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    SubjectRe: Re: Performance degradation seen after using one list for hot/cold pages.

    > I'll add the rather important text:
    >
    > Fix a post-2.6.24 performance regression caused by
    > 3dfa5721f12c3d5a441448086bee156887daa961 ("page-allocator: preserve PFN
    > ordering when __GFP_COLD is set").
    >
    > This was a pretty major screwup.
    >
    > This is why changing core MM is so worrisome - there's so much secret and
    > subtle history to it, and performance dependencies are unobvious and quite
    > indirect and the lag time to discover regressions is long.
    >
    > Narayanan, are you able to quantify the regression more clearly? All I
    > have is "2 MBps lower" which isn't very useful. What is this as a
    > percentage, and with what sort of disk controller? Thanks.

    It is around 15%. There is no disk controller as our setup is based on Samsung OneNAND
    used as a memory mapped device on a OMAP2430 based board.

    Narayanan
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