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Commit 83909a2f authored by Patrick Daly's avatar Patrick Daly Committed by Gerrit - the friendly Code Review server
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PM / Wakeup: Use rcu callbacks for better performance 



Use rcu to free objects in wakeup_source_unregister(). These objects must
be allocated through wakeup_source_register().

Replacing synchronize_rcu() with call_rcu() allows multiple calls to
wakeup_source_unregister() to be combined into a single grace period.

CRs-Fixed: 845110
Change-Id: Ib4002db042cf63abb28e6b3df6e3c70c97043bd9
Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
parent 67b6b070

drivers/base/power/wakeup.c

+31 −2
Original line number Diff line number Diff line
@@ -125,6 +125,15 @@ void wakeup_source_destroy(struct wakeup_source *ws) 
}

EXPORT_SYMBOL_GPL(wakeup_source_destroy);



/**

 * wakeup_source_destroy_cb

 * defer processing until all rcu references have expired

 */

static void wakeup_source_destroy_cb(struct rcu_head *head)

{

	wakeup_source_destroy(container_of(head, struct wakeup_source, rcu));

}



/**

 * wakeup_source_add - Add given object to the list of wakeup sources.

 * @ws: Wakeup source object to add to the list.
@@ -165,6 +174,26 @@ void wakeup_source_remove(struct wakeup_source *ws) 
}

EXPORT_SYMBOL_GPL(wakeup_source_remove);



/**

 * wakeup_source_remove_async - Remove given object from the wakeup sources

 * list.

 * @ws: Wakeup source object to remove from the list.

 *

 * Use only for wakeup source objects created with wakeup_source_create().

 * Memory for ws must be freed via rcu.

 */

static void wakeup_source_remove_async(struct wakeup_source *ws)

{

	unsigned long flags;



	if (WARN_ON(!ws))

		return;



	spin_lock_irqsave(&events_lock, flags);

	list_del_rcu(&ws->entry);

	spin_unlock_irqrestore(&events_lock, flags);

}



/**

 * wakeup_source_register - Create wakeup source and add it to the list.

 * @name: Name of the wakeup source to register.
@@ -188,8 +217,8 @@ EXPORT_SYMBOL_GPL(wakeup_source_register); 
void wakeup_source_unregister(struct wakeup_source *ws)

{

	if (ws) {

		wakeup_source_remove(ws);

		wakeup_source_destroy(ws);

		wakeup_source_remove_async(ws);

		call_rcu(&ws->rcu, wakeup_source_destroy_cb);

	}

}

EXPORT_SYMBOL_GPL(wakeup_source_unregister);

include/linux/pm_wakeup.h

+1 −0
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ 
struct wakeup_source {

	const char 		*name;

	struct list_head	entry;

	struct rcu_head		rcu;

	spinlock_t		lock;

	struct timer_list	timer;

	unsigned long		timer_expires;