From: Michael Pratt Date: Wed, 28 May 2025 20:01:33 +0000 (-0400) Subject: runtime: guarantee no GOMAXPROCS update syscalls after GOMAXPROCS call X-Git-Tag: go1.25rc1~41 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=e481a08e0ecb823f368318b142d3dec7340fe51e;p=gostls13.git runtime: guarantee no GOMAXPROCS update syscalls after GOMAXPROCS call We already guarantee that no automatic updates to GOMAXPROCS occur after a GOMAXPROCS call returns. This is easily achieved by having the update goroutine double-check that updates are still allowed during STW before committing the new value. However, it is possible for sysmon to concurrently run defaultGOMAXPROCS to compute a new GOMAXPROCS value after GOMAXPROCS returns. This new value will be discarded later, but we'll still perform the system calls necessary to compute the new value. Normally this distinction doesn't matter, but if you want to sandbox a Go program, then you may want to disable GOMAXPROCS updates to reduce the system call footprint. A call to GOMAXPROCS will disable updates, but without a guarantee on when sysmon will observe the change it is somewhat fragile. Add explicit synchronization between GOMAXPROCS and sysmon to guarantee that sysmon won't run defaultGOMAXPROCS after GOMAXPROCS returns. The synchronization is a bit complex because we can't hold a mutex across STW, nor take a semaphore from sysmon, but the result isn't too bad. One oddity is that sched.customGOMAXPROCS and gomaxprocs are no longer updated in lockstep (even though both are protected by sched.lock), but I don't believe anything should depend on that. For #73193. Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64-staticlockranking Change-Id: I6a6a636cff243a9b69ac1b5d2f98925648e60236 Reviewed-on: https://go-review.googlesource.com/c/go/+/677037 LUCI-TryBot-Result: Go LUCI Reviewed-by: Michael Knyszek --- diff --git a/src/runtime/debug.go b/src/runtime/debug.go index 94d1dab34d..bdaaa7196d 100644 --- a/src/runtime/debug.go +++ b/src/runtime/debug.go @@ -39,10 +39,18 @@ func GOMAXPROCS(n int) int { lock(&sched.lock) ret := int(gomaxprocs) - unlock(&sched.lock) if n <= 0 || n == ret { + unlock(&sched.lock) return ret } + // Set early so we can wait for sysmon befor STW. See comment on + // computeMaxProcsLock. + sched.customGOMAXPROCS = true + unlock(&sched.lock) + + // Wait for sysmon to complete running defaultGOMAXPROCS. + lock(&computeMaxProcsLock) + unlock(&computeMaxProcsLock) stw := stopTheWorldGC(stwGOMAXPROCS) @@ -51,7 +59,6 @@ func GOMAXPROCS(n int) int { // TODO(prattmic): this could use a nicer API. Perhaps add it to the // stw parameter? newprocs = int32(n) - newprocsCustom = true startTheWorldGC(stw) return ret @@ -91,7 +98,9 @@ func SetDefaultGOMAXPROCS() { // TODO(prattmic): this could use a nicer API. Perhaps add it to the // stw parameter? newprocs = procs - newprocsCustom = false + lock(&sched.lock) + sched.customGOMAXPROCS = false + unlock(&sched.lock) startTheWorldGC(stw) } diff --git a/src/runtime/lockrank.go b/src/runtime/lockrank.go index 26a8e7b30b..c10d243f77 100644 --- a/src/runtime/lockrank.go +++ b/src/runtime/lockrank.go @@ -14,6 +14,7 @@ const ( lockRankSysmon lockRankScavenge lockRankForcegc + lockRankComputeMaxProcs lockRankUpdateMaxProcsG lockRankDefer lockRankSweepWaiters @@ -91,6 +92,7 @@ var lockNames = []string{ lockRankSysmon: "sysmon", lockRankScavenge: "scavenge", lockRankForcegc: "forcegc", + lockRankComputeMaxProcs: "computeMaxProcs", lockRankUpdateMaxProcsG: "updateMaxProcsG", lockRankDefer: "defer", lockRankSweepWaiters: "sweepWaiters", @@ -174,6 +176,7 @@ var lockPartialOrder [][]lockRank = [][]lockRank{ lockRankSysmon: {}, lockRankScavenge: {lockRankSysmon}, lockRankForcegc: {lockRankSysmon}, + lockRankComputeMaxProcs: {lockRankSysmon}, lockRankUpdateMaxProcsG: {lockRankSysmon}, lockRankDefer: {}, lockRankSweepWaiters: {}, @@ -191,11 +194,11 @@ var lockPartialOrder [][]lockRank = [][]lockRank{ lockRankPollDesc: {}, lockRankWakeableSleep: {}, lockRankHchan: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankWakeableSleep, lockRankHchan}, - lockRankAllocmR: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan}, - lockRankExecR: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan}, - lockRankSched: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR}, - lockRankAllg: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched}, - lockRankAllp: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched}, + lockRankAllocmR: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan}, + lockRankExecR: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan}, + lockRankSched: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR}, + lockRankAllg: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched}, + lockRankAllp: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched}, lockRankNotifyList: {}, lockRankSudog: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankWakeableSleep, lockRankHchan, lockRankNotifyList}, lockRankTimers: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankTimers}, @@ -208,29 +211,29 @@ var lockPartialOrder [][]lockRank = [][]lockRank{ lockRankUserArenaState: {}, lockRankTraceBuf: {lockRankSysmon, lockRankScavenge}, lockRankTraceStrings: {lockRankSysmon, lockRankScavenge, lockRankTraceBuf}, - lockRankFin: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankSpanSetSpine: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankMspanSpecial: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankTraceTypeTab: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankGcBitsArenas: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankMspanSpecial}, - lockRankProfInsert: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankProfBlock: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankProfMemActive: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankProfMemFuture: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankProfMemActive}, - lockRankGscan: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture}, - lockRankStackpool: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, - lockRankStackLarge: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, - lockRankHchanLeaf: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankHchanLeaf}, - lockRankWbufSpans: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, - lockRankMheap: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans}, - lockRankMheapSpecial: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap}, - lockRankGlobalAlloc: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap, lockRankMheapSpecial}, - lockRankTrace: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap}, - lockRankTraceStackTab: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap, lockRankTrace}, + lockRankFin: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, + lockRankSpanSetSpine: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, + lockRankMspanSpecial: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, + lockRankTraceTypeTab: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, + lockRankGcBitsArenas: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankMspanSpecial}, + lockRankProfInsert: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, + lockRankProfBlock: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, + lockRankProfMemActive: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, + lockRankProfMemFuture: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankProfMemActive}, + lockRankGscan: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture}, + lockRankStackpool: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, + lockRankStackLarge: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, + lockRankHchanLeaf: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankHchanLeaf}, + lockRankWbufSpans: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, + lockRankMheap: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans}, + lockRankMheapSpecial: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap}, + lockRankGlobalAlloc: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap, lockRankMheapSpecial}, + lockRankTrace: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap}, + lockRankTraceStackTab: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankSynctest, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap, lockRankTrace}, lockRankPanic: {}, lockRankDeadlock: {lockRankPanic, lockRankDeadlock}, lockRankRaceFini: {lockRankPanic}, - lockRankAllocmRInternal: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankAllocmW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR}, - lockRankExecRInternal: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankExecR}, + lockRankAllocmRInternal: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankAllocmW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR}, + lockRankExecRInternal: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankComputeMaxProcs, lockRankUpdateMaxProcsG, lockRankSweepWaiters, lockRankAssistQueue, lockRankStrongFromWeakQueue, lockRankCleanupQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankExecR}, lockRankTestRInternal: {lockRankTestR, lockRankTestW}, } diff --git a/src/runtime/mklockrank.go b/src/runtime/mklockrank.go index c5c1328584..aa0dd65912 100644 --- a/src/runtime/mklockrank.go +++ b/src/runtime/mklockrank.go @@ -41,7 +41,7 @@ const