UPSTREAM next (v3.11): sigtimedwait: use freezable blocking call
Colin Cross [Mon, 6 May 2013 23:50:20 +0000 (23:50 +0000)]
Avoid waking up every thread sleeping in a sigtimedwait 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>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit a2d5f1f5d941593e61071dc78e9de228eda5475f)
Change-Id: I854b1ea03eb338198a7d0cbdaaf4abfc4f0e936d
Reviewed-on: http://git-master/r/228700
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Tested-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

kernel/signal.c

index 113411b..50e4107 100644 (file)
@@ -2848,7 +2848,7 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
                recalc_sigpending();
                spin_unlock_irq(&tsk->sighand->siglock);
 
-               timeout = schedule_timeout_interruptible(timeout);
+               timeout = freezable_schedule_timeout_interruptible(timeout);
 
                spin_lock_irq(&tsk->sighand->siglock);
                __set_task_blocked(tsk, &tsk->real_blocked);