RE: why swap at all?
From: Buddy Lumpkin (b.lumpkin_at_comcast.net)
To: "'Matthias Schniedermeyer'" <email@example.com>, "'Nick Piggin'" <firstname.lastname@example.org> Date: Wed, 26 May 2004 06:55:18 -0700
Well for mmapped pages, man madvise. Specifically look at MADV_SEQUENTIAL
[mailto:email@example.com] On Behalf Of Matthias
Sent: Wednesday, May 26, 2004 5:38 AM
To: Nick Piggin
Subject: Re: why swap at all?
On Wed, May 26, 2004 at 09:19:40PM +1000, Nick Piggin wrote:
> Matthias Schniedermeyer wrote:
> >On Wed, May 26, 2004 at 08:33:28PM +1000, Nick Piggin wrote:
> OK, this is obviously bad. Do you get this behaviour with 2.6.5
> or 2.6.6? If so, can you strace the program while it is writing
> an ISO? (just send 20 lines or so). Or tell me what program you
> use to create them and how to create one?
To use other words, this is the typical case where a "hint" would be
program to kernel: "i read ONCE though this file caching not useful".
The last thing i knew in this area is that there exist a thing to tell
the kernel to drop all cache after the file is closed. (IIRC!)
But this doesn't help in this case as the image-file is up to 4,4GB in
whole which means that it ALONE can fill up the whole cache. Taking
aside the files the image was created from, which can (with a size of up
to 2GB (size-limit of iso9660-filesystem/linux-kernel)) also fill a lot
of cache until they are closed.
(The/My) typical case is this.
1 create image-file
2 remove source-files
3 burn image
4 remove image-file
Step 1 and 3 trash the cache without ANY positive effect.
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