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kernel/watchdog: provide watchdog_nmi_reconfigure() for arch watchdogs

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After reconfiguring watchdog sysctls etc., architecture specific
watchdogs may not get all their parameters updated.

watchdog_nmi_reconfigure() can be implemented to pull the new values in
and set the arch NMI watchdog.

[npiggin@gmail.com: add code comments]
  Link: http://lkml.kernel.org/r/20170617125933.774d3858@roar.ozlabs.ibm.com
[arnd@arndb.de: hide unused function]
  Link: http://lkml.kernel.org/r/20170620204854.966601-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20170616065715.18390-5-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Tested-by: Babu Moger <babu.moger@oracle.com>	[sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nicholas Piggin 2017-07-12 14:35:49 -07:00 committed by Linus Torvalds
parent 05a4a95279
commit a10a842ff8
1 changed files with 44 additions and 4 deletions
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48
kernel/watchdog.c
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@ -114,6 +114,10 @@ int __read_mostly watchdog_suspended;
/*
* These functions can be overridden if an architecture implements its
* own hardlockup detector.
*
* watchdog_nmi_enable/disable can be implemented to start and stop when
* softlockup watchdog threads start and stop. The arch must select the
* SOFTLOCKUP_DETECTOR Kconfig.
*/
int __weak watchdog_nmi_enable(unsigned int cpu)
{
@ -123,6 +127,22 @@ void __weak watchdog_nmi_disable(unsigned int cpu)
{
}
/*
* watchdog_nmi_reconfigure can be implemented to be notified after any
* watchdog configuration change. The arch hardlockup watchdog should
* respond to the following variables:
* - nmi_watchdog_enabled
* - watchdog_thresh
* - watchdog_cpumask
* - sysctl_hardlockup_all_cpu_backtrace
* - hardlockup_panic
* - watchdog_suspended
*/
void __weak watchdog_nmi_reconfigure(void)
{
}
#ifdef CONFIG_SOFTLOCKUP_DETECTOR
/* Helper for online, unparked cpus. */
@ -600,6 +620,14 @@ static void watchdog_disable_all_cpus(void)
}
}
#ifdef CONFIG_SYSCTL
static int watchdog_update_cpus(void)
{
return smpboot_update_cpumask_percpu_thread(
&watchdog_threads, &watchdog_cpumask);
}
#endif
#else /* SOFTLOCKUP */
static int watchdog_park_threads(void)
{
@ -619,6 +647,13 @@ static void watchdog_disable_all_cpus(void)
{
}
#ifdef CONFIG_SYSCTL
static int watchdog_update_cpus(void)
{
return 0;
}
#endif
static void set_sample_period(void)
{
}
@ -651,6 +686,8 @@ int lockup_detector_suspend(void)
watchdog_enabled = 0;
}
watchdog_nmi_reconfigure();
mutex_unlock(&watchdog_proc_mutex);
return ret;
@ -671,6 +708,8 @@ void lockup_detector_resume(void)
if (watchdog_running && !watchdog_suspended)
watchdog_unpark_threads();
watchdog_nmi_reconfigure();
mutex_unlock(&watchdog_proc_mutex);
put_online_cpus();
}
@ -696,6 +735,8 @@ static int proc_watchdog_update(void)
else
watchdog_disable_all_cpus();
watchdog_nmi_reconfigure();
return err;
}
@ -881,12 +922,11 @@ int proc_watchdog_cpumask(struct ctl_table *table, int write,
* a temporary cpumask, so we are likely not in a
* position to do much else to make things better.
*/
#ifdef CONFIG_SOFTLOCKUP_DETECTOR
if (smpboot_update_cpumask_percpu_thread(
&watchdog_threads, &watchdog_cpumask) != 0)
if (watchdog_update_cpus() != 0)
pr_err("cpumask update failed\n");
#endif
}
watchdog_nmi_reconfigure();
}
out:
mutex_unlock(&watchdog_proc_mutex);