diff options
Diffstat (limited to 'src/runtime/debug_test.go')
| -rw-r--r-- | src/runtime/debug_test.go | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/src/runtime/debug_test.go b/src/runtime/debug_test.go index 44585b1744..5bb0c5cee3 100644 --- a/src/runtime/debug_test.go +++ b/src/runtime/debug_test.go @@ -34,10 +34,17 @@ func startDebugCallWorker(t *testing.T) (g *runtime.G, after func()) { skipUnderDebugger(t) // This can deadlock if there aren't enough threads or if a GC - // tries to interrupt an atomic loop (see issue #10958). A GC - // could also actively be in progress (see issue #49370), so we - // need to call runtime.GC to block until it has complete. We - // use 8 Ps so there's room for the debug call worker, + // tries to interrupt an atomic loop (see issue #10958). Execute + // an extra GC to ensure even the sweep phase is done (out of + // caution to prevent #49370 from happening). + // TODO(mknyszek): This extra GC cycle is likely unnecessary + // because preemption (which may happen during the sweep phase) + // isn't much of an issue anymore thanks to asynchronous preemption. + // The biggest risk is having a write barrier in the debug call + // injection test code fire, because it runs in a signal handler + // and may not have a P. + // + // We use 8 Ps so there's room for the debug call worker, // something that's trying to preempt the call worker, and the // goroutine that's trying to stop the call worker. ogomaxprocs := runtime.GOMAXPROCS(8) @@ -270,8 +277,14 @@ func TestDebugCallPanic(t *testing.T) { // progress. Wait until the current GC is done, and turn it off. // // See #10958 and #49370. - runtime.GC() defer debug.SetGCPercent(debug.SetGCPercent(-1)) + // TODO(mknyszek): This extra GC cycle is likely unnecessary + // because preemption (which may happen during the sweep phase) + // isn't much of an issue anymore thanks to asynchronous preemption. + // The biggest risk is having a write barrier in the debug call + // injection test code fire, because it runs in a signal handler + // and may not have a P. + runtime.GC() ready := make(chan *runtime.G) var stop uint32 |