From: "tip-bot2 for Petr Mladek" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Petr Mladek <pmladek@suse.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Ziljstra <peterz@infradead.org>, x86 <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [tip: core/core] watchdog/softlockup: Remove obsolete check of last reported task
Date: Thu, 16 Jan 2020 13:55:29 -0000 [thread overview]
Message-ID: <157918292903.396.3828152178044862176.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20191024114928.15377-2-pmladek@suse.com>
The following commit has been merged into the core/core branch of tip:
Commit-ID: 3a51449b7959f68cc45abe67298e40c7eb57167b
Gitweb: https://git.kernel.org/tip/3a51449b7959f68cc45abe67298e40c7eb57167b
Author: Petr Mladek <pmladek@suse.com>
AuthorDate: Thu, 24 Oct 2019 13:49:26 +02:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 16 Jan 2020 14:52:48 +01:00
watchdog/softlockup: Remove obsolete check of last reported task
commit 9cf57731b63e ("watchdog/softlockup: Replace "watchdog/%u" threads
with cpu_stop_work") ensures that the watchdog is reliably touched during
a task switch.
As a result the check for an unnoticed task switch is not longer needed.
Remove the relevant code, which effectively reverts commit b1a8de1f5343
("softlockup: make detector be aware of task switch of processes hogging
cpu")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Ziljstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20191024114928.15377-2-pmladek@suse.com
---
kernel/watchdog.c | 18 +-----------------
1 file changed, 1 insertion(+), 17 deletions(-)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 0621301..e3774e9 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -173,7 +173,6 @@ static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
static DEFINE_PER_CPU(bool, softlockup_touch_sync);
static DEFINE_PER_CPU(bool, soft_watchdog_warn);
static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts);
-static DEFINE_PER_CPU(struct task_struct *, softlockup_task_ptr_saved);
static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
static unsigned long soft_lockup_nmi_warn;
@@ -413,22 +412,8 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
return HRTIMER_RESTART;
/* only warn once */
- if (__this_cpu_read(soft_watchdog_warn) == true) {
- /*
- * When multiple processes are causing softlockups the
- * softlockup detector only warns on the first one
- * because the code relies on a full quiet cycle to
- * re-arm. The second process prevents the quiet cycle
- * and never gets reported. Use task pointers to detect
- * this.
- */
- if (__this_cpu_read(softlockup_task_ptr_saved) !=
- current) {
- __this_cpu_write(soft_watchdog_warn, false);
- __touch_watchdog();
- }
+ if (__this_cpu_read(soft_watchdog_warn) == true)
return HRTIMER_RESTART;
- }
if (softlockup_all_cpu_backtrace) {
/* Prevent multiple soft-lockup reports if one cpu is already
@@ -444,7 +429,6 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
smp_processor_id(), duration,
current->comm, task_pid_nr(current));
- __this_cpu_write(softlockup_task_ptr_saved, current);
print_modules();
print_irqtrace_events(current);
if (regs)
next prev parent reply other threads:[~2020-01-16 13:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-24 11:49 [PATCH 0/3] watchdog/softlockup: Report overall time and some cleanup Petr Mladek
2019-10-24 11:49 ` [PATCH 1/3] watchdog/softlockup: Remove obsolete check of last reported task Petr Mladek
2020-01-16 13:55 ` tip-bot2 for Petr Mladek [this message]
2019-10-24 11:49 ` [PATCH 2/3] watchdog/softlockup: Report the overall time of softlockups Petr Mladek
2020-01-16 13:39 ` Thomas Gleixner
2020-01-17 10:00 ` Petr Mladek
2019-10-24 11:49 ` [PATCH 3/3] watchdog/softlockup: Remove logic that tried to prevent repeated reports Petr Mladek
2019-11-08 10:13 ` [PATCH 0/3] watchdog/softlockup: Report overall time and some cleanup Petr Mladek
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