From: Mel Gorman <mgorman@techsingularity.net> To: Srikar Dronamraju <srikar@linux.vnet.ibm.com> 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>, Minchan Kim <minchan@kernel.org>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, LKML <linux-kernel@vger.kernel.org>, Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@lists.ozlabs.org, Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>, Hari Bathini <hbathini@linux.vnet.ibm.com> Subject: Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Date: Tue, 30 Aug 2016 16:00:51 +0100 [thread overview] Message-ID: <20160830150051.GW8119@techsingularity.net> (raw) In-Reply-To: <20160830142508.GA10514@linux.vnet.ibm.com> On Tue, Aug 30, 2016 at 07:55:08PM +0530, Srikar Dronamraju wrote: > > > > > > This patch seems to hurt FA_DUMP functionality. This behaviour is not > > > seen on v4.7 but only after this patch. > > > > > > So when a kernel on a multinode machine with memblock_reserve() such > > > that most of the nodes have zero available memory, kswapd seems to be > > > consuming 100% of the time. > > > > > > > Why is FA_DUMP specifically the trigger? If the nodes have zero available > > memory then is the zone_populated() check failing when FA_DUMP is enabled? If > > so, that would both allow kswapd to wake and stay awake. > > > > The trigger is memblock_reserve() for the complete node memory. And > this is exactly what FA_DUMP does. Here again the node has memory but > its all reserved so there is no free memory in the node. > > Did you mean populated_zone() when you said zone_populated or have I > mistaken? populated_zone() does return 1 since it checks for > zone->present_pages. > Yes, I meant populated_zone(). Using present pages may have hidden a long-lived corner case as it was unexpected that an entire node would be reserved. The old code happened to survive *probably* because pgdat_reclaimable would look false and kswapd checks for pgdat being balanced would happen to do the right thing in this case. Can you check if something like this works? diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index d572b78b65e1..cf64a5456cf6 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -830,7 +830,7 @@ unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long); static inline int populated_zone(struct zone *zone) { - return (!!zone->present_pages); + return (!!zone->managed_pages); } extern int movable_zone; -- Mel Gorman SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@techsingularity.net> To: Srikar Dronamraju <srikar@linux.vnet.ibm.com> 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>, Minchan Kim <minchan@kernel.org>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, LKML <linux-kernel@vger.kernel.org>, Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@lists.ozlabs.org, Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>, Hari Bathini <hbathini@linux.vnet.ibm.com> Subject: Re: [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Date: Tue, 30 Aug 2016 16:00:51 +0100 [thread overview] Message-ID: <20160830150051.GW8119@techsingularity.net> (raw) In-Reply-To: <20160830142508.GA10514@linux.vnet.ibm.com> On Tue, Aug 30, 2016 at 07:55:08PM +0530, Srikar Dronamraju wrote: > > > > > > This patch seems to hurt FA_DUMP functionality. This behaviour is not > > > seen on v4.7 but only after this patch. > > > > > > So when a kernel on a multinode machine with memblock_reserve() such > > > that most of the nodes have zero available memory, kswapd seems to be > > > consuming 100% of the time. > > > > > > > Why is FA_DUMP specifically the trigger? If the nodes have zero available > > memory then is the zone_populated() check failing when FA_DUMP is enabled? If > > so, that would both allow kswapd to wake and stay awake. > > > > The trigger is memblock_reserve() for the complete node memory. And > this is exactly what FA_DUMP does. Here again the node has memory but > its all reserved so there is no free memory in the node. > > Did you mean populated_zone() when you said zone_populated or have I > mistaken? populated_zone() does return 1 since it checks for > zone->present_pages. > Yes, I meant populated_zone(). Using present pages may have hidden a long-lived corner case as it was unexpected that an entire node would be reserved. The old code happened to survive *probably* because pgdat_reclaimable would look false and