diff options
Diffstat (limited to 'src/runtime/time.go')
| -rw-r--r-- | src/runtime/time.go | 30 |
1 files changed, 20 insertions, 10 deletions
diff --git a/src/runtime/time.go b/src/runtime/time.go index ad267c33656..46e9a8c2abb 100644 --- a/src/runtime/time.go +++ b/src/runtime/time.go @@ -367,9 +367,9 @@ func deltimer(t *timer) bool { // dodeltimer removes timer i from the current P's heap. // We are locked on the P when this is called. -// It reports whether it saw no problems due to races. +// It returns the smallest changed index in pp.timers. // The caller must have locked the timers for pp. -func dodeltimer(pp *p, i int) { +func dodeltimer(pp *p, i int) int { if t := pp.timers[i]; t.pp.ptr() != pp { throw("dodeltimer: wrong P") } else { @@ -381,16 +381,18 @@ func dodeltimer(pp *p, i int) { } pp.timers[last] = nil pp.timers = pp.timers[:last] + smallestChanged := i if i != last { // Moving to i may have moved the last timer to a new parent, // so sift up to preserve the heap guarantee. - siftupTimer(pp.timers, i) + smallestChanged = siftupTimer(pp.timers, i) siftdownTimer(pp.timers, i) } if i == 0 { updateTimer0When(pp) } atomic.Xadd(&pp.numTimers, -1) + return smallestChanged } // dodeltimer0 removes timer 0 from the current P's heap. @@ -675,13 +677,14 @@ func adjusttimers(pp *p, now int64) { switch s := atomic.Load(&t.status); s { case timerDeleted: if atomic.Cas(&t.status, s, timerRemoving) { - dodeltimer(pp, i) + changed := dodeltimer(pp, i) if !atomic.Cas(&t.status, timerRemoving, timerRemoved) { badTimer() } atomic.Xadd(&pp.deletedTimers, -1) - // Look at this heap position again. - i-- + // Go back to the earliest changed heap entry. + // "- 1" because the loop will add 1. + i = changed - 1 } case timerModifiedEarlier, timerModifiedLater: if atomic.Cas(&t.status, s, timerMoving) { @@ -691,10 +694,11 @@ func adjusttimers(pp *p, now int64) { // We don't add it back yet because the // heap manipulation could cause our // loop to skip some other timer. - dodeltimer(pp, i) + changed := dodeltimer(pp, i) moved = append(moved, t) - // Look at this heap position again. - i-- + // Go back to the earliest changed heap entry. + // "- 1" because the loop will add 1. + i = changed - 1 } case timerNoStatus, timerRunning, timerRemoving, timerRemoved, timerMoving: badTimer() @@ -1044,7 +1048,10 @@ func timeSleepUntil() (int64, *p) { // "panic holding locks" message. Instead, we panic while not // holding a lock. -func siftupTimer(t []*timer, i int) { +// siftupTimer puts the timer at position i in the right place +// in the heap by moving it up toward the top of the heap. +// It returns the smallest changed index. +func siftupTimer(t []*timer, i int) int { if i >= len(t) { badTimer() } @@ -1064,8 +1071,11 @@ func siftupTimer(t []*timer, i int) { if tmp != t[i] { t[i] = tmp } + return i } +// siftdownTimer puts the timer at position i in the right place +// in the heap by moving it down toward the bottom of the heap. func siftdownTimer(t []*timer, i int) { n := len(t) if i >= n { |