	 * hat_pageunload() the target pages first.
+	 */
+	if (contig) {
+		VM_STAT_ADD(segvnvmstats.fullszcpages[8]);
+		for (i = 0; i < totnpgs; i++) {
+			(void) hat_pageunload(ppa[i], HAT_FORCE_PGUNLOAD);
+		}
+		for (i = 0; i < totnpgs; i++) {
+			ppa[i]->p_szc = szc;
+		}
+		for (i = 0; i < totnpgs; i++) {
+			ASSERT(PAGE_EXCL(ppa[i]));
+			page_downgrade(ppa[i]);
+		}
+		if (pszc != NULL) {
+			*pszc = szc;
+		}
+	}
+	VM_STAT_ADD(segvnvmstats.fullszcpages[9]);
+	return (1);
+}
+
+/*
+ * Create physically contiguous pages for [vp, off] - [vp, off +
+ * page_size(szc)) range and for private segment return them in ppa array.
+ * Pages are created either via IO or relocations.
+ *
+ * Return 1 on sucess and 0 on failure.
+ *
+ * If physically contiguos pages already exist for this range return 1 without
+ * filling ppa array. Caller initializes ppa[0] as NULL to detect that ppa
+ * array wasn't filled. In this case caller fills ppa array via VOP_GETPAGE().
+ */
+
+static int
+segvn_fill_vp_pages(struct segvn_data *svd, vnode_t *vp, u_offset_t off,
+    uint_t szc, page_t **ppa, page_t **ppplist, uint_t *ret_pszc,
+    int *downsize)
+
+{
+	page_t *pplist = *ppplist;
+	size_t pgsz = page_get_pagesize(szc);
+	pgcnt_t pages = btop(pgsz);
+	ulong_t start_off = off;
+	u_offset_t eoff = off + pgsz;
+	spgcnt_t nreloc;
+	u_offset_t io_off = off;
+	size_t io_len;
+	page_t *io_pplist = NULL;
+	page_t *done_pplist = NULL;
+	pgcnt_t pgidx = 0;
+	page_t *pp;
+	page_t *newpp;
+	page_t *targpp;
+	int io_err = 0;
+	int i;
+	pfn_t pfn;
+	ulong_t ppages;
+	page_t *targ_pplist = NULL;
+	page_t *repl_pplist = NULL;
+	page_t *tmp_pplist;
+	int nios = 0;
+	uint_t pszc;
+	struct vattr va;
+
+	VM_STAT_ADD(segvnvmstats.fill_vp_pages[0]);
+
+	ASSERT(szc != 0);
+	ASSERT(pplist->p_szc == szc);
+
+	/*
+	 * downsize will be set to 1 only if we fail to lock pages. this will
+	 * allow subsequent faults to try to relocate the page again. If we
+	 * fail due to misalignment don't downsize and let the caller map the
+	 * whole region with small mappings to avoid more faults into the area
+	 * where we can't get large pages anyway.
+	 */
+	*downsize = 0;
+
+	while (off < eoff) {
+		newpp = pplist;
+		ASSERT(newpp != NULL);
+		ASSERT(PAGE_EXCL(newpp));
+		ASSERT(!PP_ISFREE(newpp));
+		/*
+		 * we pass NULL for nrelocp to page_lookup_create()
+		 * so that it doesn't relocate. We relocate here
+		 * later only after we make sure we can lock all
+		 * pages in the range we handle and they are all
+		 * aligned.
+		 */
+		pp = page_lookup_create(vp, off, SE_SHARED, newpp, NULL, 0);
+		ASSERT(pp != NULL);
+		ASSERT(!PP_ISFREE(pp));
+		ASSERT(pp->p_vnode == vp);
+		ASSERT(pp->p_offset == off);
+		if (pp == newpp) {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[1]);
+			page_sub(&pplist, pp);
+			ASSERT(PAGE_EXCL(pp));
+			ASSERT(page_iolock_assert(pp));
+			page_list_concat(&io_pplist, &pp);
+			off += PAGESIZE;
+			continue;
+		}
+		VM_STAT_ADD(segvnvmstats.fill_vp_pages[2]);
+		pfn = page_pptonum(pp);
+		pszc = pp->p_szc;
+		if (pszc >= szc && targ_pplist == NULL && io_pplist == NULL &&
+		    IS_P2ALIGNED(pfn, pages)) {
+			ASSERT(repl_pplist == NULL);
+			ASSERT(done_pplist == NULL);
+			ASSERT(pplist == *ppplist);
+			page_unlock(pp);
+			page_free_replacement_page(pplist);
+			page_create_putback(pages);
+			*ppplist = NULL;
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[3]);
+			return (1);
+		}
+		if (pszc >= szc) {
+			page_unlock(pp);
+			segvn_faultvnmpss_align_err1++;
+			goto out;
+		}
+		ppages = page_get_pagecnt(pszc);
+		if (!IS_P2ALIGNED(pfn, ppages)) {
+			ASSERT(pszc > 0);
+			/*
+			 * sizing down to pszc won't help.
+			 */
+			page_unlock(pp);
+			segvn_faultvnmpss_align_err2++;
+			goto out;
+		}
+		pfn = page_pptonum(newpp);
+		if (!IS_P2ALIGNED(pfn, ppages)) {
+			ASSERT(pszc > 0);
+			/*
+			 * sizing down to pszc won't help.
+			 */
+			page_unlock(pp);
+			segvn_faultvnmpss_align_err3++;
+			goto out;
+		}
+		if (!PAGE_EXCL(pp)) {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[4]);
+			page_unlock(pp);
+			*downsize = 1;
+			*ret_pszc = pp->p_szc;
+			goto out;
+		}
+		targpp = pp;
+		if (io_pplist != NULL) {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[5]);
+			io_len = off - io_off;
+			/*
+			 * Some file systems like NFS don't check EOF
+			 * conditions in VOP_PAGEIO(). Check it here
+			 * now that pages are locked SE_EXCL. Any file
+			 * truncation will wait until the pages are
+			 * unlocked so no need to worry that file will
+			 * be truncated after we check its size here.
+			 * XXX fix NFS to remove this check.
+			 */
+			va.va_mask = AT_SIZE;
+			if (VOP_GETATTR(vp, &va, ATTR_HINT, svd->cred) != 0) {
+				VM_STAT_ADD(segvnvmstats.fill_vp_pages[6]);
+				page_unlock(targpp);
+				goto out;
+			}
+			if (btopr(va.va_size) < btopr(io_off + io_len)) {
+				VM_STAT_ADD(segvnvmstats.fill_vp_pages[7]);
+				*downsize = 1;
+				*ret_pszc = 0;
+				page_unlock(targpp);
+				goto out;
+			}
+			io_err = VOP_PAGEIO(vp, io_pplist, io_off, io_len,
+				B_READ, svd->cred);
+			if (io_err) {
+				VM_STAT_ADD(segvnvmstats.fill_vp_pages[8]);
+				page_unlock(targpp);
+				if (io_err == EDEADLK) {
+					segvn_vmpss_pageio_deadlk_err++;
+				}
+				goto out;
+			}
+			nios++;
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[9]);
+			while (io_pplist != NULL) {
+				pp = io_pplist;
+				page_sub(&io_pplist, pp);
+				ASSERT(page_iolock_assert(pp));
+				page_io_unlock(pp);
+				pgidx = (pp->p_offset - start_off) >>
+				    PAGESHIFT;
+				ASSERT(pgidx < pages);
+				ppa[pgidx] = pp;
+				page_list_concat(&done_pplist, &pp);
+			}
+		}
+		pp = targpp;
+		ASSERT(PAGE_EXCL(pp));
+		ASSERT(pp->p_szc <= pszc);
+		if (pszc != 0 && !group_page_trylock(pp, SE_EXCL)) {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[10]);
+			page_unlock(pp);
+			*downsize = 1;
+			*ret_pszc = pp->p_szc;
+			goto out;
+		}
+		VM_STAT_ADD(segvnvmstats.fill_vp_pages[11]);
+		/*
+		 * page szc chould have changed before the entire group was
+		 * locked. reread page szc.
+		 */
+		pszc = pp->p_szc;
+		ppages = page_get_pagecnt(pszc);
+
+		/* link just the roots */
+		page_list_concat(&targ_pplist, &pp);
+		page_sub(&pplist, newpp);
+		page_list_concat(&repl_pplist, &newpp);
+		off += PAGESIZE;
+		while (--ppages != 0) {
+			newpp = pplist;
+			page_sub(&pplist, newpp);
+			off += PAGESIZE;
+		}
+		io_off = off;
+	}
+	if (io_pplist != NULL) {
+		VM_STAT_ADD(segvnvmstats.fill_vp_pages[12]);
+		io_len = eoff - io_off;
+		va.va_mask = AT_SIZE;
+		if (VOP_GETATTR(vp, &va, ATTR_HINT, svd->cred) != 0) {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[13]);
+			goto out;
+		}
+		if (btopr(va.va_size) < btopr(io_off + io_len)) {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[14]);
+			*downsize = 1;
+			*ret_pszc = 0;
+			goto out;
+		}
+		io_err = VOP_PAGEIO(vp, io_pplist, io_off, io_len,
+		    B_READ, svd->cred);
+		if (io_err) {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[15]);
+			if (io_err == EDEADLK) {
+				segvn_vmpss_pageio_deadlk_err++;
+			}
+			goto out;
+		}
+		nios++;
+		while (io_pplist != NULL) {
+			pp = io_pplist;
+			page_sub(&io_pplist, pp);
+			ASSERT(page_iolock_assert(pp));
+			page_io_unlock(pp);
+			pgidx = (pp->p_offset - start_off) >> PAGESHIFT;
+			ASSERT(pgidx < pages);
+			ppa[pgidx] = pp;
+		}
+	}
+	/*
+	 * we're now bound to succeed or panic.
+	 * remove pages from done_pplist. it's not needed anymore.
+	 */
+	while (done_pplist != NULL) {
+		pp = done_pplist;
+		page_sub(&done_pplist, pp);
+	}
+	VM_STAT_ADD(segvnvmstats.fill_vp_pages[16]);
+	ASSERT(pplist == NULL);
+	*ppplist = NULL;
+	while (targ_pplist != NULL) {
+		int ret;
+		VM_STAT_ADD(segvnvmstats.fill_vp_pages[17]);
+		ASSERT(repl_pplist);
+		pp = targ_pplist;
+		page_sub(&targ_pplist, pp);
+		pgidx = (pp->p_offset - start_off) >> PAGESHIFT;
+		newpp = repl_pplist;
+		page_sub(&repl_pplist, newpp);
+#ifdef DEBUG
+		pfn = page_pptonum(pp);
+		pszc = pp->p_szc;
+		ppages = page_get_pagecnt(pszc);
+		ASSERT(IS_P2ALIGNED(pfn, ppages));
+		pfn = page_pptonum(newpp);
+		ASSERT(IS_P2ALIGNED(pfn, ppages));
+		ASSERT(P2PHASE(pfn, pages) == pgidx);
+#endif
+		nreloc = 0;
+		ret = page_relocate(&pp, &newpp, 0, 1, &nreloc, NULL);
+		if (ret != 0 || nreloc == 0) {
+			panic("segvn_fill_vp_pages: "
+			    "page_relocate failed");
+		}
+		pp = newpp;
+		while (nreloc-- != 0) {
+			ASSERT(PAGE_EXCL(pp));
+			ASSERT(pp->p_vnode == vp);
+			ASSERT(pgidx ==
+			    ((pp->p_offset - start_off) >> PAGESHIFT));
+			ppa[pgidx++] = pp;
+			pp = page_next(pp);
+		}
+	}
+
+	if (svd->type == MAP_PRIVATE) {
+		VM_STAT_ADD(segvnvmstats.fill_vp_pages[18]);
+		for (i = 0; i < pages; i++) {
+			ASSERT(ppa[i] != NULL);
+			ASSERT(PAGE_EXCL(ppa[i]));
+			ASSERT(ppa[i]->p_vnode == vp);
+			ASSERT(ppa[i]->p_offset ==
+			    start_off + (i << PAGESHIFT));
+			page_downgrade(ppa[i]);
+		}
+		ppa[pages] = NULL;
+	} else {
+		VM_STAT_ADD(segvnvmstats.fill_vp_pages[19]);
+		/*
+		 * the caller will still call VOP_GETPAGE() for shared segments
+		 * to check FS write permissions. For private segments we map
+		 * file read only anyway.  so no VOP_GETPAGE is needed.
+		 */
+		for (i = 0; i < pages; i++) {
+			ASSERT(ppa[i] != NULL);
+			ASSERT(PAGE_EXCL(ppa[i]));
+			ASSERT(ppa[i]->p_vnode == vp);
+			ASSERT(ppa[i]->p_offset ==
+			    start_off + (i << PAGESHIFT));
+			page_unlock(ppa[i]);
+		}
+		ppa[0] = NULL;
+	}
+
+	return (1);
+out:
+	/*
+	 * Do the cleanup. Unlock target pages we didn't relocate. They are
+	 * linked on targ_pplist by root pages. reassemble unused replacement
+	 * and io pages back to pplist.
+	 */
+	if (io_pplist != NULL) {
+		VM_STAT_ADD(segvnvmstats.fill_vp_pages[20]);
+		pp = io_pplist;
+		do {
+			ASSERT(pp->p_vnode == vp);
+			ASSERT(pp->p_offset == io_off);
+			ASSERT(page_iolock_assert(pp));
+			page_io_unlock(pp);
+			page_hashout(pp, NULL);
+			io_off += PAGESIZE;
+		} while ((pp = pp->p_next) != io_pplist);
+		page_list_concat(&io_pplist, &pplist);
+		pplist = io_pplist;
+	}
+	tmp_pplist = NULL;
+	while (targ_pplist != NULL) {
+		VM_STAT_ADD(segvnvmstats.fill_vp_pages[21]);
+		pp = targ_pplist;
+		ASSERT(PAGE_EXCL(pp));
+		page_sub(&targ_pplist, pp);
+
+		pszc = pp->p_szc;
+		ppages = page_get_pagecnt(pszc);
+		ASSERT(IS_P2ALIGNED(page_pptonum(pp), ppages));
+
+		if (pszc != 0) {
+			group_page_unlock(pp);
+		}
+		page_unlock(pp);
+
+		pp = repl_pplist;
+		ASSERT(pp != NULL);
+		ASSERT(PAGE_EXCL(pp));
+		ASSERT(pp->p_szc == szc);
+		page_sub(&repl_pplist, pp);
+
+		ASSERT(IS_P2ALIGNED(page_pptonum(pp), ppages));
+
+		/* relink replacement page */
+		page_list_concat(&tmp_pplist, &pp);
+		while (--ppages != 0) {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[22]);
+			pp = page_next(pp);
+			ASSERT(PAGE_EXCL(pp));
+			ASSERT(pp->p_szc == szc);
+			page_list_concat(&tmp_pplist, &pp);
+		}
+	}
+	if (tmp_pplist != NULL) {
+		VM_STAT_ADD(segvnvmstats.fill_vp_pages[23]);
+		page_list_concat(&tmp_pplist, &pplist);
+		pplist = tmp_pplist;
+	}
+	/*
+	 * at this point all pages are either on done_pplist or
+	 * pplist. They can't be all on done_pplist otherwise
+	 * we'd've been done.
+	 */
+	ASSERT(pplist != NULL);
+	if (nios != 0) {
+		VM_STAT_ADD(segvnvmstats.fill_vp_pages[24]);
+		pp = pplist;
+		do {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[25]);
+			ASSERT(pp->p_szc == szc);
+			ASSERT(PAGE_EXCL(pp));
+			ASSERT(pp->p_vnode != vp);
+			pp->p_szc = 0;
+		} while ((pp = pp->p_next) != pplist);
+
+		pp = done_pplist;
+		do {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[26]);
+			ASSERT(pp->p_szc == szc);
+			ASSERT(PAGE_EXCL(pp));
+			ASSERT(pp->p_vnode == vp);
+			pp->p_szc = 0;
+		} while ((pp = pp->p_next) != done_pplist);
+
+		while (pplist != NULL) {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[27]);
+			pp = pplist;
+			page_sub(&pplist, pp);
+			page_free(pp, 0);
+		}
+
+		while (done_pplist != NULL) {
+			VM_STAT_ADD(segvnvmstats.fill_vp_pages[28]);
+			pp = done_pplist;
+			page_sub(&done_pplist, pp);
+			page_unlock(pp);
+		}
+		*ppplist = NULL;
+		return (0);
+	}
+	ASSERT(pplist == *ppplist);
+	if (io_err) {
+		VM_STAT_ADD(segvnvmstats.fill_vp_pages[29]);
+		/*
+		 * don't downsize on io error.
+		 * see if vop_getpage succeeds.
+		 * pplist may still be used in this case
+		 * for relocations.
+		 */
+		return (0);
+	}
+	VM_STAT_ADD(segvnvmstats.fill_vp_pages[30]);
+	page_free_replacement_page(pplist);
+	page_create_putback(pages);
+	*ppplist = NULL;
+	return (0);
+}
+
+int segvn_anypgsz = 0;
+
+#define	SEGVN_RESTORE_SOFTLOCK(type, pages) 		\
+		if ((type) == F_SOFTLOCK) {		\
+			mutex_enter(&freemem_lock);	\
+			availrmem += (pages);		\
+			segvn_pages_locked -= (pages);	\
+			svd->softlockcnt -= (pages);	\
+			mutex_exit(&freemem_lock);	\
+		}
+
+#define	SEGVN_UPDATE_MODBITS(ppa, pages, rw, prot, vpprot)		\
+		if (IS_VMODSORT((ppa)[0]->p_vnode)) {			\
+			if ((rw) == S_WRITE) {				\
+				for (i = 0; i < (pages); i++) {		\
+					ASSERT((ppa)[i]->p_vnode ==	\
+					    (ppa)[0]->p_vnode);		\
+					hat_setmod((ppa)[i]);		\
+				}					\
+			} else if ((rw) != S_OTHER &&			\
+			    ((prot) & (vpprot) & PROT_WRITE)) {		\
+				for (i = 0; i < (pages); i++) {		\
+					ASSERT((ppa)[i]->p_vnode ==	\
+					    (ppa)[0]->p_vnode);		\
+					if (!hat_ismod((ppa)[i])) {	\
+						prot &= ~PROT_WRITE;	\
+						break;			\
+					}				\
+				}					\
+			}						\
+		}
+
+#ifdef  VM_STATS
+
+#define	SEGVN_VMSTAT_FLTVNPAGES(idx)					\
+		VM_STAT_ADD(segvnvmstats.fltvnpages[(idx)]);
+
+#else /* VM_STATS */
+
+#define	SEGVN_VMSTAT_FLTVNPAGES(idx)
+
+#endif
+
+static faultcode_t
+segvn_fault_vnodepages(struct hat *hat, struct seg *seg, caddr_t lpgaddr,
+    caddr_t lpgeaddr, enum fault_type type, enum seg_rw rw, caddr_t addr,
+    caddr_t eaddr, int brkcow)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct anon_map *amp = svd->amp;
+	uchar_t segtype = svd->type;
+	uint_t szc = seg->s_szc;
+	size_t pgsz = page_get_pagesize(szc);
+	size_t maxpgsz = pgsz;
+	pgcnt_t pages = btop(pgsz);
+	pgcnt_t maxpages = pages;
+	size_t ppasize = (pages + 1) * sizeof (page_t *);
+	caddr_t a = lpgaddr;
+	caddr_t	maxlpgeaddr = lpgeaddr;
+	u_offset_t off = svd->offset + (uintptr_t)(a - seg->s_base);
+	ulong_t aindx = svd->anon_index + seg_page(seg, a);
+	struct vpage *vpage = (svd->vpage != NULL) ?
