From: Thomas Gleixner <tglx@linutronix.de>
To: Oleg Nesterov <oleg@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
x86@kernel.org, Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Don Zickus <dzickus@redhat.com>,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
Maxime Coquelin <maxime.coquelin@redhat.com>
Subject: Re: [PATCH] watchdog: Respect watchdog cpumask on CPU hotplug
Date: Wed, 27 Mar 2019 20:10:12 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.21.1903272009000.1789@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190327151653.GA23811@redhat.com>
On Wed, 27 Mar 2019, Oleg Nesterov wrote:
> On 03/26, Thomas Gleixner wrote:
> >
> > The rework of the watchdog core to use cpu_stop_work broke the watchdog
> > cpumask on CPU hotplug.
> >
> > The watchdog_enable/disable() functions are now called unconditionally from
> > the hotplug callback, i.e. even on CPUs which are not in the watchdog
> > cpumask.
> >
> > Only invoke them when the plugged CPU is in the watchdog cpumask.
>
> IIUC without this fix an NMI watchdog can too be enabled at boot time even
> if the initial watchdog_cpumask = housekeeping_cpumask(HK_FLAG_TIMER) doesn't
> include the plugged CPU.
Yes.
> And after that writing 0 to /proc/sys/kernel/nmi_watchdog clears
> NMI_WATCHDOG_ENABLED but this can't disable NMI watchdog's outside of
> watchdog_allowed_mask.
Correct
> So may be this can explain the problem reported by Maxime ?
> See https://lore.kernel.org/lkml/b99c5a25-a5fe-18dd-2f1d-bdd6834f03e5@redhat.com/
That looks so.
Thanks,
tglx
next prev parent reply other threads:[~2019-03-27 19:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-26 21:51 [PATCH] watchdog: Respect watchdog cpumask on CPU hotplug Thomas Gleixner
2019-03-27 15:16 ` Oleg Nesterov
2019-03-27 19:10 ` Thomas Gleixner [this message]
2019-03-28 9:36 ` Maxime Coquelin
2019-03-28 12:37 ` [tip:core/urgent] " tip-bot for Thomas Gleixner
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=alpine.DEB.2.21.1903272009000.1789@nanos.tec.linutronix.de \
--to=tglx@linutronix.de \
--cc=dzickus@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=maxime.coquelin@redhat.com \
--cc=mpe@ellerman.id.au \
--cc=npiggin@gmail.com \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=ricardo.neri-calderon@linux.intel.com \
--cc=x86@kernel.org \
/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;
as well as URLs for NNTP newsgroup(s).