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    SubjectRe: [PATCH] mm/vmscan.c: Clean code by removing unnecessary assignment
    It is usually preferable to Cc author of the code (added Johannes)

    On Thu 19-03-20 17:59:38, mateusznosek0@gmail.com wrote:
    > From: Mateusz Nosek <mateusznosek0@gmail.com>
    >
    > Previously 0 was assigned to 'sc->skipped_deactivate'. It could happen only
    > if 'sc->skipped_deactivate' was 0 so the assignment is unnecessary and can
    > be removed.

    The above wording was a bit hard to understdand for me. I would go with
    "
    sc->memcg_low_skipped resets skipped_deactivate to 0 but this is not
    needed as this code path is never reachable with skipped_deactivate != 0
    due to previous sc->skipped_deactivate branch.
    "

    > Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>

    The patch is correct. I am not sure it results in a better code though.
    I will defer to Johannes here. I suspect he simply wanted to express
    that skipped_deactivate should be always reset when retrying the direct
    reclaim. After this patch this could be lost in future changes so the
    code would be more subtle. But I am only guessing here.

    > ---
    > mm/vmscan.c | 1 -
    > 1 file changed, 1 deletion(-)
    >
    > diff --git a/mm/vmscan.c b/mm/vmscan.c
    > index dca623db51c8..453ff2abcb58 100644
    > --- a/mm/vmscan.c
    > +++ b/mm/vmscan.c
    > @@ -3093,7 +3093,6 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
    > if (sc->memcg_low_skipped) {
    > sc->priority = initial_priority;
    > sc->force_deactivate = 0;
    > - sc->skipped_deactivate = 0;
    > sc->memcg_low_reclaim = 1;
    > sc->memcg_low_skipped = 0;
    > goto retry;
    > --
    > 2.17.1

    --
    Michal Hocko
    SUSE Labs

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