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| author | Ulrich Drepper <drepper@redhat.com> | 2001-05-24 23:38:52 +0000 |
|---|---|---|
| committer | Ulrich Drepper <drepper@redhat.com> | 2001-05-24 23:38:52 +0000 |
| commit | 47e5d2a8b132c73bc0659baad25714326fb333c9 (patch) | |
| tree | 36c83a82b882e1d624374ac0956b8a870881ee52 /linuxthreads/spinlock.h | |
| parent | 65fa1dec4ec6d800ba9e91abe0e4ae8208b9905e (diff) | |
| download | glibc-47e5d2a8b132c73bc0659baad25714326fb333c9.tar.gz glibc-47e5d2a8b132c73bc0659baad25714326fb333c9.tar.xz glibc-47e5d2a8b132c73bc0659baad25714326fb333c9.zip | |
Update.
2001-05-24 Ulrich Drepper <drepper@redhat.com> * 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 <hans_boehm@hp.com>. * spinlock.h (__pthread_trylock): Remove need for oldstatus variable. (__pthread_alt_trylock): Likewise.
Diffstat (limited to 'linuxthreads/spinlock.h')
| -rw-r--r-- | linuxthreads/spinlock.h | 14 |
1 files changed, 2 insertions, 12 deletions
diff --git a/linuxthreads/spinlock.h b/linuxthreads/spinlock.h index 0dbaa54e2d..0ec40c57cb 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 |