From: Wang Qing Date: Tue, 29 Jun 2021 02:34:20 +0000 (-0700) Subject: doc: watchdog: modify the explanation related to watchdog thread X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e55fda8cdcba2cb3d5d46ae5fcd5f243f8b70d6e;p=linux.git doc: watchdog: modify the explanation related to watchdog thread "watchdog/%u" threads has be replaced by cpu_stop_work. The current description is extremely misleading. Link: https://lkml.kernel.org/r/1619687073-24686-4-git-send-email-wangqing@vivo.com Signed-off-by: Wang Qing Reviewed-by: Petr Mladek Cc: "Guilherme G. Piccoli" Cc: Joe Perches Cc: Jonathan Corbet Cc: Kees Cook Cc: Mauro Carvalho Chehab Cc: Qais Yousef Cc: Randy Dunlap Cc: Santosh Sivaraj Cc: Stephen Kitt Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/Documentation/admin-guide/lockup-watchdogs.rst b/Documentation/admin-guide/lockup-watchdogs.rst index 290840c160af2..3e09284a8b9be 100644 --- a/Documentation/admin-guide/lockup-watchdogs.rst +++ b/Documentation/admin-guide/lockup-watchdogs.rst @@ -39,7 +39,7 @@ in principle, they should work in any architecture where these subsystems are present. A periodic hrtimer runs to generate interrupts and kick the watchdog -task. An NMI perf event is generated every "watchdog_thresh" +job. An NMI perf event is generated every "watchdog_thresh" (compile-time initialized to 10 and configurable through sysctl of the same name) seconds to check for hardlockups. If any CPU in the system does not receive any hrtimer interrupt during that time the @@ -47,7 +47,7 @@ does not receive any hrtimer interrupt during that time the generate a kernel warning or call panic, depending on the configuration. -The watchdog task is a high priority kernel thread that updates a +The watchdog job runs in a stop scheduling thread that updates a timestamp every time it is scheduled. If that timestamp is not updated for 2*watchdog_thresh seconds (the softlockup threshold) the 'softlockup detector' (coded inside the hrtimer callback function)