From: Avi Kivity <avi@qumranet.com>
To: Glauber Costa <gcosta@redhat.com>
Cc: kvm-devel@lists.sourceforge.net, Marcelo Tosatti <marcelo@kvack.org>
Subject: Re: [PATCH] use slots_lock to protect writes to the wall clock
Date: Tue, 18 Mar 2008 11:58:09 +0200 [thread overview]
Message-ID: <47DF9231.9090104@qumranet.com> (raw)
In-Reply-To: <47DF9191.9070607@redhat.com>
Glauber Costa wrote:
>
>>> [avi@firebolt linux-2.6 (master)]$ git grep down_read.*slots_lock
>>> arch/x86/kvm/ | wc -l
>>> 16
>>
>> We take the lock for read 16 times, could be narrowed down to
>> probably once (with a drop and re-take around guest mode).
>
> Since it will be written to so rarely, that's probably fine.
>
>
Moreover, the time setting up guest entry and handling exits is bounded
and usually short.
[We need to drop the lock when emulating hlt, too, for this to hold]
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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prev parent reply other threads:[~2008-03-18 9:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-17 20:10 [PATCH] use slots_lock to protect writes to the wall clock Glauber Costa
2008-03-18 6:42 ` Avi Kivity
2008-03-18 9:46 ` Glauber Costa
2008-03-18 9:52 ` Avi Kivity
2008-03-18 9:55 ` Glauber Costa
2008-03-18 9:58 ` Avi Kivity [this message]
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