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authorFrederic Weisbecker <fweisbec@gmail.com>2015-07-17 22:25:49 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2016-03-02 16:43:41 +0100
commit76d92ac305f23cada3a9b3c48a7ccea5f71019cb (patch)
tree9008b14a9ac5192e8baedd48b0cbdd1b3fdb9a9a /kernel/time
parent01d36d0ac390895e719d0dd8ab91ebbbf506d28e (diff)
downloadlinux-76d92ac305f23cada3a9b3c48a7ccea5f71019cb.tar.bz2
sched: Migrate sched to use new tick dependency mask model
Instead of providing asynchronous checks for the nohz subsystem to verify sched tick dependency, migrate sched to the new mask. Everytime a task is enqueued or dequeued, we evaluate the state of the tick dependency on top of the policy of the tasks in the runqueue, by order of priority: SCHED_DEADLINE: Need the tick in order to periodically check for runtime SCHED_FIFO : Don't need the tick (no round-robin) SCHED_RR : Need the tick if more than 1 task of the same priority for round robin (simplified with checking if more than one SCHED_RR task no matter what priority). SCHED_NORMAL : Need the tick if more than 1 task for round-robin. We could optimize that further with one flag per sched policy on the tick dependency mask and perform only the checks relevant to the policy concerned by an enqueue/dequeue operation. Since the checks aren't based on the current task anymore, we could get rid of the task switch hook but it's still needed for posix cpu timers. Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/tick-sched.c5
1 files changed, 0 insertions, 5 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 3f79def37ca9..f312c60c3ed2 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -204,11 +204,6 @@ static bool can_stop_full_tick(struct tick_sched *ts)
return false;
}
- if (!sched_can_stop_tick()) {
- trace_tick_stop(0, TICK_DEP_MASK_SCHED);
- return false;
- }
-
if (!posix_cpu_timers_can_stop_tick(current)) {
trace_tick_stop(0, TICK_DEP_MASK_POSIX_TIMER);
return false;