From c11f3082557dd8610c487421794d3b8a862c020f Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 11 Jan 2013 11:23:51 +0100 Subject: [PATCH] completion: Use simple wait queues Completions have no long lasting callbacks and therefor do not need the complex waitqueue variant. Use simple waitqueues which reduces the contention on the waitqueue lock. Signed-off-by: Thomas Gleixner [cminyard@mvista.com: Move __prepare_to_swait() into the do loop because swake_up_locked() removes the waiter on wake from the queue while in the original code it is not the case] Signed-off-by: Sebastian Andrzej Siewior --- arch/powerpc/platforms/ps3/device-init.c | 4 +-- .../wireless/intersil/orinoco/orinoco_usb.c | 4 +-- drivers/usb/gadget/function/f_fs.c | 2 +- drivers/usb/gadget/legacy/inode.c | 4 +-- include/linux/completion.h | 8 ++--- include/linux/suspend.h | 6 ++++ include/linux/swait.h | 2 ++ kernel/power/hibernate.c | 7 ++++ kernel/power/suspend.c | 4 +++ kernel/sched/completion.c | 34 +++++++++---------- kernel/sched/swait.c | 21 +++++++++++- 11 files changed, 67 insertions(+), 29 deletions(-) diff --git a/arch/powerpc/platforms/ps3/device-init.c b/arch/powerpc/platforms/ps3/device-init.c index 2735ec90414dcc..359231cea8cd79 100644 --- a/arch/powerpc/platforms/ps3/device-init.c +++ b/arch/powerpc/platforms/ps3/device-init.c @@ -738,8 +738,8 @@ static int ps3_notification_read_write(struct ps3_notification_device *dev, } pr_debug("%s:%u: notification %s issued\n", __func__, __LINE__, op); - res = wait_event_interruptible(dev->done.wait, - dev->done.done || kthread_should_stop()); + res = swait_event_interruptible_exclusive(dev->done.wait, + dev->done.done || kthread_should_stop()); if (kthread_should_stop()) res = -EINTR; if (res) { diff --git a/drivers/net/wireless/intersil/orinoco/orinoco_usb.c b/drivers/net/wireless/intersil/orinoco/orinoco_usb.c index e2368bfe3e4682..68e640dbe7ef8b 100644 --- a/drivers/net/wireless/intersil/orinoco/orinoco_usb.c +++ b/drivers/net/wireless/intersil/orinoco/orinoco_usb.c @@ -693,8 +693,8 @@ static void ezusb_req_ctx_wait(struct ezusb_priv *upriv, while (!ctx->done.done && msecs--) udelay(1000); } else { - wait_event_interruptible(ctx->done.wait, - ctx->done.done); + swait_event_interruptible_exclusive(ctx->done.wait, + ctx->done.done); } break; default: diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 5fd4fc49aef9fb..ee0b3d43fa208a 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1719,7 +1719,7 @@ static void ffs_data_put(struct ffs_data *ffs) ffs_data_clear(ffs); ffs_release_dev(ffs->private_data); BUG_ON(waitqueue_active(&ffs->ev.waitq) || - waitqueue_active(&ffs->ep0req_completion.wait) || + swait_active(&ffs->ep0req_completion.wait) || waitqueue_active(&ffs->wait)); destroy_workqueue(ffs->io_completion_wq); kfree(ffs->dev_name); diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index 9cd80ad075bd23..18204c9a5e9b84 100644 --- a/drivers/usb/gadget/legacy/inode.c +++ b/drivers/usb/gadget/legacy/inode.c @@ -346,7 +346,7 @@ ep_io (struct ep_data *epdata, void *buf, unsigned len) spin_unlock_irq (&epdata->dev->lock); if (likely (value == 0)) { - value = wait_event_interruptible (done.wait, done.done); + value = swait_event_interruptible_exclusive(done.wait, done.done); if (value != 0) { spin_lock_irq (&epdata->dev->lock); if (likely (epdata->ep != NULL)) { @@ -355,7 +355,7 @@ ep_io (struct ep_data *epdata, void *buf, unsigned len) usb_ep_dequeue (epdata->ep, epdata->req); spin_unlock_irq (&epdata->dev->lock); - wait_event (done.wait, done.done); + swait_event_exclusive(done.wait, done.done); if (epdata->status == -ECONNRESET) epdata->status = -EINTR; } else { diff --git a/include/linux/completion.h b/include/linux/completion.h index 519e94915d1850..bf8e77001f18f1 100644 --- a/include/linux/completion.h +++ b/include/linux/completion.h @@ -9,7 +9,7 @@ * See kernel/sched/completion.c for details. */ -#include +#include /* * struct completion - structure used to maintain state for a "completion" @@ -25,7 +25,7 @@ */ struct completion { unsigned int done; - wait_queue_head_t wait; + struct swait_queue_head wait; }; #define init_completion_map(x, m) __init_completion(x) @@ -34,7 +34,7 @@ static inline void complete_acquire(struct completion *x) {} static inline void complete_release(struct completion *x) {} #define COMPLETION_INITIALIZER(work) \ - { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) } + { 0, __SWAIT_QUEUE_HEAD_INITIALIZER((work).wait) } #define COMPLETION_INITIALIZER_ONSTACK_MAP(work, map) \ (*({ init_completion_map(&(work), &(map)); &(work); })) @@ -85,7 +85,7 @@ static inline void complete_release(struct completion *x) {} 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/include/linux/suspend.h b/include/linux/suspend.h index 194e64cb25850b..f60f70801a94d7 100644 --- a/include/linux/suspend.h +++ b/include/linux/suspend.h @@ -197,6 +197,12 @@ struct platform_s2idle_ops { void (*end)(void); }; +#if defined(CONFIG_SUSPEND) || defined(CONFIG_HIBERNATION) +extern bool pm_in_action; +#else +# define pm_in_action false +#endif + #ifdef CONFIG_SUSPEND extern suspend_state_t mem_sleep_current; extern suspend_state_t mem_sleep_default; diff --git