From: Mel Gorman <mgorman@techsingularity.net>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>, Rik van Riel <riel@surriel.com>,
Vlastimil Babka <vbabka@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 11/31] mm: vmscan: do not reclaim from kswapd if there is any eligible zone
Date: Tue, 5 Jul 2016 11:38:06 +0100 [thread overview]
Message-ID: <20160705103806.GH11498@techsingularity.net> (raw)
In-Reply-To: <20160705061117.GD28164@bbox>
On Tue, Jul 05, 2016 at 03:11:17PM +0900, Minchan Kim wrote:
> > - if (i < 0)
> > - goto out;
> > + /*
> > + * Only reclaim if there are no eligible zones. Check from
> > + * high to low zone to avoid prematurely clearing pgdat
> > + * congested state.
>
> I cannot understand "prematurely clearing pgdat congested state".
> Could you add more words to clear it out?
>
It's surprisingly difficult to concisely explain. Is this any better?
/*
* Only reclaim if there are no eligible zones. Check from
* high to low zone as allocations prefer higher zones.
* Scanning from low to high zone would allow congestion to be
* cleared during a very small window when a small low
* zone was balanced even under extreme pressure when the
* overall node may be congested.
*/
> > + */
> > + for (i = classzone_idx; i >= 0; i--) {
> > + zone = pgdat->node_zones + i;
> > + if (!populated_zone(zone))
> > + continue;
> > +
> > + if (zone_balanced(zone, sc.order, classzone_idx))
>
> If buffer_head is over limit, old logic force to reclaim highmem but
> this zone_balanced logic will prevent it.
>
The old logic was always busted on 64-bit because is_highmem would always
be 0. The original intent appears to be that buffer_heads_over_limit
would release the buffers when pages went inactive. There are a number
of things we treated inconsistently that get fixed up in the series and
buffer_heads_over_limit is one of them.
--
Mel Gorman
SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@techsingularity.net>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>, Rik van Riel <riel@surriel.com>,
Vlastimil Babka <vbabka@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 11/31] mm: vmscan: do not reclaim from kswapd if there is any eligible zone
Date: Tue, 5 Jul 2016 11:38:06 +0100 [thread overview]
Message-ID: <20160705103806.GH11498@techsingularity.net> (raw)
In-Reply-To: <20160705061117.GD28164@bbox>
On Tue, Jul 05, 2016 at 03:11:17PM +0900, Minchan Kim wrote:
> > - if (i < 0)
> > - goto out;
> > + /*
> > + * Only reclaim if there are no eligible zones. Check from
> > + * high to low zone to avoid prematurely clearing pgdat
> > + * congested state.
>
> I cannot understand "prematurely clearing pgdat congested state".
> Could you add more words to clear it out?
>
It's surprisingly difficult to concisely explain. Is this any better?
/*
* Only reclaim if there are no eligible zones. Check from
* high to low zone as allocations prefer higher zones.
* Scanning from low to high zone would allow congestion to be
* cleared during a very small window when a small low
* zone was balanced even under extreme pressure when the
* overall node may be congested.
*/
> > + */
> > + for (i = classzone_idx; i >= 0; i--) {
> > + zone = pgdat->node_zones + i;
> > + if (!populated_zone(zone))
> > + continue;
> > +
> > + if (zone_balanced(zone, sc.order, classzone_idx))
>
> If buffer_head is over limit, old logic force to reclaim highmem but
> this zone_balanced logic will prevent it.
