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From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org,
	Mel Gorman <mgorman@techsingularity.net>,
	Matt Fleming <matt@codeblueprint.co.uk>,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Subject: Re: [PATCH 2/2] sched/debug: fix deadlock when enabling sched events
Date: Tue, 7 Jun 2016 16:02:37 -0500	[thread overview]
Message-ID: <20160607210237.kdkqm7typivv75l7@treble> (raw)
In-Reply-To: <20160607195448.GL30154@twins.programming.kicks-ass.net>

On Tue, Jun 07, 2016 at 09:54:48PM +0200, Peter Zijlstra wrote:
> On Tue, Jun 07, 2016 at 02:43:17PM -0500, Josh Poimboeuf wrote:
> > 1. Instead of just warning and allowing the tracepoints to be broken,
> >    I'd argue that it would be better to make them work by forcing
> >    schedstats enabled and printing a warning about that, which is what's
> 
> Forcing them enabled doesn't make them useful per se; some of these
> tracepoint rely on previously recoded state, which now wasn't previously
> recorded because back then it was disabled.

Ah, that's true.  Though this issue exists regardless of whether we
force enable schedstats or the user manually enables them.  It's a side
effect of allowing schedstats to be enabled after booting.

-- 
Josh

  reply	other threads:[~2016-06-07 21:02 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-07 19:43 [PATCH 0/2] sched/debug: more schedstats fixes Josh Poimboeuf
2016-06-07 19:43 ` [PATCH 1/2] sched/debug: fix 'schedstats=enable' cmdline option Josh Poimboeuf
2016-06-08  8:06   ` Mel Gorman
2016-06-08 14:21   ` [tip:sched/core] sched/debug: Fix " tip-bot for Josh Poimboeuf
2016-06-07 19:43 ` [PATCH 2/2] sched/debug: fix deadlock when enabling sched events Josh Poimboeuf
2016-06-07 19:54   ` Peter Zijlstra
2016-06-07 21:02     ` Josh Poimboeuf [this message]
2016-06-08  8:13     ` Mel Gorman
2016-06-07 21:06   ` Josh Poimboeuf
2016-06-08  7:56   ` Ingo Molnar
2016-06-08 13:12     ` Josh Poimboeuf
2016-06-08 13:15       ` Ingo Molnar
2016-06-13  7:32         ` [PATCH v2] " Josh Poimboeuf
2016-06-14 11:35           ` [tip:sched/urgent] sched/debug: Fix " tip-bot for Josh Poimboeuf
2016-06-08  8:11   ` [PATCH 2/2] sched/debug: fix " Mel Gorman

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