On Tue 28-02-17 16:40:00, Johannes Weiner wrote:
> PF_MEMALLOC direct reclaimers get throttled on a node when the sum of
> all free pages in each zone fall below half the min watermark. During
> the summation, we want to exclude zones that don't have reclaimables.
> Checking the same pgdat over and over again doesn't make sense.
>
> Fixes: 599d0c954f91 ("mm, vmscan: move LRU lists to node")
> Signed-off-by: Johannes Weiner <han...@cmpxchg.org>
Acked-by: Michal Hocko <mho...@suse.com>
> ---
> mm/vmscan.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 407b27831ff7..f006140f58c6 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -2838,8 +2838,10 @@ static bool pfmemalloc_watermark_ok(pg_data_t *pgdat)
>
> for (i = 0; i <= ZONE_NORMAL; i++) {
> zone = &pgdat->node_zones[i];
> - if (!managed_zone(zone) ||
> - pgdat_reclaimable_pages(pgdat) == 0)
> + if (!managed_zone(zone))
> + continue;
> +
> + if (!zone_reclaimable_pages(zone))
> continue;
>
> pfmemalloc_reserve += min_wmark_pages(zone);
> --
> 2.11.1
--
Michal Hocko
SUSE Labs
