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| author | Michael Anthony Knyszek <mknyszek@google.com> | 2019-11-21 17:05:14 +0000 |
|---|---|---|
| committer | Michael Knyszek <mknyszek@google.com> | 2020-05-08 16:24:40 +0000 |
| commit | 55ec5182d7b84eb2461c495a55984162b23f3df8 (patch) | |
| tree | 87d24203820c776f090d73e93fd931cbfdcffdb4 /src/runtime/mgcsweep.go | |
| parent | b1a48af7e8ee87cc46e1bbb07f81ac4853e0f27b (diff) | |
| download | go-55ec5182d7b84eb2461c495a55984162b23f3df8.tar.gz go-55ec5182d7b84eb2461c495a55984162b23f3df8.zip | |
runtime: remove scavAddr in favor of address ranges
This change removes the concept of s.scavAddr in favor of explicitly
reserving and unreserving address ranges. s.scavAddr has several
problems with raciness that can cause the scavenger to miss updates, or
move it back unnecessarily, forcing future scavenge calls to iterate
over searched address space unnecessarily.
This change achieves this by replacing scavAddr with a second addrRanges
which is cloned from s.inUse at the end of each sweep phase. Ranges from
this second addrRanges are then reserved by scavengers (with the
reservation size proportional to the heap size) who are then able to
safely iterate over those ranges without worry of another scavenger
coming in.
Fixes #35788.
Change-Id: Ief01ae170384174875118742f6c26b2a41cbb66d
Reviewed-on: https://go-review.googlesource.com/c/go/+/208378
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Diffstat (limited to 'src/runtime/mgcsweep.go')
| -rw-r--r-- | src/runtime/mgcsweep.go | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/src/runtime/mgcsweep.go b/src/runtime/mgcsweep.go index 2f3bf1d1e9..f9b03d3594 100644 --- a/src/runtime/mgcsweep.go +++ b/src/runtime/mgcsweep.go @@ -246,8 +246,8 @@ func sweepone() uintptr { // Decrement the number of active sweepers and if this is the // last one print trace information. if atomic.Xadd(&mheap_.sweepers, -1) == 0 && atomic.Load(&mheap_.sweepdone) != 0 { - // Since the sweeper is done, reset the scavenger's pointer - // into the heap and wake it if necessary. + // Since the sweeper is done, move the scavenge gen forward (signalling + // that there's new work to do) and wake the scavenger. // // The scavenger is signaled by the last sweeper because once // sweeping is done, we will definitely have useful work for @@ -259,7 +259,7 @@ func sweepone() uintptr { // with scavenging work. systemstack(func() { lock(&mheap_.lock) - mheap_.pages.resetScavengeAddr() + mheap_.pages.scavengeStartGen() unlock(&mheap_.lock) }) // Since we might sweep in an allocation path, it's not possible |