LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Thomas Gleixner <tglx@linutronix.de>
To: Prasad Sodagudi <psodagud@codeaurora.org>,
	rostedt@goodmis.org, pmladek@suse.com,
	sergey.senozhatsky@gmail.com, gregkh@linuxfoundation.org
Cc: linux-kernel@vger.kernel.org, tkjos@google.com,
	Prasad Sodagudi <psodagud@codeaurora.org>
Subject: Re: [PATCH 1/2] genirq/cpuhotplug: Reduce logging level for couple of prints
Date: Thu, 24 Sep 2020 20:08:30 +0200	[thread overview]
Message-ID: <87zh5f6o9t.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <1600906112-126722-1-git-send-email-psodagud@codeaurora.org>

On Wed, Sep 23 2020 at 17:08, Prasad Sodagudi wrote:
> During the cpu hot plug stress testing, couple of messages
> continuous flooding on to the console is causing timers
> migration delay. Delayed time migrations from hot plugging
> core is causing device instability with watchdog. So reduce
> log level for couple of prints in cpu hot plug flow.

This is fixing the wrong end, really.

Timer migration can be delayed by other means as well.

The real problem is that the migration happens _after_ the CPU is
completely dead and the hotplug control thread is not guaranteed to
reach the timer migration state before timers are overdue at all.

There is a bunch of related problems, e.g. the interrupt migration
mechanism kicks in late as well.

I'm not against changing the log level per se, but the justification for
doing so is just bogus.

The more obvious question is whether these printks are useful at all
other than at the pr_debug() level.

Thanks,

        tglx

      parent reply	other threads:[~2020-09-24 18:08 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-24  0:08 Prasad Sodagudi
2020-09-24  0:08 ` [PATCH 2/2] printk: Make the console flush configurable in hotplug path Prasad Sodagudi
2020-09-24  6:33   ` Greg KH
2020-09-24 18:21     ` Thomas Gleixner
2020-09-25  9:27       ` Greg KH
2020-09-25 14:16         ` Adam Borowski
2020-09-25 22:55           ` Thomas Gleixner
2020-09-28  2:05       ` psodagud
2020-09-28 12:50         ` Greg KH
2020-09-30 14:36         ` Petr Mladek
2020-09-24  6:38   ` Sergey Senozhatsky
2020-09-30 13:57   ` Petr Mladek
2020-09-24  6:31 ` [PATCH 1/2] genirq/cpuhotplug: Reduce logging level for couple of prints Greg KH
2020-09-24 18:08 ` Thomas Gleixner [this message]

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=87zh5f6o9t.fsf@nanos.tec.linutronix.de \
    --to=tglx@linutronix.de \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pmladek@suse.com \
    --cc=psodagud@codeaurora.org \
    --cc=rostedt@goodmis.org \
    --cc=sergey.senozhatsky@gmail.com \
    --cc=tkjos@google.com \
    --subject='Re: [PATCH 1/2] genirq/cpuhotplug: Reduce logging level for couple of prints' \
    /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

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).