ranks = ` # Sysmon NONE < sysmon -< scavenge, forcegc, updateMaxProcsG; +< scavenge, forcegc, computeMaxProcs, updateMaxProcsG; # Defer NONE < defer; @@ -64,6 +64,7 @@ NONE < allocmW, execW, cpuprof, pollCache, pollDesc, wakeableSleep; scavenge, sweep, testR, wakeableSleep, timerSend < hchan; assistQueue, cleanupQueue, + computeMaxProcs, cpuprof, forcegc, updateMaxProcsG, diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 4ccce90e93..5b8db2bee4 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -835,6 +835,7 @@ func schedinit() { lockInit(&reflectOffs.lock, lockRankReflectOffs) lockInit(&finlock, lockRankFin) lockInit(&cpuprof.lock, lockRankCpuprof) + lockInit(&computeMaxProcsLock, lockRankComputeMaxProcs) allocmLock.init(lockRankAllocmR, lockRankAllocmRInternal, lockRankAllocmW) execLock.init(lockRankExecR, lockRankExecRInternal, lockRankExecW) traceLockInit() @@ -1727,7 +1728,6 @@ func startTheWorldWithSema(now int64, w worldStop) int64 { procs := gomaxprocs if newprocs != 0 { procs = newprocs - sched.customGOMAXPROCS = newprocsCustom newprocs = 0 } p1 := procresize(procs) @@ -6560,7 +6560,58 @@ var ( // GOMAXPROCS updates actually change the value of GOMAXPROCS. updatemaxprocs = &godebugInc{name: "updatemaxprocs"} + // Synchronization and state between updateMaxProcsGoroutine and + // sysmon. updateMaxProcsG updateMaxProcsGState + + // Synchronization between GOMAXPROCS and sysmon. + // + // Setting GOMAXPROCS via a call to GOMAXPROCS disables automatic + // GOMAXPROCS updates. + // + // We want to make two guarantees to callers of GOMAXPROCS. After + // GOMAXPROCS returns: + // + // 1. The runtime will not make any automatic changes to GOMAXPROCS. + // + // 2. The runtime will not perform any of the system calls used to + // determine the appropriate value of GOMAXPROCS (i.e., it won't + // call defaultGOMAXPROCS). + // + // (1) is the baseline guarantee that everyone needs. The GOMAXPROCS + // API isn't useful to anyone if automatic updates may occur after it + // returns. This is easily achieved by double-checking the state under + // STW before committing an automatic GOMAXPROCS update. + // + // (2) doesn't matter to most users, as it is isn't observable as long + // as (1) holds. However, it can be important to users sandboxing Go. + // They want disable these system calls and need some way to know when + // they are guaranteed the calls will stop. + // + // This would be simple to achieve if we simply called + // defaultGOMAXPROCS under STW in updateMaxProcsGoroutine below. + // However, we would like to avoid scheduling this goroutine every + // second when it will almost never do anything. Instead, sysmon calls + // defaultGOMAXPROCS to decide whether to schedule + // updateMaxProcsGoroutine. Thus we need to synchronize between sysmon + // and GOMAXPROCS calls. + // + // GOMAXPROCS can't hold a runtime mutex across STW. It could hold a + // semaphore, but sysmon cannot take semaphores. Instead, we have a + // more complex scheme: + // + // * sysmon holds computeMaxProcsLock while calling defaultGOMAXPROCS. + // * sysmon skips the current update if sched.customGOMAXPROCS is + // set. + // * GOMAXPROCS sets sched.customGOMAXPROCS once it is committed to + // changing GOMAXPROCS. + // * GOMAXPROCS takes computeMaxProcsLock to wait for outstanding + // defaultGOMAXPROCS calls to complete. + // + // N.B. computeMaxProcsLock could simply be sched.lock, but we want to + // avoid holding that lock during the potentially slow + // defaultGOMAXPROCS. + computeMaxProcsLock mutex ) // Start GOMAXPROCS update helper goroutine. @@ -6614,25 +6665,31 @@ func updateMaxProcsGoroutine() { // TODO(prattmic): this could use a nicer API. Perhaps add it to the // stw parameter? newprocs = updateMaxProcsG.procs - newprocsCustom = false + lock(&sched.lock) + sched.customGOMAXPROCS = false + unlock(&sched.lock) startTheWorldGC(stw) } } func sysmonUpdateGOMAXPROCS() { + // Synchronize with GOMAXPROCS. See comment on computeMaxProcsLock. + lock(&computeMaxProcsLock) + // No update if GOMAXPROCS was set manually. lock(&sched.lock) custom := sched.customGOMAXPROCS curr := gomaxprocs unlock(&sched.lock) if custom { + unlock(&computeMaxProcsLock) return } // Don't hold sched.lock while we read the filesystem. procs := defaultGOMAXPROCS(0) - + unlock(&computeMaxProcsLock) if procs == curr { // Nothing to do. return diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go index cd40586bc2..589642efc6 100644 --- a/src/runtime/runtime2.go +++ b/src/runtime/runtime2.go @@ -1213,7 +1213,6 @@ var ( forcegc forcegcstate sched schedt newprocs int32 - newprocsCustom bool // newprocs value is manually set via runtime.GOMAXPROCS. ) var (