+	    &svd->vpage[seg_page(seg, a)] : NULL;
+	vnode_t *vp = svd->vp;
+	page_t **ppa;
+	uint_t	pszc;
+	size_t	ppgsz;
+	pgcnt_t	ppages;
+	faultcode_t err = 0;
+	int ierr;
+	int vop_size_err = 0;
+	uint_t protchk, prot, vpprot;
+	ulong_t i;
+	int hat_flag = (type == F_SOFTLOCK) ? HAT_LOAD_LOCK : HAT_LOAD;
+	anon_sync_obj_t an_cookie;
+	enum seg_rw arw;
+	int alloc_failed = 0;
+	int adjszc_chk;
+	struct vattr va;
+	int xhat = 0;
+	page_t *pplist;
+	pfn_t pfn;
+	int physcontig;
+	int upgrdfail;
+	int segvn_anypgsz_vnode = 0; /* for now map vnode with 2 page sizes */
+
+	ASSERT(szc != 0);
+	ASSERT(vp != NULL);
+	ASSERT(brkcow == 0 || amp != NULL);
+	ASSERT(enable_mbit_wa == 0); /* no mbit simulations with large pages */
+	ASSERT(!(svd->flags & MAP_NORESERVE));
+	ASSERT(type != F_SOFTUNLOCK);
+	ASSERT(IS_P2ALIGNED(a, maxpgsz));
+	ASSERT(amp == NULL || IS_P2ALIGNED(aindx, maxpages));
+	ASSERT(SEGVN_LOCK_HELD(seg->s_as, &svd->lock));
+	ASSERT(seg->s_szc < NBBY * sizeof (int));
+
+	VM_STAT_COND_ADD(type == F_SOFTLOCK, segvnvmstats.fltvnpages[0]);
+	VM_STAT_COND_ADD(type != F_SOFTLOCK, segvnvmstats.fltvnpages[1]);
+
+	if (svd->flags & MAP_TEXT) {
+		hat_flag |= HAT_LOAD_TEXT;
+	}
+
+	if (svd->pageprot) {
+		switch (rw) {
+		case S_READ:
+			protchk = PROT_READ;
+			break;
+		case S_WRITE:
+			protchk = PROT_WRITE;
+			break;
+		case S_EXEC:
+			protchk = PROT_EXEC;
+			break;
+		case S_OTHER:
+		default:
+			protchk = PROT_READ | PROT_WRITE | PROT_EXEC;
+			break;
+		}
+	} else {
+		prot = svd->prot;
+		/* caller has already done segment level protection check. */
+	}
+
+	if (seg->s_as->a_hat != hat) {
+		xhat = 1;
+	}
+
+	if (rw == S_WRITE && segtype == MAP_PRIVATE) {
+		SEGVN_VMSTAT_FLTVNPAGES(2);
+		arw = S_READ;
+	} else {
+		arw = rw;
+	}
+
+	ppa = kmem_alloc(ppasize, KM_SLEEP);
+
+	VM_STAT_COND_ADD(amp != NULL, segvnvmstats.fltvnpages[3]);
+
+	for (;;) {
+		adjszc_chk = 0;
+		for (; a < lpgeaddr; a += pgsz, off += pgsz, aindx += pages) {
+			if (adjszc_chk) {
+				while (szc < seg->s_szc) {
+					uintptr_t e;
+					uint_t tszc;
+					tszc = segvn_anypgsz_vnode ? szc + 1 :
+					    seg->s_szc;
+					ppgsz = page_get_pagesize(tszc);
+					if (!IS_P2ALIGNED(a, ppgsz) ||
+					    ((alloc_failed >> tszc) &
+						0x1)) {
+						break;
+					}
+					SEGVN_VMSTAT_FLTVNPAGES(4);
+					szc = tszc;
+					pgsz = ppgsz;
+					pages = btop(pgsz);
+					e = P2ROUNDUP((uintptr_t)eaddr, pgsz);
+					lpgeaddr = (caddr_t)e;
+				}
+			}
+
+		again:
+			if (IS_P2ALIGNED(a, maxpgsz) && amp != NULL) {
+				ASSERT(IS_P2ALIGNED(aindx, maxpages));
+				ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+				anon_array_enter(amp, aindx, &an_cookie);
+				if (anon_get_ptr(amp->ahp, aindx) != NULL) {
+					SEGVN_VMSTAT_FLTVNPAGES(5);
+					if (anon_pages(amp->ahp, aindx,
+					    maxpages) != maxpages) {
+						panic("segvn_fault_vnodepages:"
+						    " empty anon slots\n");
+					}
+					anon_array_exit(&an_cookie);
+					ANON_LOCK_EXIT(&amp->a_rwlock);
+					err = segvn_fault_anonpages(hat, seg,
+					    a, a + maxpgsz, type, rw,
+					    MAX(a, addr),
+					    MIN(a + maxpgsz, eaddr), brkcow);
+					if (err != 0) {
+						SEGVN_VMSTAT_FLTVNPAGES(6);
+						goto out;
+					}
+					if (szc < seg->s_szc) {
+						szc = seg->s_szc;
+						pgsz = maxpgsz;
+						pages = maxpages;
+						lpgeaddr = maxlpgeaddr;
+					}
+					goto next;
+				} else if (anon_pages(amp->ahp, aindx,
+				    maxpages)) {
+					panic("segvn_fault_vnodepages:"
+						" non empty anon slots\n");
+				} else {
+					SEGVN_VMSTAT_FLTVNPAGES(7);
+					anon_array_exit(&an_cookie);
+					ANON_LOCK_EXIT(&amp->a_rwlock);
+				}
+			}
+			ASSERT(!brkcow || IS_P2ALIGNED(a, maxpgsz));
+
+			if (svd->pageprot != 0 && IS_P2ALIGNED(a, maxpgsz)) {
+				ASSERT(vpage != NULL);
+				prot = VPP_PROT(vpage);
+				ASSERT(sameprot(seg, a, maxpgsz));
+				if ((prot & protchk) == 0) {
+					SEGVN_VMSTAT_FLTVNPAGES(8);
+					err = FC_PROT;
+					goto out;
+				}
+			}
+			if (type == F_SOFTLOCK) {
+				mutex_enter(&freemem_lock);
+				if (availrmem < tune.t_minarmem + pages) {
+					mutex_exit(&freemem_lock);
+					err = FC_MAKE_ERR(ENOMEM);
+					goto out;
+				} else {
+					availrmem -= pages;
+					segvn_pages_locked += pages;
+					svd->softlockcnt += pages;
+				}
+				mutex_exit(&freemem_lock);
+			}
+
+			pplist = NULL;
+			physcontig = 0;
+			ppa[0] = NULL;
+			if (!brkcow && szc &&
+			    !page_exists_physcontig(vp, off, szc,
+				segtype == MAP_PRIVATE ? ppa : NULL)) {
+				SEGVN_VMSTAT_FLTVNPAGES(9);
+				if (page_alloc_pages(seg, a, &pplist, NULL,
+				    szc, 0)) {
+					SEGVN_RESTORE_SOFTLOCK(type, pages);
+					SEGVN_VMSTAT_FLTVNPAGES(10);
+					pszc = 0;
+					ierr = -1;
+					alloc_failed |= (1 << szc);
+					break;
+				}
+				if (vp->v_mpssdata == SEGVN_PAGEIO) {
+					int downsize;
+					SEGVN_VMSTAT_FLTVNPAGES(11);
+					physcontig = segvn_fill_vp_pages(svd,
+					    vp, off, szc, ppa, &pplist,
+					    &pszc, &downsize);
+					ASSERT(!physcontig || pplist == NULL);
+					if (!physcontig && downsize) {
+						SEGVN_RESTORE_SOFTLOCK(type,
+						    pages);
+						ASSERT(pplist == NULL);
+						SEGVN_VMSTAT_FLTVNPAGES(12);
+						ierr = -1;
+						break;
+					}
+					ASSERT(!physcontig ||
+					    segtype == MAP_PRIVATE ||
+					    ppa[0] == NULL);
+					if (physcontig && ppa[0] == NULL) {
+						physcontig = 0;
+					}
+				}
+			} else if (!brkcow && szc && ppa[0] != NULL) {
+				SEGVN_VMSTAT_FLTVNPAGES(13);
+				ASSERT(segtype == MAP_PRIVATE);
+				physcontig = 1;
+			}
+
+			if (!physcontig) {
+				SEGVN_VMSTAT_FLTVNPAGES(14);
+				ppa[0] = NULL;
+				ierr = VOP_GETPAGE(vp, (offset_t)off, pgsz,
+				    &vpprot, ppa, pgsz, seg, a, arw,
+				    svd->cred);
+				if (segtype == MAP_PRIVATE) {
+					SEGVN_VMSTAT_FLTVNPAGES(15);
+					vpprot &= ~PROT_WRITE;
+				}
+			} else {
+				ASSERT(segtype == MAP_PRIVATE);
+				SEGVN_VMSTAT_FLTVNPAGES(16);
+				vpprot = PROT_ALL & ~PROT_WRITE;
+				ierr = 0;
+			}
+
+			if (ierr != 0) {
+				SEGVN_VMSTAT_FLTVNPAGES(17);
+				if (pplist != NULL) {
+					SEGVN_VMSTAT_FLTVNPAGES(18);
+					page_free_replacement_page(pplist);
+					page_create_putback(pages);
+				}
+				SEGVN_RESTORE_SOFTLOCK(type, pages);
+				if (a + pgsz <= eaddr) {
+					SEGVN_VMSTAT_FLTVNPAGES(19);
+					err = FC_MAKE_ERR(ierr);
+					goto out;
+				}
+				va.va_mask = AT_SIZE;
+				if (VOP_GETATTR(vp, &va, 0, svd->cred) != 0) {
+					SEGVN_VMSTAT_FLTVNPAGES(20);
+					err = FC_MAKE_ERR(EIO);
+					goto out;
+				}
+				if (btopr(va.va_size) >= btopr(off + pgsz)) {
+					SEGVN_VMSTAT_FLTVNPAGES(21);
+					err = FC_MAKE_ERR(EIO);
+					goto out;
+				}
+				if (btopr(va.va_size) <
+				    btopr(off + (eaddr - a))) {
+					SEGVN_VMSTAT_FLTVNPAGES(22);
+					err = FC_MAKE_ERR(EIO);
+					goto out;
+				}
+				if (brkcow || type == F_SOFTLOCK) {
+					/* can't reduce map area */
+					SEGVN_VMSTAT_FLTVNPAGES(23);
+					vop_size_err = 1;
+					goto out;
+				}
+				SEGVN_VMSTAT_FLTVNPAGES(24);
+				ASSERT(szc != 0);
+				pszc = 0;
+				ierr = -1;
+				break;
+			}
+
+			if (amp != NULL) {
+				ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+				anon_array_enter(amp, aindx, &an_cookie);
+			}
+			if (amp != NULL &&
+			    anon_get_ptr(amp->ahp, aindx) != NULL) {
+				ulong_t taindx = P2ALIGN(aindx, maxpages);
+
+				SEGVN_VMSTAT_FLTVNPAGES(25);
+				if (anon_pages(amp->ahp, taindx, maxpages) !=
+				    maxpages) {
+					panic("segvn_fault_vnodepages:"
+					    " empty anon slots\n");
+				}
+				for (i = 0; i < pages; i++) {
+					page_unlock(ppa[i]);
+				}
+				anon_array_exit(&an_cookie);
+				ANON_LOCK_EXIT(&amp->a_rwlock);
+				if (pplist != NULL) {
+					page_free_replacement_page(pplist);
+					page_create_putback(pages);
+				}
+				SEGVN_RESTORE_SOFTLOCK(type, pages);
+				if (szc < seg->s_szc) {
+					SEGVN_VMSTAT_FLTVNPAGES(26);
+					/*
+					 * For private segments SOFTLOCK
+					 * either always breaks cow (any rw
+					 * type except S_READ_NOCOW) or
+					 * address space is locked as writer
+					 * (S_READ_NOCOW case) and anon slots
+					 * can't show up on second check.
+					 * Therefore if we are here for
+					 * SOFTLOCK case it must be a cow
+					 * break but cow break never reduces
+					 * szc. Thus the assert below.
+					 */
+					ASSERT(!brkcow && type != F_SOFTLOCK);
+					pszc = seg->s_szc;
+					ierr = -2;
+					break;
+				}
+				ASSERT(IS_P2ALIGNED(a, maxpgsz));
+				goto again;
+			}
+#ifdef DEBUG
+			if (amp != NULL) {
+				ulong_t taindx = P2ALIGN(aindx, maxpages);
+				ASSERT(!anon_pages(amp->ahp, taindx, maxpages));
+			}
+#endif /* DEBUG */
+
+			if (brkcow) {
+				ASSERT(amp != NULL);
+				ASSERT(pplist == NULL);
+				ASSERT(szc == seg->s_szc);
+				ASSERT(IS_P2ALIGNED(a, maxpgsz));
+				ASSERT(IS_P2ALIGNED(aindx, maxpages));
+				SEGVN_VMSTAT_FLTVNPAGES(27);
+				ierr = anon_map_privatepages(amp, aindx, szc,
+				    seg, a, prot, ppa, vpage, segvn_anypgsz,
+				    svd->cred);
+				if (ierr != 0) {
+					SEGVN_VMSTAT_FLTVNPAGES(28);
+					anon_array_exit(&an_cookie);
+					ANON_LOCK_EXIT(&amp->a_rwlock);
+					SEGVN_RESTORE_SOFTLOCK(type, pages);
+					err = FC_MAKE_ERR(ierr);
+					goto out;
+				}
+
+				ASSERT(!IS_VMODSORT(ppa[0]->p_vnode));
+				/*
+				 * p_szc can't be changed for locked
+				 * swapfs pages.
+				 */
+				hat_memload_array(hat, a, pgsz, ppa, prot,
+				    hat_flag);
+
+				if (!(hat_flag & HAT_LOAD_LOCK)) {
+					SEGVN_VMSTAT_FLTVNPAGES(29);
+					for (i = 0; i < pages; i++) {
+						page_unlock(ppa[i]);
+					}
+				}
+				anon_array_exit(&an_cookie);
+				ANON_LOCK_EXIT(&amp->a_rwlock);
+				goto next;
+			}
+
+			pfn = page_pptonum(ppa[0]);
+			/*
+			 * hat_page_demote() needs an EXCl lock on one of
+			 * constituent page_t's and it decreases root's p_szc
+			 * last. This means if root's p_szc is equal szc and
+			 * all its constituent pages are locked
+			 * hat_page_demote() that could have changed p_szc to
+			 * szc is already done and no new have page_demote()
+			 * can start for this large page.
+			 */
+
+			/*
+			 * we need to make sure same mapping size is used for
+			 * the same address range if there's a possibility the
+			 * adddress is already mapped because hat layer panics
+			 * when translation is loaded for the range already
+			 * mapped with a different page size.  We achieve it
+			 * by always using largest page size possible subject
+			 * to the constraints of page size, segment page size
+			 * and page alignment.  Since mappings are invalidated
+			 * when those constraints change and make it
+			 * impossible to use previously used mapping size no
+			 * mapping size conflicts should happen.
+			 */
+
+		chkszc:
+			if ((pszc = ppa[0]->p_szc) == szc &&
+			    IS_P2ALIGNED(pfn, pages)) {
+
+				SEGVN_VMSTAT_FLTVNPAGES(30);
+#ifdef DEBUG
+				for (i = 0; i < pages; i++) {
+					ASSERT(PAGE_LOCKED(ppa[i]));
+					ASSERT(!PP_ISFREE(ppa[i]));
+					ASSERT(page_pptonum(ppa[i]) ==
+					    pfn + i);
+					ASSERT(ppa[i]->p_szc == szc);
+					ASSERT(ppa[i]->p_vnode == vp);
+					ASSERT(ppa[i]->p_offset ==
+					    off + (i << PAGESHIFT));
+				}
+#endif
+				/*
+				 * All pages are of szc we need and they are
+				 * all locked so they can't change szc. load
+				 * translations.
+				 *
+				 * if page got promoted since last check
+				 * we don't need pplist.
+				 */
+				if (pplist != NULL) {
+					page_free_replacement_page(pplist);
+					page_create_putback(pages);
+				}
+				if (PP_ISMIGRATE(ppa[0])) {
+					page_migrate(seg, a, ppa, pages);
+				}
+				SEGVN_UPDATE_MODBITS(ppa, pages, rw,
+				    prot, vpprot);
+				if (!xhat) {
+					hat_memload_array(hat, a, pgsz, ppa,
+					    prot & vpprot, hat_flag);
+				} else {
+					/*
+					 * avoid large xhat mappings to FS
+					 * pages so that hat_page_demote()
+					 * doesn't need to check for xhat
+					 * large mappings.
+					 */
+					for (i = 0; i < pages; i++) {
+						hat_memload(hat,
+						    a + (i << PAGESHIFT),
+						    ppa[i], prot & vpprot,
+						    hat_flag);
+					}
+				}
+
+				if (!(hat_flag & HAT_LOAD_LOCK)) {
+					for (i = 0; i < pages; i++) {
+						page_unlock(ppa[i]);
+					}
+				}
+				if (amp != NULL) {
+					anon_array_exit(&an_cookie);
+					ANON_LOCK_EXIT(&amp->a_rwlock);
+				}
+				goto next;
+			}
+
+			/*
+			 * See if upsize is possible.
+			 */
+			if (pszc > szc && szc < seg->s_szc &&
+			    (segvn_anypgsz_vnode || pszc >= seg->s_szc)) {
+				pgcnt_t aphase;
+				uint_t pszc1 = MIN(pszc, seg->s_szc);
+				ppgsz = page_get_pagesize(pszc1);
+				ppages = btop(ppgsz);
+				aphase = btop(P2PHASE((uintptr_t)a, ppgsz));
+
+				SEGVN_VMSTAT_FLTVNPAGES(31);
+				if (aphase != P2PHASE(pfn, ppages)) {
+					segvn_faultvnmpss_align_err4++;
+				} else if (type == F_SOFTLOCK &&
+				    a != lpgaddr &&
+				    !IS_P2ALIGNED(pfn,
+					page_get_pagecnt(ppa[0]->p_szc))) {
+					/*
+					 * if we locked previous offsets for
+					 * smaller szc page larger page can't
+					 * be here since one needs excl locks
+					 * to promote page size.
+					 */
+					panic("segvn_fault_vnodepages: "
+					    "unexpected larger than szc page"
+					    " found after SOFTLOCK");
+				} else {
+					SEGVN_VMSTAT_FLTVNPAGES(32);
+					if (pplist != NULL) {
+						page_t *pl = pplist;
+						page_free_replacement_page(pl);
+						page_create_putback(pages);
+					}
+					for (i = 0; i < pages; i++) {
+						page_unlock(ppa[i]);
+					}
+					if (amp != NULL) {
+						anon_array_exit(&an_cookie);
+						ANON_LOCK_EXIT(&amp->a_rwlock);
+					}
+					SEGVN_RESTORE_SOFTLOCK(type, pages);
+					pszc = pszc1;
+					ierr = -2;
+					break;
+				}
+			}
+
+			/*
+			 * check if we should use smallest mapping size.
+			 */
+			upgrdfail = 0;
+			if (szc == 0 || xhat ||
+			    (pszc >= szc &&
+			    !IS_P2ALIGNED(pfn, pages)) ||
+			    (pszc < szc &&
+			    !segvn_full_szcpages(ppa, szc, &upgrdfail,
+				&pszc))) {
+
+				if (upgrdfail) {
+					/*
+					 * segvn_full_szcpages failed to lock
+					 * all pages EXCL. Size down.
+					 */
+					ASSERT(pszc < szc);
+
+					SEGVN_VMSTAT_FLTVNPAGES(33);
+
+					if (pplist != NULL) {
+						page_t *pl = pplist;
+						page_free_replacement_page(pl);
+						page_create_putback(pages);
+					}
+
+					for (i = 0; i < pages; i++) {
+						page_unlock(ppa[i]);
+					}
+					if (amp != NULL) {
+						anon_array_exit(&an_cookie);
+						ANON_LOCK_EXIT(&amp->a_rwlock);
+					}
+					SEGVN_RESTORE_SOFTLOCK(type, pages);
+					ierr = -1;
+					break;
+				}
+				if (szc != 0 && !xhat) {
+					segvn_faultvnmpss_align_err5++;
+				}
+				SEGVN_VMSTAT_FLTVNPAGES(34);
+				if (pplist != NULL) {
+					page_free_replacement_page(pplist);
+					page_create_putback(pages);
+				}
+				SEGVN_UPDATE_MODBITS(ppa, pages, rw,
+				    prot, vpprot);
+				for (i = 0; i < pages; i++) {
+					hat_memload(hat, a + (i << PAGESHIFT),
+					    ppa[i], prot & vpprot, hat_flag);
+				}
+				if (!(hat_flag & HAT_LOAD_LOCK)) {
+					for (i = 0; i < pages; i++) {
+						page_unlock(ppa[i]);
+					}
+				}
+				if (amp != NULL) {
+					anon_array_exit(&an_cookie);
+					ANON_LOCK_EXIT(&amp->a_rwlock);
+				}
+				goto next;
+			}
+
+			if (pszc == szc) {
+				/*
+				 * segvn_full_szcpages() upgraded pages szc.
+				 */
+				ASSERT(pszc == ppa[0]->p_szc);
+				ASSERT(IS_P2ALIGNED(pfn, pages));
+				goto chkszc;
+			}
+
+			if (pszc > szc) {
+				kmutex_t *szcmtx;
+				SEGVN_VMSTAT_FLTVNPAGES(35);
+				/*
+				 * p_szc of ppa[0] can change since we haven't
+				 * locked all constituent pages. Call
+				 * page_lock_szc() to prevent szc changes.
+				 * This should be a rare case that happens when
+				 * multiple segments use a different page size
+				 * to map the same file offsets.
+				 */
+				szcmtx = page_szc_lock(ppa[0]);
+				pszc = ppa[0]->p_szc;
+				ASSERT(szcmtx != NULL || pszc == 0);
+				ASSERT(ppa[0]->p_szc <= pszc);
+				if (pszc <= szc) {
+					SEGVN_VMSTAT_FLTVNPAGES(36);
+					if (szcmtx != NULL) {
+						mutex_exit(szcmtx);
+					}
+					goto chkszc;
+				}
+				if (pplist != NULL) {
+					/*
+					 * page got promoted since last check.
+					 * we don't need preaalocated large
+					 * page.
+					 */
+					SEGVN_VMSTAT_FLTVNPAGES(37);
+					page_free_replacement_page(pplist);
+					page_create_putback(pages);
+				}
+				SEGVN_UPDATE_MODBITS(ppa, pages, rw,
+				    prot, vpprot);
+				hat_memload_array(hat, a, pgsz, ppa,
+				    prot & vpprot, hat_flag);
+				mutex_exit(szcmtx);
+				if (!(hat_flag & HAT_LOAD_LOCK)) {
+					for (i = 0; i < pages; i++) {
+						page_unlock(ppa[i]);
+					}
+				}
+				if (amp != NULL) {
+					anon_array_exit(&an_cookie);
+					ANON_LOCK_EXIT(&amp->a_rwlock);
+				}
+				goto next;
+			}
+
+			/*
+			 * if page got demoted since last check
+			 * we could have not allocated larger page.
+			 * allocate now.
+			 */
+			if (pplist == NULL &&
+			    page_alloc_pages(seg, a, &pplist, NULL, szc, 0)) {
+				SEGVN_VMSTAT_FLTVNPAGES(38);
+				for (i = 0; i < pages; i++) {
+					page_unlock(ppa[i]);
+				}
+				if (amp != NULL) {
+					anon_array_exit(&an_cookie);
+					ANON_LOCK_EXIT(&amp->a_rwlock);
+				}
+				SEGVN_RESTORE_SOFTLOCK(type, pages);
+				ierr = -1;
+				alloc_failed |= (1 << szc);
+				break;
+			}
+
+			SEGVN_VMSTAT_FLTVNPAGES(39);
+
+			segvn_relocate_pages(ppa, pplist);
+
+			SEGVN_UPDATE_MODBITS(ppa, pages, rw, prot, vpprot);
+			hat_memload_array(hat, a, pgsz, ppa, prot & vpprot,
+			    hat_flag);
+			if (!(hat_flag & HAT_LOAD_LOCK)) {
+				for (i = 0; i < pages; i++) {
+					ASSERT(PAGE_SHARED(ppa[i]));
+					page_unlock(ppa[i]);
+				}
+			}
+			if (amp != NULL) {
+				anon_array_exit(&an_cookie);
+				ANON_LOCK_EXIT(&amp->a_rwlock);
+			}
+
+		next:
+			if (vpage != NULL) {
+				vpage += pages;
+			}
+			adjszc_chk = 1;
+		}
+		if (a == lpgeaddr)
+			break;
+		ASSERT(a < lpgeaddr);
+		/*
+		 * ierr == -1 means we failed to map with a large page.
+		 * (either due to allocation/relocation failures or
+		 * misalignment with other mappings to this file.
+		 *
+		 * ierr == -2 means some other thread allocated a large page
+		 * after we gave up tp map with a large page.  retry with
+		 * larger mapping.
+		 */
+		ASSERT(ierr == -1 || ierr == -2);
+		ASSERT(ierr == -2 || szc != 0);
+		ASSERT(ierr == -1 || szc < seg->s_szc);
+		if (ierr == -2) {
+			SEGVN_VMSTAT_FLTVNPAGES(40);
+			ASSERT(pszc > szc && pszc <= seg->s_szc);
+			szc = pszc;
+		} else if (segvn_anypgsz_vnode) {
+			SEGVN_VMSTAT_FLTVNPAGES(41);
+			szc--;
+		} else {
+			SEGVN_VMSTAT_FLTVNPAGES(42);
+			ASSERT(pszc < szc);
+			/*
+			 * other process created pszc large page.
+			 * but we still have to drop to 0 szc.
+			 */
+			szc = 0;
+		}
+
+		pgsz = page_get_pagesize(szc);
+		pages = btop(pgsz);
+		ASSERT(type != F_SOFTLOCK || ierr == -1 ||
+		    (IS_P2ALIGNED(a, pgsz) && IS_P2ALIGNED(lpgeaddr, pgsz)));
+		if (type == F_SOFTLOCK) {
+			/*
+			 * For softlocks we cannot reduce the fault area
+			 * (calculated based on the largest page size for this
+			 * segment) for size down and a is already next
+			 * page size aligned as assertted above for size
+			 * ups. Therefore just continue in case of softlock.
+			 */
+			SEGVN_VMSTAT_FLTVNPAGES(43);
+			continue; /* keep lint happy */
+		} else if (ierr == -2) {
+
+			/*
+			 * Size up case. Note lpgaddr may only be needed for
+			 * softlock case so we don't adjust it here.
+			 */
+			a = (caddr_t)P2ALIGN((uintptr_t)a, pgsz);
+			ASSERT(a >= lpgaddr);
+			lpgeaddr = (caddr_t)P2ROUNDUP((uintptr_t)eaddr, pgsz);
+			off = svd->offset + (uintptr_t)(a - seg->s_base);
+			aindx = svd->anon_index + seg_page(seg, a);
+			vpage = (svd->vpage != NULL) ?
+			    &svd->vpage[seg_page(seg, a)] : NULL;
+		} else {
+			/*
+			 * Size down case. Note lpgaddr may only be needed for
+			 * softlock case so we don't adjust it here.
+			 */
+			ASSERT(IS_P2ALIGNED(a, pgsz));
+			ASSERT(IS_P2ALIGNED(lpgeaddr, pgsz));
+			lpgeaddr = (caddr_t)P2ROUNDUP((uintptr_t)eaddr, pgsz);
+			ASSERT(a < lpgeaddr);
+			if (a < addr) {
+				SEGVN_VMSTAT_FLTVNPAGES(44);
+				/*
+				 * The beginning of the large page region can
+				 * be pulled to the right to make a smaller
+				 * region. We haven't yet faulted a single
+				 * page.
+				 */
+				a = (caddr_t)P2ALIGN((uintptr_t)addr, pgsz);
+				ASSERT(a >= lpgaddr);
+				off = svd->offset +
+				    (uintptr_t)(a - seg->s_base);
+				aindx = svd->anon_index + seg_page(seg, a);
+				vpage = (svd->vpage != NULL) ?
+				    &svd->vpage[seg_page(seg, a)] : NULL;
+			}
+		}
+	}
+out:
+	kmem_free(ppa, ppasize);
+	if (!err && !vop_size_err) {
+		SEGVN_VMSTAT_FLTVNPAGES(45);
+		return (0);
+	}
+	if (type == F_SOFTLOCK && a > lpgaddr) {
+		SEGVN_VMSTAT_FLTVNPAGES(46);
+		segvn_softunlock(seg, lpgaddr, a - lpgaddr, S_OTHER);
+	}
+	if (!vop_size_err) {
+		SEGVN_VMSTAT_FLTVNPAGES(47);
+		return (err);
+	}
+	ASSERT(brkcow || type == F_SOFTLOCK);
+	/*
+	 * Large page end is mapped beyond the end of file and it's a cow
+	 * fault or softlock so we can't reduce the map area.  For now just
+	 * demote the segment. This should really only happen if the end of
+	 * the file changed after the mapping was established since when large
+	 * page segments are created we make sure they don't extend beyond the
+	 * end of the file.
+	 */
+	SEGVN_VMSTAT_FLTVNPAGES(48);
+
+	SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+	SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_WRITER);
+	err = 0;
+	if (seg->s_szc != 0) {
+		err = segvn_clrszc(seg);
+		if (err != 0) {
+			segvn_fltvnpages_clrszc_err++;
+		}
+	}
+	ASSERT(err || seg->s_szc == 0);
+	SEGVN_LOCK_DOWNGRADE(seg->s_as, &svd->lock);
+	/* segvn_fault will do its job as if szc had been zero to begin with */
+	return (err == 0 ? IE_RETRY : FC_MAKE_ERR(err));
+}
+
+/*
+ * This routine will attempt to fault in one large page.
+ * it will use smaller pages if that fails.
+ * It should only be called for pure anonymous segments.
+ */
+static faultcode_t
+segvn_fault_anonpages(struct hat *hat, struct seg *seg, caddr_t lpgaddr,
+    caddr_t lpgeaddr, enum fault_type type, enum seg_rw rw, caddr_t addr,
+    caddr_t eaddr, int brkcow)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct anon_map *amp = svd->amp;
+	uchar_t segtype = svd->type;
+	uint_t szc = seg->s_szc;
+	size_t pgsz = page_get_pagesize(szc);
+	size_t maxpgsz = pgsz;
+	pgcnt_t pages = btop(pgsz);
+	size_t ppasize = pages * sizeof (page_t *);
+	caddr_t a = lpgaddr;
+	ulong_t aindx = svd->anon_index + seg_page(seg, a);
+	struct vpage *vpage = (svd->vpage != NULL) ?
+	    &svd->vpage[seg_page(seg, a)] : NULL;
+	page_t **ppa;
+	uint_t	ppa_szc;
+	faultcode_t err;
+	int ierr;
+	uint_t protchk, prot, vpprot;
+	int i;
+	int hat_flag = (type == F_SOFTLOCK) ? HAT_LOAD_LOCK : HAT_LOAD;
+	anon_sync_obj_t cookie;
+
+	ASSERT(szc != 0);
+	ASSERT(amp != NULL);
+	ASSERT(enable_mbit_wa == 0); /* no mbit simulations with large pages */
+	ASSERT(!(svd->flags & MAP_NORESERVE));
+	ASSERT(type != F_SOFTUNLOCK);
+	ASSERT(segtype == MAP_PRIVATE);
+	ASSERT(IS_P2ALIGNED(a, maxpgsz));
+
+	ASSERT(SEGVN_LOCK_HELD(seg->s_as, &svd->lock));
+
+	VM_STAT_COND_ADD(type == F_SOFTLOCK, segvnvmstats.fltanpages[0]);
+	VM_STAT_COND_ADD(type != F_SOFTLOCK, segvnvmstats.fltanpages[1]);
+
+	if (svd->flags & MAP_TEXT) {
+		hat_flag |= HAT_LOAD_TEXT;
+	}
+
+	if (svd->pageprot) {
+		switch (rw) {
+		case S_READ:
+			protchk = PROT_READ;
+			break;
+		case S_WRITE:
+			protchk = PROT_WRITE;
+			break;
+		case S_EXEC:
+			protchk = PROT_EXEC;
+			break;
+		case S_OTHER:
+		default:
+			protchk = PROT_READ | PROT_WRITE | PROT_EXEC;
+			break;
+		}
+		VM_STAT_ADD(segvnvmstats.fltanpages[2]);
+	} else {
+		prot = svd->prot;
+		/* caller has already done segment level protection check. */
+	}
+
+	ppa = kmem_alloc(ppasize, KM_SLEEP);
+	ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+	for (;;) {
+		for (; a < lpgeaddr; a += pgsz, aindx += pages) {
+			if (svd->pageprot != 0 && IS_P2ALIGNED(a, maxpgsz)) {
+				VM_STAT_ADD(segvnvmstats.fltanpages[3]);
+				ASSERT(vpage != NULL);
+				prot = VPP_PROT(vpage);
+				ASSERT(sameprot(seg, a, maxpgsz));
+				if ((prot & protchk) == 0) {
+					err = FC_PROT;
+					goto error;
+				}
+			}
+			if (type == F_SOFTLOCK) {
+				mutex_enter(&freemem_lock);
+				if (availrmem < tune.t_minarmem + pages) {
+					mutex_exit(&freemem_lock);
+					err = FC_MAKE_ERR(ENOMEM);
+					goto error;
+				} else {
+					availrmem -= pages;
+					segvn_pages_locked += pages;
+					svd->softlockcnt += pages;
+				}
+				mutex_exit(&freemem_lock);
+			}
+			anon_array_enter(amp, aindx, &cookie);
+			ppa_szc = (uint_t)-1;
+			ierr = anon_map_getpages(amp, aindx, szc, seg, a,
+				prot, &vpprot, ppa, &ppa_szc, vpage, rw, brkcow,
+				segvn_anypgsz, svd->cred);
+			if (ierr != 0) {
+				anon_array_exit(&cookie);
+				VM_STAT_ADD(segvnvmstats.fltanpages[4]);
+				if (type == F_SOFTLOCK) {
+					VM_STAT_ADD(segvnvmstats.fltanpages[5]);
+					mutex_enter(&freemem_lock);
+					availrmem += pages;
+					segvn_pages_locked -= pages;
+					svd->softlockcnt -= pages;
+					mutex_exit(&freemem_lock);
+				}
+				if (ierr > 0) {
+					VM_STAT_ADD(segvnvmstats.fltanpages[6]);
+					err = FC_MAKE_ERR(ierr);
+					goto error;
+				}
+				break;
+			}
+
+			ASSERT(!IS_VMODSORT(ppa[0]->p_vnode));
+
+			/*
+			 * Handle pages that have been marked for migration
+			 */
+			if (lgrp_optimizations())
+				page_migrate(seg, a, ppa, pages);
+
+			hat_memload_array(hat, a, pgsz, ppa,
+			    prot & vpprot, hat_flag);
+
+			if (hat_flag & HAT_LOAD_LOCK) {
+				VM_STAT_ADD(segvnvmstats.fltanpages[7]);
+			} else {
+				VM_STAT_ADD(segvnvmstats.fltanpages[8]);
+				for (i = 0; i < pages; i++)
+					page_unlock(ppa[i]);
+			}
+			if (vpage != NULL)
+				vpage += pages;
+
+			anon_array_exit(&cookie);
+		}
+		if (a == lpgeaddr)
+			break;
+		ASSERT(a < lpgeaddr);
+		/*
+		 * ierr == -1 means we failed to allocate a large page.
+		 * so do a size down operation.
+		 *
+		 * ierr == -2 means some other process that privately shares
+		 * pages with this process has allocated a larger page and we
+		 * need to retry with larger pages. So do a size up
+		 * operation. This relies on the fact that large pages are
+		 * never partially shared i.e. if we share any constituent
+		 * page of a large page with another process we must share the
+		 * entire large page. Note this cannot happen for SOFTLOCK
+		 * case, unless current address (a) is at the beginning of the
+		 * next page size boundary because the other process couldn't
+		 * have relocated locked pages.
+		 */
+		ASSERT(ierr == -1 || ierr == -2);
+		if (segvn_anypgsz) {
+			ASSERT(ierr == -2 || szc != 0);
+			ASSERT(ierr == -1 || szc < seg->s_szc);
+			szc = (ierr == -1) ? szc - 1 : szc + 1;
+		} else {
+			/*
+			 * For non COW faults and segvn_anypgsz == 0
+			 * we need to be careful not to loop forever
+			 * if existing page is found with szc other
+			 * than 0 or seg->s_szc. This could be due
+			 * to page relocations on behalf of DR or
+			 * more likely large page creation. For this
+			 * case simply re-size to existing page's szc
+			 * if returned by anon_map_getpages().
+			 */
+			if (ppa_szc == (uint_t)-1) {
+				szc = (ierr == -1) ? 0 : seg->s_szc;
+			} else {
+				ASSERT(ppa_szc <= seg->s_szc);
+				ASSERT(ierr == -2 || ppa_szc < szc);
+				ASSERT(ierr == -1 || ppa_szc > szc);
+				szc = ppa_szc;
+			}
+		}
+
+		pgsz = page_get_pagesize(szc);
+		pages = btop(pgsz);
+		ASSERT(type != F_SOFTLOCK || ierr == -1 ||
+		    (IS_P2ALIGNED(a, pgsz) && IS_P2ALIGNED(lpgeaddr, pgsz)));
+		if (type == F_SOFTLOCK) {
+			/*
+			 * For softlocks we cannot reduce the fault area
+			 * (calculated based on the largest page size for this
+			 * segment) for size down and a is already next
+			 * page size aligned as assertted above for size
+			 * ups. Therefore just continue in case of softlock.
+			 */
+			VM_STAT_ADD(segvnvmstats.fltanpages[9]);
+			continue; /* keep lint happy */
+		} else if (ierr == -2) {
+
+			/*
+			 * Size up case. Note lpgaddr may only be needed for
+			 * softlock case so we don't adjust it here.
+			 */
+			VM_STAT_ADD(segvnvmstats.fltanpages[10]);
+			a = (caddr_t)P2ALIGN((uintptr_t)a, pgsz);
+			ASSERT(a >= lpgaddr);
+			lpgeaddr = (caddr_t)P2ROUNDUP((uintptr_t)eaddr, pgsz);
+			aindx = svd->anon_index + seg_page(seg, a);
+			vpage = (svd->vpage != NULL) ?
+			    &svd->vpage[seg_page(seg, a)] : NULL;
+		} else {
+			/*
+			 * Size down case. Note lpgaddr may only be needed for
+			 * softlock case so we don't adjust it here.
+			 */
+			VM_STAT_ADD(segvnvmstats.fltanpages[11]);
+			ASSERT(IS_P2ALIGNED(a, pgsz));
+			ASSERT(IS_P2ALIGNED(lpgeaddr, pgsz));
+			lpgeaddr = (caddr_t)P2ROUNDUP((uintptr_t)eaddr, pgsz);
+			ASSERT(a < lpgeaddr);
+			if (a < addr) {
+				/*
+				 * The beginning of the large page region can
+				 * be pulled to the right to make a smaller
+				 * region. We haven't yet faulted a single
+				 * page.
+				 */
+				VM_STAT_ADD(segvnvmstats.fltanpages[12]);
+				a = (caddr_t)P2ALIGN((uintptr_t)addr, pgsz);
+				ASSERT(a >= lpgaddr);
+				aindx = svd->anon_index + seg_page(seg, a);
+				vpage = (svd->vpage != NULL) ?
+				    &svd->vpage[seg_page(seg, a)] : NULL;
+			}
+		}
+	}
+	VM_STAT_ADD(segvnvmstats.fltanpages[13]);
+	ANON_LOCK_EXIT(&amp->a_rwlock);
+	kmem_free(ppa, ppasize);
+	return (0);
+error:
+	VM_STAT_ADD(segvnvmstats.fltanpages[14]);
+	ANON_LOCK_EXIT(&amp->a_rwlock);
+	kmem_free(ppa, ppasize);
+	if (type == F_SOFTLOCK && a > lpgaddr) {
+		VM_STAT_ADD(segvnvmstats.fltanpages[15]);
+		segvn_softunlock(seg, lpgaddr, a - lpgaddr, S_OTHER);
+	}
+	return (err);
+}
+
+int fltadvice = 1;	/* set to free behind pages for sequential access */
+
+/*
+ * This routine is called via a machine specific fault handling routine.
+ * It is also called by software routines wishing to lock or unlock
+ * a range of addresses.
+ *
+ * Here is the basic algorithm:
+ *	If unlocking
+ *		Call segvn_softunlock
+ *		Return
+ *	endif
+ *	Checking and set up work
+ *	If we will need some non-anonymous pages
+ *		Call VOP_GETPAGE over the range of non-anonymous pages
+ *	endif
+ *	Loop over all addresses requested
+ *		Call segvn_faultpage passing in page list
+ *		    to load up translations and handle anonymous pages
+ *	endloop
+ *	Load up translation to any additional pages in page list not
+ *	    already handled that fit into this segment
+ */
+static faultcode_t
+segvn_fault(struct hat *hat, struct seg *seg, caddr_t addr, size_t len,
+    enum fault_type type, enum seg_rw rw)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	page_t **plp, **ppp, *pp;
+	u_offset_t off;
+	caddr_t a;
+	struct vpage *vpage;
+	uint_t vpprot, prot;
+	int err;
+	page_t *pl[PVN_GETPAGE_NUM + 1];
+	size_t plsz, pl_alloc_sz;
+	size_t page;
+	ulong_t anon_index;
+	struct anon_map *amp;
+	int dogetpage = 0;
+	caddr_t	lpgaddr, lpgeaddr;
+	size_t pgsz;
+	anon_sync_obj_t cookie;
+	int brkcow = BREAK_COW_SHARE(rw, type, svd->type);
+
+	/*
+	 * S_READ_NOCOW is like read
+	 * except caller advises no need
+	 * to copy-on-write for softlock
+	 * because it holds address space
+	 * locked as writer and thus prevents
+	 * any copy on writes of a softlocked
+	 * page by another thread.
+	 * S_READ_NOCOW vs S_READ distinction was
+	 * only needed for BREAK_COW_SHARE(). After
+	 * that we treat S_READ_NOW as just S_READ.
+	 */
+	if (rw == S_READ_NOCOW) {
+		rw = S_READ;
+		ASSERT(type == F_SOFTLOCK &&
+		    AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
+	}
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	/*
+	 * First handle the easy stuff
+	 */
+	if (type == F_SOFTUNLOCK) {
+		SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+		pgsz = (seg->s_szc == 0) ? PAGESIZE :
+		    page_get_pagesize(seg->s_szc);
+		VM_STAT_COND_ADD(pgsz > PAGESIZE, segvnvmstats.fltanpages[16]);
+		CALC_LPG_REGION(pgsz, seg, addr, len, lpgaddr, lpgeaddr);
+		segvn_softunlock(seg, lpgaddr, lpgeaddr - lpgaddr, rw);
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		return (0);
+	}
+
+top:
+	SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+
+	/*
+	 * If we have the same protections for the entire segment,
+	 * insure that the access being attempted is legitimate.
+	 */
+
+	if (svd->pageprot == 0) {
+		uint_t protchk;
+
+		switch (rw) {
+		case S_READ:
+			protchk = PROT_READ;
+			break;
+		case S_WRITE:
+			protchk = PROT_WRITE;
+			break;
+		case S_EXEC:
+			protchk = PROT_EXEC;
+			break;
+		case S_OTHER:
+		default:
+			protchk = PROT_READ | PROT_WRITE | PROT_EXEC;
+			break;
+		}
+
+		if ((svd->prot & protchk) == 0) {
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (FC_PROT);	/* illegal access type */
+		}
+	}
+
+	/*
+	 * Check to see if we need to allocate an anon_map structure.
+	 */
+	if (svd->amp == NULL && (svd->vp == NULL || brkcow)) {
+		/*
+		 * Drop the "read" lock on the segment and acquire
+		 * the "write" version since we have to allocate the
+		 * anon_map.
+		 */
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_WRITER);
+
+		if (svd->amp == NULL) {
+			svd->amp = anonmap_alloc(seg->s_size, 0);
+			svd->amp->a_szc = seg->s_szc;
+		}
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+
+		/*
+		 * Start all over again since segment protections
+		 * may have changed after we dropped the "read" lock.
+		 */
+		goto top;
+	}
+
+	amp = svd->amp;
+
+	/*
+	 * MADV_SEQUENTIAL work is ignored for large page segments.
+	 */
+	if (seg->s_szc != 0) {
+		pgsz = page_get_pagesize(seg->s_szc);
+		ASSERT(SEGVN_LOCK_HELD(seg->s_as, &svd->lock));
+		/*
+		 * We may need to do relocations so purge seg_pcache to allow
+		 * pages to be locked exclusively.
+		 */
+		if (svd->softlockcnt != 0)
+			segvn_purge(seg);
+		CALC_LPG_REGION(pgsz, seg, addr, len, lpgaddr, lpgeaddr);
+		if (svd->vp == NULL) {
+			ASSERT(svd->type == MAP_PRIVATE);
+			err = segvn_fault_anonpages(hat, seg, lpgaddr,
+			    lpgeaddr, type, rw, addr, addr + len, brkcow);
+		} else {
+			err = segvn_fault_vnodepages(hat, seg, lpgaddr,
+				lpgeaddr, type, rw, addr, addr + len, brkcow);
+			if (err == IE_RETRY) {
+				ASSERT(seg->s_szc == 0);
+				ASSERT(SEGVN_READ_HELD(seg->s_as, &svd->lock));
+				goto cont;
+			}
+		}
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		return (err);
+	}
+
+cont:
+	page = seg_page(seg, addr);
+	if (amp != NULL) {
+		anon_index = svd->anon_index + page;
+
+		if ((type == F_PROT) && (rw == S_READ) &&
+		    svd->type == MAP_PRIVATE && svd->pageprot == 0) {
+			size_t index = anon_index;
+			struct anon *ap;
+
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+			/*
+			 * The fast path could apply to S_WRITE also, except
+			 * that the protection fault could be caused by lazy
+			 * tlb flush when ro->rw. In this case, the pte is
+			 * RW already. But RO in the other cpu's tlb causes
+			 * the fault. Since hat_chgprot won't do anything if
+			 * pte doesn't change, we may end up faulting
+			 * indefinitely until the RO tlb entry gets replaced.
+			 */
+			for (a = addr; a < addr + len; a += PAGESIZE, index++) {
+				anon_array_enter(amp, index, &cookie);
+				ap = anon_get_ptr(amp->ahp, index);
+				anon_array_exit(&cookie);
+				if ((ap == NULL) || (ap->an_refcnt != 1)) {
+					ANON_LOCK_EXIT(&amp->a_rwlock);
+					goto slow;
+				}
+			}
+			hat_chgprot(seg->s_as->a_hat, addr, len, svd->prot);
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (0);
+		}
+	}
+slow:
+
+	if (svd->vpage == NULL)
+		vpage = NULL;
+	else
+		vpage = &svd->vpage[page];
+
+	off = svd->offset + (uintptr_t)(addr - seg->s_base);
+
+	/*
+	 * If MADV_SEQUENTIAL has been set for the particular page we
+	 * are faulting on, free behind all pages in the segment and put
+	 * them on the free list.
