sched: Add TASK_WAKING
We're going to want to drop rq->lock in try_to_wake_up() for a
longer period of time, however we also want to deal with concurrent
waking of the same task, which is currently handled by holding
rq->lock.
So introduce a new TASK state, namely TASK_WAKING, which indicates
someone is already waking the task (other wakers will fail p->state
& state).
We also keep preemption disabled over the whole ttwu().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5d3c990..3b0ca66 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -190,6 +190,7 @@
/* in tsk->state again */
#define TASK_DEAD 64
#define TASK_WAKEKILL 128
+#define TASK_WAKING 256
/* Convenience macros for the sake of set_task_state */
#define TASK_KILLABLE (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)