Subject: Re: [Patch] idle governor: Avoid lock acquisition to read pm_qos
 before entering idle
From: James Bottomley <James.Bottomley@suse.de>
To: Tim Chen <tim.c.chen@linux.intel.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>, mark gross <markgross@thegnar.org>,
        David Alan Gilbert <linux@treblig.org>, linux-kernel@vger.kernel.org,
        Len <len.brown@intel.com>, Andi Kleen <ak@linux.intel.com>,
        Arjan van de Ven <arjan@linux.intel.com>, Len Brown <lenb@kernel.org>,
        Linux PM mailing list <linux-pm@lists.linux-foundation.org>
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Date: Fri, 11 Feb 2011 13:33:34 -0600
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On Fri, 2011-02-11 at 11:27 -0800, Tim Chen wrote:
> On Fri, 2011-02-11 at 20:22 +0100, Rafael J. Wysocki wrote:
> 
> > 
> > Thanks, but I'd put that comment before the structure definition with the
> > "NOTE:" prefix and I think you should explain the reason why that field
> > shouldn't be changed to 64-bits.
> > 
> 
> Either you or James want to suggest a comment on why the field shouldn't
> be changed to 64-bits to be placed there?

/*
 * Note: The lockless read read path depends on the CPU accessing 
 * target_value atomically.  Atomic access is only guaranteed on all CPU
 * types linux supports for 32 bit quantites
 */

James


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