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From: Tim Blechmann <tim@klingt.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-rt-users <linux-rt-users@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] [RT] avoid preemption in memory controller code
Date: Mon, 08 Dec 2008 18:07:36 +0100	[thread overview]
Message-ID: <1228756056.7862.8.camel@thinkpad> (raw)
In-Reply-To: <alpine.DEB.1.10.0812081138470.26257@gandalf.stny.rr.com>

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> > the lru_lock of struct mem_group_per_zone is used to avoid preemption
> > during the __mem_cgroup_stat_add_safe function.
> > therefore, a raw_spinlock_t should be used.
> 
> What is the reason that this must avoid preemption? 

it guards a call to smp_processor_id() in __mem_cgroup_stat_add_safe().
see http://article.gmane.org/gmane.linux.rt.user/3690

> Is there another
> way to solve this? I rather not just add a raw spinlock if we can
> help it.

not sure, maybe one can disable preemption for that specific function?

tim

--
tim@klingt.org
http://tim.klingt.org

Art is either a complaint or do something else
  John Cage quoting Jasper Johns

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  reply	other threads:[~2008-12-08 17:08 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-12-08 14:34 [PATCH] [RT] avoid preemption in memory controller code Tim Blechmann
2008-12-08 16:42 ` Steven Rostedt
2008-12-08 17:07   ` Tim Blechmann [this message]
2008-12-08 17:23     ` Steven Rostedt
2008-12-11 19:05       ` [PATCH] [RT] preempt_disable_rt for CONFIG_PREEMPT_RT Tim Blechmann
2008-12-09  1:13 ` [PATCH] [RT] avoid preemption in memory controller code Li Zefan
2008-12-09  1:32   ` KAMEZAWA Hiroyuki
     [not found] <preempt_enable_rt();>
2008-12-11 19:00 ` Tim Blechmann
2008-12-12  1:17   ` KAMEZAWA Hiroyuki
2008-12-12  9:08     ` Tim Blechmann

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