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From: Peter Zijlstra <peterz@infradead.org>
To: viresh kumar <viresh.kumar@linaro.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Christoph Lameter <cl@linux.com>,
	Linaro Kernel Mailman List <linaro-kernel@lists.linaro.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	vinmenon@codeaurora.org, shashim@codeaurora.org,
	Michal Hocko <mhocko@suse.cz>, Mel Gorman <mgorman@suse.de>,
	dave@stgolabs.net, Konstantin Khlebnikov <koct9i@gmail.com>,
	Linux Memory Management List <linux-mm@kvack.org>,
	Suresh Siddha <suresh.b.siddha@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC] vmstat: Avoid waking up idle-cpu to service shepherd work
Date: Sun, 29 Mar 2015 12:24:40 +0200	[thread overview]
Message-ID: <20150329102440.GC32047@worktop.ger.corp.intel.com> (raw)
In-Reply-To: <20150328134457.GK27490@worktop.programming.kicks-ass.net>

On Sat, Mar 28, 2015 at 02:44:57PM +0100, Peter Zijlstra wrote:
> > Now there are few issues I see here (Sorry if they are all imaginary):
> > - In case a timer re-arms itself from its handler and is migrated from CPU A to B, what
> >   happens if the re-armed timer fires before the first handler finishes ? i.e. timer->fn()
> >   hasn't finished running on CPU A and it has fired again on CPU B. Wouldn't this expose
> >   us to a lot of other problems? It wouldn't be serialized to itself anymore ?
> 
> What I said above.

What I didn't say, but had thought of is that __run_timer() should skip
any timer that has RUNNING set -- for obvious reasons :-)

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  reply	other threads:[~2015-03-29 10:24 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-26  5:39 Viresh Kumar
2015-03-26 20:18 ` Andrew Morton
2015-03-27  4:49   ` Viresh Kumar
2015-03-27  9:16     ` Peter Zijlstra
2015-03-27  9:30       ` Peter Zijlstra
2015-03-27 11:11         ` Christoph Lameter
2015-03-27 12:02           ` Peter Zijlstra
2015-03-27 19:45             ` Christoph Lameter
2015-03-28  4:28             ` Viresh Kumar
2015-03-28 11:41               ` Peter Zijlstra
2015-03-28  4:18         ` Viresh Kumar
2015-03-28  9:53           ` Peter Zijlstra
2015-03-28 11:57             ` viresh kumar
2015-03-28 12:04               ` Viresh Kumar
2015-03-28 13:44               ` Peter Zijlstra
2015-03-29 10:24                 ` Peter Zijlstra [this message]
2015-03-30 12:02                   ` Viresh Kumar
2015-03-30 12:47                     ` Peter Zijlstra
2015-03-30 13:14                       ` Viresh Kumar
2015-03-30 13:59                         ` Peter Zijlstra
2015-03-30 16:17                           ` Viresh Kumar
2015-03-30 16:25                             ` Peter Zijlstra
2015-03-29 12:01                 ` Viresh Kumar
2015-03-29 17:24                   ` Peter Zijlstra
2015-03-30 15:08             ` Michal Hocko
2015-03-30 15:14               ` Peter Zijlstra
2015-03-30 15:42               ` Christoph Lameter
2015-03-27 14:19 ` Michal Hocko
2015-03-28  4:34   ` Viresh Kumar

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