Commit-ID:  67b9ca70c3030e832999e8d1cdba2984c7bb5bfc
Gitweb:     http://git.kernel.org/tip/67b9ca70c3030e832999e8d1cdba2984c7bb5bfc
Author:     Andy Lutomirski <[email protected]>
AuthorDate: Wed, 4 Jun 2014 10:31:17 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Thu, 5 Jun 2014 12:09:52 +0200

sched/idle: Simplify wake_up_idle_cpu()

Now that rq->idle's polling bit is a reliable indication that the cpu is
polling, use it.

Signed-off-by: Andy Lutomirski <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Linus Torvalds <[email protected]>
Cc: [email protected]
Link: 
http://lkml.kernel.org/r/922f00761445a830ebb23d058e2ae53956ce2d73.1401902905.git.l...@amacapital.net
Signed-off-by: Ingo Molnar <[email protected]>
---
 kernel/sched/core.c | 21 +--------------------
 1 file changed, 1 insertion(+), 20 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index e4c0ddd..6afbfee 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -628,26 +628,7 @@ static void wake_up_idle_cpu(int cpu)
        if (cpu == smp_processor_id())
                return;
 
-       /*
-        * This is safe, as this function is called with the timer
-        * wheel base lock of (cpu) held. When the CPU is on the way
-        * to idle and has not yet set rq->curr to idle then it will
-        * be serialized on the timer wheel base lock and take the new
-        * timer into account automatically.
-        */
-       if (rq->curr != rq->idle)
-               return;
-
-       /*
-        * We can set TIF_RESCHED on the idle task of the other CPU
-        * lockless. The worst case is that the other CPU runs the
-        * idle task through an additional NOOP schedule()
-        */
-       set_tsk_need_resched(rq->idle);
-
-       /* NEED_RESCHED must be visible before we test polling */
-       smp_mb();
-       if (!tsk_is_polling(rq->idle))
+       if (set_nr_and_not_polling(rq->idle))
                smp_send_reschedule(cpu);
        else
                trace_sched_wake_idle_without_ipi(cpu);
--
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