RE: why swap at all?

From: Buddy Lumpkin (b.lumpkin_at_comcast.net)
Date: 05/26/04

  • Next message: Andi Kleen: "Re: 4k stacks in 2.6"
    To: "'Matthias Schniedermeyer'" <ms@citd.de>, "'Nick Piggin'" <nickpiggin@yahoo.com.au>
    Date:	Wed, 26 May 2004 06:55:18 -0700
    
    

    Well for mmapped pages, man madvise. Specifically look at MADV_SEQUENTIAL
    and MADV_DONTNEED.

    --Buddy

    http://lxr.linux.no/source/mm/madvise.c?v=2.6.5#L92
     

    -----Original Message-----
    From: linux-kernel-owner@vger.kernel.org
    [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Matthias
    Schniedermeyer
    Sent: Wednesday, May 26, 2004 5:38 AM
    To: Nick Piggin
    Cc: linux-kernel@vger.kernel.org
    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
    useful.

    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.

    Bis denn

    -- 
    Real Programmers consider "what you see is what you get" to be just as 
    bad a concept in Text Editors as it is in women. No, the Real Programmer
    wants a "you asked for it, you got it" text editor -- complicated, 
    cryptic, powerful, unforgiving, dangerous.
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  • Next message: Andi Kleen: "Re: 4k stacks in 2.6"

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