From: "Jan Beulich" <JBeulich@novell.com>
To: Keir Fraser <keir.fraser@eu.citrix.com>
Cc: Tim Deegan <Tim.Deegan@eu.citrix.com>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: [RFC][PATCH] walking the page lists needs the page_alloc lock
Date: Fri, 13 Aug 2010 08:06:31 +0100 [thread overview]
Message-ID: <4C650B17020000780000FAA2@vpn.id2.novell.com> (raw)
In-Reply-To: <C88AA8E0.1D980%keir.fraser@eu.citrix.com>
>>> On 13.08.10 at 08:46, Keir Fraser <keir.fraser@eu.citrix.com> wrote:
> On 13/08/2010 07:40, "Jan Beulich" <JBeulich@novell.com> 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.
Hmm, indeed. I was looking at others, and at least
domain_dump_evtchn_info() also uses a trylock - apparently for
no good reason.
Jan
next prev parent reply other threads:[~2010-08-13 7:06 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-23 13:49 [RFC][PATCH] walking the page lists needs the page_alloc lock Tim Deegan
2010-07-23 13:55 ` Tim Deegan
2010-08-12 15:09 ` Jan Beulich
2010-08-12 16:37 ` Tim Deegan
2010-08-13 6:40 ` Jan Beulich
2010-08-13 6:46 ` Keir Fraser
2010-08-13 7:06 ` Jan Beulich [this message]
2010-08-13 7:10 ` Keir Fraser
2010-08-13 7:20 ` Jan Beulich
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