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| author | Rich Felker <dalias@aerifal.cx> | 2011-09-28 19:45:37 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2011-09-28 19:45:37 -0400 |
| commit | de543b05c87d79a9313991810e9ee8ecdaad8f19 (patch) | |
| tree | abde9355e67731c9e8b48ccdd107405cb35b6e03 | |
| parent | ede5ae7b0bb5a7ed9edeb2eeb8e24d30af64d185 (diff) | |
| download | musl-de543b05c87d79a9313991810e9ee8ecdaad8f19.tar.gz | |
fix excessive/insufficient wakes in __vm_unlock
there is no need to send a wake when the lock count does not hit zero,
but when it does, all waiters must be woken (since all with the same
sign are eligible to obtain the lock).
| -rw-r--r-- | src/thread/pthread_barrier_wait.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/src/thread/pthread_barrier_wait.c b/src/thread/pthread_barrier_wait.c index 71f7b5fe..6052925a 100644 --- a/src/thread/pthread_barrier_wait.c +++ b/src/thread/pthread_barrier_wait.c @@ -13,9 +13,9 @@ void __vm_lock(int inc) void __vm_unlock(void) { - if (vmlock[0]>0) a_dec(vmlock); - else a_inc(vmlock); - if (vmlock[1]) __wake(vmlock, 1, 1); + int inc = vmlock[0]>0 ? -1 : 1; + if (a_fetch_add(vmlock, inc)==-inc && vmlock[1]) + __wake(vmlock, -1, 1); } static int pshared_barrier_wait(pthread_barrier_t *b) |