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    SubjectRe: [PATCH 5/7] mm: vmscan: Do not writeback filesystem pages in kswapd except in high priority
    On 08/10/2011 06:47 AM, Mel Gorman wrote:
    > It is preferable that no dirty pages are dispatched for cleaning from
    > the page reclaim path. At normal priorities, this patch prevents kswapd
    > writing pages.
    > However, page reclaim does have a requirement that pages be freed
    > in a particular zone. If it is failing to make sufficient progress
    > (reclaiming< SWAP_CLUSTER_MAX at any priority priority), the priority
    > is raised to scan more pages. A priority of DEF_PRIORITY - 3 is
    > considered to be the point where kswapd is getting into trouble
    > reclaiming pages. If this priority is reached, kswapd will dispatch
    > pages for writing.
    > Signed-off-by: Mel Gorman<>
    > Reviewed-by: Minchan Kim<>

    My only worry with this patch is that maybe we'll burn too
    much CPU time freeing pages from a zone. However, chances
    are we'll have freed pages from other zones when scanning
    one zone multiple times (the page cache dirty limit is global,
    the clean pages have to be _somewhere_).

    Since the bulk of the allocators are not too picky about
    which zone they get their pages from, I suspect this patch
    will be an overall improvement pretty much all the time.

    Acked-by: Rik van Riel <>

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      Last update: 2011-08-11 20:21    [W:0.021 / U:51.628 seconds]
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