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| author | Austin Clements <austin@google.com> | 2015-04-23 20:00:10 -0400 |
|---|---|---|
| committer | Austin Clements <austin@google.com> | 2015-04-24 20:10:10 +0000 |
| commit | d1cae6358ccf27bc2c864b09aad49fd8a67ac264 (patch) | |
| tree | 9f937278239d3f4a557ee040dd17f495a067d48c /src | |
| parent | 26eac917dca240b318685ac019e606d02e79e600 (diff) | |
| download | go-d1cae6358ccf27bc2c864b09aad49fd8a67ac264.tar.xz | |
runtime: fix check for pending GC work
When findRunnable considers running a fractional mark worker, it first
checks if there's any work to be done; if there isn't there's no point
in running the worker because it will just reschedule immediately.
However, currently findRunnable just checks work.full and
work.partial, whereas getfull can *also* draw work from m.currentwbuf.
As a result, findRunnable may not start a worker even though there
actually is work.
This problem manifests itself in occasional failures of the
test/init1.go test. This test is unusual because it performs a large
amount of allocation without executing any write barriers, which means
there's nothing to force the pointers in currentwbuf out to the
work.partial/full lists where findRunnable can see them.
This change fixes this problem by making findRunnable also check for a
currentwbuf. This aligns findRunnable with trygetfull's notion of
whether or not there's work.
Change-Id: Ic76d22b7b5d040bc4f58a6b5975e9217650e66c4
Reviewed-on: https://go-review.googlesource.com/9299
Reviewed-by: Russ Cox <rsc@golang.org>
Diffstat (limited to 'src')
| -rw-r--r-- | src/runtime/mgc.go | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go index 497c20f0ea..353610d50c 100644 --- a/src/runtime/mgc.go +++ b/src/runtime/mgc.go @@ -501,7 +501,7 @@ func (c *gcControllerState) findRunnable(_p_ *p) *g { // else for a while, so kick everything out of its run // queue. } else { - if work.full == 0 && work.partial == 0 { + if _p_.m.ptr().currentwbuf == 0 && work.full == 0 && work.partial == 0 { // No work to be done right now. This can // happen at the end of the mark phase when // there are still assists tapering off. Don't |