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| author | Laurent Dufour <ldufour@linux.ibm.com> | 2022-07-13 17:47:27 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-25 11:15:46 +0200 |
| commit | 81c95bebdec9537501c4806b84b169be1d6c4080 (patch) | |
| tree | 53421a31bf8d65f8c3fc65a7b21dc64faf34aa44 | |
| parent | 7ff503dbfc1a07c28f34e7407a45de1579125b17 (diff) | |
| download | linux-stable-81c95bebdec9537501c4806b84b169be1d6c4080.tar.gz linux-stable-81c95bebdec9537501c4806b84b169be1d6c4080.tar.bz2 linux-stable-81c95bebdec9537501c4806b84b169be1d6c4080.zip | |
watchdog: export lockup_detector_reconfigure
[ Upstream commit 7c56a8733d0a2a4be2438a7512566e5ce552fccf ]
In some circumstances it may be interesting to reconfigure the watchdog
from inside the kernel.
On PowerPC, this may helpful before and after a LPAR migration (LPM) is
initiated, because it implies some latencies, watchdog, and especially NMI
watchdog is expected to be triggered during this operation. Reconfiguring
the watchdog with a factor, would prevent it to happen too frequently
during LPM.
Rename lockup_detector_reconfigure() as __lockup_detector_reconfigure() and
create a new function lockup_detector_reconfigure() calling
__lockup_detector_reconfigure() under the protection of watchdog_mutex.
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
[mpe: Squash in build fix from Laurent, reported by Sachin]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220713154729.80789-3-ldufour@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | include/linux/nmi.h | 2 | ||||
| -rw-r--r-- | kernel/watchdog.c | 21 |
2 files changed, 18 insertions, 5 deletions
diff --git a/include/linux/nmi.h b/include/linux/nmi.h index 9003e29cde46..e972d1ae1ee6 100644 --- a/include/linux/nmi.h +++ b/include/linux/nmi.h @@ -122,6 +122,8 @@ int watchdog_nmi_probe(void); int watchdog_nmi_enable(unsigned int cpu); void watchdog_nmi_disable(unsigned int cpu); +void lockup_detector_reconfigure(void); + /** * touch_nmi_watchdog - restart NMI watchdog timeout. * diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 6d60701dc636..44096c4f4d60 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -561,7 +561,7 @@ int lockup_detector_offline_cpu(unsigned int cpu) return 0; } -static void lockup_detector_reconfigure(void) +static void __lockup_detector_reconfigure(void) { cpus_read_lock(); watchdog_nmi_stop(); @@ -581,6 +581,13 @@ static void lockup_detector_reconfigure(void) __lockup_detector_cleanup(); } +void lockup_detector_reconfigure(void) +{ + mutex_lock(&watchdog_mutex); + __lockup_detector_reconfigure(); + mutex_unlock(&watchdog_mutex); +} + /* * Create the watchdog thread infrastructure and configure the detector(s). * @@ -601,13 +608,13 @@ static __init void lockup_detector_setup(void) return; mutex_lock(&watchdog_mutex); - lockup_detector_reconfigure(); + __lockup_detector_reconfigure(); softlockup_initialized = true; mutex_unlock(&watchdog_mutex); } #else /* CONFIG_SOFTLOCKUP_DETECTOR */ -static void lockup_detector_reconfigure(void) +static void __lockup_detector_reconfigure(void) { cpus_read_lock(); watchdog_nmi_stop(); @@ -615,9 +622,13 @@ static void lockup_detector_reconfigure(void) watchdog_nmi_start(); cpus_read_unlock(); } +void lockup_detector_reconfigure(void) +{ + __lockup_detector_reconfigure(); +} static inline void lockup_detector_setup(void) { - lockup_detector_reconfigure(); + __lockup_detector_reconfigure(); } #endif /* !CONFIG_SOFTLOCKUP_DETECTOR */ @@ -657,7 +668,7 @@ static void proc_watchdog_update(void) { /* Remove impossible cpus to keep sysctl output clean. */ cpumask_and(&watchdog_cpumask, &watchdog_cpumask, cpu_possible_mask); - lockup_detector_reconfigure(); + __lockup_detector_reconfigure(); } /* |