Re: [PATCH 5/7] sched: Pull preemption disablement duty up to __schedule() callers

2015-05-11 Thread Frederic Weisbecker
On Mon, May 11, 2015 at 05:52:13PM +0200, Peter Zijlstra wrote: > On Mon, May 11, 2015 at 05:08:22PM +0200, Frederic Weisbecker wrote: > > +++ b/kernel/sched/core.c > > @@ -2723,9 +2723,7 @@ again: > > * - return from syscall or exception to user-space > > * - return from inte

Re: [PATCH 5/7] sched: Pull preemption disablement duty up to __schedule() callers

2015-05-11 Thread Peter Zijlstra
On Mon, May 11, 2015 at 05:08:22PM +0200, Frederic Weisbecker wrote: > +++ b/kernel/sched/core.c > @@ -2723,9 +2723,7 @@ again: > * - return from syscall or exception to user-space > * - return from interrupt-handler to user-space > * > - * WARNING: all callers must re-check

[PATCH 5/7] sched: Pull preemption disablement duty up to __schedule() callers

2015-05-11 Thread Frederic Weisbecker
Disable preemption from the last caller of __schedule() that needed to carry this duty. This way we can remove this responsability from __scheduler() so to optimize the preempt_count() operations to a single place on preempt_schedule*() functions. Suggested-by: Linus Torvalds Cc: Ingo Molnar Cc: