[PATCH] 0/2 Buddy allocator with placement policy (Version 9) + prezeroing (Version 4)

From: Mel Gorman (mel_at_csn.ul.ie)
Date: 03/07/05

  • Next message: Mel Gorman: "[PATCH] 1/2 Avoiding external fragmentation with a placement policy Version 9" 
    To: linux-mm@kvack.org
Date:	Mon,  7 Mar 2005 19:39:38 +0000 (GMT)

    Hi,

    The following two emails contain the latest version of the placement policy
    for the binary buddy allocator to reduce fragmentation and the prezeroing
    patch. The changelogs are with the patches.

    The placement policy patch should now be more Hotplug-friendly and I would like
    to hear from the Hotplug people if they have more requirements of this patch.
    Of interest, rmqueue_bulk() has been taught how to allocate large blocks of
    pages and split them up into the requested size. An impact of this is that
    refilling the per-cpu caches will sometimes be satisfied with a single 2**4
    allocation rather than 16 2**0 allocations. Lastly, the beancounters are
    now a configurable option under "Kernel Hacking".

    In terms of fragmentation, the placement policy still performs really well
    and The placement policies raw performance for aim9 and ghostscript rendering
    are comparable to the normal allocator so there should be no regressions
    there. I've posted new figures with the patch.

    The prezeroing patch still regresses fragmentation slightly but nowhere near
    as bad as previously. However, the aim9 figures for the prezeroing patch
    suck big-time. I suspect it is because zero-allocations are very common
    but the lists are usually empty so there is a lot of list traversal that
    yield nothing. Figures posted with patch. I have a solution in mind but
    it'll be a while before I implement it.

    In case others want to reproduce the allocation and ghostscript
    benchmarks, I've included them as scripts in vmregress-0.13
    (http://www.skynet.ie/~mel/projects/vmregress/vmregress-0.13.tar.gz) but
    they are still not integrated with OSDL's STP tool. The scripts are in
    bin/bench-gs.sh and bin/bench-stresshighalloc.sh and both take the --help
    switch to explain what they do.

    The patches were developed and tested heavily on 2.6.11. 

    -- 
Mel Gorman
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  • Next message: Mel Gorman: "[PATCH] 1/2 Avoiding external fragmentation with a placement policy Version 9"

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