From: Vlastimil Babka <vbabka@suse.cz> To: Mel Gorman <mgorman@techsingularity.net>, Andrew Morton <akpm@linux-foundation.org>, Linux-MM <linux-mm@kvack.org> Cc: Rik van Riel <riel@surriel.com>, Johannes Weiner <hannes@cmpxchg.org>, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 11/27] mm: vmscan: Do not reclaim from kswapd if there is any eligible zone Date: Thu, 16 Jun 2016 12:08:58 +0200 [thread overview] Message-ID: <a2be0855-c923-7338-ee37-941a6770f221@suse.cz> (raw) In-Reply-To: <1465495483-11855-12-git-send-email-mgorman@techsingularity.net> On 06/09/2016 08:04 PM, Mel Gorman wrote: > kswapd scans from highest to lowest for a zone that requires balancing. > This was necessary when reclaim was per-zone to fairly age pages on > lower zones. Now that we are reclaiming on a per-node basis, any eligible > zone can be used and pages will still be aged fairly. This patch avoids > reclaiming excessively unless buffer_heads are over the limit and it's > necessary to reclaim from a higher zone than requested by the waker of > kswapd to relieve low memory pressure. Looks like the code was even wrong before... if classzone_idx wasn't already set to the highmem zone in the first place, it wouldn't look at it. > Signed-off-by: Mel Gorman <mgorman@techsingularity.net> After fixing the bug below, Acked-by: Vlastimil Babka <vbabka@suse.cz> > --- > mm/vmscan.c | 32 +++++++++++++++++++------------- > 1 file changed, 19 insertions(+), 13 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index e4f3e068b7a0..6663fc75c3bc 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -3102,24 +3102,30 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx) > > sc.nr_reclaimed = 0; > > - /* Scan from the highest requested zone to dma */ > + /* > + * If the number of buffer_heads in the machine exceeds the > + * maximum allowed level and this node has a highmem zone, > + * force kswapd to reclaim from it to relieve lowmem pressure. > + */ > + if (buffer_heads_over_limit) { > + for (i = MAX_NR_ZONES - 1; i >= 0; i++) { i-- > + zone = pgdat->node_zones + i; > + if (!populated_zone(zone)) > + continue; > + > + if (is_highmem_idx(i)) > + classzone_idx = i; > + break; > + } > + } > + > + /* Only reclaim if there are no eligible zones */ > for (i = classzone_idx; i >= 0; i--) { > zone = pgdat->node_zones + i; > if (!populated_zone(zone)) > continue; > > - /* > - * If the number of buffer_heads in the machine > - * exceeds the maximum allowed level and this node > - * has a highmem zone, force kswapd to reclaim from > - * it to relieve lowmem pressure. > - */ > - if (buffer_heads_over_limit && is_highmem_idx(i)) { > - classzone_idx = i; > - break; > - } > - > - if (!zone_balanced(zone, order, 0)) { > + if (!zone_balanced(zone, sc.order, classzone_idx)) { > classzone_idx = i; > break; > } >
next prev parent reply other threads:[~2016-06-16 10:09 UTC|newest] Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-06-09 18:04 [PATCH 00/27] Move LRU page reclaim from zones to nodes v6 Mel Gorman 2016-06-09 18:04 ` [PATCH 01/27] mm, vmstat: Add infrastructure for per-node vmstats Mel Gorman 2016-06-10 13:31 ` Vlastimil Babka 2016-06-10 13:47 ` Mel Gorman 2016-06-13 17:26 ` Christoph Lameter 2016-06-14 14:25 ` Mel Gorman 2016-06-09 18:04 ` [PATCH 02/27] mm, vmscan: Move lru_lock to the node Mel Gorman 2016-06-10 16:39 ` Vlastimil Babka 2016-06-10 17:48 ` Peter Zijlstra 2016-06-14 14:41 ` Mel Gorman 2016-06-09 18:04 ` [PATCH 03/27] mm, vmscan: Move LRU lists to node Mel Gorman 2016-06-10 18:00 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 04/27] mm, vmscan: Begin reclaiming pages on a per-node basis Mel Gorman 2016-06-15 12:52 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 05/27] mm, vmscan: Have kswapd only scan based on the highest requested zone Mel Gorman 2016-06-15 13:13 ` Vlastimil Babka 2016-06-16 7:44 ` Mel Gorman 2016-06-09 18:04 ` [PATCH 06/27] mm, vmscan: Make kswapd reclaim in terms of nodes Mel Gorman 2016-06-15 14:23 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 07/27] mm, vmscan: Remove balance gap Mel Gorman 2016-06-15 14:28 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 08/27] mm, vmscan: Simplify the logic deciding whether kswapd sleeps Mel Gorman 2016-06-15 15:18 ` Vlastimil Babka 2016-06-16 8:30 ` Mel Gorman 2016-06-16 9:16 ` Mel Gorman 2016-06-09 18:04 ` [PATCH 09/27] mm, vmscan: By default have direct reclaim only shrink once per node Mel Gorman 2016-06-16 8:59 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 10/27] mm, vmscan: Clear congestion, dirty and need for compaction on a per-node basis Mel Gorman 2016-06-16 9:29 ` Vlastimil Babka 2016-06-16 10:29 ` Mel Gorman 2016-06-09 18:04 ` [PATCH 11/27] mm: vmscan: Do not reclaim from kswapd if there is any eligible zone Mel Gorman 2016-06-16 10:08 ` Vlastimil Babka [this message] 2016-06-09 18:04 ` [PATCH 12/27] mm, vmscan: Make shrink_node decisions more node-centric Mel Gorman 2016-06-16 13:35 ` Vlastimil Babka 2016-06-16 14:47 ` Mel Gorman 2016-06-09 18:04 ` [PATCH 13/27] mm, memcg: Move memcg limit enforcement from zones to nodes Mel Gorman 2016-06-16 15:06 ` Vlastimil Babka 2016-06-16 15:53 ` Mel Gorman 2016-06-09 18:04 ` [PATCH 14/27] mm, workingset: Make working set detection node-aware Mel Gorman 2016-06-16 15:13 ` Vlastimil Babka 2016-06-16 15:56 ` Mel Gorman 2016-06-09 18:04 ` [PATCH 15/27] mm, page_alloc: Consider dirtyable memory in terms of nodes Mel Gorman 2016-06-16 15:45 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 16/27] mm: Move page mapped accounting to the node Mel Gorman 2016-06-16 15:52 ` Vlastimil Babka 2016-06-16 16:04 ` Mel Gorman 2016-06-09 18:04 ` [PATCH 17/27] mm: Rename NR_ANON_PAGES to NR_ANON_MAPPED Mel Gorman 2016-06-17 8:28 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 18/27] mm: Move most file-based accounting to the node Mel Gorman 2016-06-17 8:35 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 19/27] mm: Move vmscan writes and file write " Mel Gorman 2016-06-17 8:51 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 20/27] mm, vmscan: Update classzone_idx if buffer_heads_over_limit Mel Gorman 2016-06-17 8:53 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 21/27] mm, vmscan: Only wakeup kswapd once per node for the requested classzone Mel Gorman 2016-06-17 10:46 ` Vlastimil Babka 2016-06-17 12:03 ` Mel Gorman 2016-06-09 18:04 ` [PATCH 22/27] mm: Convert zone_reclaim to node_reclaim Mel Gorman 2016-06-17 10:55 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 23/27] mm, vmscan: Add classzone information to tracepoints Mel Gorman 2016-06-17 10:57 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 24/27] mm, page_alloc: Remove fair zone allocation policy Mel Gorman 2016-06-17 11:27 ` Vlastimil Babka 2016-06-17 12:07 ` Mel Gorman 2016-06-09 18:04 ` [PATCH 25/27] mm: page_alloc: Cache the last node whose dirty limit is reached Mel Gorman 2016-06-17 11:31 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 26/27] mm: vmstat: Replace __count_zone_vm_events with a zone id equivalent Mel Gorman 2016-06-17 11:36 ` Vlastimil Babka 2016-06-09 18:04 ` [PATCH 27/27] mm: vmstat: Account per-zone stalls and pages skipped during reclaim Mel Gorman 2016-06-17 12:39 ` Vlastimil Babka -- strict thread matches above, loose matches on Subject: below -- 2016-06-21 14:15 [PATCH 00/27] Move LRU page reclaim from zones to nodes v7 Mel Gorman 2016-06-21 14:15 ` [PATCH 11/27] mm: vmscan: Do not reclaim from kswapd if there is any eligible zone Mel Gorman 2016-04-15 9:13 [PATCH 00/27] Move LRU page reclaim from zones to nodes v5 Mel Gorman 2016-04-15 9:13 ` [PATCH 11/27] mm: vmscan: Do not reclaim from kswapd if there is any eligible zone Mel Gorman 2016-04-06 11:19 [RFC PATCH 00/27] Move LRU page reclaim from zones to nodes v3 Mel Gorman 2016-04-06 11:20 ` [PATCH 11/27] mm: vmscan: Do not reclaim from kswapd if there is any eligible zone Mel Gorman
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