lkml.org 
[lkml]   [2009]   [Jun]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [patch 2/2] mm: remove task assumptions from swap token
    Hi, Hannes. 

    How about adding Hugh's comment ?

    I think that is more straightforward and easy.
    And it explained even real example like KSM.

    So I suggest following as..

    ==
    grab_swap_token() should not make any assumptions about the running
    process as the swap token is an attribute of the address space and the
    faulting mm is not necessarily current->mm.

    If a kthread happens to use get_user_pages() on an mm (as KSM does),
    there's a chance that it will end up trying to read in a swap page,
    then oops in grab_swap_token() because the kthread has no mm: GUP
    passes down the right mm, so grab_swap_token() ought to be using it.
    ==

    Anyway, It looks good to me.
    It might be just nitpick :)
    If you feel it, ignore me.
    Anyway I am OK.

    On Tue, 16 Jun 2009 23:50:37 +0200
    Johannes Weiner <hannes@cmpxchg.org> wrote:

    > From: Hugh Dickins <hugh.dickins@tiscali.co.uk>
    >
    > grab_swap_token() should not make any assumptions about the running
    > process as the swap token is an attribute of the address space and the
    > faulting mm is not necessarily current->mm.
    >
    > This fixes get_user_pages() from kernel threads which would blow up
    > when encountering a swapped out page and grab_swap_token()
    > dereferencing the unset for kernel threads current->mm.
    >
    > Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
    > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

    Reviewed-by: Minchan Kim <minchan.kim@gmail.com>

    --
    Kinds Regards
    Minchan Kim


    \
     
     \ /
      Last update: 2009-06-17 04:03    [W:0.023 / U:6.412 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site