From: Steven Rostedt <rostedt@goodmis.org>
To: Wei Li <liwei391@huawei.com>
Cc: <mingo@redhat.com>, <peterz@infradead.org>,
<juri.lelli@redhat.com>, <vincent.guittot@linaro.org>,
<dietmar.eggemann@arm.com>, <bsegall@google.com>,
<mgorman@suse.de>, <huawei.libin@huawei.com>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched/debug: Reset watchdog on all CPUs while processing sysrq-t
Date: Thu, 2 Jan 2020 14:45:14 -0500 [thread overview]
Message-ID: <20200102144514.646df101@gandalf.local.home> (raw)
In-Reply-To: <20191226085224.48942-1-liwei391@huawei.com>
On Thu, 26 Dec 2019 16:52:24 +0800
Wei Li <liwei391@huawei.com> wrote:
> Lengthy output of sysrq-t may take a lot of time on slow serial console
> with lots of processes and CPUs.
>
> So we need to reset NMI-watchdog to avoid spurious lockup messages, and
> we also reset softlockup watchdogs on all other CPUs since another CPU
> might be blocked waiting for us to process an IPI or stop_machine.
Have you had this triggered?
>
> Add to sysrq_sched_debug_show() as what we did in show_state_filter().
>
> Signed-off-by: Wei Li <liwei391@huawei.com>
> ---
> kernel/sched/debug.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index f7e4579e746c..879d3ccf3806 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -751,9 +751,16 @@ void sysrq_sched_debug_show(void)
> int cpu;
>
> sched_debug_header(NULL);
> - for_each_online_cpu(cpu)
> + for_each_online_cpu(cpu) {
> + /*
> + * Need to reset softlockup watchdogs on all CPUs, because
> + * another CPU might be blocked waiting for us to process
> + * an IPI or stop_machine.
> + */
> + touch_nmi_watchdog();
> + touch_all_softlockup_watchdogs();
This doesn't seem to hurt to add, thus.
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
-- Steve
> print_cpu(NULL, cpu);
> -
> + }
> }
>
> /*
next prev parent reply other threads:[~2020-01-02 19:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-26 8:52 [PATCH] sched/debug: Reset watchdog on all CPUs while processing sysrq-t Wei Li
2020-01-02 19:45 ` Steven Rostedt [this message]
2020-01-03 1:54 ` liwei (GF)
2020-01-07 9:32 ` Peter Zijlstra
2020-01-17 10:08 ` [tip: sched/core] " tip-bot2 for Wei Li
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=20200102144514.646df101@gandalf.local.home \
--to=rostedt@goodmis.org \
--cc=bsegall@google.com \
--cc=dietmar.eggemann@arm.com \
--cc=huawei.libin@huawei.com \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=liwei391@huawei.com \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=vincent.guittot@linaro.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).