diff options
Diffstat (limited to 'libgo/runtime/proc.c')
| -rw-r--r-- | libgo/runtime/proc.c | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/libgo/runtime/proc.c b/libgo/runtime/proc.c index 31e8287e704..9ad9f9659b9 100644 --- a/libgo/runtime/proc.c +++ b/libgo/runtime/proc.c @@ -406,7 +406,9 @@ runtime_schedinit(void) n = maxgomaxprocs; runtime_gomaxprocs = n; } - setmcpumax(runtime_gomaxprocs); + // wait for the main goroutine to start before taking + // GOMAXPROCS into account. + setmcpumax(1); runtime_singleproc = runtime_gomaxprocs == 1; canaddmcpu(); // mcpu++ to account for bootstrap m @@ -432,6 +434,8 @@ runtime_main(void) // by calling runtime.LockOSThread during initialization // to preserve the lock. runtime_LockOSThread(); + // From now on, newgoroutines may use non-main threads. + setmcpumax(runtime_gomaxprocs); runtime_sched.init = true; scvg = __go_go(runtime_MHeap_Scavenger, nil); main_init(); @@ -444,6 +448,11 @@ runtime_main(void) // roots. mstats.enablegc = 1; + // The deadlock detection has false negatives. + // Let scvg start up, to eliminate the false negative + // for the trivial program func main() { select{} }. + runtime_gosched(); + main_main(); runtime_exit(0); for(;;) @@ -791,6 +800,20 @@ top: } // Look for deadlock situation. + // There is a race with the scavenger that causes false negatives: + // if the scavenger is just starting, then we have + // scvg != nil && grunning == 0 && gwait == 0 + // and we do not detect a deadlock. It is possible that we should + // add that case to the if statement here, but it is too close to Go 1 + // to make such a subtle change. Instead, we work around the + // false negative in trivial programs by calling runtime.gosched + // from the main goroutine just before main.main. + // See runtime_main above. + // + // On a related note, it is also possible that the scvg == nil case is + // wrong and should include gwait, but that does not happen in + // standard Go programs, which all start the scavenger. + // if((scvg == nil && runtime_sched.grunning == 0) || (scvg != nil && runtime_sched.grunning == 1 && runtime_sched.gwait == 0 && (scvg->status == Grunning || scvg->status == Gsyscall))) { @@ -962,6 +985,11 @@ runtime_mstart(void* mp) } #endif + // Install signal handlers; after minit so that minit can + // prepare the thread to be able to handle the signals. + if(m == &runtime_m0) + runtime_initsig(); + schedule(nil); return nil; } |