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From: Don Zickus <dzickus@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>,
	Mandeep Singh Baines <msb@chromium.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Michal Hocko <mhocko@suse.cz>
Subject: Re: [PATCH] watchdog: Make sure the watchdog thread gets CPU on loaded system
Date: Thu, 15 Mar 2012 10:35:49 -0400	[thread overview]
Message-ID: <20120315143549.GC3941@redhat.com> (raw)
In-Reply-To: <1331820051.18960.187.camel@twins>

On Thu, Mar 15, 2012 at 03:00:51PM +0100, Peter Zijlstra wrote:
> On Thu, 2012-03-15 at 13:42 +0100, Ingo Molnar wrote:
> > So unless there's concensus to remove everything but the hard 
> > lockup detection facilities, lets solve the technical problem at 
> > hand, ok? 
> 
> Well, at least make it possible to disable the silly soft thing.
> 
> And I really wouldn't know how the soft thing could possible help,
> except when not actually having a NMI watchdog. What case does it
> trigger where the NMI one doesn't?

I think softlockup really boils down to a pre-emption disabled detector
much like how the hardlockup really is a interrupts disabled detector.

The amount of code preventing the scheduler from running is most likely a
lot lower than the code the prevents interrrupts from happening.

Cheers,
Don


  reply	other threads:[~2012-03-15 14:36 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-14 20:38 [PATCH] watchdog: Make sure the watchdog thread gets CPU on loaded system Don Zickus
2012-03-14 20:59 ` Mandeep Singh Baines
2012-03-14 23:19 ` Andrew Morton
2012-03-15  1:45   ` Mandeep Singh Baines
2012-03-15 11:00     ` Peter Zijlstra
2012-03-15 11:06       ` Peter Zijlstra
2012-03-15 12:42         ` Ingo Molnar
2012-03-15 14:00           ` Peter Zijlstra
2012-03-15 14:35             ` Don Zickus [this message]
2012-03-15 15:39               ` Mandeep Singh Baines
2012-03-15 16:10                 ` Peter Zijlstra
2012-03-15 16:11                   ` Peter Zijlstra
2012-03-15 16:16                     ` Peter Zijlstra
2012-03-15 17:04                       ` Mandeep Singh Baines
2012-03-15  8:02   ` Michal Hocko
2012-03-15 15:54     ` Don Zickus
2012-03-15 16:04       ` Peter Zijlstra
2012-03-19 22:00         ` Andrew Morton
2012-03-15 16:14       ` Michal Hocko
2012-03-15 17:14         ` Don Zickus
  -- strict thread matches above, loose matches on Subject: below --
2012-03-13  9:45 [PATCH] watchdog: make " Michal Hocko
2012-03-13 13:42 ` Don Zickus

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