+	 */
+	if ((page != 0) && fltadvice) {	/* not if first page in segment */
+		struct vpage *vpp;
+		ulong_t fanon_index;
+		size_t fpage;
+		u_offset_t pgoff, fpgoff;
+		struct vnode *fvp;
+		struct anon *fap = NULL;
+
+		if (svd->advice == MADV_SEQUENTIAL ||
+		    (svd->pageadvice &&
+		    VPP_ADVICE(vpage) == MADV_SEQUENTIAL)) {
+			pgoff = off - PAGESIZE;
+			fpage = page - 1;
+			if (vpage != NULL)
+				vpp = &svd->vpage[fpage];
+			if (amp != NULL)
+				fanon_index = svd->anon_index + fpage;
+
+			while (pgoff > svd->offset) {
+				if (svd->advice != MADV_SEQUENTIAL &&
+				    (!svd->pageadvice || (vpage &&
+				    VPP_ADVICE(vpp) != MADV_SEQUENTIAL)))
+					break;
+
+				/*
+				 * If this is an anon page, we must find the
+				 * correct <vp, offset> for it
+				 */
+				fap = NULL;
+				if (amp != NULL) {
+					ANON_LOCK_ENTER(&amp->a_rwlock,
+						RW_READER);
+					anon_array_enter(amp, fanon_index,
+						&cookie);
+					fap = anon_get_ptr(amp->ahp,
+					    fanon_index);
+					if (fap != NULL) {
+						swap_xlate(fap, &fvp, &fpgoff);
+					} else {
+						fpgoff = pgoff;
+						fvp = svd->vp;
+					}
+					anon_array_exit(&cookie);
+					ANON_LOCK_EXIT(&amp->a_rwlock);
+				} else {
+					fpgoff = pgoff;
+					fvp = svd->vp;
+				}
+				if (fvp == NULL)
+					break;	/* XXX */
+				/*
+				 * Skip pages that are free or have an
+				 * "exclusive" lock.
+				 */
+				pp = page_lookup_nowait(fvp, fpgoff, SE_SHARED);
+				if (pp == NULL)
+					break;
+				/*
+				 * We don't need the page_struct_lock to test
+				 * as this is only advisory; even if we
+				 * acquire it someone might race in and lock
+				 * the page after we unlock and before the
+				 * PUTPAGE, then VOP_PUTPAGE will do nothing.
+				 */
+				if (pp->p_lckcnt == 0 && pp->p_cowcnt == 0) {
+					/*
+					 * Hold the vnode before releasing
+					 * the page lock to prevent it from
+					 * being freed and re-used by some
+					 * other thread.
+					 */
+					VN_HOLD(fvp);
+					page_unlock(pp);
+					/*
+					 * We should build a page list
+					 * to kluster putpages XXX
+					 */
+					(void) VOP_PUTPAGE(fvp,
+					    (offset_t)fpgoff, PAGESIZE,
+					    (B_DONTNEED|B_FREE|B_ASYNC),
+					    svd->cred);
+					VN_RELE(fvp);
+				} else {
+					/*
+					 * XXX - Should the loop terminate if
+					 * the page is `locked'?
+					 */
+					page_unlock(pp);
+				}
+				--vpp;
+				--fanon_index;
+				pgoff -= PAGESIZE;
+			}
+		}
+	}
+
+	plp = pl;
+	*plp = NULL;
+	pl_alloc_sz = 0;
+
+	/*
+	 * See if we need to call VOP_GETPAGE for
+	 * *any* of the range being faulted on.
+	 * We can skip all of this work if there
+	 * was no original vnode.
+	 */
+	if (svd->vp != NULL) {
+		u_offset_t vp_off;
+		size_t vp_len;
+		struct anon *ap;
+		vnode_t *vp;
+
+		vp_off = off;
+		vp_len = len;
+
+		if (amp == NULL)
+			dogetpage = 1;
+		else {
+			/*
+			 * Only acquire reader lock to prevent amp->ahp
+			 * from being changed.  It's ok to miss pages,
+			 * hence we don't do anon_array_enter
+			 */
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+			ap = anon_get_ptr(amp->ahp, anon_index);
+
+			if (len <= PAGESIZE)
+				/* inline non_anon() */
+				dogetpage = (ap == NULL);
+			else
+				dogetpage = non_anon(amp->ahp, anon_index,
+				    &vp_off, &vp_len);
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+		}
+
+		if (dogetpage) {
+			enum seg_rw arw;
+			struct as *as = seg->s_as;
+
+			if (len > ptob((sizeof (pl) / sizeof (pl[0])) - 1)) {
+				/*
+				 * Page list won't fit in local array,
+				 * allocate one of the needed size.
+				 */
+				pl_alloc_sz =
+				    (btop(len) + 1) * sizeof (page_t *);
+				plp = kmem_alloc(pl_alloc_sz, KM_SLEEP);
+				plp[0] = NULL;
+				plsz = len;
+			} else if (rw == S_WRITE && svd->type == MAP_PRIVATE ||
+			    rw == S_OTHER ||
+			    (((size_t)(addr + PAGESIZE) <
+			    (size_t)(seg->s_base + seg->s_size)) &&
+			    hat_probe(as->a_hat, addr + PAGESIZE))) {
+				/*
+				 * Ask VOP_GETPAGE to return the exact number
+				 * of pages if
+				 * (a) this is a COW fault, or
+				 * (b) this is a software fault, or
+				 * (c) next page is already mapped.
+				 */
+				plsz = len;
+			} else {
+				/*
+				 * Ask VOP_GETPAGE to return adjacent pages
+				 * within the segment.
+				 */
+				plsz = MIN((size_t)PVN_GETPAGE_SZ, (size_t)
+					((seg->s_base + seg->s_size) - addr));
+				ASSERT((addr + plsz) <=
+				    (seg->s_base + seg->s_size));
+			}
+
+			/*
+			 * Need to get some non-anonymous pages.
+			 * We need to make only one call to GETPAGE to do
+			 * this to prevent certain deadlocking conditions
+			 * when we are doing locking.  In this case
+			 * non_anon() should have picked up the smallest
+			 * range which includes all the non-anonymous
+			 * pages in the requested range.  We have to
+			 * be careful regarding which rw flag to pass in
+			 * because on a private mapping, the underlying
+			 * object is never allowed to be written.
+			 */
+			if (rw == S_WRITE && svd->type == MAP_PRIVATE) {
+				arw = S_READ;
+			} else {
+				arw = rw;
+			}
+			vp = svd->vp;
+			TRACE_3(TR_FAC_VM, TR_SEGVN_GETPAGE,
+				"segvn_getpage:seg %p addr %p vp %p",
+				seg, addr, vp);
+			err = VOP_GETPAGE(vp, (offset_t)vp_off, vp_len,
+			    &vpprot, plp, plsz, seg, addr + (vp_off - off), arw,
+			    svd->cred);
+			if (err) {
+				SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+				segvn_pagelist_rele(plp);
+				if (pl_alloc_sz)
+					kmem_free(plp, pl_alloc_sz);
+				return (FC_MAKE_ERR(err));
+			}
+			if (svd->type == MAP_PRIVATE)
+				vpprot &= ~PROT_WRITE;
+		}
+	}
+
+	/*
+	 * N.B. at this time the plp array has all the needed non-anon
+	 * pages in addition to (possibly) having some adjacent pages.
+	 */
+
+	/*
+	 * Always acquire the anon_array_lock to prevent
+	 * 2 threads from allocating separate anon slots for
+	 * the same "addr".
+	 *
+	 * If this is a copy-on-write fault and we don't already
+	 * have the anon_array_lock, acquire it to prevent the
+	 * fault routine from handling multiple copy-on-write faults
+	 * on the same "addr" in the same address space.
+	 *
+	 * Only one thread should deal with the fault since after
+	 * it is handled, the other threads can acquire a translation
+	 * to the newly created private page.  This prevents two or
+	 * more threads from creating different private pages for the
+	 * same fault.
+	 *
+	 * We grab "serialization" lock here if this is a MAP_PRIVATE segment
+	 * to prevent deadlock between this thread and another thread
+	 * which has soft-locked this page and wants to acquire serial_lock.
+	 * ( bug 4026339 )
+	 *
+	 * The fix for bug 4026339 becomes unnecessary when using the
+	 * locking scheme with per amp rwlock and a global set of hash
+	 * lock, anon_array_lock.  If we steal a vnode page when low
+	 * on memory and upgrad the page lock through page_rename,
+	 * then the page is PAGE_HANDLED, nothing needs to be done
+	 * for this page after returning from segvn_faultpage.
+	 *
+	 * But really, the page lock should be downgraded after
+	 * the stolen page is page_rename'd.
+	 */
+
+	if (amp != NULL)
+		ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+
+	/*
+	 * Ok, now loop over the address range and handle faults
+	 */
+	for (a = addr; a < addr + len; a += PAGESIZE, off += PAGESIZE) {
+		err = segvn_faultpage(hat, seg, a, off, vpage, plp, vpprot,
+		    type, rw, brkcow);
+		if (err) {
+			if (amp != NULL)
+				ANON_LOCK_EXIT(&amp->a_rwlock);
+			if (type == F_SOFTLOCK && a > addr)
+				segvn_softunlock(seg, addr, (a - addr),
+				    S_OTHER);
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			segvn_pagelist_rele(plp);
+			if (pl_alloc_sz)
+				kmem_free(plp, pl_alloc_sz);
+			return (err);
+		}
+		if (vpage) {
+			vpage++;
+		} else if (svd->vpage) {
+			page = seg_page(seg, addr);
+			vpage = &svd->vpage[++page];
+		}
+	}
+
+	/* Didn't get pages from the underlying fs so we're done */
+	if (!dogetpage)
+		goto done;
+
+	/*
+	 * Now handle any other pages in the list returned.
+	 * If the page can be used, load up the translations now.
+	 * Note that the for loop will only be entered if "plp"
+	 * is pointing to a non-NULL page pointer which means that
+	 * VOP_GETPAGE() was called and vpprot has been initialized.
+	 */
+	if (svd->pageprot == 0)
+		prot = svd->prot & vpprot;
+
+
+	/*
+	 * Large Files: diff should be unsigned value because we started
+	 * supporting > 2GB segment sizes from 2.5.1 and when a
+	 * large file of size > 2GB gets mapped to address space
+	 * the diff value can be > 2GB.
+	 */
+
+	for (ppp = plp; (pp = *ppp) != NULL; ppp++) {
+		size_t diff;
+		struct anon *ap;
+		int anon_index;
+		anon_sync_obj_t cookie;
+		int hat_flag = HAT_LOAD_ADV;
+
+		if (svd->flags & MAP_TEXT) {
+			hat_flag |= HAT_LOAD_TEXT;
+		}
+
+		if (pp == PAGE_HANDLED)
+			continue;
+
+		if (pp->p_offset >=  svd->offset &&
+			(pp->p_offset < svd->offset + seg->s_size)) {
+
+			diff = pp->p_offset - svd->offset;
+
+			/*
+			 * Large Files: Following is the assertion
+			 * validating the above cast.
+			 */
+			ASSERT(svd->vp == pp->p_vnode);
+
+			page = btop(diff);
+			if (svd->pageprot)
+				prot = VPP_PROT(&svd->vpage[page]) & vpprot;
+
+			/*
+			 * Prevent other threads in the address space from
+			 * creating private pages (i.e., allocating anon slots)
+			 * while we are in the process of loading translations
+			 * to additional pages returned by the underlying
+			 * object.
+			 */
+			if (amp != NULL) {
+				anon_index = svd->anon_index + page;
+				anon_array_enter(amp, anon_index, &cookie);
+				ap = anon_get_ptr(amp->ahp, anon_index);
+			}
+			if ((amp == NULL) || (ap == NULL)) {
+				if (IS_VMODSORT(pp->p_vnode) ||
+				    enable_mbit_wa) {
+					if (rw == S_WRITE)
+						hat_setmod(pp);
+					else if (rw != S_OTHER &&
+					    !hat_ismod(pp))
+						prot &= ~PROT_WRITE;
+				}
+				/*
+				 * Skip mapping read ahead pages marked
+				 * for migration, so they will get migrated
+				 * properly on fault
+				 */
+				if ((prot & PROT_READ) && !PP_ISMIGRATE(pp)) {
+					hat_memload(hat, seg->s_base + diff,
+						pp, prot, hat_flag);
+				}
+			}
+			if (amp != NULL)
+				anon_array_exit(&cookie);
+		}
+		page_unlock(pp);
+	}
+done:
+	if (amp != NULL)
+		ANON_LOCK_EXIT(&amp->a_rwlock);
+	SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+	if (pl_alloc_sz)
+		kmem_free(plp, pl_alloc_sz);
+	return (0);
+}
+
+/*
+ * This routine is used to start I/O on pages asynchronously.  XXX it will
+ * only create PAGESIZE pages. At fault time they will be relocated into
+ * larger pages.
+ */
+static faultcode_t
+segvn_faulta(struct seg *seg, caddr_t addr)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	int err;
+	struct anon_map *amp;
+	vnode_t *vp;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+	if ((amp = svd->amp) != NULL) {
+		struct anon *ap;
+
+		/*
+		 * Reader lock to prevent amp->ahp from being changed.
+		 * This is advisory, it's ok to miss a page, so
+		 * we don't do anon_array_enter lock.
+		 */
+		ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+		if ((ap = anon_get_ptr(amp->ahp,
+			svd->anon_index + seg_page(seg, addr))) != NULL) {
+
+			err = anon_getpage(&ap, NULL, NULL,
+			    0, seg, addr, S_READ, svd->cred);
+
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			if (err)
+				return (FC_MAKE_ERR(err));
+			return (0);
+		}
+		ANON_LOCK_EXIT(&amp->a_rwlock);
+	}
+
+	if (svd->vp == NULL) {
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		return (0);			/* zfod page - do nothing now */
+	}
+
+	vp = svd->vp;
+	TRACE_3(TR_FAC_VM, TR_SEGVN_GETPAGE,
+		"segvn_getpage:seg %p addr %p vp %p", seg, addr, vp);
+	err = VOP_GETPAGE(vp,
+	    (offset_t)(svd->offset + (uintptr_t)(addr - seg->s_base)),
+	    PAGESIZE, NULL, NULL, 0, seg, addr,
+	    S_OTHER, svd->cred);
+
+	SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+	if (err)
+		return (FC_MAKE_ERR(err));
+	return (0);
+}
+
+static int
+segvn_setprot(struct seg *seg, caddr_t addr, size_t len, uint_t prot)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct vpage *svp, *evp;
+	struct vnode *vp;
+	size_t pgsz;
+	pgcnt_t pgcnt;
+	anon_sync_obj_t cookie;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	if ((svd->maxprot & prot) != prot)
+		return (EACCES);			/* violated maxprot */
+
+	SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_WRITER);
+
+	/* return if prot is the same */
+	if (!svd->pageprot && svd->prot == prot) {
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		return (0);
+	}
+
+	/*
+	 * Since we change protections we first have to flush the cache.
+	 * This makes sure all the pagelock calls have to recheck
+	 * protections.
+	 */
+	if (svd->softlockcnt > 0) {
+		/*
+		 * Since we do have the segvn writers lock nobody can fill
+		 * the cache with entries belonging to this seg during
+		 * the purge. The flush either succeeds or we still have
+		 * pending I/Os.
+		 */
+		segvn_purge(seg);
+		if (svd->softlockcnt > 0) {
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (EAGAIN);
+		}
+	}
+
+	if (seg->s_szc != 0) {
+		int err;
+		pgsz = page_get_pagesize(seg->s_szc);
+		pgcnt = pgsz >> PAGESHIFT;
+		ASSERT(IS_P2ALIGNED(pgcnt, pgcnt));
+		if (!IS_P2ALIGNED(addr, pgsz) || !IS_P2ALIGNED(len, pgsz)) {
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			ASSERT(seg->s_base != addr || seg->s_size != len);
+			/*
+			 * If we are holding the as lock as a reader then
+			 * we need to return IE_RETRY and let the as
+			 * layer drop and re-aquire the lock as a writer.
+			 */
+			if (AS_READ_HELD(seg->s_as, &seg->s_as->a_lock))
+				return (IE_RETRY);
+			VM_STAT_ADD(segvnvmstats.demoterange[1]);
+			err = segvn_demote_range(seg, addr, len, SDR_END);
+			if (err == 0)
+				return (IE_RETRY);
+			if (err == ENOMEM)
+				return (IE_NOMEM);
+			return (err);
+		}
+	}
+
+
+	/*
+	 * If it's a private mapping and we're making it writable
+	 * and no swap space has been reserved, have to reserve
+	 * it all now.  If it's a private mapping to a file (i.e., vp != NULL)
+	 * and we're removing write permission on the entire segment and
+	 * we haven't modified any pages, we can release the swap space.
+	 */
+	if (svd->type == MAP_PRIVATE) {
+		if (prot & PROT_WRITE) {
+			size_t sz;
+			if (svd->swresv == 0 && !(svd->flags & MAP_NORESERVE)) {
+				if (anon_resv(seg->s_size) == 0) {
+					SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+					return (IE_NOMEM);
+				}
+				sz = svd->swresv = seg->s_size;
+				TRACE_3(TR_FAC_VM, TR_ANON_PROC,
+					"anon proc:%p %lu %u",
+					seg, sz, 1);
+			}
+		} else {
+			/*
+			 * Swap space is released only if this segment
+			 * does not map anonymous memory, since read faults
+			 * on such segments still need an anon slot to read
+			 * in the data.
+			 */
+			if (svd->swresv != 0 && svd->vp != NULL &&
+			    svd->amp == NULL && addr == seg->s_base &&
+			    len == seg->s_size && svd->pageprot == 0) {
+				anon_unresv(svd->swresv);
+				svd->swresv = 0;
+				TRACE_3(TR_FAC_VM, TR_ANON_PROC,
+					"anon proc:%p %lu %u",
+					seg, 0, 0);
+			}
+		}
+	}
+
+	if (addr == seg->s_base && len == seg->s_size && svd->pageprot == 0) {
+		if (svd->prot == prot) {
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (0);			/* all done */
+		}
+		svd->prot = (uchar_t)prot;
+	} else {
+		struct anon *ap = NULL;
+		page_t *pp;
+		u_offset_t offset, off;
+		struct anon_map *amp;
+		ulong_t anon_idx = 0;
+
+		/*
+		 * A vpage structure exists or else the change does not
+		 * involve the entire segment.  Establish a vpage structure
+		 * if none is there.  Then, for each page in the range,
+		 * adjust its individual permissions.  Note that write-
+		 * enabling a MAP_PRIVATE page can affect the claims for
+		 * locked down memory.  Overcommitting memory terminates
+		 * the operation.
+		 */
+		segvn_vpage(seg);
+		if ((amp = svd->amp) != NULL) {
+			anon_idx = svd->anon_index + seg_page(seg, addr);
+			ASSERT(seg->s_szc == 0 ||
+			    IS_P2ALIGNED(anon_idx, pgcnt));
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+		}
+
+		offset = svd->offset + (uintptr_t)(addr - seg->s_base);
+		evp = &svd->vpage[seg_page(seg, addr + len)];
+
+		/*
+		 * See Statement at the beginning of segvn_lockop regarding
+		 * the way cowcnts and lckcnts are handled.
+		 */
+		for (svp = &svd->vpage[seg_page(seg, addr)]; svp < evp; svp++) {
+
+			ASSERT(seg->s_szc == 0 ||
+			    (svd->vp != NULL || svd->type == MAP_PRIVATE));
+
+			if (seg->s_szc != 0 && svd->type == MAP_PRIVATE) {
+				if (amp != NULL) {
+					anon_array_enter(amp, anon_idx,
+					    &cookie);
+				}
+				if (IS_P2ALIGNED(anon_idx, pgcnt) &&
+				    !segvn_claim_pages(seg, svp, offset,
+					anon_idx, prot)) {
+					if (amp != NULL) {
+						anon_array_exit(&cookie);
+					}
+					break;
+				}
+				if (amp != NULL) {
+					anon_array_exit(&cookie);
+				}
+				anon_idx++;
+			} else {
+				if (amp != NULL) {
+					anon_array_enter(amp, anon_idx,
+						&cookie);
+					ap = anon_get_ptr(amp->ahp, anon_idx++);
+				}
+
+				if (VPP_ISPPLOCK(svp) &&
+				    (VPP_PROT(svp) != prot) &&
+				    (svd->type == MAP_PRIVATE)) {
+
+					if (amp == NULL || ap == NULL) {
+						vp = svd->vp;
+						off = offset;
+					} else
+						swap_xlate(ap, &vp, &off);
+					if (amp != NULL)
+						anon_array_exit(&cookie);
+
+					if ((pp = page_lookup(vp, off,
+					    SE_SHARED)) == NULL) {
+						panic("segvn_setprot: no page");
+						/*NOTREACHED*/
+					}
+					ASSERT(seg->s_szc == 0);
+					if ((VPP_PROT(svp) ^ prot) &
+					    PROT_WRITE) {
+						if (prot & PROT_WRITE) {
+						    if (!page_addclaim(pp)) {
+							page_unlock(pp);
+							break;
+						    }
+						} else {
+						    if (!page_subclaim(pp)) {
+							page_unlock(pp);
+							break;
+						    }
+						}
+					}
+					page_unlock(pp);
+				} else if (amp != NULL)
+					anon_array_exit(&cookie);
+			}
+			VPP_SETPROT(svp, prot);
+			offset += PAGESIZE;
+		}
+		if (amp != NULL)
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+
+		/*
+		 * Did we terminate prematurely?  If so, simply unload
+		 * the translations to the things we've updated so far.
+		 */
+		if (svp != evp) {
+			len = (svp - &svd->vpage[seg_page(seg, addr)]) *
+			    PAGESIZE;
+			ASSERT(seg->s_szc == 0 || IS_P2ALIGNED(len, pgsz));
+			if (len != 0)
+				hat_unload(seg->s_as->a_hat, addr,
+				    len, HAT_UNLOAD);
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (IE_NOMEM);
+		}
+	}
+
+	if ((prot & PROT_WRITE) != 0 || (prot & ~PROT_USER) == PROT_NONE) {
+		/*
+		 * Either private or shared data with write access (in
+		 * which case we need to throw out all former translations
+		 * so that we get the right translations set up on fault
+		 * and we don't allow write access to any copy-on-write pages
+		 * that might be around or to prevent write access to pages
+		 * representing holes in a file), or we don't have permission
+		 * to access the memory at all (in which case we have to
+		 * unload any current translations that might exist).
