linux-kernel - [PATCH] [PATCH]: Reset clocksource watchdog after sysrq-t

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Message-Id: <1320241585-28056-1-git-send-email-prarit@redhat.com>
Date:	Wed,  2 Nov 2011 09:46:25 -0400
From:	Prarit Bhargava <prarit@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	Prarit Bhargava <prarit@...hat.com>, tglx@...utronix.de,
	johnstul@...ibm.com
Subject: [PATCH] [PATCH]: Reset clocksource watchdog after sysrq-t

When doing a sysrq-t other processes are starved out because the task_list
lock is held.  On a large enough system this means that the clocksource
watchdog does not fire for a long time and when system operation resumes the
watchdog erroneously marks the current clocksource as unstable.

Reset the clocksource watchdog after show_state_filter() has dumped the
task states.

Cc: tglx@...utronix.de
Cc: johnstul@...ibm.com
---
 kernel/sched.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index d87c6e5..b09c053 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -71,6 +71,7 @@
 #include <linux/ctype.h>
 #include <linux/ftrace.h>
 #include <linux/slab.h>
+#include <linux/clocksource.h>
 
 #include <asm/tlb.h>
 #include <asm/irq_regs.h>
@@ -6034,6 +6035,7 @@ void show_state_filter(unsigned long state_filter)
 	} while_each_thread(g, p);
 
 	touch_all_softlockup_watchdogs();
+	clocksource_touch_watchdog();
 
 #ifdef CONFIG_SCHED_DEBUG
 	sysrq_sched_debug_show();
-- 
1.7.1

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