From: Nicholas Piggin <npiggin@xxxxxxxxx> Subject: kernel/watchdog: provide watchdog_nmi_reconfigure() for arch watchdogs 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@xxxxxxxxx: add code comments] Link: http://lkml.kernel.org/r/20170617125933.774d3858@xxxxxxxxxxxxxxxxxxx [arnd@xxxxxxxx: hide unused function] Link: http://lkml.kernel.org/r/20170620204854.966601-1-arnd@xxxxxxxx Link: http://lkml.kernel.org/r/20170616065715.18390-5-npiggin@xxxxxxxxx Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Reviewed-by: Don Zickus <dzickus@xxxxxxxxxx> Tested-by: Babu Moger <babu.moger@xxxxxxxxxx> [sparc] Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/watchdog.c | 48 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 44 insertions(+), 4 deletions(-) diff -puN kernel/watchdog.c~watchdog-provide-watchdog_reconfigure-for-arch-watchdogs kernel/watchdog.c --- a/kernel/watchdog.c~watchdog-provide-watchdog_reconfigure-for-arch-watchdogs +++ a/kernel/watchdog.c @@ -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(unsigne { } +/* + * 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(vo } } +#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(vo { } +#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_tab * 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); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