+		 */
+		hat_unload(seg->s_as->a_hat, addr, len, HAT_UNLOAD);
+	} else {
+		/*
+		 * A shared mapping or a private mapping in which write
+		 * protection is going to be denied - just change all the
+		 * protections over the range of addresses in question.
+		 * segvn does not support any other attributes other
+		 * than prot so we can use hat_chgattr.
+		 */
+		hat_chgattr(seg->s_as->a_hat, addr, len, prot);
+	}
+
+	SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+
+	return (0);
+}
+
+/*
+ * segvn_setpagesize is called via SEGOP_SETPAGESIZE from as_setpagesize,
+ * to determine if the seg is capable of mapping the requested szc.
+ */
+static int
+segvn_setpagesize(struct seg *seg, caddr_t addr, size_t len, uint_t szc)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct segvn_data *nsvd;
+	struct anon_map *amp = svd->amp;
+	struct seg *nseg;
+	caddr_t eaddr = addr + len, a;
+	size_t pgsz = page_get_pagesize(szc);
+	int err;
+	u_offset_t off = svd->offset + (uintptr_t)(addr - seg->s_base);
+	extern struct vnode kvp;
+
+	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
+	ASSERT(addr >= seg->s_base && eaddr <= seg->s_base + seg->s_size);
+
+	if (seg->s_szc == szc || segvn_lpg_disable != 0) {
+		return (0);
+	}
+
+	/*
+	 * addr should always be pgsz aligned but eaddr may be misaligned if
+	 * it's at the end of the segment.
+	 *
+	 * XXX we should assert this condition since as_setpagesize() logic
+	 * guarantees it.
+	 */
+	if (!IS_P2ALIGNED(addr, pgsz) ||
+	    (!IS_P2ALIGNED(eaddr, pgsz) &&
+		eaddr != seg->s_base + seg->s_size)) {
+
+		segvn_setpgsz_align_err++;
+		return (EINVAL);
+	}
+
+	if ((svd->vp == NULL && svd->type == MAP_SHARED) ||
+	    (svd->flags & MAP_NORESERVE) || seg->s_as == &kas ||
+	    szc > segvn_maxpgszc) {
+		return (EINVAL);
+	}
+
+	/* paranoid check */
+	if (svd->vp != NULL &&
+	    (IS_SWAPFSVP(svd->vp) || svd->vp == &kvp)) {
+		    return (EINVAL);
+	}
+
+	if (seg->s_szc == 0 && svd->vp != NULL &&
+	    map_addr_vacalign_check(addr, off)) {
+		return (EINVAL);
+	}
+
+	/*
+	 * Check that protections are the same within new page
+	 * size boundaries.
+	 */
+	if (svd->pageprot) {
+		for (a = addr; a < eaddr; a += pgsz) {
+			if ((a + pgsz) > eaddr) {
+				if (!sameprot(seg, a, eaddr - a)) {
+					return (EINVAL);
+				}
+			} else {
+				if (!sameprot(seg, a, pgsz)) {
+					return (EINVAL);
+				}
+			}
+		}
+	}
+
+	/*
+	 * Since we are changing page size we first have to flush
+	 * the cache. This makes sure all the pagelock calls have
+	 * to recheck protections.
+	 */
+	if (svd->softlockcnt > 0) {
+		/*
+		 * Since we do have the segvn writers lock nobody can fill
+		 * the cache with entries belonging to this seg during
+		 * the purge. The flush either succeeds or we still have
+		 * pending I/Os.
+		 */
+		segvn_purge(seg);
+		if (svd->softlockcnt > 0) {
+			return (EAGAIN);
+		}
+	}
+
+	/*
+	 * Operation for sub range of existing segment.
+	 */
+	if (addr != seg->s_base || eaddr != (seg->s_base + seg->s_size)) {
+		if (szc < seg->s_szc) {
+			VM_STAT_ADD(segvnvmstats.demoterange[2]);
+			err = segvn_demote_range(seg, addr, len, SDR_RANGE);
+			if (err == 0) {
+				return (IE_RETRY);
+			}
+			if (err == ENOMEM) {
+				return (IE_NOMEM);
+			}
+			return (err);
+		}
+		if (addr != seg->s_base) {
+			nseg = segvn_split_seg(seg, addr);
+			if (eaddr != (nseg->s_base + nseg->s_size)) {
+				/* eaddr is szc aligned */
+				(void) segvn_split_seg(nseg, eaddr);
+			}
+			return (IE_RETRY);
+		}
+		if (eaddr != (seg->s_base + seg->s_size)) {
+			/* eaddr is szc aligned */
+			(void) segvn_split_seg(seg, eaddr);
+		}
+		return (IE_RETRY);
+	}
+
+	/*
+	 * Break any low level sharing and reset seg->s_szc to 0.
+	 */
+	if ((err = segvn_clrszc(seg)) != 0) {
+		if (err == ENOMEM) {
+			err = IE_NOMEM;
+		}
+		return (err);
+	}
+	ASSERT(seg->s_szc == 0);
+
+	/*
+	 * If the end of the current segment is not pgsz aligned
+	 * then attempt to concatenate with the next segment.
+	 */
+	if (!IS_P2ALIGNED(eaddr, pgsz)) {
+		nseg = AS_SEGNEXT(seg->s_as, seg);
+		if (nseg == NULL || nseg == seg || eaddr != nseg->s_base) {
+			return (ENOMEM);
+		}
+		if (nseg->s_ops != &segvn_ops) {
+			return (EINVAL);
+		}
+		nsvd = (struct segvn_data *)nseg->s_data;
+		if (nsvd->softlockcnt > 0) {
+			segvn_purge(nseg);
+			if (nsvd->softlockcnt > 0) {
+				return (EAGAIN);
+			}
+		}
+		err = segvn_clrszc(nseg);
+		if (err == ENOMEM) {
+			err = IE_NOMEM;
+		}
+		if (err != 0) {
+			return (err);
+		}
+		err = segvn_concat(seg, nseg, 1);
+		if (err == -1) {
+			return (EINVAL);
+		}
+		if (err == -2) {
+			return (IE_NOMEM);
+		}
+		return (IE_RETRY);
+	}
+
+	/*
+	 * May need to re-align anon array to
+	 * new szc.
+	 */
+	if (amp != NULL) {
+		pgcnt_t pgcnt = pgsz >> PAGESHIFT;
+		if (!IS_P2ALIGNED(svd->anon_index, pgcnt)) {
+			struct anon_hdr *nahp;
+
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
+			ASSERT(amp->refcnt == 1);
+			nahp = anon_create(btop(amp->size), ANON_NOSLEEP);
+			if (nahp == NULL) {
+				ANON_LOCK_EXIT(&amp->a_rwlock);
+				return (IE_NOMEM);
+			}
+			if (anon_copy_ptr(amp->ahp, svd->anon_index,
+				nahp, 0, btop(seg->s_size), ANON_NOSLEEP)) {
+				anon_release(nahp, btop(amp->size));
+				ANON_LOCK_EXIT(&amp->a_rwlock);
+				return (IE_NOMEM);
+			}
+			anon_release(amp->ahp, btop(amp->size));
+			amp->ahp = nahp;
+			svd->anon_index = 0;
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+		}
+	}
+	if (svd->vp != NULL && szc != 0) {
+		struct vattr va;
+		u_offset_t eoffpage = svd->offset;
+		va.va_mask = AT_SIZE;
+		eoffpage += seg->s_size;
+		eoffpage = btopr(eoffpage);
+		if (VOP_GETATTR(svd->vp, &va, 0, svd->cred) != 0) {
+			segvn_setpgsz_getattr_err++;
+			return (EINVAL);
+		}
+		if (btopr(va.va_size) < eoffpage) {
+			segvn_setpgsz_eof_err++;
+			return (EINVAL);
+		}
+		if (amp != NULL) {
+			/*
+			 * anon_fill_cow_holes() may call VOP_GETPAGE().
+			 * don't take anon map lock here to avoid holding it
+			 * across VOP_GETPAGE() calls that may call back into
+			 * segvn for klsutering checks. We don't really need
+			 * anon map lock here since it's a private segment and
+			 * we hold as level lock as writers.
+			 */
+			if ((err = anon_fill_cow_holes(seg, seg->s_base,
+			    amp->ahp, svd->anon_index, svd->vp, svd->offset,
+			    seg->s_size, szc, svd->prot, svd->vpage,
+			    svd->cred)) != 0) {
+				return (EINVAL);
+			}
+		}
+		segvn_setvnode_mpss(svd->vp);
+	}
+
+	if (amp != NULL) {
+		ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
+		amp->a_szc = szc;
+		ANON_LOCK_EXIT(&amp->a_rwlock);
+	}
+
+	seg->s_szc = szc;
+
+	return (0);
+}
+
+static int
+segvn_clrszc(struct seg *seg)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct anon_map *amp = svd->amp;
+	size_t pgsz;
+	pgcnt_t pages;
+	int err = 0;
+	caddr_t a = seg->s_base;
+	caddr_t ea = a + seg->s_size;
+	ulong_t an_idx = svd->anon_index;
+	vnode_t *vp = svd->vp;
+	struct vpage *vpage = svd->vpage;
+	page_t *anon_pl[1 + 1], *pp;
+	struct anon *ap, *oldap;
+	uint_t prot = svd->prot, vpprot;
+
+	ASSERT(AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock) ||
+	    SEGVN_WRITE_HELD(seg->s_as, &svd->lock));
+	ASSERT(svd->type == MAP_PRIVATE ||
+	    (vp != NULL && svd->amp == NULL));
+
+	if (vp == NULL && amp == NULL) {
+		seg->s_szc = 0;
+		return (0);
+	}
+
+	/*
+	 * do HAT_UNLOAD_UNMAP since we are changing the pagesize.
+	 * unload argument is 0 when we are freeing the segment
+	 * and unload was already done.
+	 */
+	hat_unload(seg->s_as->a_hat, seg->s_base, seg->s_size,
+	    HAT_UNLOAD_UNMAP);
+
+	if (amp == NULL) {
+		seg->s_szc = 0;
+		return (0);
+	}
+
+	pgsz = page_get_pagesize(seg->s_szc);
+	pages = btop(pgsz);
+
+	/*
+	 * XXX anon rwlock is not really needed because this is a
+	 * private segment and we are writers.
+	 */
+	ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
+
+	for (; a < ea; a += pgsz, an_idx += pages) {
+		if ((oldap = anon_get_ptr(amp->ahp, an_idx)) != NULL) {
+			if (svd->pageprot != 0) {
+				ASSERT(vpage != NULL);
+				prot = VPP_PROT(vpage);
+				ASSERT(sameprot(seg, a, pgsz));
+			}
+			if (seg->s_szc != 0) {
+				ASSERT(vp == NULL || anon_pages(amp->ahp,
+				    an_idx, pages) == pages);
+				if ((err = anon_map_demotepages(amp, an_idx,
+				    seg, a, prot, vpage, svd->cred)) != 0) {
+					goto out;
+				}
+			} else {
+				if (oldap->an_refcnt == 1) {
+					continue;
+				}
+				if ((err = anon_getpage(&oldap, &vpprot,
+				    anon_pl, PAGESIZE, seg, a, S_READ,
+				    svd->cred))) {
+					goto out;
+				}
+				if ((pp = anon_private(&ap, seg, a, prot,
+				    anon_pl[0], 0, svd->cred)) == NULL) {
+					err = ENOMEM;
+					goto out;
+				}
+				anon_decref(oldap);
+				(void) anon_set_ptr(amp->ahp, an_idx, ap,
+				    ANON_SLEEP);
+				page_unlock(pp);
+			}
+		}
+		vpage = (vpage == NULL) ? NULL : vpage + pages;
+	}
+
+	amp->a_szc = 0;
+	seg->s_szc = 0;
+out:
+	ANON_LOCK_EXIT(&amp->a_rwlock);
+	return (err);
+}
+
+static int
+segvn_claim_pages(
+	struct seg *seg,
+	struct vpage *svp,
+	u_offset_t off,
+	ulong_t anon_idx,
+	uint_t prot)
+{
+	pgcnt_t	pgcnt = page_get_pagecnt(seg->s_szc);
+	size_t ppasize = (pgcnt + 1) * sizeof (page_t *);
+	page_t	**ppa;
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct anon_map *amp = svd->amp;
+	struct vpage *evp = svp + pgcnt;
+	caddr_t addr = ((uintptr_t)(svp - svd->vpage) << PAGESHIFT)
+	    + seg->s_base;
+	struct anon *ap;
+	struct vnode *vp = svd->vp;
+	page_t *pp;
+	pgcnt_t pg_idx, i;
+	int err = 0;
+	anoff_t	aoff;
+	int anon = (amp != NULL) ? 1 : 0;
+
+	ASSERT(svd->type == MAP_PRIVATE);
+	ASSERT(svd->vpage != NULL);
+	ASSERT(seg->s_szc != 0);
+	ASSERT(IS_P2ALIGNED(pgcnt, pgcnt));
+	ASSERT(amp == NULL || IS_P2ALIGNED(anon_idx, pgcnt));
+	ASSERT(sameprot(seg, addr, pgcnt << PAGESHIFT));
+
+	if (VPP_PROT(svp) == prot)
+		return (1);
+	if (!((VPP_PROT(svp) ^ prot) & PROT_WRITE))
+		return (1);
+
+	ppa = kmem_alloc(ppasize, KM_SLEEP);
+	if (anon && vp != NULL) {
+		if (anon_get_ptr(amp->ahp, anon_idx) == NULL) {
+			anon = 0;
+			ASSERT(!anon_pages(amp->ahp, anon_idx, pgcnt));
+		}
+		ASSERT(!anon ||
+		    anon_pages(amp->ahp, anon_idx, pgcnt) == pgcnt);
+	}
+
+	for (*ppa = NULL, pg_idx = 0; svp < evp; svp++, anon_idx++) {
+		if (!VPP_ISPPLOCK(svp))
+			continue;
+		if (anon) {
+			ap = anon_get_ptr(amp->ahp, anon_idx);
+			if (ap == NULL) {
+				panic("segvn_claim_pages: no anon slot");
+			}
+			swap_xlate(ap, &vp, &aoff);
+			off = (u_offset_t)aoff;
+		}
+		ASSERT(vp != NULL);
+		if ((pp = page_lookup(vp,
+		    (u_offset_t)off, SE_SHARED)) == NULL) {
+			panic("segvn_claim_pages: no page");
+		}
+		ppa[pg_idx++] = pp;
+		off += PAGESIZE;
+	}
+
+	if (ppa[0] == NULL) {
+		kmem_free(ppa, ppasize);
+		return (1);
+	}
+
+	ASSERT(pg_idx <= pgcnt);
+	ppa[pg_idx] = NULL;
+
+	if (prot & PROT_WRITE)
+		err = page_addclaim_pages(ppa);
+	else
+		err = page_subclaim_pages(ppa);
+
+	for (i = 0; i < pg_idx; i++) {
+		ASSERT(ppa[i] != NULL);
+		page_unlock(ppa[i]);
+	}
+
+	kmem_free(ppa, ppasize);
+	return (err);
+}
+
+/*
+ * Returns right (upper address) segment if split occured.
+ * If the address is equal to the beginning or end of its segment it returns
+ * the current segment.
+ */
+static struct seg *
+segvn_split_seg(struct seg *seg, caddr_t addr)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct seg *nseg;
+	size_t nsize;
+	struct segvn_data *nsvd;
+
+	ASSERT(AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
+	ASSERT(svd->type == MAP_PRIVATE || svd->amp == NULL);
+	ASSERT(addr >= seg->s_base);
+	ASSERT(addr <= seg->s_base + seg->s_size);
+
+	if (addr == seg->s_base || addr == seg->s_base + seg->s_size)
+		return (seg);
+
+	nsize = seg->s_base + seg->s_size - addr;
+	seg->s_size = addr - seg->s_base;
+	nseg = seg_alloc(seg->s_as, addr, nsize);
+	ASSERT(nseg != NULL);
+	nseg->s_ops = seg->s_ops;
+	nsvd = kmem_cache_alloc(segvn_cache, KM_SLEEP);
+	nseg->s_data = (void *)nsvd;
+	nseg->s_szc = seg->s_szc;
+	*nsvd = *svd;
+	rw_init(&nsvd->lock, NULL, RW_DEFAULT, NULL);
+
+	if (nsvd->vp != NULL) {
+		VN_HOLD(nsvd->vp);
+		nsvd->offset = svd->offset +
+		    (uintptr_t)(nseg->s_base - seg->s_base);
+		if (nsvd->type == MAP_SHARED)
+			lgrp_shm_policy_init(NULL, nsvd->vp);
+	} else {
+		/*
+		 * The offset for an anonymous segment has no signifigance in
+		 * terms of an offset into a file. If we were to use the above
+		 * calculation instead, the structures read out of
+		 * /proc/<pid>/xmap would be more difficult to decipher since
+		 * it would be unclear whether two seemingly contiguous
+		 * prxmap_t structures represented different segments or a
+		 * single segment that had been split up into multiple prxmap_t
+		 * structures (e.g. if some part of the segment had not yet
+		 * been faulted in).
+		 */
+		nsvd->offset = 0;
+	}
+
+	ASSERT(svd->softlockcnt == 0);
+	crhold(svd->cred);
+
+	if (svd->vpage != NULL) {
+		size_t bytes = vpgtob(seg_pages(seg));
+		size_t nbytes = vpgtob(seg_pages(nseg));
+		struct vpage *ovpage = svd->vpage;
+
+		svd->vpage = kmem_alloc(bytes, KM_SLEEP);
+		bcopy(ovpage, svd->vpage, bytes);
+		nsvd->vpage = kmem_alloc(nbytes, KM_SLEEP);
+		bcopy(ovpage + seg_pages(seg), nsvd->vpage, nbytes);
+		kmem_free(ovpage, bytes + nbytes);
+	}
+	if (svd->amp != NULL) {
+		struct anon_map *oamp = svd->amp, *namp;
+		struct anon_hdr *nahp;
+
+		ANON_LOCK_ENTER(&oamp->a_rwlock, RW_WRITER);
+		ASSERT(oamp->refcnt == 1);
+		nahp = anon_create(btop(seg->s_size), ANON_SLEEP);
+		(void) anon_copy_ptr(oamp->ahp, svd->anon_index,
+		    nahp, 0, btop(seg->s_size), ANON_SLEEP);
+
+		namp = anonmap_alloc(nseg->s_size, 0);
+		namp->a_szc = nseg->s_szc;
+		(void) anon_copy_ptr(oamp->ahp,
+		    svd->anon_index + btop(seg->s_size),
+		    namp->ahp, 0, btop(nseg->s_size), ANON_SLEEP);
+		anon_release(oamp->ahp, btop(oamp->size));
+		oamp->ahp = nahp;
+		oamp->size = seg->s_size;
+		svd->anon_index = 0;
+		nsvd->amp = namp;
+		nsvd->anon_index = 0;
+		ANON_LOCK_EXIT(&oamp->a_rwlock);
+	}
+
+	/*
+	 * Split amount of swap reserve
+	 */
+	if (svd->swresv) {
+		/*
+		 * For MAP_NORESERVE, only allocate swap reserve for pages
+		 * being used.  Other segments get enough to cover whole
+		 * segment.
+		 */
+		if (svd->flags & MAP_NORESERVE) {
+			size_t	oswresv;
+
+			ASSERT(svd->amp);
+			oswresv = svd->swresv;
+			svd->swresv = ptob(anon_pages(svd->amp->ahp,
+				svd->anon_index, btop(seg->s_size)));
+			nsvd->swresv = ptob(anon_pages(nsvd->amp->ahp,
+				nsvd->anon_index, btop(nseg->s_size)));
+			ASSERT(oswresv >= (svd->swresv + nsvd->swresv));
+		} else {
+			ASSERT(svd->swresv == seg->s_size + nseg->s_size);
+			svd->swresv = seg->s_size;
+			nsvd->swresv = nseg->s_size;
+		}
+	}
+
+	return (nseg);
+}
+
+
+/*
+ * called on memory operations (unmap, setprot, setpagesize) for a subset
+ * of a large page segment to either demote the memory range (SDR_RANGE)
+ * or the ends (SDR_END) by addr/len.
+ *
+ * returns 0 on success. returns errno, including ENOMEM, on failure.
+ */
+static int
+segvn_demote_range(struct seg *seg, caddr_t addr, size_t len, int flag)
+{
+	caddr_t eaddr = addr + len;
+	caddr_t lpgaddr, lpgeaddr;
+	struct seg *nseg;
+	struct seg *badseg1 = NULL;
+	struct seg *badseg2 = NULL;
+	size_t pgsz;
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	int err;
+
+	ASSERT(AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
+	ASSERT(seg->s_szc != 0);
+	pgsz = page_get_pagesize(seg->s_szc);
+	ASSERT(seg->s_base != addr || seg->s_size != len);
+	ASSERT(addr >= seg->s_base && eaddr <= seg->s_base + seg->s_size);
+	ASSERT(svd->softlockcnt == 0);
+	ASSERT(svd->type == MAP_PRIVATE ||
+	    (svd->vp != NULL && svd->amp == NULL));
+
+	CALC_LPG_REGION(pgsz, seg, addr, len, lpgaddr, lpgeaddr);
+	ASSERT(flag == SDR_RANGE || eaddr < lpgeaddr || addr > lpgaddr);
+	if (flag == SDR_RANGE) {
+		/* demote entire range */
+		badseg1 = nseg = segvn_split_seg(seg, lpgaddr);
+		(void) segvn_split_seg(nseg, lpgeaddr);
+		ASSERT(badseg1->s_base == lpgaddr);
+		ASSERT(badseg1->s_size == lpgeaddr - lpgaddr);
+	} else if (addr != lpgaddr) {
+		ASSERT(flag == SDR_END);
+		badseg1 = nseg = segvn_split_seg(seg, lpgaddr);
+		if (eaddr != lpgeaddr && eaddr > lpgaddr + pgsz &&
+		    eaddr < lpgaddr + 2 * pgsz) {
+			(void) segvn_split_seg(nseg, lpgeaddr);
+			ASSERT(badseg1->s_base == lpgaddr);
+			ASSERT(badseg1->s_size == 2 * pgsz);
+		} else {
+			nseg = segvn_split_seg(nseg, lpgaddr + pgsz);
+			ASSERT(badseg1->s_base == lpgaddr);
+			ASSERT(badseg1->s_size == pgsz);
+			if (eaddr != lpgeaddr && eaddr > lpgaddr + pgsz) {
+				ASSERT(lpgeaddr - lpgaddr > 2 * pgsz);
+				nseg = segvn_split_seg(nseg, lpgeaddr - pgsz);
+				badseg2 = nseg;
+				(void) segvn_split_seg(nseg, lpgeaddr);
+				ASSERT(badseg2->s_base == lpgeaddr - pgsz);
+				ASSERT(badseg2->s_size == pgsz);
+			}
+		}
+	} else {
+		ASSERT(flag == SDR_END);
+		ASSERT(eaddr < lpgeaddr);
+		badseg1 = nseg = segvn_split_seg(seg, lpgeaddr - pgsz);
+		(void) segvn_split_seg(nseg, lpgeaddr);
+		ASSERT(badseg1->s_base == lpgeaddr - pgsz);
+		ASSERT(badseg1->s_size == pgsz);
+	}
+
+	ASSERT(badseg1 != NULL);
+	ASSERT(badseg1->s_szc != 0);
+	ASSERT(page_get_pagesize(badseg1->s_szc) == pgsz);
+	ASSERT(flag == SDR_RANGE || badseg1->s_size == pgsz ||
+	    badseg1->s_size == 2 * pgsz);
+	if (err = segvn_clrszc(badseg1)) {
+		return (err);
+	}
+	ASSERT(badseg1->s_szc == 0);
+
+	if (badseg2 == NULL)
+		return (0);
+	ASSERT(badseg2->s_szc != 0);
+	ASSERT(page_get_pagesize(badseg2->s_szc) == pgsz);
+	ASSERT(badseg2->s_size == pgsz);
+	ASSERT(sameprot(badseg2, badseg2->s_base, badseg2->s_size));
+	if (err = segvn_clrszc(badseg2)) {
+		return (err);
+	}
+	ASSERT(badseg2->s_szc == 0);
+	return (0);
+}
+
+static int
+segvn_checkprot(struct seg *seg, caddr_t addr, size_t len, uint_t prot)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct vpage *vp, *evp;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+	/*
+	 * If segment protection can be used, simply check against them.
