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    Subject[PATCH 0/7] Kill PF_MEMALLOC abuse

    PF_MEMALLOC have following effects.
    (1) Ignore zone watermark
    (2) Don't call reclaim although allocation failure, instead return ENOMEM
    (3) Don't invoke OOM Killer
    (4) Don't retry internally in page alloc

    Some subsystem paid attention (1) only, and start to use PF_MEMALLOC abuse.
    But, the fact is, PF_MEMALLOC is the promise of "I have lots freeable memory.
    if I allocate few memory, I can return more much meory to the system!".
    Non MM subsystem must not use PF_MEMALLOC. Memory reclaim
    need few memory, anyone must not prevent it. Otherwise the system cause
    mysterious hang-up and/or OOM Killer invokation.

    if many subsystem will be able to use emergency memory without any
    usage rule, it isn't for emergency. it can become empty easily.

    Plus, characteristics (2)-(4) mean PF_MEMALLOC don't fit to general
    high priority memory allocation.

    Thus, We kill all PF_MEMALLOC usage in no MM subsystem.

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      Last update: 2009-11-17 08:19    [W:0.022 / U:5.480 seconds]
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