diff options
Diffstat (limited to 'src/runtime')
| -rw-r--r-- | src/runtime/chan.go | 48 | ||||
| -rw-r--r-- | src/runtime/lockrank.go | 63 | ||||
| -rw-r--r-- | src/runtime/mklockrank.go | 6 | ||||
| -rw-r--r-- | src/runtime/time.go | 141 |
4 files changed, 201 insertions, 57 deletions
diff --git a/src/runtime/chan.go b/src/runtime/chan.go index ae26be3c42..8aca024c4c 100644 --- a/src/runtime/chan.go +++ b/src/runtime/chan.go @@ -323,6 +323,35 @@ func send(c *hchan, sg *sudog, ep unsafe.Pointer, unlockf func(), skip int) { goready(gp, skip+1) } +// timerchandrain removes all elements in channel c's buffer. +// It reports whether any elements were removed. +// Because it is only intended for timers, it does not +// handle waiting senders at all (all timer channels +// use non-blocking sends to fill the buffer). +func timerchandrain(c *hchan) bool { + // Note: Cannot use empty(c) because we are called + // while holding c.timer.sendLock, and empty(c) will + // call c.timer.maybeRunChan, which will deadlock. + // We are emptying the channel, so we only care about + // the count, not about potentially filling it up. + if atomic.Loaduint(&c.qcount) == 0 { + return false + } + lock(&c.lock) + any := false + for c.qcount > 0 { + any = true + typedmemclr(c.elemtype, chanbuf(c, c.recvx)) + c.recvx++ + if c.recvx == c.dataqsiz { + c.recvx = 0 + } + c.qcount-- + } + unlock(&c.lock) + return any +} + // Sends and receives on unbuffered or empty-buffered channels are the // only operations where one running goroutine writes to the stack of // another running goroutine. The GC assumes that stack writes only @@ -748,9 +777,16 @@ func chanlen(c *hchan) int { if c == nil { return 0 } - if c.timer != nil { + async := debug.asynctimerchan.Load() != 0 + if c.timer != nil && async { c.timer.maybeRunChan() } + if c.timer != nil && !async { + // timer channels have a buffered implementation + // but present to users as unbuffered, so that we can + // undo sends without users noticing. + return 0 + } return int(c.qcount) } @@ -758,6 +794,16 @@ func chancap(c *hchan) int { if c == nil { return 0 } + if c.timer != nil { + async := debug.asynctimerchan.Load() != 0 + if async { + return int(c.dataqsiz) + } + // timer channels have a buffered implementation + // but present to users as unbuffered, so that we can + // undo sends without users noticing. + return 0 + } return int(c.dataqsiz) } diff --git a/src/runtime/lockrank.go b/src/runtime/lockrank.go index a6f61240db..33b0387686 100644 --- a/src/runtime/lockrank.go +++ b/src/runtime/lockrank.go @@ -20,6 +20,7 @@ const ( lockRankSweep lockRankTestR lockRankTestW + lockRankTimerSend lockRankAllocmW lockRankExecW lockRankCpuprof @@ -91,6 +92,7 @@ var lockNames = []string{ lockRankSweep: "sweep", lockRankTestR: "testR", lockRankTestW: "testW", + lockRankTimerSend: "timerSend", lockRankAllocmW: "allocmW", lockRankExecW: "execW", lockRankCpuprof: "cpuprof", @@ -168,51 +170,52 @@ var lockPartialOrder [][]lockRank = [][]lockRank{ lockRankSweep: {}, lockRankTestR: {}, lockRankTestW: {}, + lockRankTimerSend: {}, lockRankAllocmW: {}, lockRankExecW: {}, lockRankCpuprof: {}, lockRankPollCache: {}, lockRankPollDesc: {}, lockRankWakeableSleep: {}, - lockRankHchan: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankWakeableSleep, lockRankHchan}, - lockRankAllocmR: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan}, - lockRankExecR: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan}, - lockRankSched: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR}, - lockRankAllg: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched}, - lockRankAllp: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched}, + lockRankHchan: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankWakeableSleep, lockRankHchan}, + lockRankAllocmR: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan}, + lockRankExecR: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan}, + lockRankSched: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR}, + lockRankAllg: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched}, + lockRankAllp: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched}, lockRankNotifyList: {}, - lockRankSudog: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankWakeableSleep, lockRankHchan, lockRankNotifyList}, - lockRankTimers: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankTimers}, - lockRankTimer: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankTimers}, - lockRankNetpollInit: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankTimers, lockRankTimer}, + lockRankSudog: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankWakeableSleep, lockRankHchan, lockRankNotifyList}, + lockRankTimers: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankTimers}, + lockRankTimer: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankTimers}, + lockRankNetpollInit: {lockRankSysmon, lockRankScavenge, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankTimers, lockRankTimer}, lockRankRoot: {}, lockRankItab: {}, lockRankReflectOffs: {lockRankItab}, lockRankUserArenaState: {}, lockRankTraceBuf: {lockRankSysmon, lockRankScavenge}, lockRankTraceStrings: {lockRankSysmon, lockRankScavenge, lockRankTraceBuf}, - lockRankFin: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankSpanSetSpine: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankMspanSpecial: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankGcBitsArenas: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankMspanSpecial}, - lockRankProfInsert: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankProfBlock: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankProfMemActive: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings}, - lockRankProfMemFuture: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankProfMemActive}, - lockRankGscan: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture}, - lockRankStackpool: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, - lockRankStackLarge: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, - lockRankHchanLeaf: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankHchanLeaf}, - lockRankWbufSpans: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, - lockRankMheap: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans}, - lockRankMheapSpecial: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap}, - lockRankGlobalAlloc: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap, lockRankMheapSpecial}, - lockRankTrace: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap}, - lockRankTraceStackTab: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap, lockRankTrace}, + lockRankFin: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, 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, lockRankSweepWaiters, lockRankAssistQueue, 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, lockRankSweepWaiters, lockRankAssistQueue, 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, lockRankSweepWaiters, lockRankAssistQueue, 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, lockRankSweepWaiters, lockRankAssistQueue, 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, lockRankSweepWaiters, lockRankAssistQueue, 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, lockRankSweepWaiters, lockRankAssistQueue, 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, lockRankSweepWaiters, lockRankAssistQueue, 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, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture}, + lockRankStackpool: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, + lockRankStackLarge: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, + lockRankHchanLeaf: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankHchanLeaf}, + lockRankWbufSpans: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan}, + lockRankMheap: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans}, + lockRankMheapSpecial: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap}, + lockRankGlobalAlloc: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap, lockRankMheapSpecial}, + lockRankTrace: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, lockRankUserArenaState, lockRankTraceBuf, lockRankTraceStrings, lockRankFin, lockRankSpanSetSpine, lockRankMspanSpecial, lockRankGcBitsArenas, lockRankProfInsert, lockRankProfBlock, lockRankProfMemActive, lockRankProfMemFuture, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankWbufSpans, lockRankMheap}, + lockRankTraceStackTab: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankDefer, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankExecW, lockRankCpuprof, lockRankPollCache, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR, lockRankExecR, lockRankSched, lockRankAllg, lockRankAllp, lockRankNotifyList, lockRankSudog, lockRankTimers, lockRankTimer, lockRankNetpollInit, lockRankRoot, lockRankItab, lockRankReflectOffs, 