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| author | Austin Clements <austin@google.com> | 2015-10-15 13:25:19 -0400 |
|---|---|---|
| committer | Austin Clements <austin@google.com> | 2015-10-15 19:33:11 +0000 |
| commit | 71a76476627fb0752d1b816406da4e5a6511c2c9 (patch) | |
| tree | b2e4d66dad0a23a0b29f13a83ffafa071982813b | |
| parent | c257dfb178f00449dd344204219aad56e3e90de6 (diff) | |
| download | go-71a76476627fb0752d1b816406da4e5a6511c2c9.tar.gz go-71a76476627fb0752d1b816406da4e5a6511c2c9.zip | |
[release-branch.go1.5] runtime: fix recursive GC assist better
Commit c257dfb attempted to fix recursive allocation in gcAssistAlloc;
however, it only reduced it: setting gp.gcalloc to 0 isn't sufficient
to disable assists at the beginning of the GC cycle when gp.gcscanwork
is also small or zero.
Fix this recursion more completely by setting gcalloc to a sentinel
value that directly disables assists.
Fixes #12894 (again).
Change-Id: I9599566222d8f540d0b39806846bfc702e6666e5
Reviewed-on: https://go-review.googlesource.com/15891
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
| -rw-r--r-- | src/runtime/mgcmark.go | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/src/runtime/mgcmark.go b/src/runtime/mgcmark.go index e5dfa72026..64cc1af64f 100644 --- a/src/runtime/mgcmark.go +++ b/src/runtime/mgcmark.go @@ -152,6 +152,11 @@ func gcAssistAlloc(size uintptr, allowAssist bool) { } // Record allocation. + if gp.gcalloc+size < gp.gcalloc { + // gcalloc would overflow, or it's set to a sentinel + // value to prevent recursive assist. + return + } gp.gcalloc += size if !allowAssist { @@ -295,7 +300,7 @@ retry: // timeSleep may allocate, so avoid recursive assist. gcalloc := gp.gcalloc - gp.gcalloc = 0 + gp.gcalloc = ^uintptr(0) timeSleep(100 * 1000) gp.gcalloc = gcalloc goto retry |