diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-09-13 15:09:40 +0200 |
|---|---|---|
| committer | Clark Williams <williams@redhat.com> | 2011-12-28 16:25:51 -0600 |
| commit | 8a85c68ebd32c70c20d2ad7158372f3bf10c256d (patch) | |
| tree | 92b85bd31cd33205a0746de0825d4daa30d74234 /lib/debugobjects.c | |
| parent | 6539c3c62945d3340544bc45dc112714e2427d54 (diff) | |
ipc/sem: Rework semaphore wakeups
Current sysv sems have a weird ass wakeup scheme that involves keeping
preemption disabled over a potential O(n^2) loop and busy waiting on
that on other CPUs.
Kill this and simply wake the task directly from under the sem_lock.
This was discovered by a migrate_disable() debug feature that
disallows:
spin_lock();
preempt_disable();
spin_unlock()
preempt_enable();
Cc: Manfred Spraul <manfred@colorfullife.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Manfred Spraul <manfred@colorfullife.com>
Link: http://lkml.kernel.org/r/1315994224.5040.1.camel@twins
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'lib/debugobjects.c')
0 files changed, 0 insertions, 0 deletions