>
The old logic was always busted on 64-bit because is_highmem would always
be 0. The original intent appears to be that buffer_heads_over_limit
would release the buffers when pages went inactive. There are a number
of things we treated inconsistently that get fixed up in the series and
buffer_heads_over_limit is one of them.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2016-07-05 10:38 UTC|newest]
Thread overview: 181+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-01 20:01 [PATCH 00/31] Move LRU page reclaim from zones to nodes v8 Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 01/31] mm, vmstat: add infrastructure for per-node vmstats Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-04 23:50 ` Minchan Kim
2016-07-04 23:50 ` Minchan Kim
2016-07-05 8:14 ` Mel Gorman
2016-07-05 8:14 ` Mel Gorman
2016-07-06 0:15 ` Minchan Kim
2016-07-06 0:15 ` Minchan Kim
2016-07-01 20:01 ` [PATCH 02/31] mm, vmscan: move lru_lock to the node Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-05 0:03 ` Minchan Kim
2016-07-05 0:03 ` Minchan Kim
2016-07-01 20:01 ` [PATCH 03/31] mm, vmscan: move LRU lists to node Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-05 1:19 ` Minchan Kim
2016-07-05 1:19 ` Minchan Kim
2016-07-05 10:14 ` Mel Gorman
2016-07-05 10:14 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 04/31] mm, vmscan: begin reclaiming pages on a per-node basis Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-07 1:12 ` Joonsoo Kim
2016-07-07 1:12 ` Joonsoo Kim
2016-07-07 9:48 ` Mel Gorman
2016-07-07 9:48 ` Mel Gorman
2016-07-08 2:28 ` Joonsoo Kim
2016-07-08 2:28 ` Joonsoo Kim
2016-07-08 10:05 ` Mel Gorman
2016-07-08 10:05 ` Mel Gorman
2016-07-14 6:28 ` Joonsoo Kim
2016-07-14 6:28 ` Joonsoo Kim
2016-07-14 7:48 ` Vlastimil Babka
2016-07-14 7:48 ` Vlastimil Babka
2016-07-18 4:52 ` Joonsoo Kim
2016-07-18 4:52 ` Joonsoo Kim
2016-07-18 12:11 ` Mel Gorman
2016-07-18 12:11 ` Mel Gorman
2016-07-18 14:27 ` Mel Gorman
2016-07-18 14:27 ` Mel Gorman
2016-07-19 8:30 ` Joonsoo Kim
2016-07-19 8:30 ` Joonsoo Kim
2016-07-19 14:25 ` Mel Gorman
2016-07-19 14:25 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 05/31] mm, vmscan: have kswapd only scan based on the highest requested zone Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 06/31] mm, vmscan: make kswapd reclaim in terms of nodes Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 07/31] mm, vmscan: remove balance gap Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 08/31] mm, vmscan: simplify the logic deciding whether kswapd sleeps Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-05 5:59 ` Minchan Kim
2016-07-05 5:59 ` Minchan Kim
2016-07-05 10:26 ` Mel Gorman
2016-07-05 10:26 ` Mel Gorman
2016-07-06 0:30 ` Minchan Kim
2016-07-06 0:30 ` Minchan Kim
2016-07-06 8:31 ` Mel Gorman
2016-07-06 8:31 ` Mel Gorman
2016-07-07 5:51 ` Minchan Kim
2016-07-07 5:51 ` Minchan Kim
2016-07-07 9:56 ` Mel Gorman
2016-07-07 9:56 ` Mel Gorman
2016-07-07 1:20 ` Joonsoo Kim
2016-07-07 1:20 ` Joonsoo Kim
2016-07-07 10:17 ` Mel Gorman
2016-07-07 10:17 ` Mel Gorman
2016-07-08 2:44 ` Joonsoo Kim
2016-07-08 2:44 ` Joonsoo Kim
2016-07-08 10:11 ` Mel Gorman
2016-07-08 10:11 ` Mel Gorman
2016-07-14 5:23 ` Joonsoo Kim
2016-07-14 5:23 ` Joonsoo Kim
2016-07-14 8:32 ` Vlastimil Babka
2016-07-14 8:32 ` Vlastimil Babka
2016-07-18 5:07 ` Joonsoo Kim
2016-07-18 5:07 ` Joonsoo Kim
2016-07-18 6:51 ` Vlastimil Babka
2016-07-18 6:51 ` Vlastimil Babka
2016-07-18 7:24 ` Joonsoo Kim
2016-07-18 7:24 ` Joonsoo Kim
2016-07-14 9:05 ` Mel Gorman
2016-07-14 9:05 ` Mel Gorman
2016-07-18 5:03 ` Joonsoo Kim
2016-07-18 5:03 ` Joonsoo Kim
2016-07-01 20:01 ` [PATCH 09/31] mm, vmscan: by default have direct reclaim only shrink once per node Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-07 1:43 ` Joonsoo Kim
2016-07-07 1:43 ` Joonsoo Kim
2016-07-07 10:27 ` Mel Gorman
2016-07-07 10:27 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 10/31] mm, vmscan: remove duplicate logic clearing node congestion and dirty state Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 11/31] mm: vmscan: do not reclaim from kswapd if there is any eligible zone Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-05 6:11 ` Minchan Kim
