diff --git a/src/runtime/proc.go b/src/runtime/proc.go index c477910c9e..0a7321254c 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -2615,6 +2615,23 @@ top: resetspinning() } + if sched.disable.user && !schedEnabled(gp) { + // Scheduling of this goroutine is disabled. Put it on + // the list of pending runnable goroutines for when we + // re-enable user scheduling and look again. + lock(&sched.lock) + if schedEnabled(gp) { + // Something re-enabled scheduling while we + // were acquiring the lock. + unlock(&sched.lock) + } else { + sched.disable.runnable.pushBack(gp) + sched.disable.n++ + unlock(&sched.lock) + goto top + } + } + if gp.lockedm != 0 { // Hands off own p to the locked m, // then blocks waiting for a new p. @@ -3033,6 +3050,12 @@ func exitsyscall() { _g_.stackguard0 = _g_.stack.lo + _StackGuard } _g_.throwsplit = false + + if sched.disable.user && !schedEnabled(_g_) { + // Scheduling of this goroutine is disabled. + Gosched() + } + return } @@ -3168,7 +3191,10 @@ func exitsyscall0(gp *g) { casgstatus(gp, _Gsyscall, _Grunnable) dropg() lock(&sched.lock) - _p_ := pidleget() + var _p_ *p + if schedEnabled(_g_) { + _p_ = pidleget() + } if _p_ == nil { globrunqput(gp) } else if atomic.Load(&sched.sysmonwait) != 0 { @@ -4625,6 +4651,40 @@ func schedtrace(detailed bool) { unlock(&sched.lock) } +// schedEnableUser enables or disables the scheduling of user +// goroutines. +// +// This does not stop already running user goroutines, so the caller +// should first stop the world when disabling user goroutines. +func schedEnableUser(enable bool) { + lock(&sched.lock) + if sched.disable.user == !enable { + unlock(&sched.lock) + return + } + sched.disable.user = !enable + if enable { + n := sched.disable.n + sched.disable.n = 0 + globrunqputbatch(&sched.disable.runnable, n) + unlock(&sched.lock) + for ; n != 0 && sched.npidle != 0; n-- { + startm(nil, false) + } + } else { + unlock(&sched.lock) + } +} + +// schedEnabled returns whether gp should be scheduled. It returns +// false is scheduling of gp is disabled. +func schedEnabled(gp *g) bool { + if sched.disable.user { + return isSystemGoroutine(gp, true) + } + return true +} + // Put mp on midle list. // Sched must be locked. // May run during STW, so write barriers are not allowed. diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go index 259bb376ae..fbca3d3ba6 100644 --- a/src/runtime/runtime2.go +++ b/src/runtime/runtime2.go @@ -580,6 +580,18 @@ type schedt struct { runq gQueue runqsize int32 + // disable controls selective disabling of the scheduler. + // + // Use schedEnableUser to control this. + // + // disable is protected by sched.lock. + disable struct { + // user disables scheduling of user goroutines. + user bool + runnable gQueue // pending runnable Gs + n int32 // length of runnable + } + // Global cache of dead G's. gFree struct { lock mutex