+	 */
+	if (svd->pageprot == 0) {
+		int err;
+
+		err = ((svd->prot & prot) != prot) ? EACCES : 0;
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		return (err);
+	}
+
+	/*
+	 * Have to check down to the vpage level.
+	 */
+	evp = &svd->vpage[seg_page(seg, addr + len)];
+	for (vp = &svd->vpage[seg_page(seg, addr)]; vp < evp; vp++) {
+		if ((VPP_PROT(vp) & prot) != prot) {
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (EACCES);
+		}
+	}
+	SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+	return (0);
+}
+
+static int
+segvn_getprot(struct seg *seg, caddr_t addr, size_t len, uint_t *protv)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	size_t pgno = seg_page(seg, addr + len) - seg_page(seg, addr) + 1;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	if (pgno != 0) {
+		SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+		if (svd->pageprot == 0) {
+			do
+				protv[--pgno] = svd->prot;
+			while (pgno != 0);
+		} else {
+			size_t pgoff = seg_page(seg, addr);
+
+			do {
+				pgno--;
+				protv[pgno] = VPP_PROT(&svd->vpage[pgno+pgoff]);
+			} while (pgno != 0);
+		}
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+	}
+	return (0);
+}
+
+static u_offset_t
+segvn_getoffset(struct seg *seg, caddr_t addr)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	return (svd->offset + (uintptr_t)(addr - seg->s_base));
+}
+
+/*ARGSUSED*/
+static int
+segvn_gettype(struct seg *seg, caddr_t addr)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	return (svd->type | (svd->flags & MAP_NORESERVE));
+}
+
+/*ARGSUSED*/
+static int
+segvn_getvp(struct seg *seg, caddr_t addr, struct vnode **vpp)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	*vpp = svd->vp;
+	return (0);
+}
+
+/*
+ * Check to see if it makes sense to do kluster/read ahead to
+ * addr + delta relative to the mapping at addr.  We assume here
+ * that delta is a signed PAGESIZE'd multiple (which can be negative).
+ *
+ * For segvn, we currently "approve" of the action if we are
+ * still in the segment and it maps from the same vp/off,
+ * or if the advice stored in segvn_data or vpages allows it.
+ * Currently, klustering is not allowed only if MADV_RANDOM is set.
+ */
+static int
+segvn_kluster(struct seg *seg, caddr_t addr, ssize_t delta)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct anon *oap, *ap;
+	ssize_t pd;
+	size_t page;
+	struct vnode *vp1, *vp2;
+	u_offset_t off1, off2;
+	struct anon_map *amp;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+	ASSERT(AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock) ||
+	    SEGVN_LOCK_HELD(seg->s_as, &svd->lock));
+
+	if (addr + delta < seg->s_base ||
+	    addr + delta >= (seg->s_base + seg->s_size))
+		return (-1);		/* exceeded segment bounds */
+
+	pd = delta / (ssize_t)PAGESIZE;	/* divide to preserve sign bit */
+	page = seg_page(seg, addr);
+
+	/*
+	 * Check to see if either of the pages addr or addr + delta
+	 * have advice set that prevents klustering (if MADV_RANDOM advice
+	 * is set for entire segment, or MADV_SEQUENTIAL is set and delta
+	 * is negative).
+	 */
+	if (svd->advice == MADV_RANDOM ||
+	    svd->advice == MADV_SEQUENTIAL && delta < 0)
+		return (-1);
+	else if (svd->pageadvice && svd->vpage) {
+		struct vpage *bvpp, *evpp;
+
+		bvpp = &svd->vpage[page];
+		evpp = &svd->vpage[page + pd];
+		if (VPP_ADVICE(bvpp) == MADV_RANDOM ||
+		    VPP_ADVICE(evpp) == MADV_SEQUENTIAL && delta < 0)
+			return (-1);
+		if (VPP_ADVICE(bvpp) != VPP_ADVICE(evpp) &&
+		    VPP_ADVICE(evpp) == MADV_RANDOM)
+			return (-1);
+	}
+
+	if (svd->type == MAP_SHARED)
+		return (0);		/* shared mapping - all ok */
+
+	if ((amp = svd->amp) == NULL)
+		return (0);		/* off original vnode */
+
+	page += svd->anon_index;
+
+	ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+
+	oap = anon_get_ptr(amp->ahp, page);
+	ap = anon_get_ptr(amp->ahp, page + pd);
+
+	ANON_LOCK_EXIT(&amp->a_rwlock);
+
+	if ((oap == NULL && ap != NULL) || (oap != NULL && ap == NULL)) {
+		return (-1);		/* one with and one without an anon */
+	}
+
+	if (oap == NULL) {		/* implies that ap == NULL */
+		return (0);		/* off original vnode */
+	}
+
+	/*
+	 * Now we know we have two anon pointers - check to
+	 * see if they happen to be properly allocated.
+	 */
+
+	/*
+	 * XXX We cheat here and don't lock the anon slots. We can't because
+	 * we may have been called from the anon layer which might already
+	 * have locked them. We are holding a refcnt on the slots so they
+	 * can't disappear. The worst that will happen is we'll get the wrong
+	 * names (vp, off) for the slots and make a poor klustering decision.
+	 */
+	swap_xlate(ap, &vp1, &off1);
+	swap_xlate(oap, &vp2, &off2);
+
+
+	if (!VOP_CMP(vp1, vp2) || off1 - off2 != delta)
+		return (-1);
+	return (0);
+}
+
+/*
+ * Swap the pages of seg out to secondary storage, returning the
+ * number of bytes of storage freed.
+ *
+ * The basic idea is first to unload all translations and then to call
+ * VOP_PUTPAGE() for all newly-unmapped pages, to push them out to the
+ * swap device.  Pages to which other segments have mappings will remain
+ * mapped and won't be swapped.  Our caller (as_swapout) has already
+ * performed the unloading step.
+ *
+ * The value returned is intended to correlate well with the process's
+ * memory requirements.  However, there are some caveats:
+ * 1)	When given a shared segment as argument, this routine will
+ *	only succeed in swapping out pages for the last sharer of the
+ *	segment.  (Previous callers will only have decremented mapping
+ *	reference counts.)
+ * 2)	We assume that the hat layer maintains a large enough translation
+ *	cache to capture process reference patterns.
+ */
+static size_t
+segvn_swapout(struct seg *seg)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct anon_map *amp;
+	pgcnt_t pgcnt = 0;
+	pgcnt_t npages;
+	pgcnt_t page;
+	ulong_t anon_index;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+	/*
+	 * Find pages unmapped by our caller and force them
+	 * out to the virtual swap device.
+	 */
+	if ((amp = svd->amp) != NULL)
+		anon_index = svd->anon_index;
+	npages = seg->s_size >> PAGESHIFT;
+	for (page = 0; page < npages; page++) {
+		page_t *pp;
+		struct anon *ap;
+		struct vnode *vp;
+		u_offset_t off;
+		anon_sync_obj_t cookie;
+
+		/*
+		 * Obtain <vp, off> pair for the page, then look it up.
+		 *
+		 * Note that this code is willing to consider regular
+		 * pages as well as anon pages.  Is this appropriate here?
+		 */
+		ap = NULL;
+		if (amp != NULL) {
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+			anon_array_enter(amp, anon_index + page, &cookie);
+			ap = anon_get_ptr(amp->ahp, anon_index + page);
+			if (ap != NULL) {
+				swap_xlate(ap, &vp, &off);
+			} else {
+				vp = svd->vp;
+				off = svd->offset + ptob(page);
+			}
+			anon_array_exit(&cookie);
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+		} else {
+			vp = svd->vp;
+			off = svd->offset + ptob(page);
+		}
+		if (vp == NULL) {		/* untouched zfod page */
+			ASSERT(ap == NULL);
+			continue;
+		}
+
+		pp = page_lookup_nowait(vp, off, SE_SHARED);
+		if (pp == NULL)
+			continue;
+
+
+		/*
+		 * Examine the page to see whether it can be tossed out,
+		 * keeping track of how many we've found.
+		 */
+		if (!page_tryupgrade(pp)) {
+			/*
+			 * If the page has an i/o lock and no mappings,
+			 * it's very likely that the page is being
+			 * written out as a result of klustering.
+			 * Assume this is so and take credit for it here.
+			 */
+			if (!page_io_trylock(pp)) {
+				if (!hat_page_is_mapped(pp))
+					pgcnt++;
+			} else {
+				page_io_unlock(pp);
+			}
+			page_unlock(pp);
+			continue;
+		}
+		ASSERT(!page_iolock_assert(pp));
+
+
+		/*
+		 * Skip if page is locked or has mappings.
+		 * We don't need the page_struct_lock to look at lckcnt
+		 * and cowcnt because the page is exclusive locked.
+		 */
+		if (pp->p_lckcnt != 0 || pp->p_cowcnt != 0 ||
+		    hat_page_is_mapped(pp)) {
+			page_unlock(pp);
+			continue;
+		}
+
+		/*
+		 * dispose skips large pages so try to demote first.
+		 */
+		if (pp->p_szc != 0 && !page_try_demote_pages(pp)) {
+			page_unlock(pp);
+			/*
+			 * XXX should skip the remaining page_t's of this
+			 * large page.
+			 */
+			continue;
+		}
+
+		ASSERT(pp->p_szc == 0);
+
+		/*
+		 * No longer mapped -- we can toss it out.  How
+		 * we do so depends on whether or not it's dirty.
+		 */
+		if (hat_ismod(pp) && pp->p_vnode) {
+			/*
+			 * We must clean the page before it can be
+			 * freed.  Setting B_FREE will cause pvn_done
+			 * to free the page when the i/o completes.
+			 * XXX:	This also causes it to be accounted
+			 *	as a pageout instead of a swap: need
+			 *	B_SWAPOUT bit to use instead of B_FREE.
+			 *
+			 * Hold the vnode before releasing the page lock
+			 * to prevent it from being freed and re-used by
+			 * some other thread.
+			 */
+			VN_HOLD(vp);
+			page_unlock(pp);
+
+			/*
+			 * Queue all i/o requests for the pageout thread
+			 * to avoid saturating the pageout devices.
+			 */
+			if (!queue_io_request(vp, off))
+				VN_RELE(vp);
+		} else {
+			/*
+			 * The page was clean, free it.
+			 *
+			 * XXX:	Can we ever encounter modified pages
+			 *	with no associated vnode here?
+			 */
+			ASSERT(pp->p_vnode != NULL);
+			/*LINTED: constant in conditional context*/
+			VN_DISPOSE(pp, B_FREE, 0, kcred);
+		}
+
+		/*
+		 * Credit now even if i/o is in progress.
+		 */
+		pgcnt++;
+	}
+	SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+
+	/*
+	 * Wakeup pageout to initiate i/o on all queued requests.
+	 */
+	cv_signal_pageout();
+	return (ptob(pgcnt));
+}
+
+/*
+ * Synchronize primary storage cache with real object in virtual memory.
+ *
+ * XXX - Anonymous pages should not be sync'ed out at all.
+ */
+static int
+segvn_sync(struct seg *seg, caddr_t addr, size_t len, int attr, uint_t flags)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct vpage *vpp;
+	page_t *pp;
+	u_offset_t offset;
+	struct vnode *vp;
+	u_offset_t off;
+	caddr_t eaddr;
+	int bflags;
+	int err = 0;
+	int segtype;
+	int pageprot;
+	int prot;
+	ulong_t anon_index;
+	struct anon_map *amp;
+	struct anon *ap;
+	anon_sync_obj_t cookie;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+
+	if (svd->softlockcnt > 0) {
+		/*
+		 * flush all pages from seg cache
+		 * otherwise we may deadlock in swap_putpage
+		 * for B_INVAL page (4175402).
+		 *
+		 * Even if we grab segvn WRITER's lock or segp_slock
+		 * here, there might be another thread which could've
+		 * successfully performed lookup/insert just before
+		 * we acquired the lock here.  So, grabbing either
+		 * lock here is of not much use.  Until we devise
+		 * a strategy at upper layers to solve the
+		 * synchronization issues completely, we expect
+		 * applications to handle this appropriately.
+		 */
+		segvn_purge(seg);
+		if (svd->softlockcnt > 0) {
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (EAGAIN);
+		}
+	}
+
+	vpp = svd->vpage;
+	offset = svd->offset + (uintptr_t)(addr - seg->s_base);
+	bflags = ((flags & MS_ASYNC) ? B_ASYNC : 0) |
+	    ((flags & MS_INVALIDATE) ? B_INVAL : 0);
+
+	if (attr) {
+		pageprot = attr & ~(SHARED|PRIVATE);
+		segtype = (attr & SHARED) ? MAP_SHARED : MAP_PRIVATE;
+
+		/*
+		 * We are done if the segment types don't match
+		 * or if we have segment level protections and
+		 * they don't match.
+		 */
+		if (svd->type != segtype) {
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (0);
+		}
+		if (vpp == NULL) {
+			if (svd->prot != pageprot) {
+				SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+				return (0);
+			}
+			prot = svd->prot;
+		} else
+			vpp = &svd->vpage[seg_page(seg, addr)];
+
+	} else if (svd->vp && svd->amp == NULL &&
+	    (flags & MS_INVALIDATE) == 0) {
+
+		/*
+		 * No attributes, no anonymous pages and MS_INVALIDATE flag
+		 * is not on, just use one big request.
+		 */
+		err = VOP_PUTPAGE(svd->vp, (offset_t)offset, len,
+		    bflags, svd->cred);
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		return (err);
+	}
+
+	if ((amp = svd->amp) != NULL)
+		anon_index = svd->anon_index + seg_page(seg, addr);
+
+	for (eaddr = addr + len; addr < eaddr; addr += PAGESIZE) {
+		ap = NULL;
+		if (amp != NULL) {
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+			anon_array_enter(amp, anon_index, &cookie);
+			ap = anon_get_ptr(amp->ahp, anon_index++);
+			if (ap != NULL) {
+				swap_xlate(ap, &vp, &off);
+			} else {
+				vp = svd->vp;
+				off = offset;
+			}
+			anon_array_exit(&cookie);
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+		} else {
+			vp = svd->vp;
+			off = offset;
+		}
+		offset += PAGESIZE;
+
+		if (vp == NULL)		/* untouched zfod page */
+			continue;
+
+		if (attr) {
+			if (vpp) {
+				prot = VPP_PROT(vpp);
+				vpp++;
+			}
+			if (prot != pageprot) {
+				continue;
+			}
+		}
+
+		/*
+		 * See if any of these pages are locked --  if so, then we
+		 * will have to truncate an invalidate request at the first
+		 * locked one. We don't need the page_struct_lock to test
+		 * as this is only advisory; even if we acquire it someone
+		 * might race in and lock the page after we unlock and before
+		 * we do the PUTPAGE, then PUTPAGE simply does nothing.
+		 */
+		if (flags & MS_INVALIDATE) {
+			if ((pp = page_lookup(vp, off, SE_SHARED)) != NULL) {
+				if (pp->p_lckcnt != 0 || pp->p_cowcnt != 0) {
+					page_unlock(pp);
+					SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+					return (EBUSY);
+				}
+				if (ap != NULL && pp->p_szc != 0 &&
+				    page_tryupgrade(pp)) {
+					if (pp->p_lckcnt == 0 &&
+					    pp->p_cowcnt == 0) {
+						/*
+						 * swapfs VN_DISPOSE() won't
+						 * invalidate large pages.
+						 * Attempt to demote.
+						 * XXX can't help it if it
+						 * fails. But for swapfs
+						 * pages it is no big deal.
+						 */
+						(void) page_try_demote_pages(
+						    pp);
+				    }
+				}
+				page_unlock(pp);
+			}
+		} else if (svd->type == MAP_SHARED && amp != NULL) {
+			/*
+			 * Avoid writting out to disk ISM's large pages
+			 * because segspt_free_pages() relies on NULL an_pvp
+			 * of anon slots of such pages.
+			 */
+
+			ASSERT(svd->vp == NULL);
+			/*
+			 * swapfs uses page_lookup_nowait if not freeing or
+			 * invalidating and skips a page if
+			 * page_lookup_nowait returns NULL.
+			 */
+			pp = page_lookup_nowait(vp, off, SE_SHARED);
+			if (pp == NULL) {
+				continue;
+			}
+			if (pp->p_szc != 0) {
+				page_unlock(pp);
+				continue;
+			}
+
+			/*
+			 * Note ISM pages are created large so (vp, off)'s
+			 * page cannot suddenly become large after we unlock
+			 * pp.
+			 */
+			page_unlock(pp);
+		}
+		/*
+		 * XXX - Should ultimately try to kluster
+		 * calls to VOP_PUTPAGE() for performance.
+		 */
+		VN_HOLD(vp);
+		err = VOP_PUTPAGE(vp, (offset_t)off, PAGESIZE,
+		    bflags, svd->cred);
+		VN_RELE(vp);
+		if (err)
+			break;
+	}
+	SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+	return (err);
+}
+
+/*
+ * Determine if we have data corresponding to pages in the
+ * primary storage virtual memory cache (i.e., "in core").
+ */
+static size_t
+segvn_incore(struct seg *seg, caddr_t addr, size_t len, char *vec)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct vnode *vp, *avp;
+	u_offset_t offset, aoffset;
+	size_t p, ep;
+	int ret;
+	struct vpage *vpp;
+	page_t *pp;
+	uint_t start;
+	struct anon_map *amp;		/* XXX - for locknest */
+	struct anon *ap;
+	uint_t attr;
+	anon_sync_obj_t cookie;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+	if (svd->amp == NULL && svd->vp == NULL) {
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		bzero(vec, btopr(len));
+		return (len);	/* no anonymous pages created yet */
+	}
+
+	p = seg_page(seg, addr);
+	ep = seg_page(seg, addr + len);
+	start = svd->vp ? SEG_PAGE_VNODEBACKED : 0;
+
+	amp = svd->amp;
+	for (; p < ep; p++, addr += PAGESIZE) {
+		vpp = (svd->vpage) ? &svd->vpage[p]: NULL;
+		ret = start;
+		ap = NULL;
+		avp = NULL;
+		/* Grab the vnode/offset for the anon slot */
+		if (amp != NULL) {
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+			anon_array_enter(amp, svd->anon_index + p, &cookie);
+			ap = anon_get_ptr(amp->ahp, svd->anon_index + p);
+			if (ap != NULL) {
+				swap_xlate(ap, &avp, &aoffset);
+			}
+			anon_array_exit(&cookie);
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+		}
+		if ((avp != NULL) && page_exists(avp, aoffset)) {
+			/* A page exists for the anon slot */
+			ret |= SEG_PAGE_INCORE;
+
+			/*
+			 * If page is mapped and writable
+			 */
+			attr = (uint_t)0;
+			if ((hat_getattr(seg->s_as->a_hat, addr,
+			    &attr) != -1) && (attr & PROT_WRITE)) {
+				ret |= SEG_PAGE_ANON;
+			}
+			/*
+			 * Don't get page_struct lock for lckcnt and cowcnt,
+			 * since this is purely advisory.
+			 */
+			if ((pp = page_lookup_nowait(avp, aoffset,
+			    SE_SHARED)) != NULL) {
+				if (pp->p_lckcnt)
+					ret |= SEG_PAGE_SOFTLOCK;
+				if (pp->p_cowcnt)
+					ret |= SEG_PAGE_HASCOW;
+				page_unlock(pp);
+			}
+		}
+
+		/* Gather vnode statistics */
+		vp = svd->vp;
+		offset = svd->offset + (uintptr_t)(addr - seg->s_base);
+
+		if (vp != NULL) {
+			/*
+			 * Try to obtain a "shared" lock on the page
+			 * without blocking.  If this fails, determine
+			 * if the page is in memory.
+			 */
+			pp = page_lookup_nowait(vp, offset, SE_SHARED);
+			if ((pp == NULL) && (page_exists(vp, offset))) {
+				/* Page is incore, and is named */
+				ret |= (SEG_PAGE_INCORE | SEG_PAGE_VNODE);
+			}
+			/*
+			 * Don't get page_struct lock for lckcnt and cowcnt,
+			 * since this is purely advisory.
