From 47e5d2a8b132c73bc0659baad25714326fb333c9 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Thu, 24 May 2001 23:38:52 +0000 Subject: Update. 2001-05-24 Ulrich Drepper * spinlock.c (__pthread_lock) [HAS_COMPARE_AND_SWAP]: Before doing any serious work try once whether the lock is uncontested. Remove duplicate reading of __status before loop. Change suggested by Hans Boehm . * spinlock.h (__pthread_trylock): Remove need for oldstatus variable. (__pthread_alt_trylock): Likewise. --- linuxthreads/spinlock.h | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) (limited to 'linuxthreads/spinlock.h') diff --git a/linuxthreads/spinlock.h b/linuxthreads/spinlock.h index 0dbaa54..0ec40c5 100644 --- a/linuxthreads/spinlock.h +++ b/linuxthreads/spinlock.h @@ -104,10 +104,6 @@ static inline void __pthread_init_lock(struct _pthread_fastlock * lock) static inline int __pthread_trylock (struct _pthread_fastlock * lock) { -#if defined HAS_COMPARE_AND_SWAP - long oldstatus; -#endif - #if defined TEST_FOR_COMPARE_AND_SWAP if (!__pthread_has_cas) #endif @@ -119,8 +115,7 @@ static inline int __pthread_trylock (struct _pthread_fastlock * lock) #if defined HAS_COMPARE_AND_SWAP do { - oldstatus = lock->__status; - if (oldstatus != 0) return EBUSY; + if (lock->__status != 0) return EBUSY; } while(! __compare_and_swap(&lock->__status, 0, 1)); return 0; #endif @@ -146,10 +141,6 @@ static inline void __pthread_alt_init_lock(struct _pthread_fastlock * lock) static inline int __pthread_alt_trylock (struct _pthread_fastlock * lock) { -#if defined HAS_COMPARE_AND_SWAP - long oldstatus; -#endif - #if defined TEST_FOR_COMPARE_AND_SWAP if (!__pthread_has_cas) #endif @@ -173,8 +164,7 @@ static inline int __pthread_alt_trylock (struct _pthread_fastlock * lock) #if defined HAS_COMPARE_AND_SWAP do { - oldstatus = lock->__status; - if (oldstatus != 0) return EBUSY; + if (lock->__status != 0) return EBUSY; } while(! compare_and_swap(&lock->__status, 0, 1, &lock->__spinlock)); return 0; #endif -- cgit v1.1