diff options
author | John Baldwin <jhb@FreeBSD.org> | 2015-05-21 16:43:26 +0000 |
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committer | John Baldwin <jhb@FreeBSD.org> | 2015-05-21 16:43:26 +0000 |
commit | c636f94bd2ff15be5b904939872b4bce31456c18 (patch) | |
tree | e3d629fdffd1d096c7a4fe3aa0ad5da3f0a1ec47 /sys/kern/kern_condvar.c | |
parent | b6fb3fe0bdf0633561b09353e6dc425a82188b77 (diff) | |
download | src-c636f94bd2ff15be5b904939872b4bce31456c18.tar.gz src-c636f94bd2ff15be5b904939872b4bce31456c18.zip |
Revert r282971. It depends on condvar consumers not destroying condvars
until all threads sleeping on a condvar have resumed execution after being
awakened. However, there are cases where that guarantee is very hard to
provide.
Notes
Notes:
svn path=/head/; revision=283250
Diffstat (limited to 'sys/kern/kern_condvar.c')
-rw-r--r-- | sys/kern/kern_condvar.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/sys/kern/kern_condvar.c b/sys/kern/kern_condvar.c index 21807649296d..2700a25d477c 100644 --- a/sys/kern/kern_condvar.c +++ b/sys/kern/kern_condvar.c @@ -122,7 +122,7 @@ _cv_wait(struct cv *cvp, struct lock_object *lock) sleepq_lock(cvp); - atomic_add_int(&cvp->cv_waiters, 1); + cvp->cv_waiters++; if (lock == &Giant.lock_object) mtx_assert(&Giant, MA_OWNED); DROP_GIANT(); @@ -137,7 +137,6 @@ _cv_wait(struct cv *cvp, struct lock_object *lock) sleepq_lock(cvp); } sleepq_wait(cvp, 0); - atomic_subtract_int(&cvp->cv_waiters, 1); #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) @@ -185,7 +184,7 @@ _cv_wait_unlock(struct cv *cvp, struct lock_object *lock) sleepq_lock(cvp); - atomic_add_int(&cvp->cv_waiters, 1); + cvp->cv_waiters++; DROP_GIANT(); sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR, 0); @@ -195,7 +194,6 @@ _cv_wait_unlock(struct cv *cvp, struct lock_object *lock) if (class->lc_flags & LC_SLEEPABLE) sleepq_lock(cvp); sleepq_wait(cvp, 0); - atomic_subtract_int(&cvp->cv_waiters, 1); #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) @@ -242,7 +240,7 @@ _cv_wait_sig(struct cv *cvp, struct lock_object *lock) sleepq_lock(cvp); - atomic_add_int(&cvp->cv_waiters, 1); + cvp->cv_waiters++; if (lock == &Giant.lock_object) mtx_assert(&Giant, MA_OWNED); DROP_GIANT(); @@ -258,7 +256,6 @@ _cv_wait_sig(struct cv *cvp, struct lock_object *lock) sleepq_lock(cvp); } rval = sleepq_wait_sig(cvp, 0); - atomic_subtract_int(&cvp->cv_waiters, 1); #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) @@ -310,7 +307,7 @@ _cv_timedwait_sbt(struct cv *cvp, struct lock_object *lock, sbintime_t sbt, sleepq_lock(cvp); - atomic_add_int(&cvp->cv_waiters, 1); + cvp->cv_waiters++; if (lock == &Giant.lock_object) mtx_assert(&Giant, MA_OWNED); DROP_GIANT(); @@ -326,7 +323,6 @@ _cv_timedwait_sbt(struct cv *cvp, struct lock_object *lock, sbintime_t sbt, sleepq_lock(cvp); } rval = sleepq_timedwait(cvp, 0); - atomic_subtract_int(&cvp->cv_waiters, 1); #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) @@ -380,7 +376,7 @@ _cv_timedwait_sig_sbt(struct cv *cvp, struct lock_object *lock, sleepq_lock(cvp); - atomic_add_int(&cvp->cv_waiters, 1); + cvp->cv_waiters++; if (lock == &Giant.lock_object) mtx_assert(&Giant, MA_OWNED); DROP_GIANT(); @@ -397,7 +393,6 @@ _cv_timedwait_sig_sbt(struct cv *cvp, struct lock_object *lock, sleepq_lock(cvp); } rval = sleepq_timedwait_sig(cvp, 0); - atomic_subtract_int(&cvp->cv_waiters, 1); #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) @@ -426,8 +421,10 @@ cv_signal(struct cv *cvp) wakeup_swapper = 0; sleepq_lock(cvp); - if (cvp->cv_waiters > 0) + if (cvp->cv_waiters > 0) { + cvp->cv_waiters--; wakeup_swapper = sleepq_signal(cvp, SLEEPQ_CONDVAR, 0, 0); + } sleepq_release(cvp); if (wakeup_swapper) kick_proc0(); @@ -450,8 +447,10 @@ cv_broadcastpri(struct cv *cvp, int pri) if (pri == -1) pri = 0; sleepq_lock(cvp); - if (cvp->cv_waiters > 0) + if (cvp->cv_waiters > 0) { + cvp->cv_waiters = 0; wakeup_swapper = sleepq_broadcast(cvp, SLEEPQ_CONDVAR, pri, 0); + } sleepq_release(cvp); if (wakeup_swapper) kick_proc0(); |