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Groups > linux.kernel > #1590439
| From | Michal Hocko <mhocko@kernel.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 5/9] mm: don't avoid high-priority reclaim on unreclaimable nodes |
| Date | 2017-03-01 17:00 +0100 |
| Message-ID | <tgePw-5b2-13@gated-at.bofh.it> (permalink) |
| References | <tfZQt-2Vc-9@gated-at.bofh.it> <tgcXn-3Po-13@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue 28-02-17 16:40:03, Johannes Weiner wrote:
> 246e87a93934 ("memcg: fix get_scan_count() for small targets") sought
> to avoid high reclaim priorities for kswapd by forcing it to scan a
> minimum amount of pages when lru_pages >> priority yielded nothing.
>
> b95a2f2d486d ("mm: vmscan: convert global reclaim to per-memcg LRU
> lists"), due to switching global reclaim to a round-robin scheme over
> all cgroups, had to restrict this forceful behavior to unreclaimable
> zones in order to prevent massive overreclaim with many cgroups.
>
> The latter patch effectively neutered the behavior completely for all
> but extreme memory pressure. But in those situations we might as well
> drop the reclaimers to lower priority levels. Remove the check.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> mm/vmscan.c | 19 +++++--------------
> 1 file changed, 5 insertions(+), 14 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 911957b66622..46b6223fe7f3 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -2129,22 +2129,13 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,
> int pass;
>
> /*
> - * If the zone or memcg is small, nr[l] can be 0. This
> - * results in no scanning on this priority and a potential
> - * priority drop. Global direct reclaim can go to the next
> - * zone and tends to have no problems. Global kswapd is for
> - * zone balancing and it needs to scan a minimum amount. When
> + * If the zone or memcg is small, nr[l] can be 0. When
> * reclaiming for a memcg, a priority drop can cause high
> - * latencies, so it's better to scan a minimum amount there as
> - * well.
> + * latencies, so it's better to scan a minimum amount. When a
> + * cgroup has already been deleted, scrape out the remaining
> + * cache forcefully to get rid of the lingering state.
> */
> - if (current_is_kswapd()) {
> - if (!pgdat_reclaimable(pgdat))
> - force_scan = true;
> - if (!mem_cgroup_online(memcg))
> - force_scan = true;
> - }
> - if (!global_reclaim(sc))
> + if (!global_reclaim(sc) || !mem_cgroup_online(memcg))
> force_scan = true;
>
> /* If we have no swap space, do not bother scanning anon pages. */
> --
> 2.11.1
--
Michal Hocko
SUSE Labs
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[PATCH 0/9] mm: kswapd spinning on unreclaimable nodes - fixes and cleanups Johannes Weiner <hannes@cmpxchg.org> - 2017-03-01 01:00 +0100
[PATCH 4/9] mm: remove unnecessary reclaimability check from NUMA balancing target Johannes Weiner <hannes@cmpxchg.org> - 2017-03-01 01:10 +0100
Re: [PATCH 4/9] mm: remove unnecessary reclaimability check from NUMA balancing target Michal Hocko <mhocko@kernel.org> - 2017-03-01 20:30 +0100
Re: [PATCH 4/9] mm: remove unnecessary reclaimability check from NUMA balancing target "Hillf Danton" <hillf.zj@alibaba-inc.com> - 2017-03-02 04:40 +0100
[PATCH 8/9] Revert "mm, vmscan: account for skipped pages as a partial scan" Johannes Weiner <hannes@cmpxchg.org> - 2017-03-01 01:10 +0100
Re: [PATCH 8/9] Revert "mm, vmscan: account for skipped pages as a partial scan" Michal Hocko <mhocko@kernel.org> - 2017-03-01 17:00 +0100
[PATCH 3/9] mm: remove seemingly spurious reclaimability check from laptop_mode gating Johannes Weiner <hannes@cmpxchg.org> - 2017-03-01 09:00 +0100
Re: [PATCH 3/9] mm: remove seemingly spurious reclaimability check from laptop_mode gating Mel Gorman <mgorman@suse.de> - 2017-03-01 16:20 +0100