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, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankAllocmW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR}, - lockRankExecRInternal: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankExecW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankExecR}, + lockRankAllocmRInternal: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankTestR, lockRankTimerSend, lockRankAllocmW, lockRankCpuprof, lockRankPollDesc, lockRankWakeableSleep, lockRankHchan, lockRankAllocmR}, + lockRankExecRInternal: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, 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 75dc6f62cf..2b4b5e99cd 100644 --- a/src/runtime/mklockrank.go +++ b/src/runtime/mklockrank.go @@ -55,9 +55,11 @@ NONE < # Test only NONE < testR, testW; +NONE < timerSend; + # Scheduler, timers, netpoll NONE < allocmW, execW, cpuprof, pollCache, pollDesc, wakeableSleep; -scavenge, sweep, testR, wakeableSleep < hchan; +scavenge, sweep, testR, wakeableSleep, timerSend < hchan; assistQueue, cpuprof, forcegc, @@ -81,7 +83,7 @@ NONE < notifyList; hchan, notifyList < sudog; hchan, pollDesc, wakeableSleep < timers; -timers < timer < netpollInit; +timers, timerSend < timer < netpollInit; # Semaphores NONE < root; diff --git a/src/runtime/time.go b/src/runtime/time.go index 37c55b2b46..31c83ca4e3 100644 --- a/src/runtime/time.go +++ b/src/runtime/time.go @@ -36,11 +36,18 @@ type timer struct { // a well-behaved function and not block. // // The arg and seq are client-specified opaque arguments passed back to f. - // When used from package time, arg is a channel (for After, NewTicker) - // or the function to call (for AfterFunc) and seq is unused (0). // When used from netpoll, arg and seq have meanings defined by netpoll // and are completely opaque to this code; in that context, seq is a sequence // number to recognize and squech stale function invocations. + // When used from package time, arg is a channel (for After, NewTicker) + // or the function to call (for AfterFunc) and seq is unused (0). + // + // Package time does not know about seq, but if this is a channel timer (t.isChan == true), + // this file uses t.seq as a sequence number to recognize and squelch + // sends that correspond to an earlier (stale) timer configuration, + // similar to its use in netpoll. In this usage (that is, when t.isChan == true), + // writes to seq are protected by both t.mu and t.sendLock, + // so reads are allowed when holding either of the two mutexes. // // The delay argument is nanotime() - t.when, meaning the delay in ns between // when the timer should have gone off and now. Normally that amount is @@ -69,6 +76,10 @@ type timer struct { // Since writes to whenHeap are protected by two locks (t.mu and t.ts.mu), // it is permitted to read whenHeap when holding either one. whenHeap int64 + + // sendLock protects sends on the timer's channel. + // Not used for async (pre-Go 1.23) behavior when debug.asynctimerchan.Load() != 0. + sendLock mutex } // init initializes a newly allocated timer t. @@ -167,7 +178,7 @@ func (t *timer) trace1(op string) { return } bits := [4]string{"h", "m", "z", "c"} - for i := range bits { + for i := range 3 { if t.state&(1<<i) == 0 { bits[i] = "-" } @@ -199,6 +210,18 @@ func (t *timer) unlock() { unlock(&t.mu) } +// hchan returns the channel in t.arg. +// t must be a timer with a channel. +func (t *timer) hchan() *hchan { + if !t.isChan { + badTimer() + } + // Note: t.arg is a chan time.Time, + // and runtime cannot refer to that type, + // so we cannot use a type assertion. + return (*hchan)(efaceOf(&t.arg).data) +} + // updateHeap updates t.whenHeap as directed by t.state, updating t.state // and returning a bool indicating whether the state (and t.whenHeap) changed. // The caller must hold t's lock, or the world can be stopped instead. @@ -309,6 +332,7 @@ func newTimer(when, period int64, f func(arg any, seq uintptr, delay int64), arg racerelease(unsafe.Pointer(&t.timer)) } if c != nil { + lockInit(&t.sendLock, lockRankTimerSend) t.isChan = true c.timer = &t.timer if c.dataqsiz == 0 { @@ -372,17 +396,21 @@ func (ts *timers) addHeap(t *timer) { } } -// stop stops the timer t. It may be on some other P, so we can't -// actually remove it from the timers heap. We can only mark it as stopped. -// It will be removed in due course by the P whose heap it is on. -// Reports whether the timer was stopped before it was run. -func (t *timer) stop() bool { - t.lock() - t.trace("stop") +// maybeRunAsync checks whether t needs to be triggered and runs it if so. +// The caller is responsible for locking the timer and for checking that we +// are running timers in async mode. If the timer needs to be run, +// maybeRunAsync will unlock and re-lock it. +// The timer is always locked on return. +func (t *timer) maybeRunAsync() { + assertLockHeld(&t.mu) if t.state&timerHeaped == 0 && t.isChan && t.when > 0 { // If timer should have triggered already (but nothing looked at it yet), // trigger now, so that a receive after the stop sees the "old" value // that should be there. + // (It is possible to have t.blocked > 0 if there is a racing receive + // in blockTimerChan, but timerHeaped not being set means + // it hasn't run t.maybeAdd yet; in that case, running the + // timer ourselves now is fine.) if now := nanotime(); t.when <= now { systemstack(func() { t.unlockAndRun(now) // resets t.when @@ -390,6 +418,23 @@ func (t *timer) stop() bool { t.lock() } } +} + +// stop stops the timer t. It may be on some other P, so we can't +// actually remove it from the timers heap. We can only mark it as stopped. +// It will be removed in due course by the P whose heap it is on. +// Reports whether the timer was stopped before it was run. +func (t *timer) stop() bool { + async := debug.asynctimerchan.Load() != 0 + if !async && t.isChan { + lock(&t.sendLock) + } + + t.lock() + t.trace("stop") + if async { + t.maybeRunAsync() + } if t.state&timerHeaped != 0 { t.state |= timerModified if t.state&timerZombie == 0 { @@ -399,7 +444,20 @@ func (t *timer) stop() bool { } pending := t.when > 0 t.when = 0 + + if !async && t.isChan { + // Stop any future sends with stale values. + // See timer.unlockAndRun. + t.seq++ + } t.unlock() + if !async && t.isChan { + unlock(&t.sendLock) + if timerchandrain(t.hchan()) { + pending = true + } + } + return pending } @@ -439,8 +497,16 @@ func (t *timer) modify(when, period int64, f func(arg any, seq uintptr, delay in if period < 0 { throw("timer period must be non-negative") } + async := debug.asynctimerchan.Load() != 0 + + if !async && t.isChan { + lock(&t.sendLock) + } t.lock() + if async { + t.maybeRunAsync() + } t.trace("modify") t.period = period if f != nil { @@ -449,20 +515,6 @@ func (t *timer) modify(when, period int64, f func(arg any, seq uintptr, delay in t.seq = seq } - if t.state&timerHeaped == 0 && t.isChan && t.when > 0 { - // This is a timer for an unblocked channel. - // Perhaps it should have expired already. - if now := nanotime(); t.when <= now { - // The timer should have run already, - // but nothing has checked it yet. - // Run it now. - systemstack(func() { - t.unlockAndRun(now) // resets t.when - }) - t.lock() - } - } - wake := false pending := t.when > 0 t.when = when @@ -483,7 +535,20 @@ func (t *timer) modify(when, period int64, f func(arg any, seq uintptr, delay in } add := t.needsAdd() + + if !async && t.isChan { + // Stop any future sends with stale values. + // See timer.unlockAndRun. + t.seq++ + } t.unlock() + if !async && t.isChan { + if timerchandrain(t.hchan()) { + pending = true + } + unlock(&t.sendLock) + } + if add { t.maybeAdd() } @@ -936,7 +1001,35 @@ func (t *timer) unlockAndRun(now int64) { if ts != nil { ts.unlock() } + + async := debug.asynctimerchan.Load() != 0 + if !async && t.isChan { + // For a timer channel, we want to make sure that no stale sends + // happen after a t.stop or t.modify, but we cannot hold t.mu + // during the actual send (which f does) due to lock ordering. + // It can happen that we are holding t's lock above, we decide + // it's time to send a time value (by calling f), grab the parameters, + // unlock above, and then a t.stop or t.modify changes the timer + // and returns. At that point, the send needs not to happen after all. + // The way we arrange for it not to happen is that t.stop and t.modify + // both increment t.seq while holding both t.mu and t.sendLock. + // We copied the seq value above while holding t.mu. + // Now we can acquire t.sendLock (which will be held across the send) + // and double-check that t.seq is still the seq value we saw above. + // If not, the timer has been updated and we should skip the send. + // We skip the send by reassigning f to a no-op function. + lock(&t.sendLock) + if t.seq != seq { + f = func(any, uintptr, int64) {} + } + } + f(arg, seq, delay) + + if !async && t.isChan { + unlock(&t.sendLock) + } + if ts != nil { ts.lock() } |