From: Nick Piggin <piggin@cyberone.com.au>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: Mike Fedyk <mfedyk@matchmail.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Linux Memory Management <linux-mm@kvack.org>
Subject: Re: [RFC][PATCH 4/4] vm-mapped-x-active-lists
Date: Tue, 09 Mar 2004 18:23:53 +1100 [thread overview]
Message-ID: <404D7109.10902@cyberone.com.au> (raw)
In-Reply-To: <20040309070246.GI655@holomorphy.com>
William Lee Irwin III wrote:
>On Tue, Mar 09, 2004 at 05:06:37PM +1100, Nick Piggin wrote:
>
>>Not sure to be honest, I haven't looked at it :\. I'm not really
>>sure if the rmap mitigation direction is just a holdover until
>>page clustering or intended as a permanent feature...
>>Either way, I trust its proponents will take the onus for regressions.
>>
>
>Actually, anobjrmap does wonderful things wrt. liberating pgcl
>internals from some very frustrating complications having to do with
>assumptions of a 1:1 correspondence between pte pages and struct pages,
>so I would regard work in the direction of anobjrmap as useful to
>advance the state of page clustering regardless of its rmap mitigation
>overtones. The "partial" objrmap is actually insufficient to clean up
>this assumption, and introduces new failure modes I don't like (which
>it is in fact not necessary to do; aa's code is very close to doing the
>partial-but-insufficient-for-pgcl objrmap properly apart from trying to
>allocate more pte_chains than necessary and not falling back to the vma
>lists for linear/nonlinear mapping mixtures). The current port has some
>code to deal with this I'm extremely eager to dump as soon as things
>such as anobjrmap etc. make it possible, if they're merged.
>
>Current efforts are now a background/spare time affair centering around
>non-i386 architectures and driver audits.
>
OK. I had just noticed that the people complaining about rmap most
are the ones using 4K page size (x86-64 uses 4K, doesn't it?). Not
that this fact means it is OK to ignore them problem, but I thought
maybe pgcl might solve it in a more general way.
I wonder how much you gain with objrmap / anobjrmap on say a 64K page
architecture?
next prev parent reply other threads:[~2004-03-09 7:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-09 5:32 [RFC][PATCH 0/4] VM split active lists Nick Piggin
2004-03-09 5:33 ` [RFC][PATCH 1/4] vm-lrutopage-cleanup Nick Piggin
2004-03-09 5:33 ` [RFC][PATCH 2/4] vm-nofixed-active-list Nick Piggin
2004-03-09 5:34 ` [RFC][PATCH 3/4] vm-no-reclaim_mapped Nick Piggin
2004-03-09 5:35 ` [RFC][PATCH 4/4] vm-mapped-x-active-lists Nick Piggin
2004-03-09 5:39 ` Nick Piggin
2004-03-09 5:47 ` Mike Fedyk
2004-03-09 6:06 ` Nick Piggin
2004-03-09 7:02 ` William Lee Irwin III
2004-03-09 7:23 ` Nick Piggin [this message]
2004-03-09 7:37 ` William Lee Irwin III
2004-03-09 9:24 ` William Lee Irwin III
2004-03-09 15:26 ` Marc-Christian Petersen
2004-03-09 15:42 ` Nikita Danilov
2004-03-10 2:49 ` Nick Piggin
2004-03-10 5:10 ` [RFC][PATCH 0/4] VM split active lists Nick Piggin
2004-03-12 9:58 ` Hans Reiser
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