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runtime: convert schedt.sysmonwait to atomic type

This converts a few unsynchronized accesses.

For #53821.

Change-Id: Ie2728779111e3e042696f15648981c5d5a86ca6d
Reviewed-on: https://go-review.googlesource.com/c/go/+/419448
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This commit is contained in:
Michael Pratt 2022-07-25 15:39:07 -04:00
parent 88ef50e662
commit 09cc9bac72
2 changed files with 13 additions and 13 deletions

View File

@ -1271,8 +1271,8 @@ func startTheWorldWithSema(emitTraceEvent bool) int64 {
} }
p1 := procresize(procs) p1 := procresize(procs)
sched.gcwaiting.Store(false) sched.gcwaiting.Store(false)
if sched.sysmonwait != 0 { if sched.sysmonwait.Load() {
sched.sysmonwait = 0 sched.sysmonwait.Store(false)
notewakeup(&sched.sysmonnote) notewakeup(&sched.sysmonnote)
} }
unlock(&sched.lock) unlock(&sched.lock)
@ -3632,7 +3632,7 @@ func reentersyscall(pc, sp uintptr) {
save(pc, sp) save(pc, sp)
} }
if atomic.Load(&sched.sysmonwait) != 0 { if sched.sysmonwait.Load() {
systemstack(entersyscall_sysmon) systemstack(entersyscall_sysmon)
save(pc, sp) save(pc, sp)
} }
@ -3670,8 +3670,8 @@ func entersyscall() {
func entersyscall_sysmon() { func entersyscall_sysmon() {
lock(&sched.lock) lock(&sched.lock)
if atomic.Load(&sched.sysmonwait) != 0 { if sched.sysmonwait.Load() {
atomic.Store(&sched.sysmonwait, 0) sched.sysmonwait.Store(false)
notewakeup(&sched.sysmonnote) notewakeup(&sched.sysmonnote)
} }
unlock(&sched.lock) unlock(&sched.lock)
@ -3908,8 +3908,8 @@ func exitsyscallfast_reacquired() {
func exitsyscallfast_pidle() bool { func exitsyscallfast_pidle() bool {
lock(&sched.lock) lock(&sched.lock)
pp, _ := pidleget(0) pp, _ := pidleget(0)
if pp != nil && atomic.Load(&sched.sysmonwait) != 0 { if pp != nil && sched.sysmonwait.Load() {
atomic.Store(&sched.sysmonwait, 0) sched.sysmonwait.Store(false)
notewakeup(&sched.sysmonnote) notewakeup(&sched.sysmonnote)
} }
unlock(&sched.lock) unlock(&sched.lock)
@ -3944,8 +3944,8 @@ func exitsyscall0(gp *g) {
// could race with another M transitioning gp from unlocked to // could race with another M transitioning gp from unlocked to
// locked. // locked.
locked = gp.lockedm != 0 locked = gp.lockedm != 0
} else if atomic.Load(&sched.sysmonwait) != 0 { } else if sched.sysmonwait.Load() {
atomic.Store(&sched.sysmonwait, 0) sched.sysmonwait.Store(false)
notewakeup(&sched.sysmonnote) notewakeup(&sched.sysmonnote)
} }
unlock(&sched.lock) unlock(&sched.lock)
@ -5161,7 +5161,7 @@ func sysmon() {
syscallWake := false syscallWake := false
next := timeSleepUntil() next := timeSleepUntil()
if next > now { if next > now {
atomic.Store(&sched.sysmonwait, 1) sched.sysmonwait.Store(true)
unlock(&sched.lock) unlock(&sched.lock)
// Make wake-up period small enough // Make wake-up period small enough
// for the sampling to be correct. // for the sampling to be correct.
@ -5178,7 +5178,7 @@ func sysmon() {
osRelax(false) osRelax(false)
} }
lock(&sched.lock) lock(&sched.lock)
atomic.Store(&sched.sysmonwait, 0) sched.sysmonwait.Store(false)
noteclear(&sched.sysmonnote) noteclear(&sched.sysmonnote)
} }
if syscallWake { if syscallWake {
@ -5410,7 +5410,7 @@ func schedtrace(detailed bool) {
lock(&sched.lock) lock(&sched.lock)
print("SCHED ", (now-starttime)/1e6, "ms: gomaxprocs=", gomaxprocs, " idleprocs=", sched.npidle.Load(), " threads=", mcount(), " spinningthreads=", sched.nmspinning.Load(), " idlethreads=", sched.nmidle, " runqueue=", sched.runqsize) print("SCHED ", (now-starttime)/1e6, "ms: gomaxprocs=", gomaxprocs, " idleprocs=", sched.npidle.Load(), " threads=", mcount(), " spinningthreads=", sched.nmspinning.Load(), " idlethreads=", sched.nmidle, " runqueue=", sched.runqsize)
if detailed { if detailed {
print(" gcwaiting=", sched.gcwaiting.Load(), " nmidlelocked=", sched.nmidlelocked, " stopwait=", sched.stopwait, " sysmonwait=", sched.sysmonwait, "\n") print(" gcwaiting=", sched.gcwaiting.Load(), " nmidlelocked=", sched.nmidlelocked, " stopwait=", sched.stopwait, " sysmonwait=", sched.sysmonwait.Load(), "\n")
} }
// We must be careful while reading data from P's, M's and G's. // We must be careful while reading data from P's, M's and G's.
// Even if we hold schedlock, most data can be changed concurrently. // Even if we hold schedlock, most data can be changed concurrently.

View File

@ -820,7 +820,7 @@ type schedt struct {
gcwaiting atomic.Bool // gc is waiting to run gcwaiting atomic.Bool // gc is waiting to run
stopwait int32 stopwait int32
stopnote note stopnote note
sysmonwait uint32 sysmonwait atomic.Bool
sysmonnote note sysmonnote note
// safepointFn should be called on each P at the next GC // safepointFn should be called on each P at the next GC