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Wed, 13 Jul 2022 15:47:31 +0000 (GMT) Received: from localhost.localdomain (unknown [9.145.2.121]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 13 Jul 2022 15:47:31 +0000 (GMT) From: Laurent Dufour To: mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, wim@linux-watchdog.org, linux@roeck-us.net, nathanl@linux.ibm.com, rdunlap@infradead.org Cc: haren@linux.vnet.ibm.com, hch@infradead.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-watchdog@vger.kernel.org Subject: [PATCH v5 2/4] watchdog: export lockup_detector_reconfigure Date: Wed, 13 Jul 2022 17:47:27 +0200 Message-Id: <20220713154729.80789-3-ldufour@linux.ibm.com> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220713154729.80789-1-ldufour@linux.ibm.com> References: <20220713154729.80789-1-ldufour@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: rqJP_mbwYCmnQydzmQ3Ap22ZOt3BR0mg X-Proofpoint-GUID: A8FtXGMeQqSr63HUK0sI1DiJRnUWJEq3 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.883,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-07-13_04,2022-07-13_03,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 suspectscore=0 priorityscore=1501 adultscore=0 spamscore=0 lowpriorityscore=0 mlxlogscore=999 phishscore=0 mlxscore=0 impostorscore=0 bulkscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2206140000 definitions=main-2207130062 Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org 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. Cc: Christoph Hellwig Signed-off-by: Laurent Dufour --- include/linux/nmi.h | 2 ++ kernel/watchdog.c | 21 ++++++++++++++++----- 2 files changed, 18 insertions(+), 5 deletions(-) diff --git a/include/linux/nmi.h b/include/linux/nmi.h index 750c7f395ca9..f700ff2df074 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 20a7a55e62b6..90e6c41d5e33 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -541,7 +541,7 @@ 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(); @@ -561,6 +561,13 @@ 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 infrastructure and configure the detector(s). */ @@ -577,13 +584,13 @@ 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) +void __lockup_detector_reconfigure(void) { cpus_read_lock(); watchdog_nmi_stop(); @@ -591,9 +598,13 @@ static void lockup_detector_reconfigure(void) watchdog_nmi_start(); cpus_read_unlock(); } +static inline 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 */ @@ -633,7 +644,7 @@ 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(); } /*