path: root/kernel/time
diff options
authorFrederic Weisbecker <fweisbec@gmail.com>2013-04-20 16:40:31 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2013-04-22 20:29:05 +0200
commit5811d9963e26146898a24b535b301f7654257f8a (patch)
tree1aba8d997214fc1979b049ab23d6430cbd774aee /kernel/time
parent9014c45d9e2dbb935498a5f1d106e220e8624643 (diff)
nohz: Prepare to stop the tick on irq exit
Interrupt exit is a natural place to stop the tick: it happens after all events happening before and during the irq which are liable to update the dependency on the tick occured. Also it makes sure that any check on tick dependency is well ordered against dynticks kick IPIs. Bring in the infrastructure that performs the tick dependency checks on irq exit and shut it down if these checks show that we can do it safely. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> 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: Oleg Nesterov <oleg@redhat.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/time')
1 files changed, 25 insertions, 6 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 95d79aeb3e2..d0ed1905a85 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -647,6 +647,24 @@ out:
return ret;
+static void tick_nohz_full_stop_tick(struct tick_sched *ts)
+ int cpu = smp_processor_id();
+ if (!tick_nohz_full_cpu(cpu) || is_idle_task(current))
+ return;
+ if (!ts->tick_stopped && ts->nohz_mode == NOHZ_MODE_INACTIVE)
+ return;
+ if (!can_stop_full_tick())
+ return;
+ tick_nohz_stop_sched_tick(ts, ktime_get(), cpu);
static bool can_stop_idle_tick(int cpu, struct tick_sched *ts)
@@ -773,12 +791,13 @@ void tick_nohz_irq_exit(void)
struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
- if (!ts->inidle)
- return;
- /* Cancel the timer because CPU already waken up from the C-states*/
- menu_hrtimer_cancel();
- __tick_nohz_idle_enter(ts);
+ if (ts->inidle) {
+ /* Cancel the timer because CPU already waken up from the C-states*/
+ menu_hrtimer_cancel();
+ __tick_nohz_idle_enter(ts);
+ } else {
+ tick_nohz_full_stop_tick(ts);
+ }