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Date: Thu, 08 Nov 2007 16:19:49 -0800
From: Jeremy Fitzhardinge <jeremy@goop.org>
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To: Andi Kleen <ak@suse.de>
CC: Christoph Lameter <clameter@sgi.com>, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org, Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Subject: Re: Some interesting observations when trying to optimize vmstat
 handling
References: <Pine.LNX.4.64.0711081141180.9694@schroedinger.engr.sgi.com> <200711090007.43424.ak@suse.de>
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Andi Kleen wrote:
> The only problem is that there might be some code who relies on 
> restore_flags() restoring other flags that IF, but at least for interrupts
> and local_irq_save/restore it should be fine to change.
>   

I don't think so.  We don't bother to save/restore the other flags in
Xen paravirt and it doesn't seem to cause a problem.  The semantics
really are specific to the state of the interrupt flag.

    J