From: Daniel Phillips <phillips@bonn-fries.net>
To: Linus Torvalds <torvalds@transmeta.com>,
Oliver Xymoron <oxymoron@waste.org>
Cc: Rik van Riel <riel@conectiva.com.br>,
Josh MacDonald <jmacd@CS.Berkeley.EDU>,
linux-kernel <linux-kernel@vger.kernel.org>,
<reiserfs-list@namesys.com>, <reiserfs-dev@namesys.com>
Subject: Re: Note describing poor dcache utilization under high memory pressure
Date: Tue, 29 Jan 2002 23:53:04 +0100 [thread overview]
Message-ID: <E16Vh7h-0000AX-00@starship.berlin> (raw)
In-Reply-To: <Pine.LNX.4.33.0201291326340.1334-100000@penguin.transmeta.com>
In-Reply-To: <Pine.LNX.4.33.0201291326340.1334-100000@penguin.transmeta.com>
On January 29, 2002 10:50 pm, Linus Torvalds wrote:
> On Tue, 29 Jan 2002, Oliver Xymoron wrote:
> >
> > I don't think read-only for the tables is sufficient if the pages
> > themselves are writable.
>
> At least on x86, the WRITE bit in the page directory entries will override
> any bits int he PTE. In other words, it doesn't make the page directory
> entries thmselves unwritable - it makes the final pages unwritable.
Ah, didn't know that.
> Which are exactly the semantics we want.
Yes. This feature might be useful to grab back a few cycles at the expense
of some extra complexity. It is not however, a fundamental change to my
algorithm, just a decoration of it. It's also possible that the cost of the
resulting extra fault will wipe out the (small) saving of setting pte entries
RO in the average case.
It's likely there are architectures where this won't work, and just not doing
this optimization is the correct approach.
--
Daniel
next prev parent reply other threads:[~2002-01-29 22:49 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-28 17:13 Josh MacDonald
2002-01-28 17:39 ` Linus Torvalds
2002-01-28 18:01 ` Rik van Riel
2002-01-28 18:21 ` Linus Torvalds
2002-01-28 18:37 ` Rik van Riel
2002-01-28 19:28 ` William Lee Irwin III
2002-01-28 20:01 ` Daniel Phillips
2002-01-28 21:33 ` Rick Stevens
2002-01-28 21:43 ` Rik van Riel
2002-01-28 22:00 ` Rick Stevens
2002-01-28 22:43 ` Daniel Phillips
2002-01-28 23:06 ` Rick Stevens
2002-01-28 23:51 ` [OT] " jepler
2002-01-29 2:30 ` IPmonger
2002-01-29 12:02 ` Karl & Betty Schendel
2002-01-28 22:26 ` Daniel Phillips
2002-01-28 22:34 ` Brian Gerst
2002-01-28 23:08 ` Daniel Phillips
2002-01-28 22:39 ` Daniel Phillips
2002-01-28 23:12 ` Rick Stevens
2002-01-28 23:27 ` Daniel Phillips
2002-01-28 22:01 ` Momchil Velikov
2002-01-28 22:19 ` Daniel Phillips
2002-01-29 1:29 ` Oliver Xymoron
2002-01-29 1:37 ` [reiserfs-list] " Valdis.Kletnieks
2002-01-29 1:45 ` Daniel Phillips
2002-01-29 8:39 ` Momchil Velikov
2002-01-29 8:55 ` Daniel Phillips
2002-01-29 9:20 ` William Lee Irwin III
2002-01-29 9:55 ` Daniel Phillips
2002-01-29 10:18 ` Momchil Velikov
2002-01-29 19:55 ` William Lee Irwin III
2002-01-29 20:08 ` Linus Torvalds
2002-01-29 20:39 ` William Lee Irwin III
2002-01-29 20:49 ` Linus Torvalds
2002-01-29 21:01 ` William Lee Irwin III
2002-01-29 9:20 ` Momchil Velikov
2002-01-29 10:27 ` Daniel Phillips
2002-01-29 11:54 ` Helge Hafting
2002-01-29 12:33 ` Daniel Phillips
2002-01-30 9:07 ` Horst von Brand
2002-01-30 10:55 ` Daniel Phillips
2002-01-30 14:46 ` Rik van Riel
2002-01-30 14:59 ` Daniel Phillips
2002-01-30 15:54 ` Rik van Riel
2002-01-30 16:34 ` Daniel Phillips
2002-01-29 10:59 ` Rik van Riel
2002-01-29 11:28 ` Daniel Phillips
2002-01-29 11:38 ` Rik van Riel
2002-01-29 12:01 ` Daniel Phillips
2002-01-29 16:57 ` Oliver Xymoron
2002-01-29 17:25 ` Rik van Riel
2002-01-29 20:48 ` Daniel Phillips
2002-01-29 21:00 ` Oliver Xymoron
2002-01-29 21:08 ` Linus Torvalds
2002-01-29 21:13 ` Oliver Xymoron
2002-01-29 21:50 ` Linus Torvalds
2002-01-29 22:02 ` Oliver Xymoron
2002-01-29 22:10 ` Linus Torvalds
2002-01-29 22:53 ` Daniel Phillips [this message]
2002-01-29 22:53 ` Daniel Phillips
2002-01-29 23:02 ` Oliver Xymoron
2002-01-29 23:21 ` Daniel Phillips
2002-01-28 19:25 ` [reiserfs-dev] " Hans Reiser
2002-01-28 23:52 ` Daniel Phillips
2002-01-29 0:16 ` Hans Reiser
2002-01-29 0:30 ` Alexander Viro
2002-01-29 10:46 ` Hans Reiser
2002-01-29 14:50 ` Chris Mason
2002-01-29 21:10 ` Hans Reiser
2002-01-30 7:11 ` Oliver Xymoron
2002-01-30 9:57 ` Hans Reiser
2002-01-29 17:28 ` Josh MacDonald
2002-01-29 18:44 ` [reiserfs-list] " Andreas Dilger
2002-01-29 19:55 ` Andrew Morton
2002-01-30 7:17 ` Oliver Xymoron
2002-01-30 7:32 ` [reiserfs-list] Re: [reiserfs-dev] Re: Note describing poordcache " Andrew Morton
2002-01-30 7:52 ` Oliver Xymoron
2002-01-30 10:03 ` Hans Reiser
2002-01-30 10:07 ` [reiserfs-dev] Re: Note describing poor dcache " Horst von Brand
2002-01-29 18:29 ` Horst von Brand
2002-01-29 0:51 ` Daniel Phillips
2002-01-29 1:32 ` Daniel Phillips
2002-01-28 22:46 ` Alex Bligh - linux-kernel
2002-01-29 17:27 ` Josh MacDonald
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