Re: [PATCH 3/9] mm: remove seemingly spurious reclaimability check from laptop_mode gating Michal Hocko <mhocko@kernel.org> - 2017-03-01 16:50 +0100
Re: [PATCH 3/9] mm: remove seemingly spurious reclaimability check from laptop_mode gating "Hillf Danton" <hillf.zj@alibaba-inc.com> - 2017-03-02 04:30 +0100
[PATCH 6/9] mm: don't avoid high-priority reclaim on memcg limit reclaim Johannes Weiner <hannes@cmpxchg.org> - 2017-03-01 09:00 +0100
Re: [PATCH 6/9] mm: don't avoid high-priority reclaim on memcg limit reclaim Michal Hocko <mhocko@kernel.org> - 2017-03-01 17:00 +0100
Re: [PATCH 6/9] mm: don't avoid high-priority reclaim on memcg limit reclaim Johannes Weiner <hannes@cmpxchg.org> - 2017-03-01 19:30 +0100
Re: [PATCH 6/9] mm: don't avoid high-priority reclaim on memcg limit reclaim Michal Hocko <mhocko@kernel.org> - 2017-03-01 20:20 +0100
Re: [PATCH 6/9] mm: don't avoid high-priority reclaim on memcg limit reclaim "Hillf Danton" <hillf.zj@alibaba-inc.com> - 2017-03-02 04:40 +0100
[PATCH 2/9] mm: fix check for reclaimable pages in PF_MEMALLOC reclaim throttling Johannes Weiner <hannes@cmpxchg.org> - 2017-03-01 09:00 +0100
Re: [PATCH 2/9] mm: fix check for reclaimable pages in PF_MEMALLOC reclaim throttling Michal Hocko <mhocko@kernel.org> - 2017-03-01 16:10 +0100
Re: [PATCH 2/9] mm: fix check for reclaimable pages in PF_MEMALLOC reclaim throttling "Hillf Danton" <hillf.zj@alibaba-inc.com> - 2017-03-02 04:30 +0100
[PATCH 7/9] mm: delete NR_PAGES_SCANNED and pgdat_reclaimable() Johannes Weiner <hannes@cmpxchg.org> - 2017-03-01 09:00 +0100
Re: [PATCH 7/9] mm: delete NR_PAGES_SCANNED and pgdat_reclaimable() Michal Hocko <mhocko@kernel.org> - 2017-03-01 16:50 +0100
[PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Johannes Weiner <hannes@cmpxchg.org> - 2017-03-01 09:00 +0100
Re: [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes "Hillf Danton" <hillf.zj@alibaba-inc.com> - 2017-03-02 04:30 +0100
Re: [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Shakeel Butt <shakeelb@google.com> - 2017-03-03 02:40 +0100
Re: [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Minchan Kim <minchan@kernel.org> - 2017-03-03 02:50 +0100
Re: [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Michal Hocko <mhocko@kernel.org> - 2017-03-03 09:10 +0100
Re: [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Minchan Kim <minchan@kernel.org> - 2017-03-06 02:40 +0100
Re: [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Johannes Weiner <hannes@cmpxchg.org> - 2017-03-06 17:40 +0100
Re: [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes "Hillf Danton" <hillf.zj@alibaba-inc.com> - 2017-03-07 02:10 +0100
Re: [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Minchan Kim <minchan@kernel.org> - 2017-03-07 08:50 +0100
Re: [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Michal Hocko <mhocko@kernel.org> - 2017-03-07 11:30 +0100
Re: [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Johannes Weiner <hannes@cmpxchg.org> - 2017-03-07 20:00 +0100
Re: [PATCH 1/9] mm: fix 100% CPU kswapd busyloop on unreclaimable nodes Mel Gorman <mgorman@suse.de> - 2017-03-09 15:40 +0100
[PATCH 9/9] mm: remove unnecessary back-off function when retrying page reclaim Johannes Weiner <hannes@cmpxchg.org> - 2017-03-01 15:00 +0100
Re: [PATCH 9/9] mm: remove unnecessary back-off function when retrying page reclaim Michal Hocko <mhocko@kernel.org> - 2017-03-01 16:50 +0100
[PATCH 5/9] mm: don't avoid high-priority reclaim on unreclaimable nodes Johannes Weiner <hannes@cmpxchg.org> - 2017-03-01 15:00 +0100
Re: [PATCH 5/9] mm: don't avoid high-priority reclaim on unreclaimable nodes Michal Hocko <mhocko@kernel.org> - 2017-03-01 17:00 +0100
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