path: root/kernel/sched/core.c
diff options
authorFrederic Weisbecker <fweisbec@gmail.com>2011-08-10 23:21:01 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2013-03-21 15:55:59 +0100
commit1c20091e77fc5a9b7d7d905176443b4822a23cdb (patch)
treeef3c2edc749ccfc87b5f9682973f54414de746c3 /kernel/sched/core.c
parenta382bf934449ddeb625167537ae81daa0211b477 (diff)
nohz: Wake up full dynticks CPUs when a timer gets enqueued
Wake up a CPU when a timer list timer is enqueued there and the target is part of the full dynticks range. Sending an IPI to it makes it reconsidering the next timer to program on top of recent updates. This may later be improved by checking if the tick is really stopped on the target. This would need some careful synchronization though. So deal with such optimization later and start simple. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/sched/core.c')
1 files changed, 19 insertions, 1 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 849deb96e61..e91ee589f79 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -587,7 +587,7 @@ unlock:
* account when the CPU goes back to idle and evaluates the timer
* wheel for the next timer event.
-void wake_up_idle_cpu(int cpu)
+static void wake_up_idle_cpu(int cpu)
struct rq *rq = cpu_rq(cpu);
@@ -617,6 +617,24 @@ void wake_up_idle_cpu(int cpu)
+static bool wake_up_extended_nohz_cpu(int cpu)
+ if (tick_nohz_extended_cpu(cpu)) {
+ if (cpu != smp_processor_id() ||
+ tick_nohz_tick_stopped())
+ smp_send_reschedule(cpu);
+ return true;
+ }
+ return false;
+void wake_up_nohz_cpu(int cpu)
+ if (!wake_up_extended_nohz_cpu(cpu))
+ wake_up_idle_cpu(cpu);
static inline bool got_nohz_idle_kick(void)
int cpu = smp_processor_id();