From: Petr Mladek <pmladek@suse.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Laurence Oberman <loberman@redhat.com>,
Vincent Whitchurch <vincent.whitchurch@axis.com>,
Michal Hocko <mhocko@suse.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] watchdog/softlockup: Report the same softlockup regularly
Date: Mon, 21 Oct 2019 15:40:38 +0200 [thread overview]
Message-ID: <20191021134038.fz2cdpxrd3p3yhb7@pathway.suse.cz> (raw)
In-Reply-To: <20191021124339.GE1817@hirez.programming.kicks-ass.net>
On Mon 2019-10-21 14:43:39, Peter Zijlstra wrote:
> On Mon, Aug 19, 2019 at 12:47:31PM +0200, Petr Mladek wrote:
> > Softlockup report means that there is no progress on the given CPU. It
> > might be a "short" affair where the system gets recovered. But often
> > the system stops being responsive and need to get rebooted.
> >
> > The softlockup might be root of the problems or just a symptom. It might
> > be a deadlock, livelock, or often repeated state.
> >
> > Regular reports help to distinguish different situations. Fortunately,
> > the watchdog is finally able to show correct information how long
> > softlockup_fn() was not scheduled.
> >
> > Report before this patch:
> >
> > [ 320.248948] watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [cat:4916]
> >
> > And after this patch:
> >
> > [ 480.372418] watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [cat:4943]
> > [ 508.372359] watchdog: BUG: soft lockup - CPU#2 stuck for 52s! [cat:4943]
> > [ 548.372359] watchdog: BUG: soft lockup - CPU#2 stuck for 89s! [cat:4943]
> > [ 576.372351] watchdog: BUG: soft lockup - CPU#2 stuck for 115s! [cat:4943]
> >
> > Note that the horrible code never really worked before the accounting
> > was fixed. The last working timestamp was regularly lost by the many
> > touch*watchdog() calls.
>
> So what's the point of patch 1? Just confusing people?
I was not sure what was the expected behavior. The code actually
looked like only the first report was wanted. But it probably never
worked that way.
Should I squash the two patches and send it again, please?
Best Regards,
Petr
next prev parent reply other threads:[~2019-10-21 13:40 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 10:47 [PATCH 0/3] watchdog/softlockup: Make softlockup reports more reliable and useful Petr Mladek
2019-08-19 10:47 ` [PATCH 1/3] watchdog/softlockup: Preserve original timestamp when touching watchdog externally Petr Mladek
2019-10-21 12:42 ` Peter Zijlstra
2019-10-21 13:04 ` Petr Mladek
2019-08-19 10:47 ` [PATCH 2/3] watchdog/softlockup: Report the same softlockup regularly Petr Mladek
2019-10-21 12:43 ` Peter Zijlstra
2019-10-21 13:40 ` Petr Mladek [this message]
2019-10-21 14:09 ` Peter Zijlstra
2019-08-19 10:47 ` [PATCH 3/3] Test softlockup Petr Mladek
2019-10-21 12:45 ` Peter Zijlstra
2019-10-21 13:06 ` Petr Mladek
2019-10-21 12:32 ` [PATCH 0/3] watchdog/softlockup: Make softlockup reports more reliable and useful Petr Mladek
-- strict thread matches above, loose matches on Subject: below --
2019-06-05 14:09 [RFC " Petr Mladek
2019-06-05 14:09 ` [PATCH 2/3] watchdog/softlockup: Report the same softlockup regularly Petr Mladek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191021134038.fz2cdpxrd3p3yhb7@pathway.suse.cz \
--to=pmladek@suse.com \
--cc=linux-kernel@vger.kernel.org \
--cc=loberman@redhat.com \
--cc=mhocko@suse.com \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=vincent.whitchurch@axis.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®