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nohz: Implement wide kick on top of irq work 

It simplifies it and allows wide kick to be performed, even when IRQs
are disabled, without an asynchronous level in the middle.

This comes at a cost of some more overhead on features like perf and
posix cpu timers slow-paths, which is probably not much important
for nohz full users.

Requested-by: Peter Zijlstra <peterz@infradead.org>
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>
This commit is contained in:
Frederic Weisbecker 2015-12-07 16:55:23 +01:00
parent 5fd7a09cfb
commit 8537bb95a6
1 changed files with 4 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
kernel/time/tick-sched.c
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@ -234,24 +234,20 @@ void tick_nohz_full_kick_cpu(int cpu)
irq_work_queue_on(&per_cpu(nohz_full_kick_work, cpu), cpu); irq_work_queue_on(&per_cpu(nohz_full_kick_work, cpu), cpu);
} }
static void nohz_full_kick_ipi(void *info)
{
/* Empty, the tick restart happens on tick_nohz_irq_exit() */
}
/* /*
* Kick all full dynticks CPUs in order to force these to re-evaluate * Kick all full dynticks CPUs in order to force these to re-evaluate
* their dependency on the tick and restart it if necessary. * their dependency on the tick and restart it if necessary.
*/ */
void tick_nohz_full_kick_all(void) void tick_nohz_full_kick_all(void)
{ {
int cpu;
if (!tick_nohz_full_running) if (!tick_nohz_full_running)
return; return;
preempt_disable(); preempt_disable();
smp_call_function_many(tick_nohz_full_mask, for_each_cpu_and(cpu, tick_nohz_full_mask, cpu_online_mask)
nohz_full_kick_ipi, NULL, false); tick_nohz_full_kick_cpu(cpu);
tick_nohz_full_kick();
preempt_enable(); preempt_enable();
} }