From: Rich Felker <dalias@aerifal.cx>
Date: Wed, 22 Apr 2015 07:16:50 +0000 (-0400)
Subject: optimize spin lock not to dirty cache line while spinning
X-Git-Tag: v1.1.9~28
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=7b1fb0c526936873a260e860ce3bca82113c3d4c;p=oweals%2Fmusl.git

optimize spin lock not to dirty cache line while spinning
---

diff --git a/src/thread/pthread_spin_lock.c b/src/thread/pthread_spin_lock.c
index df575f08..0462e0f3 100644
--- a/src/thread/pthread_spin_lock.c
+++ b/src/thread/pthread_spin_lock.c
@@ -2,6 +2,6 @@
 
 int pthread_spin_lock(pthread_spinlock_t *s)
 {
-	while (a_swap(s, 1)) a_spin();
+	while (*(volatile int *)s || a_cas(s, 0, 1)) a_spin();
 	return 0;
 }