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authorRich Felker <dalias@aerifal.cx>2015-04-22 03:24:37 -0400
committerRich Felker <dalias@aerifal.cx>2015-04-22 03:24:37 -0400
commitafbcac6826988d12d9a874359cab735049c17500 (patch)
tree61a1f9e9066c22003337266d5847079ede7067d5 /src
parent7b1fb0c526936873a260e860ce3bca82113c3d4c (diff)
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minor optimization to pthread_spin_trylock
use CAS instead of swap since it's lighter for most archs, and keep
EBUSY in the lock value so that the old value obtained by CAS can be
used directly as the return value for pthread_spin_trylock.
Diffstat (limited to 'src')
-rw-r--r--src/thread/pthread_spin_lock.c3
-rw-r--r--src/thread/pthread_spin_trylock.c3
2 files changed, 4 insertions, 2 deletions
diff --git a/src/thread/pthread_spin_lock.c b/src/thread/pthread_spin_lock.c
index 0462e0f3..ded2b653 100644
--- a/src/thread/pthread_spin_lock.c
+++ b/src/thread/pthread_spin_lock.c
@@ -1,7 +1,8 @@
 #include "pthread_impl.h"
+#include <errno.h>
 
 int pthread_spin_lock(pthread_spinlock_t *s)
 {
-	while (*(volatile int *)s || a_cas(s, 0, 1)) a_spin();
+	while (*(volatile int *)s || a_cas(s, 0, EBUSY)) a_spin();
 	return 0;
 }
diff --git a/src/thread/pthread_spin_trylock.c b/src/thread/pthread_spin_trylock.c
index 59de695d..5284fdac 100644
--- a/src/thread/pthread_spin_trylock.c
+++ b/src/thread/pthread_spin_trylock.c
@@ -1,6 +1,7 @@
 #include "pthread_impl.h"
+#include <errno.h>
 
 int pthread_spin_trylock(pthread_spinlock_t *s)
 {
-	return -a_swap(s, 1) & EBUSY;
+	return a_cas(s, 0, EBUSY);
 }