From: Mike Fedyk <mfedyk@matchmail.com>
To: Giuliano Pochini <pochini@shiny.it>
Cc: Robert Love <rml@tech9.net>,
linux-kernel@vger.kernel.org, Mark Mielke <mark@mark.mielke.cc>,
Jamie Lokier <lk@tantalophile.demon.co.uk>,
andersen@codepoet.org
Subject: Re: [PATCH] O_STREAMING - flag for optimal streaming I/O
Date: Thu, 10 Oct 2002 15:50:50 -0700 [thread overview]
Message-ID: <20021010225050.GC2673@matchmail.com> (raw)
In-Reply-To: <XFMail.20021010153919.pochini@shiny.it>
On Thu, Oct 10, 2002 at 03:39:19PM +0200, Giuliano Pochini wrote:
>
> > Look, the pagecache is already smart. New stuff will replace unusued
> > old stuff. On VM pressure, the pagecache will be pruned. Streaming I/O
> > is a fundamentally different problem in that the data is so large it
> > _continually_ thrashes the pagecache. Such I/O is sequential and
> > use-once. You end up with a permanent waste of memory (the cached
> > I/O).
>
> When a process opens a file with O_STREAMING, it tells the kernel
> it will use the data only once, but it tells nothing about other
> tasks. If that process reads something which is already cached,
> then it must not drop it because someone other used it recently
> and IMHO pagecache only should be allowed to drop it.
>
You are missing the point. If the app thinks that might happen, it
shouldn't use O_STREAMING.
Though, how do you get around some binary app using O_STREAMING when it
shouldn't?
next prev parent reply other threads:[~2002-10-10 22:45 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-08 2:38 [PATCH] O_STREAMING - flag for optimal streaming I/O Robert Love
2002-10-08 10:42 ` J.A. Magallon
2002-10-08 18:08 ` Robert Love
2002-10-08 18:38 ` Chris Wedgwood
2002-10-08 18:49 ` Robert Love
2002-10-08 19:05 ` Chris Wedgwood
2002-10-08 19:17 ` Robert Love
2002-10-08 19:30 ` Andrew Morton
2002-10-09 14:14 ` Marco Colombo
2002-10-09 16:30 ` kernel
2002-10-08 19:52 ` Chris Wedgwood
2002-10-08 19:59 ` Robert Love
2002-10-08 20:01 ` Chris Wedgwood
2002-10-09 8:33 ` Giuliano Pochini
2002-10-09 8:43 ` Andrew Morton
2002-10-09 10:55 ` Giuliano Pochini
2002-10-09 17:05 ` Mark Mielke
2002-10-09 19:36 ` Giuliano Pochini
2002-10-09 22:24 ` Mark Mielke
2002-10-09 23:20 ` Jamie Lokier
2002-10-10 3:07 ` Mark Mielke
2002-10-10 10:55 ` Helge Hafting
2002-10-10 17:50 ` Mark Mielke
2002-10-10 3:29 ` Erik Andersen
2002-10-10 3:37 ` Robert Love
2002-10-10 13:39 ` Giuliano Pochini
2002-10-10 22:50 ` Mike Fedyk [this message]
2002-10-10 22:58 ` Erik Andersen
2002-10-11 8:26 ` Giuliano Pochini
2002-10-11 8:32 ` Helge Hafting
2002-10-10 8:33 ` Giuliano Pochini
2002-10-10 9:10 ` Erik Andersen
2002-10-10 9:38 ` Giuliano Pochini
2002-10-10 10:40 ` Miquel van Smoorenburg
2002-10-10 11:01 ` Helge Hafting
2002-10-10 12:29 ` Xavier Bestel
2002-10-10 13:17 ` Giuliano Pochini
2002-10-10 22:44 ` Mike Fedyk
2002-10-11 8:13 ` Giuliano Pochini
2002-10-10 11:38 ` O_STREAMING has insufficient info - how about fadvise() ? Alan Cox
2002-10-10 11:47 ` William Lee Irwin III
2002-10-10 15:34 ` Andrew Morton
2002-10-10 16:08 ` Alan Cox
2002-10-10 16:49 ` Oliver Xymoron
2002-10-10 15:37 ` [PATCH] O_STREAMING - flag for optimal streaming I/O Gerhard Mack
2002-10-10 22:47 ` Mike Fedyk
2002-10-11 2:14 ` Gerhard Mack
2002-10-11 8:10 ` Chris Wedgwood
2002-10-10 9:14 ` David Lang
2002-10-10 14:51 ` Denis Vlasenko
2002-10-08 19:53 ` Matthias Schniedermeyer
2002-10-08 19:59 ` Chris Wedgwood
2002-10-08 20:03 ` Andrew Morton
2002-10-08 20:34 ` Matthias Schniedermeyer
2002-10-08 20:42 ` Andrew Morton
2002-10-08 20:37 ` Larry McVoy
2002-10-09 11:53 ` Roy Sigurd Karlsbakk
2002-10-09 14:10 ` Marco Colombo
2002-10-09 14:14 ` Robert Love
2002-10-09 14:33 ` Richard B. Johnson
2002-10-09 15:27 ` Andreas Dilger
2002-10-09 23:17 ` Jamie Lokier
2002-10-09 23:46 ` Rik van Riel
2002-10-10 0:16 ` Jamie Lokier
2002-10-10 2:39 ` Erik Andersen
2002-10-10 10:33 ` Marco Colombo
2002-10-10 20:00 ` Erik Andersen
-- strict thread matches above, loose matches on Subject: below --
2002-10-11 4:16 Hank Leininger
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