From: Daniel Phillips <phillips@bonn-fries.net>
To: Rik van Riel <riel@conectiva.com.br>, Pavel Machek <pavel@suse.cz>
Cc: Jeff Garzik <garzik@havoc.gtf.org>, <arjan@fenrus.demon.nl>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Radix-tree pagecache for 2.5
Date: Wed, 6 Feb 2002 10:07:02 +0100 [thread overview]
Message-ID: <E16YO2g-0002Mq-00@starship.berlin> (raw)
In-Reply-To: <Pine.LNX.4.33L.0202051644340.12225-100000@duckman.distro.conectiva>
In-Reply-To: <Pine.LNX.4.33L.0202051644340.12225-100000@duckman.distro.conectiva>
On February 5, 2002 07:45 pm, Rik van Riel wrote:
> On Tue, 5 Feb 2002, Pavel Machek wrote:
> > > > > the biggest reason for this is that we *suck* at readahead for
> > > > > mmap....
> > > >
> > > > Is there not also fault overhead and similar issues related to mmap(2)
> > > > in general, that are not present with read(2)/write(2)?
> > >
> > > If a fault is more expensive than a system call, we're doing
> > > something wrong in the page fault path ;)
> >
> > You can read 128K at a time, but you can't fault 128K...
>
> Why not ?
>
> If the pages are present (read-ahead) and the page table
> is present, I see no reason why we couldn't fill in 32
> page table entries at once.
Yes, essentially what you want is to schedule a generic_file_readahead, which
we'd need to cook up a mechanism for doing. The other part - much harder -
is deciding when to readahead, and how much.
I'd amend your original statement to just 'we *suck* at readahead'.
--
Daniel
next prev parent reply other threads:[~2002-02-06 9:02 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-29 15:54 [PATCH] Radix-tree pagecache for 2.5 Christoph Hellwig
2002-01-29 19:27 ` Linus Torvalds
2002-01-29 21:40 ` David S. Miller
2002-01-29 22:07 ` Linus Torvalds
2002-01-29 23:01 ` Rik van Riel
2002-01-29 23:32 ` Alan Cox
2002-01-29 23:35 ` Rik van Riel
2002-01-30 3:00 ` Daniel Phillips
2002-01-31 23:44 ` Anton Blanchard
2002-02-01 0:34 ` Alan Cox
2002-02-01 11:04 ` Rik van Riel
2002-02-01 11:33 ` Arjan van de Ven
2002-02-02 18:57 ` Richard Henderson
2002-02-02 21:15 ` Rik van Riel
2002-01-29 23:02 ` Momchil Velikov
2002-01-29 23:33 ` Linus Torvalds
2002-01-29 23:45 ` Christoph Hellwig
2002-01-30 21:25 ` Momchil Velikov
2002-01-30 22:05 ` John Stoffel
2002-01-30 22:15 ` Momchil Velikov
2002-01-31 2:33 ` Andrea Arcangeli
2002-01-31 13:58 ` Rik van Riel
2002-01-31 14:36 ` Andrea Arcangeli
2002-01-31 15:32 ` Alan Cox
2002-01-31 16:39 ` William Lee Irwin III
2002-01-31 17:19 ` William Lee Irwin III
2002-01-31 17:21 ` Andrea Arcangeli
2002-01-31 17:50 ` William Lee Irwin III
2002-01-31 17:46 ` Linus Torvalds
2002-01-31 18:02 ` Andrea Arcangeli
2002-01-31 18:32 ` Linus Torvalds
2002-01-31 18:38 ` Rik van Riel
2002-01-31 18:49 ` Linus Torvalds
2002-01-31 19:09 ` Momchil Velikov
2002-01-31 19:26 ` Andrew Morton
2002-01-31 21:12 ` Momchil Velikov
2002-01-31 19:14 ` Andrea Arcangeli
2002-01-31 19:23 ` Linus Torvalds
2002-01-31 21:34 ` Ingo Molnar
2002-01-31 23:12 ` Anton Blanchard
2002-01-31 23:55 ` Andrea Arcangeli
2002-02-01 0:01 ` David S. Miller
2002-02-16 16:20 ` Andrea Arcangeli
2002-02-01 3:56 ` Anton Blanchard
2002-02-01 6:32 ` Momchil Velikov
2002-02-01 18:38 ` Anton Blanchard
2002-02-01 9:04 ` Ingo Molnar
2002-02-01 7:59 ` Momchil Velikov
2002-02-01 10:29 ` Ingo Molnar
2002-02-01 9:01 ` Momchil Velikov
2002-02-01 9:10 ` David S. Miller
2002-02-01 9:07 ` David S. Miller
2002-02-01 9:13 ` Momchil Velikov
2002-02-01 17:06 ` Linus Torvalds
2002-02-01 18:29 ` Jeff Garzik
2002-02-01 18:44 ` arjan
2002-02-01 19:47 ` Jeff Garzik
2002-02-02 15:39 ` Rik van Riel
2002-02-05 14:21 ` Pavel Machek
2002-02-05 18:45 ` Rik van Riel
2002-02-05 20:30 ` Eric Dumazet
2002-02-05 20:46 ` Pavel Machek
2002-02-06 9:07 ` Daniel Phillips [this message]
2002-02-05 9:19 ` Zdenek Kabelac
2002-02-01 23:49 ` Ingo Molnar
2002-02-01 14:44 ` Andrea Arcangeli
2002-02-01 14:59 ` Momchil Velikov
2002-02-01 17:03 ` Ingo Molnar
2002-02-01 15:26 ` Momchil Velikov
2002-02-01 23:45 ` Ingo Molnar
2002-01-31 10:41 ` Josh MacDonald
2002-01-31 14:00 ` Rik van Riel
2002-01-31 14:21 ` Momchil Velikov
2002-01-30 22:22 ` Christoph Hellwig
2002-01-30 3:02 ` Daniel Phillips
2002-01-29 23:00 ` William Lee Irwin III
-- strict thread matches above, loose matches on Subject: below --
2002-02-02 19:23 rwhron
2002-02-03 14:31 ` chris
2002-02-03 23:33 ` Momchil Velikov
2002-02-04 3:59 ` rwhron
2002-02-06 2:04 ` rwhron
2002-02-06 11:44 ` Rik van Riel
2002-02-06 21:34 rwhron
2002-02-06 21:37 ` Rik van Riel
2002-02-06 22:06 ` rwhron
2002-02-07 11:32 ` Daniel Phillips
2002-02-07 11:32 ` Daniel Phillips
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