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| author | Austin Clements <austin@google.com> | 2017-09-25 14:58:13 -0400 |
|---|---|---|
| committer | Russ Cox <rsc@golang.org> | 2017-10-25 20:23:11 +0000 |
| commit | ebfcdef90174ea86b2952abec511c0be96b05099 (patch) | |
| tree | f1aef34b367a97037dad492416c1074077354deb | |
| parent | 0ab99b396df9fc45c5cf1ac412da4f1848c3462c (diff) | |
| download | go-ebfcdef90174ea86b2952abec511c0be96b05099.tar.gz go-ebfcdef90174ea86b2952abec511c0be96b05099.zip | |
[release-branch.go1.9] runtime: make runtime.GC() trigger GC even if GOGC=off
Currently, the priority of checks in (gcTrigger).test() puts the
gcpercent<0 test above gcTriggerCycle, which is used for runtime.GC().
This is an unintentional change from 1.8 and before, where
runtime.GC() triggered a GC even if GOGC=off.
Fix this by rearranging the priority so the gcTriggerCycle test
executes even if gcpercent < 0.
Fixes #22023.
Change-Id: I109328d7b643b6824eb9d79061a9e775f0149575
Reviewed-on: https://go-review.googlesource.com/65994
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-on: https://go-review.googlesource.com/70979
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
| -rw-r--r-- | src/runtime/gc_test.go | 16 | ||||
| -rw-r--r-- | src/runtime/mgc.go | 5 |
2 files changed, 20 insertions, 1 deletions
diff --git a/src/runtime/gc_test.go b/src/runtime/gc_test.go index 25dc869caa..0620f2d61e 100644 --- a/src/runtime/gc_test.go +++ b/src/runtime/gc_test.go @@ -499,3 +499,19 @@ func BenchmarkReadMemStats(b *testing.B) { hugeSink = nil } + +func TestUserForcedGC(t *testing.T) { + // Test that runtime.GC() triggers a GC even if GOGC=off. + defer debug.SetGCPercent(debug.SetGCPercent(-1)) + + var ms1, ms2 runtime.MemStats + runtime.ReadMemStats(&ms1) + runtime.GC() + runtime.ReadMemStats(&ms2) + if ms1.NumGC == ms2.NumGC { + t.Fatalf("runtime.GC() did not trigger GC") + } + if ms1.NumForcedGC == ms2.NumForcedGC { + t.Fatalf("runtime.GC() was not accounted in NumForcedGC") + } +} diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go index 111fa781e1..b708720322 100644 --- a/src/runtime/mgc.go +++ b/src/runtime/mgc.go @@ -1158,7 +1158,7 @@ func (t gcTrigger) test() bool { if t.kind == gcTriggerAlways { return true } - if gcphase != _GCoff || gcpercent < 0 { + if gcphase != _GCoff { return false } switch t.kind { @@ -1169,6 +1169,9 @@ func (t gcTrigger) test() bool { // own write. return memstats.heap_live >= memstats.gc_trigger case gcTriggerTime: + if gcpercent < 0 { + return false + } lastgc := int64(atomic.Load64(&memstats.last_gc_nanotime)) return lastgc != 0 && t.now-lastgc > forcegcperiod case gcTriggerCycle: |