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authorRich Felker <dalias@aerifal.cx>2011-04-06 12:24:34 -0400
committerRich Felker <dalias@aerifal.cx>2011-04-06 12:24:34 -0400
commita113434cd68ce30642c4995b1caadcd084be6f09 (patch)
treeb26daaeda2c9e2caf1605615c497a4a84191e01d /src/thread/sem_post.c
parentcd3bb38412cfcc3bc47985ba25287e0af463609a (diff)
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major semaphore improvements (performance and correctness)
1. make sem_[timed]wait interruptible by signals, per POSIX
2. keep a waiter count in order to avoid unnecessary futex wake syscalls
Diffstat (limited to 'src/thread/sem_post.c')
-rw-r--r--src/thread/sem_post.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/src/thread/sem_post.c b/src/thread/sem_post.c
index 0bd8a462..8f4700c3 100644
--- a/src/thread/sem_post.c
+++ b/src/thread/sem_post.c
@@ -3,7 +3,8 @@
 
 int sem_post(sem_t *sem)
 {
-	if (!a_fetch_add(sem->__val, 1))
+	a_inc(sem->__val);
+	if (sem->__val[1])
 		__wake(sem->__val, 1, 0);
 	return 0;
 }