+			 */
+			if (pp != NULL) {
+				ret |= (SEG_PAGE_INCORE | SEG_PAGE_VNODE);
+				if (pp->p_lckcnt)
+					ret |= SEG_PAGE_SOFTLOCK;
+				if (pp->p_cowcnt)
+					ret |= SEG_PAGE_HASCOW;
+				page_unlock(pp);
+			}
+		}
+
+		/* Gather virtual page information */
+		if (vpp) {
+			if (VPP_ISPPLOCK(vpp))
+				ret |= SEG_PAGE_LOCKED;
+			vpp++;
+		}
+
+		*vec++ = (char)ret;
+	}
+	SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+	return (len);
+}
+
+/*
+ * Statement for p_cowcnts/p_lckcnts.
+ *
+ * p_cowcnt is updated while mlock/munlocking MAP_PRIVATE and PROT_WRITE region
+ * irrespective of the following factors or anything else:
+ *
+ *	(1) anon slots are populated or not
+ *	(2) cow is broken or not
+ *	(3) refcnt on ap is 1 or greater than 1
+ *
+ * If it's not MAP_PRIVATE and PROT_WRITE, p_lckcnt is updated during mlock
+ * and munlock.
+ *
+ *
+ * Handling p_cowcnts/p_lckcnts during copy-on-write fault:
+ *
+ *	if vpage has PROT_WRITE
+ *		transfer cowcnt on the oldpage -> cowcnt on the newpage
+ *	else
+ *		transfer lckcnt on the oldpage -> lckcnt on the newpage
+ *
+ *	During copy-on-write, decrement p_cowcnt on the oldpage and increment
+ *	p_cowcnt on the newpage *if* the corresponding vpage has PROT_WRITE.
+ *
+ *	We may also break COW if softlocking on read access in the physio case.
+ *	In this case, vpage may not have PROT_WRITE. So, we need to decrement
+ *	p_lckcnt on the oldpage and increment p_lckcnt on the newpage *if* the
+ *	vpage doesn't have PROT_WRITE.
+ *
+ *
+ * Handling p_cowcnts/p_lckcnts during mprotect on mlocked region:
+ *
+ * 	If a MAP_PRIVATE region loses PROT_WRITE, we decrement p_cowcnt and
+ *	increment p_lckcnt by calling page_subclaim() which takes care of
+ * 	availrmem accounting and p_lckcnt overflow.
+ *
+ *	If a MAP_PRIVATE region gains PROT_WRITE, we decrement p_lckcnt and
+ *	increment p_cowcnt by calling page_addclaim() which takes care of
+ *	availrmem availability and p_cowcnt overflow.
+ */
+
+/*
+ * Lock down (or unlock) pages mapped by this segment.
+ *
+ * XXX only creates PAGESIZE pages if anon slots are not initialized.
+ * At fault time they will be relocated into larger pages.
+ */
+static int
+segvn_lockop(struct seg *seg, caddr_t addr, size_t len,
+    int attr, int op, ulong_t *lockmap, size_t pos)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct vpage *vpp;
+	struct vpage *evp;
+	page_t *pp;
+	u_offset_t offset;
+	u_offset_t off;
+	int segtype;
+	int pageprot;
+	int claim;
+	struct vnode *vp;
+	ulong_t anon_index;
+	struct anon_map *amp;
+	struct anon *ap;
+	struct vattr va;
+	anon_sync_obj_t cookie;
+
+	/*
+	 * Hold write lock on address space because may split or concatenate
+	 * segments
+	 */
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_WRITER);
+	if (attr) {
+		pageprot = attr & ~(SHARED|PRIVATE);
+		segtype = attr & SHARED ? MAP_SHARED : MAP_PRIVATE;
+
+		/*
+		 * We are done if the segment types don't match
+		 * or if we have segment level protections and
+		 * they don't match.
+		 */
+		if (svd->type != segtype) {
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (0);
+		}
+		if (svd->pageprot == 0 && svd->prot != pageprot) {
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (0);
+		}
+	}
+
+	/*
+	 * If we're locking, then we must create a vpage structure if
+	 * none exists.  If we're unlocking, then check to see if there
+	 * is a vpage --  if not, then we could not have locked anything.
+	 */
+
+	if ((vpp = svd->vpage) == NULL) {
+		if (op == MC_LOCK)
+			segvn_vpage(seg);
+		else {
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (0);
+		}
+	}
+
+	/*
+	 * The anonymous data vector (i.e., previously
+	 * unreferenced mapping to swap space) can be allocated
+	 * by lazily testing for its existence.
+	 */
+	if (op == MC_LOCK && svd->amp == NULL && svd->vp == NULL) {
+		svd->amp = anonmap_alloc(seg->s_size, 0);
+		svd->amp->a_szc = seg->s_szc;
+	}
+
+	if ((amp = svd->amp) != NULL) {
+		anon_index = svd->anon_index + seg_page(seg, addr);
+	}
+
+	offset = svd->offset + (uintptr_t)(addr - seg->s_base);
+	evp = &svd->vpage[seg_page(seg, addr + len)];
+
+	/*
+	 * Loop over all pages in the range.  Process if we're locking and
+	 * page has not already been locked in this mapping; or if we're
+	 * unlocking and the page has been locked.
+	 */
+	for (vpp = &svd->vpage[seg_page(seg, addr)]; vpp < evp;
+	    vpp++, pos++, addr += PAGESIZE, offset += PAGESIZE, anon_index++) {
+		if ((attr == 0 || VPP_PROT(vpp) == pageprot) &&
+		    ((op == MC_LOCK && !VPP_ISPPLOCK(vpp)) ||
+		    (op == MC_UNLOCK && VPP_ISPPLOCK(vpp)))) {
+
+			if (amp != NULL)
+				ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+			/*
+			 * If this isn't a MAP_NORESERVE segment and
+			 * we're locking, allocate anon slots if they
+			 * don't exist.  The page is brought in later on.
+			 */
+			if (op == MC_LOCK && svd->vp == NULL &&
+			    ((svd->flags & MAP_NORESERVE) == 0) &&
+			    amp != NULL &&
+			    ((ap = anon_get_ptr(amp->ahp, anon_index))
+								== NULL)) {
+				anon_array_enter(amp, anon_index, &cookie);
+
+				if ((ap = anon_get_ptr(amp->ahp,
+						anon_index)) == NULL) {
+					pp = anon_zero(seg, addr, &ap,
+					    svd->cred);
+					if (pp == NULL) {
+						anon_array_exit(&cookie);
+						ANON_LOCK_EXIT(&amp->a_rwlock);
+						SEGVN_LOCK_EXIT(seg->s_as,
+						    &svd->lock);
+						return (ENOMEM);
+					}
+					ASSERT(anon_get_ptr(amp->ahp,
+						anon_index) == NULL);
+					(void) anon_set_ptr(amp->ahp,
+						anon_index, ap, ANON_SLEEP);
+					page_unlock(pp);
+				}
+				anon_array_exit(&cookie);
+			}
+
+			/*
+			 * Get name for page, accounting for
+			 * existence of private copy.
+			 */
+			ap = NULL;
+			if (amp != NULL) {
+				anon_array_enter(amp, anon_index, &cookie);
+				ap = anon_get_ptr(amp->ahp, anon_index);
+				if (ap != NULL) {
+					swap_xlate(ap, &vp, &off);
+				} else {
+					if (svd->vp == NULL &&
+					    (svd->flags & MAP_NORESERVE)) {
+						anon_array_exit(&cookie);
+						ANON_LOCK_EXIT(&amp->a_rwlock);
+						continue;
+					}
+					vp = svd->vp;
+					off = offset;
+				}
+				anon_array_exit(&cookie);
+				ANON_LOCK_EXIT(&amp->a_rwlock);
+			} else {
+				vp = svd->vp;
+				off = offset;
+			}
+
+			/*
+			 * Get page frame.  It's ok if the page is
+			 * not available when we're unlocking, as this
+			 * may simply mean that a page we locked got
+			 * truncated out of existence after we locked it.
+			 *
+			 * Invoke VOP_GETPAGE() to obtain the page struct
+			 * since we may need to read it from disk if its
+			 * been paged out.
+			 */
+			if (op != MC_LOCK)
+				pp = page_lookup(vp, off, SE_SHARED);
+			else {
+				page_t *pl[1 + 1];
+				int error;
+
+				ASSERT(vp != NULL);
+
+				error = VOP_GETPAGE(vp, (offset_t)off, PAGESIZE,
+				    (uint_t *)NULL, pl, PAGESIZE, seg, addr,
+				    S_OTHER, svd->cred);
+
+				/*
+				 * If the error is EDEADLK then we must bounce
+				 * up and drop all vm subsystem locks and then
+				 * retry the operation later
+				 * This behavior is a temporary measure because
+				 * ufs/sds logging is badly designed and will
+				 * deadlock if we don't allow this bounce to
+				 * happen.  The real solution is to re-design
+				 * the logging code to work properly.  See bug
+				 * 4125102 for details of the problem.
+				 */
+				if (error == EDEADLK) {
+					SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+					return (error);
+				}
+				/*
+				 * Quit if we fail to fault in the page.  Treat
+				 * the failure as an error, unless the addr
+				 * is mapped beyond the end of a file.
+				 */
+				if (error && svd->vp) {
+					va.va_mask = AT_SIZE;
+					if (VOP_GETATTR(svd->vp, &va, 0,
+					    svd->cred) != 0) {
+						SEGVN_LOCK_EXIT(seg->s_as,
+						    &svd->lock);
+						return (EIO);
+					}
+					if (btopr(va.va_size) >=
+					    btopr(off + 1)) {
+						SEGVN_LOCK_EXIT(seg->s_as,
+						    &svd->lock);
+						return (EIO);
+					}
+					SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+					return (0);
+				} else if (error) {
+					SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+					return (EIO);
+				}
+				pp = pl[0];
+				ASSERT(pp != NULL);
+			}
+
+			/*
+			 * See Statement at the beginning of this routine.
+			 *
+			 * claim is always set if MAP_PRIVATE and PROT_WRITE
+			 * irrespective of following factors:
+			 *
+			 * (1) anon slots are populated or not
+			 * (2) cow is broken or not
+			 * (3) refcnt on ap is 1 or greater than 1
+			 *
+			 * See 4140683 for details
+			 */
+			claim = ((VPP_PROT(vpp) & PROT_WRITE) &&
+				(svd->type == MAP_PRIVATE));
+
+			/*
+			 * Perform page-level operation appropriate to
+			 * operation.  If locking, undo the SOFTLOCK
+			 * performed to bring the page into memory
+			 * after setting the lock.  If unlocking,
+			 * and no page was found, account for the claim
+			 * separately.
+			 */
+			if (op == MC_LOCK) {
+				int ret = 1;	/* Assume success */
+
+				/*
+				 * Make sure another thread didn't lock
+				 * the page after we released the segment
+				 * lock.
+				 */
+				if ((attr == 0 || VPP_PROT(vpp) == pageprot) &&
+				    !VPP_ISPPLOCK(vpp)) {
+					ret = page_pp_lock(pp, claim, 0);
+					if (ret != 0) {
+						VPP_SETPPLOCK(vpp);
+						if (lockmap != (ulong_t *)NULL)
+							BT_SET(lockmap, pos);
+					}
+				}
+				page_unlock(pp);
+				if (ret == 0) {
+					SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+					return (EAGAIN);
+				}
+			} else {
+				if (pp != NULL) {
+					if ((attr == 0 ||
+					    VPP_PROT(vpp) == pageprot) &&
+					    VPP_ISPPLOCK(vpp))
+						page_pp_unlock(pp, claim, 0);
+					page_unlock(pp);
+				}
+				VPP_CLRPPLOCK(vpp);
+			}
+		}
+	}
+	SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+	return (0);
+}
+
+/*
+ * Set advice from user for specified pages
+ * There are 5 types of advice:
+ *	MADV_NORMAL	- Normal (default) behavior (whatever that is)
+ *	MADV_RANDOM	- Random page references
+ *				do not allow readahead or 'klustering'
+ *	MADV_SEQUENTIAL	- Sequential page references
+ *				Pages previous to the one currently being
+ *				accessed (determined by fault) are 'not needed'
+ *				and are freed immediately
+ *	MADV_WILLNEED	- Pages are likely to be used (fault ahead in mctl)
+ *	MADV_DONTNEED	- Pages are not needed (synced out in mctl)
+ *	MADV_FREE	- Contents can be discarded
+ *	MADV_ACCESS_DEFAULT- Default access
+ *	MADV_ACCESS_LWP	- Next LWP will access heavily
+ *	MADV_ACCESS_MANY- Many LWPs or processes will access heavily
+ */
+static int
+segvn_advise(struct seg *seg, caddr_t addr, size_t len, uint_t behav)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	size_t page;
+	int err = 0;
+	int already_set;
+	struct anon_map *amp;
+	ulong_t anon_index;
+	struct seg *next;
+	lgrp_mem_policy_t policy;
+	struct seg *prev;
+	struct vnode *vp;
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+
+	/*
+	 * In case of MADV_FREE, we won't be modifying any segment private
+	 * data structures; so, we only need to grab READER's lock
+	 */
+	if (behav != MADV_FREE)
+		SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_WRITER);
+	else
+		SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+
+	/*
+	 * Large pages are assumed to be only turned on when accesses to the
+	 * segment's address range have spatial and temporal locality. That
+	 * justifies ignoring MADV_SEQUENTIAL for large page segments.
+	 * Also, ignore advice affecting lgroup memory allocation
+	 * if don't need to do lgroup optimizations on this system
+	 */
+
+	if ((behav == MADV_SEQUENTIAL && seg->s_szc != 0) ||
+	    (!lgrp_optimizations() && (behav == MADV_ACCESS_DEFAULT ||
+	    behav == MADV_ACCESS_LWP || behav == MADV_ACCESS_MANY))) {
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		return (0);
+	}
+
+	if (behav == MADV_SEQUENTIAL || behav == MADV_ACCESS_DEFAULT ||
+	    behav == MADV_ACCESS_LWP || behav == MADV_ACCESS_MANY) {
+		/*
+		 * Since we are going to unload hat mappings
+		 * we first have to flush the cache. Otherwise
+		 * this might lead to system panic if another
+		 * thread is doing physio on the range whose
+		 * mappings are unloaded by madvise(3C).
+		 */
+		if (svd->softlockcnt > 0) {
+			/*
+			 * Since we do have the segvn writers lock
+			 * nobody can fill the cache with entries
+			 * belonging to this seg during the purge.
+			 * The flush either succeeds or we still
+			 * have pending I/Os. In the later case,
+			 * madvise(3C) fails.
+			 */
+			segvn_purge(seg);
+			if (svd->softlockcnt > 0) {
+				/*
+				 * Since madvise(3C) is advisory and
+				 * it's not part of UNIX98, madvise(3C)
+				 * failure here doesn't cause any hardship.
+				 * Note that we don't block in "as" layer.
+				 */
+				SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+				return (EAGAIN);
+			}
+		}
+	}
+
+	amp = svd->amp;
+	vp = svd->vp;
+	if (behav == MADV_FREE) {
+		/*
+		 * MADV_FREE is not supported for segments with
+		 * underlying object; if anonmap is NULL, anon slots
+		 * are not yet populated and there is nothing for
+		 * us to do. As MADV_FREE is advisory, we don't
+		 * return error in either case.
+		 */
+		if (vp || amp == NULL) {
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+			return (0);
+		}
+
+		page = seg_page(seg, addr);
+		ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+		anon_disclaim(amp, svd->anon_index + page, len, 0);
+		ANON_LOCK_EXIT(&amp->a_rwlock);
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		return (0);
+	}
+
+	/*
+	 * If advice is to be applied to entire segment,
+	 * use advice field in seg_data structure
+	 * otherwise use appropriate vpage entry.
+	 */
+	if ((addr == seg->s_base) && (len == seg->s_size)) {
+		switch (behav) {
+		case MADV_ACCESS_LWP:
+		case MADV_ACCESS_MANY:
+		case MADV_ACCESS_DEFAULT:
+			/*
+			 * Set memory allocation policy for this segment
+			 */
+			policy = lgrp_madv_to_policy(behav, len, svd->type);
+			if (svd->type == MAP_SHARED)
+				already_set = lgrp_shm_policy_set(policy, amp,
+				    svd->anon_index, vp, svd->offset, len);
+			else {
+				/*
+				 * For private memory, need writers lock on
+				 * address space because the segment may be
+				 * split or concatenated when changing policy
+				 */
+				if (AS_READ_HELD(seg->s_as,
+				    &seg->s_as->a_lock)) {
+					SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+					return (IE_RETRY);
+				}
+
+				already_set = lgrp_privm_policy_set(policy,
+				    &svd->policy_info, len);
+			}
+
+			/*
+			 * If policy set already and it shouldn't be reapplied,
+			 * don't do anything.
+			 */
+			if (already_set &&
+			    !LGRP_MEM_POLICY_REAPPLICABLE(policy))
+				break;
+
+			/*
+			 * Mark any existing pages in given range for
+			 * migration
+			 */
+			page_mark_migrate(seg, addr, len, amp, svd->anon_index,
+			    vp, svd->offset, 1);
+
+			/*
+			 * If same policy set already or this is a shared
+			 * memory segment, don't need to try to concatenate
+			 * segment with adjacent ones.
+			 */
+			if (already_set || svd->type == MAP_SHARED)
+				break;
+
+			/*
+			 * Try to concatenate this segment with previous
+			 * one and next one, since we changed policy for
+			 * this one and it may be compatible with adjacent
+			 * ones now.
+			 */
+			prev = AS_SEGPREV(seg->s_as, seg);
+			next = AS_SEGNEXT(seg->s_as, seg);
+
+			if (next && next->s_ops == &segvn_ops &&
+			    addr + len == next->s_base)
+				(void) segvn_concat(seg, next, 1);
+
+			if (prev && prev->s_ops == &segvn_ops &&
+			    addr == prev->s_base + prev->s_size) {
+				/*
+				 * Drop lock for private data of current
+				 * segment before concatenating (deleting) it
+				 * and return IE_REATTACH to tell as_ctl() that
+				 * current segment has changed
+				 */
+				SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+				if (!segvn_concat(prev, seg, 1))
+					err = IE_REATTACH;
+
+				return (err);
+			}
+			break;
+
+		case MADV_SEQUENTIAL:
+			/*
+			 * unloading mapping guarantees
+			 * detection in segvn_fault
+			 */
+			ASSERT(seg->s_szc == 0);
+			hat_unload(seg->s_as->a_hat, addr, len,
+				HAT_UNLOAD);
+			/* FALLTHROUGH */
+		case MADV_NORMAL:
+		case MADV_RANDOM:
+			svd->advice = (uchar_t)behav;
+			svd->pageadvice = 0;
+			break;
+		case MADV_WILLNEED:	/* handled in memcntl */
+		case MADV_DONTNEED:	/* handled in memcntl */
+		case MADV_FREE:		/* handled above */
+			break;
+		default:
+			err = EINVAL;
+		}
+	} else {
+		caddr_t			eaddr;
+		struct seg		*new_seg;
+		struct segvn_data	*new_svd;
+		u_offset_t		off;
+		caddr_t			oldeaddr;
+
+		page = seg_page(seg, addr);
+
+		segvn_vpage(seg);
+
+		switch (behav) {
+			struct vpage *bvpp, *evpp;
+
+		case MADV_ACCESS_LWP:
+		case MADV_ACCESS_MANY:
+		case MADV_ACCESS_DEFAULT:
+			/*
+			 * Set memory allocation policy for portion of this
+			 * segment
+			 */
+
+			/*
+			 * Align address and length of advice to page
+			 * boundaries for large pages
+			 */
+			if (seg->s_szc != 0) {
+				size_t	pgsz;
+
+				pgsz = page_get_pagesize(seg->s_szc);
+				addr = (caddr_t)P2ALIGN((uintptr_t)addr, pgsz);
+				len = P2ROUNDUP(len, pgsz);
+			}
+
+			/*
+			 * Check to see whether policy is set already
+			 */
+			policy = lgrp_madv_to_policy(behav, len, svd->type);
+
+			anon_index = svd->anon_index + page;
+			off = svd->offset + (uintptr_t)(addr - seg->s_base);
+
+			if (svd->type == MAP_SHARED)
+				already_set = lgrp_shm_policy_set(policy, amp,
+				    anon_index, vp, off, len);
+			else
+				already_set =
+				    (policy == svd->policy_info.mem_policy);
+
+			/*
+			 * If policy set already and it shouldn't be reapplied,
+			 * don't do anything.
+			 */
+			if (already_set &&
+			    !LGRP_MEM_POLICY_REAPPLICABLE(policy))
+				break;
+
+			/*
+			 * For private memory, need writers lock on
+			 * address space because the segment may be
+			 * split or concatenated when changing policy
+			 */
+			if (svd->type == MAP_PRIVATE &&
+			    AS_READ_HELD(seg->s_as, &seg->s_as->a_lock)) {
+				SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+				return (IE_RETRY);
+			}
+
+			/*
+			 * Mark any existing pages in given range for
+			 * migration
+			 */
+			page_mark_migrate(seg, addr, len, amp, svd->anon_index,
+			    vp, svd->offset, 1);
+
+			/*
+			 * Don't need to try to split or concatenate
+			 * segments, since policy is same or this is a shared
+			 * memory segment
+			 */
+			if (already_set || svd->type == MAP_SHARED)
+				break;
+
+			/*
+			 * Split off new segment if advice only applies to a
+			 * portion of existing segment starting in middle
+			 */
+			new_seg = NULL;
+			eaddr = addr + len;
+			oldeaddr = seg->s_base + seg->s_size;
+			if (addr > seg->s_base) {
+				/*
+				 * Must flush I/O page cache
+				 * before splitting segment
+				 */
+				if (svd->softlockcnt > 0)
+					segvn_purge(seg);
+
+				/*
+				 * Split segment and return IE_REATTACH to tell
+				 * as_ctl() that current segment changed
+				 */
+				new_seg = segvn_split_seg(seg, addr);
+				new_svd = (struct segvn_data *)new_seg->s_data;
+				err = IE_REATTACH;
+
+				/*
+				 * If new segment ends where old one
+				 * did, try to concatenate the new
+				 * segment with next one.
+				 */
+				if (eaddr == oldeaddr) {
+					/*
+					 * Set policy for new segment
+					 */
+					(void) lgrp_privm_policy_set(policy,
+					    &new_svd->policy_info,
+					    new_seg->s_size);
+
+					next = AS_SEGNEXT(new_seg->s_as,
+					    new_seg);
+
+					if (next &&
+					    next->s_ops == &segvn_ops &&
+					    eaddr == next->s_base)
+						(void) segvn_concat(new_seg,
+						    next, 1);
+				}
+			}
+
+			/*
+			 * Split off end of existing segment if advice only
+			 * applies to a portion of segment ending before
+			 * end of the existing segment
+			 */
+			if (eaddr < oldeaddr) {
+				/*
+				 * Must flush I/O page cache
+				 * before splitting segment
+				 */
+				if (svd->softlockcnt > 0)
+					segvn_purge(seg);
+
+				/*
+				 * If beginning of old segment was already
+				 * split off, use new segment to split end off
+				 * from.
