From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Laurent Dufour <ldufour@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Sasha Levin <sashal@kernel.org>,
pmladek@suse.com, akpm@linux-foundation.org,
juri.lelli@redhat.com, peterz@infradead.org, mcgrof@kernel.org,
nixiaoming@huawei.com, frederic@kernel.org,
john.ogness@linutronix.de, linux@rasmusvillemoes.dk
Subject: [PATCH AUTOSEL 5.4 08/16] watchdog: export lockup_detector_reconfigure
Date: Sun, 14 Aug 2022 12:28:23 -0400 [thread overview]
Message-ID: <20220814162833.2398478-8-sashal@kernel.org> (raw)
In-Reply-To: <20220814162833.2398478-1-sashal@kernel.org>
From: Laurent Dufour <ldufour@linux.ibm.com>
[ 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>
---
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 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 cbd3cf503c90..a3d0e928305c 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -568,7 +568,7 @@ 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();
@@ -588,6 +588,13 @@ 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).
*
@@ -608,13 +615,13 @@ 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();
@@ -622,9 +629,13 @@ 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 */
@@ -664,7 +675,7 @@ 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();
}
/*
--
2.35.1
next prev parent reply other threads:[~2022-08-14 16:38 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-14 16:28 [PATCH AUTOSEL 5.4 01/16] lib/list_debug.c: Detect uninitialized lists Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 02/16] tty: serial: Fix refcount leak bug in ucc_uart.c Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 03/16] vfio: Clear the caps->buf to NULL after free Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 04/16] mips: cavium-octeon: Fix missing of_node_put() in octeon2_usb_clocks_start Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 05/16] riscv: dts: sifive: Add fu540 topology information Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 06/16] riscv: mmap with PROT_WRITE but no PROT_READ is invalid Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 07/16] RISC-V: Add fast call path of crash_kexec() Sasha Levin
2022-08-14 16:28 ` Sasha Levin [this message]
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 09/16] powerpc/32: Don't always pass -mcpu=powerpc to the compiler Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 10/16] ALSA: core: Add async signal helpers Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 11/16] ALSA: timer: Use deferred fasync helper Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 12/16] f2fs: fix to avoid use f2fs_bug_on() in f2fs_new_node_page() Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 13/16] smb3: check xattr value length earlier Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 14/16] powerpc/64: Init jump labels before parse_early_param() Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 15/16] video: fbdev: i740fb: Check the argument of i740_calc_vclk() Sasha Levin
2022-08-14 16:28 ` [PATCH AUTOSEL 5.4 16/16] MIPS: tlbex: Explicitly compare _PAGE_NO_EXEC against 0 Sasha Levin
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