Messages in this thread | | | Subject | Re: watchdog: softdog: fire watchdog even if softirqs do not get to run | From | Niklas Cassel <> | Date | Mon, 27 Feb 2017 13:58:20 +0100 |
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On 02/27/2017 05:04 AM, Guenter Roeck wrote: > On Fri, Feb 17, 2017 at 07:25:02PM +0100, Niklas Cassel wrote: >> From: Niklas Cassel <niklas.cassel@axis.com> >> >> Checking for timer expiration is done from the softirq TIMER_SOFTIRQ. >> >> Since commit 4cd13c21b207 ("softirq: Let ksoftirqd do its job"), >> pending softirqs are no longer always handled immediately, instead, >> if there are pending softirqs, and ksoftirqd is in state TASK_RUNNING, >> the handling of the softirqs are deferred, and are instead supposed >> to be handled by ksoftirqd, when ksoftirqd gets scheduled. >> >> If a user space process with a real-time policy starts to misbehave >> by never relinquishing the CPU while ksoftirqd is in state TASK_RUNNING, >> what will happen is that all softirqs will get deferred, while ksoftirqd, >> which is supposed to handle the deferred softirqs, will never get to run. >> >> To make sure that the watchdog is able to fire even when we do not get >> to run softirqs, replace the timers with hrtimers. >> >> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> >> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > Niklas, > > Please rebase onto current mainline, test, and resubmit.
I've sent out a v2 now :)
Although, I thought that it was a bit weird that the conflicting patch was in Linus tree but is not in next-20170227.
I'm not sure if you are the web master for www.linux-watchdog.org, but their cgit seems to be broken: http://www.linux-watchdog.org/cgi-bin/gitweb.cgi?p=linux-watchdog.git;a=summary http://www.linux-watchdog.org/cgi-bin/gitweb.cgi?p=linux-watchdog-next.git;a=summary
> > Thanks, > Guenter >
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