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| author | Michael Anthony Knyszek <mknyszek@google.com> | 2020-07-23 20:24:56 +0000 |
|---|---|---|
| committer | Michael Knyszek <mknyszek@google.com> | 2020-10-26 17:25:54 +0000 |
| commit | f5c6875f3228951afa1fcf2ec01c614e0fb7e2dd (patch) | |
| tree | 319fc30ada1b03b23908229d77f6662d2e8cf30d /src/runtime/mstats.go | |
| parent | 93d7d1685ee9e9f296e20f6c712796e54602e891 (diff) | |
| download | go-f5c6875f3228951afa1fcf2ec01c614e0fb7e2dd.tar.gz go-f5c6875f3228951afa1fcf2ec01c614e0fb7e2dd.zip | |
runtime: make next_gc atomically accessed
next_gc is mostly updated only during a STW, but may occasionally be
updated by calls to e.g. debug.SetGCPercent. In this case the update is
supposed to be protected by the heap lock, but in reality it's accessed
by gcController.revise which may be called without the heap lock held
(despite its documentation, which will be updated in a later change).
Change the synchronization policy on next_gc so that it's atomically
accessed when the world is not stopped to aid in making revise safe for
concurrent use.
Change-Id: I79657a72f91563f3241aaeda66e8a7757d399529
Reviewed-on: https://go-review.googlesource.com/c/go/+/246962
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
Diffstat (limited to 'src/runtime/mstats.go')
| -rw-r--r-- | src/runtime/mstats.go | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/src/runtime/mstats.go b/src/runtime/mstats.go index 2c217ecf84..8cc20552fb 100644 --- a/src/runtime/mstats.go +++ b/src/runtime/mstats.go @@ -57,9 +57,15 @@ type mstats struct { gc_sys uint64 // updated atomically or during STW other_sys uint64 // updated atomically or during STW - // Statistics about garbage collector. + // Statistics about the garbage collector. + + // next_gc is the goal heap_live for when next GC ends. + // Set to ^uint64(0) if disabled. + // + // Read and written atomically, unless the world is stopped. + next_gc uint64 + // Protected by mheap or stopping the world during GC. - next_gc uint64 // goal heap_live for when next GC ends; ^0 if disabled last_gc_unix uint64 // last gc (in unix time) pause_total_ns uint64 pause_ns [256]uint64 // circular buffer of recent gc pause lengths |