From: Carsten Otte <cotte-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>
To: Andrea Arcangeli <andrea-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
Subject: Re: [PATCH] kvm memslot read-locking with mmu_lock
Date: Wed, 23 Jan 2008 09:15:05 +0100 [thread overview]
Message-ID: <4796F789.4080708@de.ibm.com> (raw)
In-Reply-To: <20080122145043.GF7331-lysg2Xt5kKMAvxtiuMwx3w@public.gmane.org>
Andrea Arcangeli wrote:
> On Tue, Jan 22, 2008 at 04:38:49PM +0200, Avi Kivity wrote:
>> Andrea Arcangeli wrote:
>>>> This is arch independent code, I'm surprised mmu_lock is visible here?
>>>>
>>> The mmu_lock is arch independent as far as I can tell. Pretty much
>>> like the mm->page_table_lock is also independent. All archs will have
>>> some form of shadow pagetables in software or hardware, and mmu_lock
>>> is the lock to take to serialize the pagetable updates and it also
>>> allows to walk the memslots in readonly mode.
>>>
>>>
>> Well, s390 has everything in hardware, but I suppose they can just ignore
>> the lock.
>
> If they don't take it in their lowlevel it's enough I think. It'll
> still be useful to lookup memslots like in every other arch.
The lock won't be a performance issue for s390. We don't need to look
them up frequently afaics.
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prev parent reply other threads:[~2008-01-23 8:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-21 12:37 [PATCH] kvm memslot read-locking with mmu_lock Andrea Arcangeli
[not found] ` <20080121123710.GF6970-lysg2Xt5kKMAvxtiuMwx3w@public.gmane.org>
2008-01-22 13:47 ` Avi Kivity
[not found] ` <4795F3F0.90403-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2008-01-22 14:32 ` Andrea Arcangeli
[not found] ` <20080122143210.GC7331-lysg2Xt5kKMAvxtiuMwx3w@public.gmane.org>
2008-01-22 14:38 ` Avi Kivity
[not found] ` <4795FFF9.8010400-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2008-01-22 14:50 ` Andrea Arcangeli
[not found] ` <20080122145043.GF7331-lysg2Xt5kKMAvxtiuMwx3w@public.gmane.org>
2008-01-23 8:15 ` Carsten Otte [this message]
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