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futex: use freezable blocking call 

Avoid waking up every thread sleeping in a futex_wait call during
suspend and resume by calling a freezable blocking call.  Previous
patches modified the freezer to avoid sending wakeups to threads
that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Colin Cross 2013-05-06 23:50:18 +00:00 committed by Rafael J. Wysocki
parent 9745cdb36d
commit 56467c7697
1 changed files with 2 additions and 1 deletions
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3
kernel/futex.c
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@ -61,6 +61,7 @@
#include <linux/nsproxy.h> #include <linux/nsproxy.h>
#include <linux/ptrace.h> #include <linux/ptrace.h>
#include <linux/sched/rt.h> #include <linux/sched/rt.h>
#include <linux/freezer.h>
#include <asm/futex.h> #include <asm/futex.h>
@ -1807,7 +1808,7 @@ static void futex_wait_queue_me(struct futex_hash_bucket *hb, struct futex_q *q,
* is no timeout, or if it has yet to expire. * is no timeout, or if it has yet to expire.
*/ */
if (!timeout || timeout->task) if (!timeout || timeout->task)
schedule(); freezable_schedule();
} }
__set_current_state(TASK_RUNNING); __set_current_state(TASK_RUNNING);
} }