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    SubjectRe: [PATCH] numa: fix slab_node(MPOL_BIND)
    Le jeudi 28 octobre 2010 à 08:59 -0700, Linus Torvalds a écrit :
    > Hmm. More people added to the discussion..
    > This code seems to go back all the way to commit 19770b32609b: "mm:
    > filter based on a nodemask as well as a gfp_mask". Which was back in
    > April 2008. and got merged into 2.6.26.
    > And I'd be happy to commit it (in fact, I was going to), but when
    > looking for other uses of first_zones_zonelist(), I found
    > local_memory_node() which does the exact same thing: ignore the return
    > value, and unconditionally dereference the resulting 'zone' variable.
    > And so does - although less obviously - mm/vmscan.c for the
    > wait_iff_confgested() thing.
    > So are those buggy too, since first_zones_zonelist() can apparently return NULL?
    > Please advise...

    local_memory_node() is for ia64 only, and it is a bit different :

    (void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),

    Apparently node_zonelist(node, GFP_KERNEL) returns a pointer to
    something that must have a zone suitable for GFP_KERNEL

    While the code I tried to fix uses :

    zonelist = &NODE_DATA(numa_node_id())->node_zonelists[0];
    without any guarantee it contains a LOWMEM zone

    Also check commit 7eb54824b76793dd86afb54f182ef9aa64b3a45a
    for a similar fix in the past.

    About do_try_to_free_pages(), I can not comment on this one, sorry.

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      Last update: 2010-10-28 18:31    [W:0.023 / U:8.160 seconds]
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