Eric Lee / smarc-ti-linux-kernel

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Commit 5811d9963e26146898a24b535b301f7654257f8a

Authored by Frederic Weisbecker
1 parent 9014c45d9e
Exists in master and in 20 other branches dlt-processor-sdk-linux-03.00.00.04, newt-ti-linux-3.12.y, processor-sdk-linux-01.00.00, processor-sdk-linux-02.00.01, smarc-ti-linux-3.12.10, smarc-ti-linux-3.12.y, smarc-ti-linux-3.14.y, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.12.y, ti-linux-3.14.y, ti-linux-3.15.y, ti-lsk-linux-4.1.y

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>

Showing 1 changed file with 25 additions and 6 deletions Side-by-side Diff

kernel/time/tick-sched.c
Diff comments   View file @ 5811d99
... ... @@ -647,6 +647,24 @@
647 647 return ret;
648 648 }
649 649  
  650 +static void tick_nohz_full_stop_tick(struct tick_sched *ts)
  651 +{
  652 +#ifdef CONFIG_NO_HZ_FULL
  653 + int cpu = smp_processor_id();
  654 +
  655 + if (!tick_nohz_full_cpu(cpu) || is_idle_task(current))
  656 + return;
  657 +
  658 + if (!ts->tick_stopped && ts->nohz_mode == NOHZ_MODE_INACTIVE)
  659 + return;
  660 +
  661 + if (!can_stop_full_tick())
  662 + return;
  663 +
  664 + tick_nohz_stop_sched_tick(ts, ktime_get(), cpu);
  665 +#endif
  666 +}
  667 +
650 668 static bool can_stop_idle_tick(int cpu, struct tick_sched *ts)
651 669 {
652 670 /*
... ... @@ -773,12 +791,13 @@
773 791 {
774 792 struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
775 793  
776   - if (!ts->inidle)
777   - return;
778   -
779   - /* Cancel the timer because CPU already waken up from the C-states*/
780   - menu_hrtimer_cancel();
781   - __tick_nohz_idle_enter(ts);
  794 + if (ts->inidle) {
  795 + /* Cancel the timer because CPU already waken up from the C-states*/
  796 + menu_hrtimer_cancel();
  797 + __tick_nohz_idle_enter(ts);
  798 + } else {
  799 + tick_nohz_full_stop_tick(ts);
  800 + }
782 801 }
783 802  
784 803 /**