2016-07-05 6:11 ` Minchan Kim
2016-07-05 10:38 ` Mel Gorman [this message]
2016-07-05 10:38 ` Mel Gorman
2016-07-06 1:25 ` Minchan Kim
2016-07-06 1:25 ` Minchan Kim
2016-07-06 8:42 ` Mel Gorman
2016-07-06 8:42 ` Mel Gorman
2016-07-07 6:27 ` Minchan Kim
2016-07-07 6:27 ` Minchan Kim
2016-07-07 10:55 ` Mel Gorman
2016-07-07 10:55 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 12/31] mm, vmscan: make shrink_node decisions more node-centric Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-05 6:24 ` Minchan Kim
2016-07-05 6:24 ` Minchan Kim
2016-07-05 10:40 ` Mel Gorman
2016-07-05 10:40 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 13/31] mm, memcg: move memcg limit enforcement from zones to nodes Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 14/31] mm, workingset: make working set detection node-aware Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 15/31] mm, page_alloc: consider dirtyable memory in terms of nodes Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 16/31] mm: move page mapped accounting to the node Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 17/31] mm: rename NR_ANON_PAGES to NR_ANON_MAPPED Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 18/31] mm: move most file-based accounting to the node Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 19/31] mm: move vmscan writes and file write " Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 20/31] mm, vmscan: only wakeup kswapd once per node for the requested classzone Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-07 1:24 ` Joonsoo Kim
2016-07-07 1:24 ` Joonsoo Kim
2016-07-07 10:58 ` Mel Gorman
2016-07-07 10:58 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 21/31] mm, page_alloc: Wake kswapd based on the highest eligible zone Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 22/31] mm: convert zone_reclaim to node_reclaim Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 23/31] mm, vmscan: Avoid passing in classzone_idx unnecessarily to shrink_node Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 24/31] mm, vmscan: Avoid passing in classzone_idx unnecessarily to compaction_ready Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 25/31] mm, vmscan: add classzone information to tracepoints Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 26/31] mm, page_alloc: remove fair zone allocation policy Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 27/31] mm: page_alloc: cache the last node whose dirty limit is reached Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 28/31] mm: vmstat: replace __count_zone_vm_events with a zone id equivalent Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 29/31] mm: vmstat: account per-zone stalls and pages skipped during reclaim Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 30/31] mm, vmstat: print node-based stats in zoneinfo file Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 31/31] mm, vmstat: Remove zone and node double accounting by approximating retries Mel Gorman
2016-07-01 20:01 ` Mel Gorman
2016-07-06 0:02 ` Minchan Kim
2016-07-06 0:02 ` Minchan Kim
2016-07-06 8:58 ` Mel Gorman
2016-07-06 8:58 ` Mel Gorman
2016-07-06 9:33 ` Mel Gorman
2016-07-06 9:33 ` Mel Gorman
2016-07-07 6:47 ` Minchan Kim
2016-07-07 6:47 ` Minchan Kim
2016-07-06 18:12 ` Dave Hansen
2016-07-06 18:12 ` Dave Hansen
2016-07-07 11:26 ` Mel Gorman
2016-07-07 11:26 ` Mel Gorman
2016-07-04 1:37 ` [PATCH 00/31] Move LRU page reclaim from zones to nodes v8 Minchan Kim
2016-07-04 1:37 ` Minchan Kim
2016-07-04 4:34 ` Mel Gorman
2016-07-04 4:34 ` Mel Gorman
2016-07-04 8:04 ` Minchan Kim
2016-07-04 8:04 ` Minchan Kim
2016-07-04 8:04 ` Minchan Kim
2016-07-04 9:55 ` Mel Gorman
2016-07-04 9:55 ` Mel Gorman
2016-07-06 1:51 ` Minchan Kim
2016-07-06 1:51 ` Minchan Kim
-- strict thread matches above, loose matches on Subject: below --
2016-07-01 15:37 Mel Gorman
2016-07-01 15:37 ` [PATCH 11/31] mm: vmscan: do not reclaim from kswapd if there is any eligible zone Mel Gorman
2016-07-01 15:37 ` Mel Gorman
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