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    SubjectRe: [PATCH 02/11] memcg: Reclaim when more than one page needed.
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    On Mon, Jun 25, 2012 at 7:15 AM, Glauber Costa <glommer@parallels.com> wrote:
    > From: Suleiman Souhlal <ssouhlal@FreeBSD.org>
    >
    > mem_cgroup_do_charge() was written before slab accounting, and expects
    > three cases: being called for 1 page, being called for a stock of 32 pages,
    > or being called for a hugepage. If we call for 2 or 3 pages (and several
    > slabs used in process creation are such, at least with the debug options I
    > had), it assumed it's being called for stock and just retried without reclaiming.
    >
    > Fix that by passing down a minsize argument in addition to the csize.
    >
    > And what to do about that (csize == PAGE_SIZE && ret) retry? If it's
    > needed at all (and presumably is since it's there, perhaps to handle
    > races), then it should be extended to more than PAGE_SIZE, yet how far?
    > And should there be a retry count limit, of what? For now retry up to
    > COSTLY_ORDER (as page_alloc.c does), stay safe with a cond_resched(),
    > and make sure not to do it if __GFP_NORETRY.

    The commit description mentions COSTLY_ORDER, but it's not actually
    used in the patch.

    -- Suleiman


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