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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?

  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
2002-10-11  4:16 Hank Leininger

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