a/include/linux/swait.h b/include/linux/swait.h index 12612823c2cb1f..21ae66cd41d306 100644 --- a/include/linux/swait.h +++ b/include/linux/swait.h @@ -160,7 +160,9 @@ static inline bool swq_has_sleeper(struct swait_queue_head *wq) extern void swake_up_one(struct swait_queue_head *q); extern void swake_up_all(struct swait_queue_head *q); extern void swake_up_locked(struct swait_queue_head *q); +extern void swake_up_all_locked(struct swait_queue_head *q); +extern void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait); extern void prepare_to_swait_exclusive(struct swait_queue_head *q, struct swait_queue *wait, int state); extern long prepare_to_swait_event(struct swait_queue_head *q, struct swait_queue *wait, int state); diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 6cafb2e910a111..7b6d2f59361716 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -689,6 +689,10 @@ static int load_image_and_restore(void) return error; } +#ifndef CONFIG_SUSPEND +bool pm_in_action; +#endif + /** * hibernate - Carry out system hibernation, including saving the image. */ @@ -702,6 +706,8 @@ int hibernate(void) return -EPERM; } + pm_in_action = true; + lock_system_sleep(); /* The snapshot device should not be opened while we're running */ if (!atomic_add_unless(&snapshot_device_available, -1, 0)) { @@ -778,6 +784,7 @@ int hibernate(void) atomic_inc(&snapshot_device_available); Unlock: unlock_system_sleep(); + pm_in_action = false; pr_info("hibernation exit\n"); return error; diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 5dea2778a3dbbf..6dd83ca98adcf6 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -593,6 +593,8 @@ static int enter_state(suspend_state_t state) return error; } +bool pm_in_action; + /** * pm_suspend - Externally visible function for suspending the system. * @state: System sleep state to enter. @@ -607,6 +609,7 @@ int pm_suspend(suspend_state_t state) if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX) return -EINVAL; + pm_in_action = true; pr_info("suspend entry (%s)\n", mem_sleep_labels[state]); error = enter_state(state); if (error) { @@ -616,6 +619,7 @@ int pm_suspend(suspend_state_t state) suspend_stats.success++; } pr_info("suspend exit\n"); + pm_in_action = false; return error; } EXPORT_SYMBOL(pm_suspend); diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c index a1ad5b7d5521be..49c14137988ea5 100644 --- a/kernel/sched/completion.c +++ b/kernel/sched/completion.c @@ -29,12 +29,12 @@ void complete(struct completion *x) { unsigned long flags; - spin_lock_irqsave(&x->wait.lock, flags); + raw_spin_lock_irqsave(&x->wait.lock, flags); if (x->done != UINT_MAX) 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); @@ -58,10 +58,10 @@ 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; - __wake_up_locked(&x->wait, TASK_NORMAL, 0); - spin_unlock_irqrestore(&x->wait.lock, flags); + swake_up_all_locked(&x->wait); + raw_spin_unlock_irqrestore(&x->wait.lock, flags); } EXPORT_SYMBOL(complete_all); @@ -70,20 +70,20 @@ 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_entry_tail_exclusive(&x->wait, &wait); do { if (signal_pending_state(state, current)) { timeout = -ERESTARTSYS; break; } + __prepare_to_swait(&x->wait, &wait); __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; } @@ -100,9 +100,9 @@ __wait_for_common(struct completion *x, complete_acquire(x); - 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); complete_release(x); @@ -291,12 +291,12 @@ bool try_wait_for_completion(struct completion *x) if (!READ_ONCE(x->done)) return false; - spin_lock_irqsave(&x->wait.lock, flags); + raw_spin_lock_irqsave(&x->wait.lock, flags); if (!x->done) ret = false; else if (x->done != UINT_MAX) 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); @@ -322,8 +322,8 @@ bool completion_done(struct completion *x) * otherwise we can end up freeing the completion before complete() * is done referencing it. */ - spin_lock_irqsave(&x->wait.lock, flags); - spin_unlock_irqrestore(&x->wait.lock, flags); + raw_spin_lock_irqsave(&x->wait.lock, flags); + raw_spin_unlock_irqrestore(&x->wait.lock, flags); return true; } EXPORT_SYMBOL(completion_done); diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c index 091347205736c5..c58068d2ee06ce 100644 --- a/kernel/sched/swait.c +++ b/kernel/sched/swait.c @@ -32,6 +32,25 @@ void swake_up_locked(struct swait_queue_head *q) } EXPORT_SYMBOL(swake_up_locked); +void swake_up_all_locked(struct swait_queue_head *q) +{ + struct swait_queue *curr; + int wakes = 0; + + while (!list_empty(&q->task_list)) { + + curr = list_first_entry(&q->task_list, typeof(*curr), + task_list); + wake_up_process(curr->task); + list_del_init(&curr->task_list); + wakes++; + } + if (pm_in_action) + return; + WARN(wakes > 2, "complete_all() with %d waiters\n", wakes); +} +EXPORT_SYMBOL(swake_up_all_locked); + void swake_up_one(struct swait_queue_head *q) { unsigned long flags; @@ -70,7 +89,7 @@ void swake_up_all(struct swait_queue_head *q) } EXPORT_SYMBOL(swake_up_all); -static void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait) +void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait) { wait->task = current; if (list_empty(&wait->task_list))