+				 */
+				if (new_seg != NULL && new_seg != seg) {
+					/*
+					 * Split segment
+					 */
+					(void) segvn_split_seg(new_seg, eaddr);
+
+					/*
+					 * Set policy for new segment
+					 */
+					(void) lgrp_privm_policy_set(policy,
+					    &new_svd->policy_info,
+					    new_seg->s_size);
+				} else {
+					/*
+					 * Split segment and return IE_REATTACH
+					 * to tell as_ctl() that current
+					 * segment changed
+					 */
+					(void) segvn_split_seg(seg, eaddr);
+					err = IE_REATTACH;
+
+					(void) lgrp_privm_policy_set(policy,
+					    &svd->policy_info, seg->s_size);
+
+					/*
+					 * If new segment starts where old one
+					 * did, try to concatenate it with
+					 * previous segment.
+					 */
+					if (addr == seg->s_base) {
+						prev = AS_SEGPREV(seg->s_as,
+						    seg);
+
+						/*
+						 * Drop lock for private data
+						 * of current segment before
+						 * concatenating (deleting) it
+						 */
+						if (prev &&
+						    prev->s_ops ==
+						    &segvn_ops &&
+						    addr == prev->s_base +
+						    prev->s_size) {
+							SEGVN_LOCK_EXIT(
+							    seg->s_as,
+							    &svd->lock);
+							(void) segvn_concat(
+							    prev, seg, 1);
+							return (err);
+						}
+					}
+				}
+			}
+			break;
+		case MADV_SEQUENTIAL:
+			ASSERT(seg->s_szc == 0);
+			hat_unload(seg->s_as->a_hat, addr, len, HAT_UNLOAD);
+			/* FALLTHROUGH */
+		case MADV_NORMAL:
+		case MADV_RANDOM:
+			bvpp = &svd->vpage[page];
+			evpp = &svd->vpage[page + (len >> PAGESHIFT)];
+			for (; bvpp < evpp; bvpp++)
+				VPP_SETADVICE(bvpp, behav);
+			svd->advice = MADV_NORMAL;
+			break;
+		case MADV_WILLNEED:	/* handled in memcntl */
+		case MADV_DONTNEED:	/* handled in memcntl */
+		case MADV_FREE:		/* handled above */
+			break;
+		default:
+			err = EINVAL;
+		}
+	}
+	SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+	return (err);
+}
+
+/*
+ * Create a vpage structure for this seg.
+ */
+static void
+segvn_vpage(struct seg *seg)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct vpage *vp, *evp;
+
+	ASSERT(SEGVN_WRITE_HELD(seg->s_as, &svd->lock));
+
+	/*
+	 * If no vpage structure exists, allocate one.  Copy the protections
+	 * and the advice from the segment itself to the individual pages.
+	 */
+	if (svd->vpage == NULL) {
+		svd->pageprot = 1;
+		svd->pageadvice = 1;
+		svd->vpage = kmem_zalloc(seg_pages(seg) * sizeof (struct vpage),
+		    KM_SLEEP);
+		evp = &svd->vpage[seg_page(seg, seg->s_base + seg->s_size)];
+		for (vp = svd->vpage; vp < evp; vp++) {
+			VPP_SETPROT(vp, svd->prot);
+			VPP_SETADVICE(vp, svd->advice);
+		}
+	}
+}
+
+/*
+ * Dump the pages belonging to this segvn segment.
+ */
+static void
+segvn_dump(struct seg *seg)
+{
+	struct segvn_data *svd;
+	page_t *pp;
+	struct anon_map *amp;
+	ulong_t	anon_index;
+	struct vnode *vp;
+	u_offset_t off, offset;
+	pfn_t pfn;
+	pgcnt_t page, npages;
+	caddr_t addr;
+
+	npages = seg_pages(seg);
+	svd = (struct segvn_data *)seg->s_data;
+	vp = svd->vp;
+	off = offset = svd->offset;
+	addr = seg->s_base;
+
+	if ((amp = svd->amp) != NULL) {
+		anon_index = svd->anon_index;
+		ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+	}
+
+	for (page = 0; page < npages; page++, offset += PAGESIZE) {
+		struct anon *ap;
+		int we_own_it = 0;
+
+		if (amp && (ap = anon_get_ptr(svd->amp->ahp, anon_index++))) {
+			swap_xlate_nopanic(ap, &vp, &off);
+		} else {
+			vp = svd->vp;
+			off = offset;
+		}
+
+		/*
+		 * If pp == NULL, the page either does not exist
+		 * or is exclusively locked.  So determine if it
+		 * exists before searching for it.
+		 */
+
+		if ((pp = page_lookup_nowait(vp, off, SE_SHARED)))
+			we_own_it = 1;
+		else
+			pp = page_exists(vp, off);
+
+		if (pp) {
+			pfn = page_pptonum(pp);
+			dump_addpage(seg->s_as, addr, pfn);
+			if (we_own_it)
+				page_unlock(pp);
+		}
+		addr += PAGESIZE;
+		dump_timeleft = dump_timeout;
+	}
+
+	if (amp != NULL)
+		ANON_LOCK_EXIT(&amp->a_rwlock);
+}
+
+/*
+ * lock/unlock anon pages over a given range. Return shadow list
+ */
+static int
+segvn_pagelock(struct seg *seg, caddr_t addr, size_t len, struct page ***ppp,
+    enum lock_type type, enum seg_rw rw)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	size_t np, adjustpages = 0, npages = (len >> PAGESHIFT);
+	ulong_t anon_index;
+	uint_t protchk;
+	uint_t error;
+	struct anon_map *amp;
+	struct page **pplist, **pl, *pp;
+	caddr_t a;
+	size_t page;
+	caddr_t lpgaddr, lpgeaddr;
+
+	TRACE_2(TR_FAC_PHYSIO, TR_PHYSIO_SEGVN_START,
+		"segvn_pagelock: start seg %p addr %p", seg, addr);
+
+	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
+	if (seg->s_szc != 0 && (type == L_PAGELOCK || type == L_PAGEUNLOCK)) {
+		/*
+		 * We are adjusting the pagelock region to the large page size
+		 * boundary because the unlocked part of a large page cannot
+		 * be freed anyway unless all constituent pages of a large
+		 * page are locked. Therefore this adjustment allows us to
+		 * decrement availrmem by the right value (note we don't want
+		 * to just decrement availrem by the large page size without
+		 * adjusting addr and len because then we may end up
+		 * decrementing availrmem by large page size for every
+		 * constituent page locked by a new as_pagelock call).
+		 * as_pageunlock caller must always match as_pagelock call's
+		 * addr and len.
+		 *
+		 * Note segment's page size cannot change while we are holding
+		 * as lock.  And then it cannot change while softlockcnt is
+		 * not 0. This will allow us to correctly recalculate large
+		 * page size region for the matching pageunlock/reclaim call.
+		 *
+		 * for pageunlock *ppp points to the pointer of page_t that
+		 * corresponds to the real unadjusted start address. Similar
+		 * for pagelock *ppp must point to the pointer of page_t that
+		 * corresponds to the real unadjusted start address.
+		 */
+		size_t pgsz = page_get_pagesize(seg->s_szc);
+		CALC_LPG_REGION(pgsz, seg, addr, len, lpgaddr, lpgeaddr);
+		adjustpages = ((uintptr_t)(addr - lpgaddr)) >> PAGESHIFT;
+	}
+
+	if (type == L_PAGEUNLOCK) {
+
+		/*
+		 * update hat ref bits for /proc. We need to make sure
+		 * that threads tracing the ref and mod bits of the
+		 * address space get the right data.
+		 * Note: page ref and mod bits are updated at reclaim time
+		 */
+		if (seg->s_as->a_vbits) {
+			for (a = addr; a < addr + len; a += PAGESIZE) {
+				if (rw == S_WRITE) {
+					hat_setstat(seg->s_as, a,
+					    PAGESIZE, P_REF | P_MOD);
+				} else {
+					hat_setstat(seg->s_as, a,
+					    PAGESIZE, P_REF);
+				}
+			}
+		}
+		SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+		if (seg->s_szc != 0) {
+			VM_STAT_ADD(segvnvmstats.pagelock[0]);
+			seg_pinactive(seg, lpgaddr, lpgeaddr - lpgaddr,
+			    *ppp - adjustpages, rw, segvn_reclaim);
+		} else {
+			seg_pinactive(seg, addr, len, *ppp, rw, segvn_reclaim);
+		}
+
+		/*
+		 * If someone is blocked while unmapping, we purge
+		 * segment page cache and thus reclaim pplist synchronously
+		 * without waiting for seg_pasync_thread. This speeds up
+		 * unmapping in cases where munmap(2) is called, while
+		 * raw async i/o is still in progress or where a thread
+		 * exits on data fault in a multithreaded application.
+		 */
+		if (AS_ISUNMAPWAIT(seg->s_as) && (svd->softlockcnt > 0)) {
+			/*
+			 * Even if we grab segvn WRITER's lock or segp_slock
+			 * here, there might be another thread which could've
+			 * successfully performed lookup/insert just before
+			 * we acquired the lock here.  So, grabbing either
+			 * lock here is of not much use.  Until we devise
+			 * a strategy at upper layers to solve the
+			 * synchronization issues completely, we expect
+			 * applications to handle this appropriately.
+			 */
+			segvn_purge(seg);
+		}
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		TRACE_2(TR_FAC_PHYSIO, TR_PHYSIO_SEGVN_UNLOCK_END,
+			"segvn_pagelock: unlock seg %p addr %p", seg, addr);
+		return (0);
+	} else if (type == L_PAGERECLAIM) {
+		VM_STAT_COND_ADD(seg->s_szc != 0, segvnvmstats.pagelock[1]);
+		SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+		(void) segvn_reclaim(seg, addr, len, *ppp, rw);
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		TRACE_2(TR_FAC_PHYSIO, TR_PHYSIO_SEGVN_UNLOCK_END,
+			"segvn_pagelock: reclaim seg %p addr %p", seg, addr);
+		return (0);
+	}
+
+	if (seg->s_szc != 0) {
+		VM_STAT_ADD(segvnvmstats.pagelock[2]);
+		addr = lpgaddr;
+		len = lpgeaddr - lpgaddr;
+		npages = (len >> PAGESHIFT);
+	}
+
+	/*
+	 * for now we only support pagelock to anon memory. We've to check
+	 * protections for vnode objects and call into the vnode driver.
+	 * That's too much for a fast path. Let the fault entry point handle it.
+	 */
+	if (svd->vp != NULL) {
+		TRACE_2(TR_FAC_PHYSIO, TR_PHYSIO_SEGVN_MISS_END,
+		    "segvn_pagelock: mapped vnode seg %p addr %p", seg, addr);
+		*ppp = NULL;
+		return (ENOTSUP);
+	}
+
+	/*
+	 * if anonmap is not yet created, let the fault entry point populate it
+	 * with anon ptrs.
+	 */
+	if ((amp = svd->amp) == NULL) {
+		TRACE_2(TR_FAC_PHYSIO, TR_PHYSIO_SEGVN_MISS_END,
+		    "segvn_pagelock: anonmap null seg %p addr %p", seg, addr);
+		*ppp = NULL;
+		return (EFAULT);
+	}
+
+	SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+
+	/*
+	 * we acquire segp_slock to prevent duplicate entries
+	 * in seg_pcache
+	 */
+	mutex_enter(&svd->segp_slock);
+
+	/*
+	 * try to find pages in segment page cache
+	 */
+	pplist = seg_plookup(seg, addr, len, rw);
+	if (pplist != NULL) {
+		mutex_exit(&svd->segp_slock);
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		*ppp = pplist + adjustpages;
+		TRACE_2(TR_FAC_PHYSIO, TR_PHYSIO_SEGVN_HIT_END,
+			"segvn_pagelock: cache hit seg %p addr %p", seg, addr);
+		return (0);
+	}
+
+	if (rw == S_READ) {
+		protchk = PROT_READ;
+	} else {
+		protchk = PROT_WRITE;
+	}
+
+	if (svd->pageprot == 0) {
+		if ((svd->prot & protchk) == 0) {
+			mutex_exit(&svd->segp_slock);
+			error = EFAULT;
+			goto out;
+		}
+	} else {
+		/*
+		 * check page protections
+		 */
+		for (a = addr; a < addr + len; a += PAGESIZE) {
+			struct vpage *vp;
+
+			vp = &svd->vpage[seg_page(seg, a)];
+			if ((VPP_PROT(vp) & protchk) == 0) {
+				mutex_exit(&svd->segp_slock);
+				error = EFAULT;
+				goto out;
+			}
+		}
+	}
+
+	mutex_enter(&freemem_lock);
+	if (availrmem < tune.t_minarmem + npages) {
+		mutex_exit(&freemem_lock);
+		mutex_exit(&svd->segp_slock);
+		error = ENOMEM;
+		goto out;
+	} else {
+		svd->softlockcnt += npages;
+		availrmem -= npages;
+		segvn_pages_locked += npages;
+	}
+	mutex_exit(&freemem_lock);
+
+	pplist = kmem_alloc(sizeof (page_t *) * npages, KM_SLEEP);
+	pl = pplist;
+	*ppp = pplist + adjustpages;
+
+	page = seg_page(seg, addr);
+	anon_index = svd->anon_index + page;
+
+	ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+	for (a = addr; a < addr + len; a += PAGESIZE, anon_index++) {
+		struct anon *ap;
+		struct vnode *vp;
+		u_offset_t off;
+		anon_sync_obj_t cookie;
+
+		anon_array_enter(amp, anon_index, &cookie);
+		ap = anon_get_ptr(amp->ahp, anon_index);
+		if (ap == NULL) {
+			anon_array_exit(&cookie);
+			break;
+		} else {
+			/*
+			 * We must never use seg_pcache for COW pages
+			 * because we might end up with original page still
+			 * lying in seg_pcache even after private page is
+			 * created. This leads to data corruption as
+			 * aio_write refers to the page still in cache
+			 * while all other accesses refer to the private
+			 * page.
+			 */
+			if (ap->an_refcnt != 1) {
+				anon_array_exit(&cookie);
+				break;
+			}
+		}
+		swap_xlate(ap, &vp, &off);
+		anon_array_exit(&cookie);
+
+		pp = page_lookup_nowait(vp, off, SE_SHARED);
+		if (pp == NULL) {
+			break;
+		}
+		*pplist++ = pp;
+	}
+	ANON_LOCK_EXIT(&amp->a_rwlock);
+
+	if (a >= addr + len) {
+		(void) seg_pinsert(seg, addr, len, pl, rw, SEGP_ASYNC_FLUSH,
+			segvn_reclaim);
+		mutex_exit(&svd->segp_slock);
+		SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+		TRACE_2(TR_FAC_PHYSIO, TR_PHYSIO_SEGVN_FILL_END,
+		    "segvn_pagelock: cache fill seg %p addr %p", seg, addr);
+		return (0);
+	}
+
+	mutex_exit(&svd->segp_slock);
+	error = EFAULT;
+	pplist = pl;
+	np = ((uintptr_t)(a - addr)) >> PAGESHIFT;
+	while (np > (uint_t)0) {
+		page_unlock(*pplist);
+		np--;
+		pplist++;
+	}
+	kmem_free(pl, sizeof (page_t *) * npages);
+	mutex_enter(&freemem_lock);
+	svd->softlockcnt -= npages;
+	availrmem += npages;
+	segvn_pages_locked -= npages;
+	mutex_exit(&freemem_lock);
+	if (svd->softlockcnt <= 0) {
+		if (AS_ISUNMAPWAIT(seg->s_as)) {
+			mutex_enter(&seg->s_as->a_contents);
+			if (AS_ISUNMAPWAIT(seg->s_as)) {
+				AS_CLRUNMAPWAIT(seg->s_as);
+				cv_broadcast(&seg->s_as->a_cv);
+			}
+			mutex_exit(&seg->s_as->a_contents);
+		}
+	}
+
+out:
+	SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+	*ppp = NULL;
+	TRACE_2(TR_FAC_PHYSIO, TR_PHYSIO_SEGVN_MISS_END,
+		"segvn_pagelock: cache miss seg %p addr %p", seg, addr);
+	return (error);
+}
+
+/*
+ * purge any cached pages in the I/O page cache
+ */
+static void
+segvn_purge(struct seg *seg)
+{
+	seg_ppurge(seg);
+}
+
+static int
+segvn_reclaim(struct seg *seg, caddr_t addr, size_t len, struct page **pplist,
+	enum seg_rw rw)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	pgcnt_t np, npages;
+	struct page **pl;
+
+#ifdef lint
+	addr = addr;
+#endif
+
+	npages = np = (len >> PAGESHIFT);
+	ASSERT(npages);
+	pl = pplist;
+	if (seg->s_szc != 0) {
+		size_t pgsz = page_get_pagesize(seg->s_szc);
+		if (!IS_P2ALIGNED(addr, pgsz) || !IS_P2ALIGNED(len, pgsz)) {
+			panic("segvn_reclaim: unaligned addr or len");
+			/*NOTREACHED*/
+		}
+	}
+
+	while (np > (uint_t)0) {
+		if (rw == S_WRITE) {
+			hat_setrefmod(*pplist);
+		} else {
+			hat_setref(*pplist);
+		}
+		page_unlock(*pplist);
+		np--;
+		pplist++;
+	}
+	kmem_free(pl, sizeof (page_t *) * npages);
+
+	mutex_enter(&freemem_lock);
+	availrmem += npages;
+	segvn_pages_locked -= npages;
+	svd->softlockcnt -= npages;
+	mutex_exit(&freemem_lock);
+	if (svd->softlockcnt <= 0) {
+		if (AS_ISUNMAPWAIT(seg->s_as)) {
+			mutex_enter(&seg->s_as->a_contents);
+			if (AS_ISUNMAPWAIT(seg->s_as)) {
+				AS_CLRUNMAPWAIT(seg->s_as);
+				cv_broadcast(&seg->s_as->a_cv);
+			}
+			mutex_exit(&seg->s_as->a_contents);
+		}
+	}
+	return (0);
+}
+/*
+ * get a memory ID for an addr in a given segment
+ *
+ * XXX only creates PAGESIZE pages if anon slots are not initialized.
+ * At fault time they will be relocated into larger pages.
+ */
+static int
+segvn_getmemid(struct seg *seg, caddr_t addr, memid_t *memidp)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct anon 	*ap = NULL;
+	ulong_t		anon_index;
+	struct anon_map	*amp;
+	anon_sync_obj_t cookie;
+
+	if (svd->type == MAP_PRIVATE) {
+		memidp->val[0] = (uintptr_t)seg->s_as;
+		memidp->val[1] = (uintptr_t)addr;
+		return (0);
+	}
+
+	if (svd->type == MAP_SHARED) {
+		if (svd->vp) {
+			memidp->val[0] = (uintptr_t)svd->vp;
+			memidp->val[1] = (u_longlong_t)svd->offset +
+			    (uintptr_t)(addr - seg->s_base);
+			return (0);
+		} else {
+
+			SEGVN_LOCK_ENTER(seg->s_as, &svd->lock, RW_READER);
+			if ((amp = svd->amp) != NULL) {
+				anon_index = svd->anon_index +
+				    seg_page(seg, addr);
+			}
+			SEGVN_LOCK_EXIT(seg->s_as, &svd->lock);
+
+			ASSERT(amp != NULL);
+
+			ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
+			anon_array_enter(amp, anon_index, &cookie);
+			ap = anon_get_ptr(amp->ahp, anon_index);
+			if (ap == NULL) {
+				page_t		*pp;
+
+				pp = anon_zero(seg, addr, &ap, svd->cred);
+				if (pp == NULL) {
+					anon_array_exit(&cookie);
+					ANON_LOCK_EXIT(&amp->a_rwlock);
+					return (ENOMEM);
+				}
+				ASSERT(anon_get_ptr(amp->ahp, anon_index)
+								== NULL);
+				(void) anon_set_ptr(amp->ahp, anon_index,
+				    ap, ANON_SLEEP);
+				page_unlock(pp);
+			}
+
+			anon_array_exit(&cookie);
+			ANON_LOCK_EXIT(&amp->a_rwlock);
+
+			memidp->val[0] = (uintptr_t)ap;
+			memidp->val[1] = (uintptr_t)addr & PAGEOFFSET;
+			return (0);
+		}
+	}
+	return (EINVAL);
+}
+
+static int
+sameprot(struct seg *seg, caddr_t a, size_t len)
+{
+	struct segvn_data *svd = (struct segvn_data *)seg->s_data;
+	struct vpage *vpage;
+	spgcnt_t pages = btop(len);
+	uint_t prot;
+
+	if (svd->pageprot == 0)
+		return (1);
+
+	ASSERT(svd->vpage != NULL);
+
+	vpage = &svd->vpage[seg_page(seg, a)];
+	prot = VPP_PROT(vpage);
+	vpage++;
+	pages--;
+	while (pages-- > 0) {
+		if (prot != VPP_PROT(vpage))
+			return (0);
+		vpage++;
+	}
+	return (1);
+}
+
+/*
+ * Get memory allocation policy info for specified address in given segment
+ */
+static lgrp_mem_policy_info_t *
+segvn_getpolicy(struct seg *seg, caddr_t addr)
+{
+	struct anon_map		*amp;
+	ulong_t			anon_index;
+	lgrp_mem_policy_info_t	*policy_info;
+	struct segvn_data	*svn_data;
+	u_offset_t		vn_off;
+	vnode_t			*vp;
+
+	ASSERT(seg != NULL);
+
+	svn_data = (struct segvn_data *)seg->s_data;
+	if (svn_data == NULL)
+		return (NULL);
+
+	/*
+	 * Get policy info for private or shared memory
+	 */
+	if (svn_data->type != MAP_SHARED)
+		policy_info = &svn_data->policy_info;
+	else {
+		amp = svn_data->amp;
+		anon_index = svn_data->anon_index + seg_page(seg, addr);
+		vp = svn_data->vp;
+		vn_off = svn_data->offset + (uintptr_t)(addr - seg->s_base);
+		policy_info = lgrp_shm_policy_get(amp, anon_index, vp, vn_off);
+	}
+
+	return (policy_info);
+}