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Re: [Xen-devel] [RFC][PATCH] walking the page lists needs the page_alloc

To: Jan Beulich <JBeulich@xxxxxxxxxx>, Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [RFC][PATCH] walking the page lists needs the page_alloc lock
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Fri, 13 Aug 2010 07:46:40 +0100
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On 13/08/2010 07:40, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

>> Sorry, my intention was to say that changes to the debug-key printouts
>> are safe, not that they didn't require changes.
>> The debug-key printouts (in particular the NUMA one) are where I
>> actually hit this bug on a running system.
> But then, to avoid a hanging system, these should be trylock-s
> rather than plain locks, shouldn't they?

Why? The handler is called in softirq context. It should be safe to spin.

 -- Keir

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