From: Paul Gortmaker <[email protected]> Completions have no long lasting callbacks and therefore do not need the complex waitqueue variant. Use simple waitqueues which reduces the contention on the waitqueue lock.
This was a carry forward from v3.10-rt, with some RT specific chunks, dropped, and updated to align with names that were chosen to match the simple waitqueue support. Originally-by: Thomas Gleixner <[email protected]> Signed-off-by: Paul Gortmaker <[email protected]> --- include/linux/completion.h | 8 ++++---- kernel/sched/completion.c | 32 ++++++++++++++++---------------- 2 files changed, 20 insertions(+), 20 deletions(-) diff --git a/include/linux/completion.h b/include/linux/completion.h index 5d5aaae..8b3bca8 100644 --- a/include/linux/completion.h +++ b/include/linux/completion.h @@ -8,7 +8,7 @@ * See kernel/sched/completion.c for details. */ -#include <linux/wait.h> +#include <linux/swait.h> /* * struct completion - structure used to maintain state for a "completion" @@ -24,11 +24,11 @@ */ struct completion { unsigned int done; - wait_queue_head_t wait; + struct swait_queue_head wait; }; #define COMPLETION_INITIALIZER(work) \ - { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) } + { 0, __SWAIT_QUEUE_HEAD_INITIALIZER((work).wait) } #define COMPLETION_INITIALIZER_ONSTACK(work) \ ({ init_completion(&work); work; }) @@ -73,7 +73,7 @@ struct completion { static inline void init_completion(struct completion *x) { x->done = 0; - init_waitqueue_head(&x->wait); + init_swait_queue_head(&x->wait); } /** diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c index 8d0f35d..b020159 100644 --- a/kernel/sched/completion.c +++ b/kernel/sched/completion.c @@ -30,10 +30,10 @@ void complete(struct completion *x) { unsigned long flags; - spin_lock_irqsave(&x->wait.lock, flags); + raw_spin_lock_irqsave(&x->wait.lock, flags); x->done++; - __wake_up_locked(&x->wait, TASK_NORMAL, 1); - spin_unlock_irqrestore(&x->wait.lock, flags); + swake_up_locked(&x->wait); + raw_spin_unlock_irqrestore(&x->wait.lock, flags); } EXPORT_SYMBOL(complete); @@ -50,10 +50,10 @@ void complete_all(struct completion *x) { unsigned long flags; - spin_lock_irqsave(&x->wait.lock, flags); + raw_spin_lock_irqsave(&x->wait.lock, flags); x->done += UINT_MAX/2; - __wake_up_locked(&x->wait, TASK_NORMAL, 0); - spin_unlock_irqrestore(&x->wait.lock, flags); + swake_up_locked(&x->wait); + raw_spin_unlock_irqrestore(&x->wait.lock, flags); } EXPORT_SYMBOL(complete_all); @@ -62,20 +62,20 @@ do_wait_for_common(struct completion *x, long (*action)(long), long timeout, int state) { if (!x->done) { - DECLARE_WAITQUEUE(wait, current); + DECLARE_SWAITQUEUE(wait); - __add_wait_queue_tail_exclusive(&x->wait, &wait); + __prepare_to_swait(&x->wait, &wait); do { if (signal_pending_state(state, current)) { timeout = -ERESTARTSYS; break; } __set_current_state(state); - spin_unlock_irq(&x->wait.lock); + raw_spin_unlock_irq(&x->wait.lock); timeout = action(timeout); - spin_lock_irq(&x->wait.lock); + raw_spin_lock_irq(&x->wait.lock); } while (!x->done && timeout); - __remove_wait_queue(&x->wait, &wait); + __finish_swait(&x->wait, &wait); if (!x->done) return timeout; } @@ -89,9 +89,9 @@ __wait_for_common(struct completion *x, { might_sleep(); - spin_lock_irq(&x->wait.lock); + raw_spin_lock_irq(&x->wait.lock); timeout = do_wait_for_common(x, action, timeout, state); - spin_unlock_irq(&x->wait.lock); + raw_spin_unlock_irq(&x->wait.lock); return timeout; } @@ -277,12 +277,12 @@ bool try_wait_for_completion(struct completion *x) if (!READ_ONCE(x->done)) return 0; - spin_lock_irqsave(&x->wait.lock, flags); + raw_spin_lock_irqsave(&x->wait.lock, flags); if (!x->done) ret = 0; else x->done--; - spin_unlock_irqrestore(&x->wait.lock, flags); + raw_spin_unlock_irqrestore(&x->wait.lock, flags); return ret; } EXPORT_SYMBOL(try_wait_for_completion); @@ -311,7 +311,7 @@ bool completion_done(struct completion *x) * after it's acquired the lock. */ smp_rmb(); - spin_unlock_wait(&x->wait.lock); + raw_spin_unlock_wait(&x->wait.lock); return true; } EXPORT_SYMBOL(completion_done); -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
