mirror_zfs/module/spl
Brian Behlendorf d599e4fa79 Block in cv_destroy() on all waiters
Previously we would ASSERT in cv_destroy() if it was ever called
with active waiters.  However, I've now seen several instances in
OpenSolaris code where they do the following:

  cv_broadcast();
  cv_destroy();

This leaves no time for active waiters to be woken up and scheduled
and we trip the ASSERT.  This has not been observed to be an issue
on OpenSolaris because their cv_destroy() basically does nothing.
They still do run the risk of the memory being free'd after the
cv_destroy() and hitting a bad paging request.  But in practice
this race is so small and unlikely it either doesn't happen, or
is so unlikely when it does happen the root cause has not yet been
identified.

Rather than risk the same issue in our code this change updates
cv_destroy() to block until all waiters have been woken and
scheduled.  This may take some time because each waiter must
acquire the mutex.

This change may have an impact on performance for frequently
created and destroyed condition variables.  That however is a price
worth paying it avoid crashing your system.  If performance issues
are observed they can be addressed by the caller.
2011-02-04 14:09:08 -08:00
..
.gitignore sun-misc-gitignore 2010-01-08 09:37:54 -08:00
Makefile.in Add Thread Specific Data (TSD) Implementation 2010-12-07 10:02:32 -08:00
spl-atomic.c Public Release Prep 2010-05-17 15:18:00 -07:00
spl-condvar.c Block in cv_destroy() on all waiters 2011-02-04 14:09:08 -08:00
spl-cred.c Public Release Prep 2010-05-17 15:18:00 -07:00
spl-debug.c Add Thread Specific Data (TSD) Implementation 2010-12-07 10:02:32 -08:00
spl-err.c Prefix all SPL debug macros with 'S' 2010-07-20 13:30:40 -07:00
spl-generic.c Add Thread Specific Data (TSD) Implementation 2010-12-07 10:02:32 -08:00
spl-kmem.c Fix 2.6.35 shrinker callback API change 2010-10-22 14:51:26 -07:00
spl-kobj.c Remove VN_HOLD/VN_RELE/VOP_PUTPAGE 2011-01-12 11:38:05 -08:00
spl-kstat.c Prefix all SPL debug macros with 'S' 2010-07-20 13:30:40 -07:00
spl-module.c Linux 2.6.36 compat, use fops->unlocked_ioctl() 2010-11-10 13:16:12 -08:00
spl-mutex.c Public Release Prep 2010-05-17 15:18:00 -07:00
spl-proc.c Prefix all SPL debug macros with 'S' 2010-07-20 13:30:40 -07:00
spl-rwlock.c Public Release Prep 2010-05-17 15:18:00 -07:00
spl-taskq.c Fix taskq code to not drop tasks when TQ_SLEEP is used. 2010-08-02 11:20:31 -07:00
spl-thread.c Add Thread Specific Data (TSD) Implementation 2010-12-07 10:02:32 -08:00
spl-time.c Minor 32-bit fix cast to hrtime_t before the mutliply. 2010-05-23 09:51:17 -07:00
spl-tsd.c Add Thread Specific Data (TSD) Implementation 2010-12-07 10:02:32 -08:00
spl-vnode.c Make vn_cache|vn_file_cache kmem caches 2011-01-12 11:38:05 -08:00
spl-xdr.c Prefix all SPL debug macros with 'S' 2010-07-20 13:30:40 -07:00