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To: Terry Lambert <terry@lambert.org>
cc: dyson@freebsd.org, peter@spinner.dialix.com, smp@freebsd.org,
        haertel@ichips.intel.com
Subject: Re: some questions concerning TLB shootdowns in FreeBSD 
In-reply-to: Your message of "Sat, 14 Dec 1996 14:12:47 MST."
             <199612142112.OAA22198@phaeton.artisoft.com> 
Date: Sat, 14 Dec 1996 22:45:49 +0100
Message-ID: <8256.850599949@critter.tfs.com>
From: Poul-Henning Kamp <phk@critter.tfs.com>
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In message <199612142112.OAA22198@phaeton.artisoft.com>, Terry Lambert writes:
>> The crucial thing, as far as I can see, is to find out >if< we need to
>> tell the other CPU's about this change to the pagetables.  For a 2cpu
>> system the penalty of stopping the other CPU is still within bounds
>> of the reasonable, but stopping three CPUs needlessly is not a good idea.
>> 
>> Is there any cheap way to keep a refcount (or bitmap) per vm-object so
>> we can see if we need to kick the other CPUs if we fiddle it ?
>
>Oh, I like this.
>
>It would make it very easy to have multiple references in the UP case,
>as well as the MP case.
>
>This would let us do device/offset as well as vnode/offset based caching
>(for instance, hanging all cache buffers for vnodes on a device off the
>device vnode).
>
>I've wanted this for some time, since I am determined that vclean must
>die...
>

Cool.  send patches when done :-)

--
Poul-Henning Kamp           | phk@FreeBSD.ORG       FreeBSD Core-team.
http://www.freebsd.org/~phk | phk@login.dknet.dk    Private mailbox.
whois: [PHK]                | phk@tfs.com           TRW Financial Systems, Inc.
Power and ignorance is a disgusting cocktail.