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    Subject[PATCH 10/30] mm: system wide ALLOC_NO_WATERMARK
    The reserve is proportionally distributed over all (!highmem) zones in the
    system. So we need to allow an emergency allocation access to all zones. In
    order to do that we need to break out of any mempolicy boundaries we might
    have.

    In my opinion that does not break mempolicies as those are user oriented
    and not system oriented. That is, system allocations are not guaranteed to be
    within mempolicy boundaries. For instance IRQs don't even have a mempolicy.

    So breaking out of mempolicy boundaries for 'rare' emergency allocations,
    which are always system allocations (as opposed to user) is ok.

    Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
    ---
    mm/page_alloc.c | 6 ++++++
    1 file changed, 6 insertions(+)

    Index: linux-2.6/mm/page_alloc.c
    ===================================================================
    --- linux-2.6.orig/mm/page_alloc.c
    +++ linux-2.6/mm/page_alloc.c
    @@ -1625,6 +1625,12 @@ restart:
    rebalance:
    if (alloc_flags & ALLOC_NO_WATERMARKS) {
    nofail_alloc:
    + /*
    + * break out of mempolicy boundaries
    + */
    + zonelist = NODE_DATA(numa_node_id())->node_zonelists +
    + gfp_zone(gfp_mask);
    +
    /* go through the zonelist yet again, ignoring mins */
    page = get_page_from_freelist(gfp_mask, nodemask, order,
    zonelist, high_zoneidx, ALLOC_NO_WATERMARKS);
    --



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