From: Pavel Machek <pavel@suse.cz>
To: Jeff Garzik <jgarzik@mandrakesoft.com>
Cc: Anton Altaparmakov <aia21@cam.ac.uk>,
Andrew Morton <akpm@zip.com.au>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: fadvise syscall?
Date: Fri, 22 Mar 2002 16:05:43 +0000 [thread overview]
Message-ID: <20020322160542.G37@toy.ucw.cz> (raw)
In-Reply-To: <3C945635.4050101@mandrakesoft.com> <3C945A5A.9673053F@zip.com.au> <5.1.0.14.2.20020317131910.0522b490@pop.cus.cam.ac.uk> <3C959716.6040308@mandrakesoft.com>
Hi!
> > We don't need fadvise IMHO. That is what open(2) is for. The streaming
> > request you are asking for is just a normal open(2). It will do read
> > ahead which is perfect for streaming (of data size << RAM size in its
> > current form).
> >
> > When you want large data streaming, i.e. you start getting worried
> > about memory pressure, then you want open(2) + O_DIRECT. No caching
> > done. Perfect for large data streams and we have that already. I agree
> > that you may want some form of asynchronous read ahead with passed
> > pages being dropped from the cache but that could be just a open(2) +
> > O_SEQUENTIAL (doesn't exist yet).
> >
> > All of what you are asking for exists in Windows and all the semantics
> > are implemented through a very powerful open(2) equivalent. I don't
> > see why we shouldn't do the same. It makes more sense to me than
> > inventing yet another system call...
>
>
>
> I disagree, and here's the main reasons:
>
> * fadvise(2) usefulness extends past open(2). It may be useful to call
> it at various points during runtime.
open(/proc/self/fd/0, O_NEW_FLAGS)?
> * I think putting hints in open(2) is the wrong direction to go. Hints
> have a potential to be very flexible. open(2) O_xxx bits are not to be
> squandered lightly, while I see a lot more value in being a little more
> loose and free with the bit assignment for an "fadvise mask" (just a
> list of hint bits). IMO it should be easier to introduce and retire
> hints, far easier than O_xxx flags.
I don't like idea of new syscall when open works just fine. First prove
O_X hints are usefull, then extend them.
Pavel
--
Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt,
details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.
next prev parent reply other threads:[~2002-03-22 20:24 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-17 8:39 fadvise syscall? Jeff Garzik
2002-03-17 8:56 ` Andrew Morton
2002-03-17 9:10 ` Jeff Garzik
2002-03-17 23:59 ` Anton Altaparmakov
2002-03-17 13:41 ` Anton Altaparmakov
2002-03-17 14:31 ` Simon Richter
2002-03-17 14:56 ` Jan Hudec
2002-03-17 15:00 ` Anton Altaparmakov
2002-03-17 19:20 ` Joel Becker
2002-03-18 7:28 ` Jeff Garzik
2002-03-18 7:55 ` Andrew Morton
2002-03-18 8:07 ` Jeff Garzik
2002-03-18 8:17 ` Andrew Morton
2002-03-18 16:41 ` Richard Gooch
2002-03-18 19:00 ` Andrew Morton
2002-03-18 19:15 ` Richard Gooch
2002-03-22 16:05 ` Pavel Machek [this message]
2002-03-24 6:38 ` Stevie O
2002-03-24 11:24 ` Pavel Machek
2002-03-24 12:52 ` Anton Altaparmakov
2002-03-25 11:12 ` Pavel Machek
2002-03-18 8:05 ` Joel Becker
2002-03-18 8:10 ` Jeff Garzik
2002-03-18 8:20 ` Joel Becker
2002-03-18 8:14 ` Andrew Morton
2002-03-18 14:39 ` Martin K. Petersen
2002-03-18 19:15 ` Andrew Morton
2002-03-18 19:42 ` Martin K. Petersen
2002-03-19 20:08 ` Eric W. Biederman
2002-03-19 23:38 ` Martin K. Petersen
2002-03-17 20:18 ` Richard Gooch
2002-03-17 15:13 ` Ken Hirsch
2002-03-17 17:14 ` Anton Altaparmakov
2002-03-17 18:31 ` Mark Mielke
2002-03-17 18:35 ` Ken Hirsch
2002-03-17 19:06 ` Anton Altaparmakov
2002-03-17 20:19 ` Ken Hirsch
2002-03-18 0:12 ` Anton Altaparmakov
[not found] ` <a73ujs$5mc$1@cesium.transmeta.com>
2002-03-18 8:58 ` Jan Hudec
2002-03-18 10:08 ` Jeff Garzik
2002-03-18 17:29 ` Mark Mielke
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