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From: Jeremy Fitzhardinge <jeremy@goop.org>
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
Date: Thu, 08 Nov 2007 16:19:49 -0800	[thread overview]
Message-ID: <4733A7A5.9000900@goop.org> (raw)
In-Reply-To: <200711090007.43424.ak@suse.de>

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

WARNING: multiple messages have this Message-ID (diff)
From: Jeremy Fitzhardinge <jeremy@goop.org>
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
Date: Thu, 08 Nov 2007 16:19:49 -0800	[thread overview]
Message-ID: <4733A7A5.9000900@goop.org> (raw)
In-Reply-To: <200711090007.43424.ak@suse.de>

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

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  parent reply	other threads:[~2007-11-09  1:25 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-08 19:58 Some interesting observations when trying to optimize vmstat handling Christoph Lameter
2007-11-08 23:07 ` Andi Kleen
2007-11-08 23:07   ` Andi Kleen
2007-11-08 23:25   ` Christoph Lameter
2007-11-08 23:25     ` Christoph Lameter
2007-11-09  0:19   ` Jeremy Fitzhardinge [this message]
2007-11-09  0:19     ` Jeremy Fitzhardinge
2007-11-09 15:56     ` Andi Kleen
2007-11-09 15:56       ` Andi Kleen
2007-11-08 23:24 ` David Miller
2007-11-08 23:24   ` David Miller, Christoph Lameter

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