watchdog: Make it work under full dynticks

A perf event can be used without forcing the tick to
stay alive if it doesn't use a frequency but a sample
period and if it doesn't throttle (raise storm of events).

Since the lockup detector neither use a perf event frequency
nor should ever throttle due to its high period, it can now
run concurrently with the full dynticks feature.

So remove the hack that disabled the watchdog.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Anish Singh <anish198519851985@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-9-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Frederic Weisbecker 2013-07-23 02:31:06 +02:00 committed by Ingo Molnar
parent d84153d6c9
commit 93786a5f6a

View file

@ -553,14 +553,6 @@ void __init lockup_detector_init(void)
{
set_sample_period();
#ifdef CONFIG_NO_HZ_FULL
if (watchdog_user_enabled) {
watchdog_user_enabled = 0;
pr_warning("Disabled lockup detectors by default for full dynticks\n");
pr_warning("You can reactivate it with 'sysctl -w kernel.watchdog=1'\n");
}
#endif
if (watchdog_user_enabled)
watchdog_enable_all_cpus();
}