diff options
| author | Michael Anthony Knyszek <mknyszek@google.com> | 2021-10-04 19:52:48 +0000 |
|---|---|---|
| committer | Michael Knyszek <mknyszek@google.com> | 2021-11-04 20:01:11 +0000 |
| commit | fc5e8cd6c9de00f8d7da645343934c548e62223e (patch) | |
| tree | 083c4a068fc0f971af4c6b31e3f8ea23b2a26c32 /src | |
| parent | 9b2dd1f7714b38f1bfe25676357b62c1bb4cad64 (diff) | |
| download | go-fc5e8cd6c9de00f8d7da645343934c548e62223e.tar.xz | |
runtime: update and access scavengeGoal atomically
The first step toward acquiring the heap lock less frequently in the
scavenger.
Change-Id: Idc69fd8602be2c83268c155951230d60e20b42fe
Reviewed-on: https://go-review.googlesource.com/c/go/+/353973
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')
| -rw-r--r-- | src/runtime/mgcscavenge.go | 8 | ||||
| -rw-r--r-- | src/runtime/mheap.go | 7 |
2 files changed, 9 insertions, 6 deletions
diff --git a/src/runtime/mgcscavenge.go b/src/runtime/mgcscavenge.go index fb9b5c8694..4edeb8739e 100644 --- a/src/runtime/mgcscavenge.go +++ b/src/runtime/mgcscavenge.go @@ -125,7 +125,7 @@ func gcPaceScavenger(heapGoal, lastHeapGoal uint64) { // information about the heap yet) so this is fine, and avoids a fault // or garbage data later. if lastHeapGoal == 0 { - mheap_.scavengeGoal = ^uint64(0) + atomic.Store64(&mheap_.scavengeGoal, ^uint64(0)) return } // Compute our scavenging goal. @@ -157,10 +157,10 @@ func gcPaceScavenger(heapGoal, lastHeapGoal uint64) { // the background scavenger. We disable the background scavenger if there's // less than one physical page of work to do because it's not worth it. if retainedNow <= retainedGoal || retainedNow-retainedGoal < uint64(physPageSize) { - mheap_.scavengeGoal = ^uint64(0) + atomic.Store64(&mheap_.scavengeGoal, ^uint64(0)) return } - mheap_.scavengeGoal = retainedGoal + atomic.Store64(&mheap_.scavengeGoal, retainedGoal) } // Sleep/wait state of the background scavenger. @@ -299,7 +299,7 @@ func bgscavenge(c chan int) { lock(&mheap_.lock) // If background scavenging is disabled or if there's no work to do just park. - retained, goal := heapRetained(), mheap_.scavengeGoal + retained, goal := heapRetained(), atomic.Load64(&mheap_.scavengeGoal) if retained <= goal { unlock(&mheap_.lock) return diff --git a/src/runtime/mheap.go b/src/runtime/mheap.go index 057ab06b1d..f2f6e7f4cf 100644 --- a/src/runtime/mheap.go +++ b/src/runtime/mheap.go @@ -111,6 +111,8 @@ type mheap struct { // scavengeGoal is the amount of total retained heap memory (measured by // heapRetained) that the runtime will try to maintain by returning memory // to the OS. + // + // Accessed atomically. scavengeGoal uint64 // Page reclaimer state @@ -1399,9 +1401,10 @@ func (h *mheap) grow(npage uintptr) bool { // By scavenging inline we deal with the failure to allocate out of // memory fragments by scavenging the memory fragments that are least // likely to be re-used. - if retained := heapRetained(); retained+uint64(totalGrowth) > h.scavengeGoal { + scavengeGoal := atomic.Load64(&h.scavengeGoal) + if retained := heapRetained(); retained+uint64(totalGrowth) > scavengeGoal { todo := totalGrowth - if overage := uintptr(retained + uint64(totalGrowth) - h.scavengeGoal); todo > overage { + if overage := uintptr(retained + uint64(totalGrowth) - scavengeGoal); todo > overage { todo = overage } h.pages.scavenge(todo, false) |