On Tue 07-06-11 23:38:18, Minchan Kim wrote:
> In __zone_reclaim case, we don't want to shrink mapped page.
> Nonetheless, we have isolated mapped page and re-add it into
> LRU's head. It's unnecessary CPU overhead and makes LRU churning.
>
> Of course, when we isolate the page, the page might be mapped but
> when we try to migrate the page, the page would be not mapped.
> So it could be migrated. But race is rare and although it happens,
> it's no big deal.
Same like with the previous patch. I think it would be better to
introduce ISOLATE_UNMAPPED here.
Other than that looks good to me
Reviewed-by: Michal Hocko <mhocko@xxxxxxx>
>
> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxx>
> Cc: Rik van Riel <riel@xxxxxxxxxx>
> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
> ---
> mm/vmscan.c | 17 +++++++++++++++--
> 1 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 26aa627..c08911d 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1408,6 +1408,12 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone,
> reclaim_mode |= ISOLATE_ACTIVE;
>
> lru_add_drain();
> +
> + if (!sc->may_unmap)
> + reclaim_mode |= ISOLATE_UNMAPPED;
> + if (!sc->may_writepage)
> + reclaim_mode |= ISOLATE_CLEAN;
> +
> spin_lock_irq(&zone->lru_lock);
>
> if (scanning_global_lru(sc)) {
> @@ -1525,19 +1531,26 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
> struct page *page;
> struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
> unsigned long nr_rotated = 0;
> + enum ISOLATE_MODE reclaim_mode = ISOLATE_ACTIVE;
>
> lru_add_drain();
> +
> + if (!sc->may_unmap)
> + reclaim_mode |= ISOLATE_UNMAPPED;
> + if (!sc->may_writepage)
> + reclaim_mode |= ISOLATE_CLEAN;
> +
> spin_lock_irq(&zone->lru_lock);
> if (scanning_global_lru(sc)) {
> nr_taken = isolate_pages_global(nr_pages, &l_hold,
> &pgscanned, sc->order,
> - ISOLATE_ACTIVE, zone,
> + reclaim_mode, zone,
> 1, file);
> zone->pages_scanned += pgscanned;
> } else {
> nr_taken = mem_cgroup_isolate_pages(nr_pages, &l_hold,
> &pgscanned, sc->order,
> - ISOLATE_ACTIVE, zone,
> + reclaim_mode, zone,
> sc->mem_cgroup, 1, file);
> /*
> * mem_cgroup_isolate_pages() keeps track of
> --
> 1.7.0.4
>
> --
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--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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