author | Shawn Walker-Salas <shawn.walker@oracle.com> |
Thu, 21 Jan 2016 09:20:59 -0800 | |
changeset 5331 | 9c955076ffe3 |
permissions | -rw-r--r-- |
5331
9c955076ffe3
PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
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From c257dfb178f00449dd344204219aad56e3e90de6 Mon Sep 17 00:00:00 2001 |
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PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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From: Austin Clements <[email protected]> |
9c955076ffe3
PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
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Date: Fri, 9 Oct 2015 17:20:34 -0400 |
9c955076ffe3
PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
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Subject: [PATCH 26/63] [release-branch.go1.5] runtime: fix recursive GC assist |
9c955076ffe3
PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
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If gcAssistAlloc is unable to steal or perform enough scan work, it |
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Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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calls timeSleep, which allocates. If this allocation requires |
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Shawn Walker-Salas <shawn.walker@oracle.com>
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obtaining a new span, it will in turn attempt to assist GC. Since |
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PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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there's likely still no way to satisfy the assist, it will sleep |
9c955076ffe3
PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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again, and so on, leading to potentially deep (not infinite, but also |
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PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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not bounded) recursion. |
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PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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Shawn Walker-Salas <shawn.walker@oracle.com>
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Fix this by disallowing assists during the timeSleep. |
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PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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This same problem was fixed on master by 65aa2da. That commit built on |
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PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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several other changes and hence can't be directly cherry-picked. This |
9c955076ffe3
PSARC/2015/203 Google Go version 1.5
Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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commit implements the same idea. |
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Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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Shawn Walker-Salas <shawn.walker@oracle.com>
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Fixes #12894. |
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Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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Shawn Walker-Salas <shawn.walker@oracle.com>
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Change-Id: I152977eb1d0a3005c42ff3985d58778f054a86d4 |
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Reviewed-on: https://go-review.googlesource.com/15720 |
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Reviewed-by: Rick Hudson <[email protected]> |
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--- |
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src/runtime/mgcmark.go | 5 +++++ |
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Shawn Walker-Salas <shawn.walker@oracle.com>
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1 file changed, 5 insertions(+) |
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Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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diff --git a/src/runtime/mgcmark.go b/src/runtime/mgcmark.go |
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index 44f9512..e5dfa72 100644 |
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--- a/src/runtime/mgcmark.go |
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+++ b/src/runtime/mgcmark.go |
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@@ -292,7 +292,12 @@ retry: |
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Shawn Walker-Salas <shawn.walker@oracle.com>
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// more, so go around again after performing an |
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parents:
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// interruptible sleep for 100 us (the same as the |
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Shawn Walker-Salas <shawn.walker@oracle.com>
parents:
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// getfull barrier) to let other mutators run. |
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Shawn Walker-Salas <shawn.walker@oracle.com>
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+ |
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+ // timeSleep may allocate, so avoid recursive assist. |
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Shawn Walker-Salas <shawn.walker@oracle.com>
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+ gcalloc := gp.gcalloc |
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+ gp.gcalloc = 0 |
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Shawn Walker-Salas <shawn.walker@oracle.com>
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timeSleep(100 * 1000) |
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Shawn Walker-Salas <shawn.walker@oracle.com>
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+ gp.gcalloc = gcalloc |
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Shawn Walker-Salas <shawn.walker@oracle.com>
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goto retry |
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Shawn Walker-Salas <shawn.walker@oracle.com>
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} |
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} |
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-- |
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Shawn Walker-Salas <shawn.walker@oracle.com>
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2.6.1 |
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Shawn Walker-Salas <shawn.walker@oracle.com>
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