diff options
author | jhb <jhb@FreeBSD.org> | 2009-05-29 13:56:34 +0000 |
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committer | jhb <jhb@FreeBSD.org> | 2009-05-29 13:56:34 +0000 |
commit | cdcee493a206829c1a3ccc94df157c9720285eb7 (patch) | |
tree | 778d8b116b84c956f481f3604b85ee7646ea031f /sys | |
parent | 9217f2901bf3eb4d8b3a4fd833f32c26cba41164 (diff) | |
download | FreeBSD-src-cdcee493a206829c1a3ccc94df157c9720285eb7.zip FreeBSD-src-cdcee493a206829c1a3ccc94df157c9720285eb7.tar.gz |
Tweak a few comments on adaptive spinning.
Diffstat (limited to 'sys')
-rw-r--r-- | sys/kern/kern_mutex.c | 7 | ||||
-rw-r--r-- | sys/kern/kern_rwlock.c | 14 |
2 files changed, 15 insertions, 6 deletions
diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c index 49f9c59..17c72eb 100644 --- a/sys/kern/kern_mutex.c +++ b/sys/kern/kern_mutex.c @@ -399,8 +399,11 @@ _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, const char *file, #ifdef ADAPTIVE_MUTEXES /* - * If the current owner of the lock is executing on another - * CPU quit the hard path and try to spin. + * The current lock owner might have started executing + * on another CPU (or the lock could have changed + * owners) while we were waiting on the turnstile + * chain lock. If so, drop the turnstile lock and try + * again. */ owner = (struct thread *)(v & ~MTX_FLAGMASK); if (TD_IS_RUNNING(owner)) { diff --git a/sys/kern/kern_rwlock.c b/sys/kern/kern_rwlock.c index 993acfa..cc5f4f132 100644 --- a/sys/kern/kern_rwlock.c +++ b/sys/kern/kern_rwlock.c @@ -412,8 +412,11 @@ _rw_rlock(struct rwlock *rw, const char *file, int line) #ifdef ADAPTIVE_RWLOCKS /* - * If the current owner of the lock is executing on another - * CPU quit the hard path and try to spin. + * The current lock owner might have started executing + * on another CPU (or the lock could have changed + * owners) while we were waiting on the turnstile + * chain lock. If so, drop the turnstile lock and try + * again. */ if ((v & RW_LOCK_READ) == 0) { owner = (struct thread *)RW_OWNER(v); @@ -714,8 +717,11 @@ _rw_wlock_hard(struct rwlock *rw, uintptr_t tid, const char *file, int line) #ifdef ADAPTIVE_RWLOCKS /* - * If the current owner of the lock is executing on another - * CPU quit the hard path and try to spin. + * The current lock owner might have started executing + * on another CPU (or the lock could have changed + * owners) while we were waiting on the turnstile + * chain lock. If so, drop the turnstile lock and try + * again. */ if (!(v & RW_LOCK_READ)) { owner = (struct thread *)RW_OWNER(v); |