mirror of
https://github.com/torvalds/linux.git
synced 2026-10-07 22:37:45 -04:00
Davidlohr Bueso
fa6004ad45
This patch moves the wakeup_process() invocation so it is not done under the info->lock by making use of a lockless wake_q. With this change, the waiter is woken up once it is STATE_READY and it does not need to loop on SMP if it is still in STATE_PENDING. In the timeout case we still need to grab the info->lock to verify the state. This change should also avoid the introduction of preempt_disable() in -rt which avoids a busy-loop which pools for the STATE_PENDING -> STATE_READY change if the waiter has a higher priority compared to the waker. Additionally, this patch micro-optimizes wq_sleep by using the cheaper cousin of set_current_state(TASK_INTERRUPTABLE) as we will block no matter what, thus get rid of the implied barrier. Signed-off-by: Davidlohr Bueso <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Acked-by: George Spelvin <[email protected]> Acked-by: Thomas Gleixner <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Chris Mason <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Manfred Spraul <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>