kswapd checks for pgdat being balanced would happen to do the right thing in this case. Can you check if something like this works? diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index d572b78b65e1..cf64a5456cf6 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -830,7 +830,7 @@ unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long); static inline int populated_zone(struct zone *zone) { - return (!!zone->present_pages); + return (!!zone->managed_pages); } extern int movable_zone; -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-08-30 15:00 UTC|newest] Thread overview: 220+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-07-08 9:34 [PATCH 00/34] Move LRU page reclaim from zones to nodes v9 Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-08 9:34 ` [PATCH 01/34] mm, vmstat: add infrastructure for per-node vmstats Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-08-03 19:13 ` Reza Arbab 2016-08-03 19:13 ` Reza Arbab 2016-07-08 9:34 ` [PATCH 02/34] mm, vmscan: move lru_lock to the node Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 11:06 ` Balbir Singh 2016-07-12 11:06 ` Balbir Singh 2016-07-12 11:18 ` Mel Gorman 2016-07-12 11:18 ` Mel Gorman 2016-07-13 5:50 ` Balbir Singh 2016-07-13 5:50 ` Balbir Singh 2016-07-13 8:39 ` Vlastimil Babka 2016-07-13 8:39 ` Vlastimil Babka 2016-07-08 9:34 ` [PATCH 03/34] mm, vmscan: move LRU lists to node Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-08-04 20:59 ` James Hogan 2016-08-04 20:59 ` James Hogan 2016-08-04 20:59 ` James Hogan 2016-08-05 8:41 ` Mel Gorman 2016-08-05 8:41 ` Mel Gorman 2016-08-05 10:52 ` James Hogan 2016-08-05 10:52 ` James Hogan 2016-08-05 11:55 ` Mel Gorman 2016-08-05 11:55 ` Mel Gorman 2016-08-05 11:55 ` Mel Gorman 2016-08-05 12:02 ` James Hogan 2016-08-05 12:02 ` James Hogan 2016-07-08 9:34 ` [PATCH 04/34] mm, mmzone: clarify the usage of zone padding Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 13:49 ` Johannes Weiner 2016-07-12 13:49 ` Johannes Weiner 2016-07-08 9:34 ` [PATCH 05/34] mm, vmscan: begin reclaiming pages on a per-node basis Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 13:54 ` Johannes Weiner 2016-07-12 13:54 ` Johannes Weiner 2016-07-14 9:19 ` Vlastimil Babka 2016-07-14 9:19 ` Vlastimil Babka 2016-07-08 9:34 ` [PATCH 06/34] mm, vmscan: have kswapd only scan based on the highest requested zone Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 14:05 ` Johannes Weiner 2016-07-12 14:05 ` Johannes Weiner 2016-07-13 8:37 ` Mel Gorman 2016-07-13 8:37 ` Mel Gorman 2016-07-08 9:34 ` [PATCH 07/34] mm, vmscan: make kswapd reclaim in terms of nodes Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-08-29 9:38 ` Srikar Dronamraju 2016-08-29 9:38 ` Srikar Dronamraju 2016-08-30 12:07 ` Mel Gorman 2016-08-30 12:07 ` Mel Gorman 2016-08-30 14:25 ` Srikar Dronamraju 2016-08-30 14:25 ` Srikar Dronamraju 2016-08-30 15:00 ` Mel Gorman [this message] 2016-08-30 15:00 ` Mel Gorman 2016-08-31 6:09 ` Srikar Dronamraju 2016-08-31 6:09 ` Srikar Dronamraju 2016-08-31 8:49 ` Mel Gorman 2016-08-31 8:49 ` Mel Gorman 2016-08-31 11:09 ` Michal Hocko 2016-08-31 11:09 ` Michal Hocko 2016-08-31 12:46 ` Mel Gorman 2016-08-31 12:46 ` Mel Gorman 2016-08-31 17:33 ` Srikar Dronamraju 2016-08-31 17:33 ` Srikar Dronamraju 2016-07-08 9:34 ` [PATCH 08/34] mm, vmscan: remove balance gap Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 14:06 ` Johannes Weiner 2016-07-12 14:06 ` Johannes Weiner 2016-07-08 9:34 ` [PATCH 09/34] mm, vmscan: simplify the logic deciding whether kswapd sleeps Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-08 9:34 ` [PATCH 10/34] mm, vmscan: by default have direct reclaim only shrink once per node Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-08 9:34 ` [PATCH 11/34] mm, vmscan: remove duplicate logic clearing node congestion and dirty state Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 14:22 ` Johannes Weiner 2016-07-12 14:22 ` Johannes Weiner 2016-07-13 8:40 ` Mel Gorman 2016-07-13 8:40 ` Mel Gorman 2016-07-14 9:45 ` Vlastimil Babka 2016-07-14 9:45 ` Vlastimil Babka 2016-07-08 9:34 ` [PATCH 12/34] mm: vmscan: do not reclaim from kswapd if there is any eligible zone Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 14:29 ` Johannes Weiner 2016-07-12 14:29 ` Johannes Weiner 2016-07-13 8:47 ` Mel Gorman 2016-07-13 8:47 ` Mel Gorman 2016-07-13 12:28 ` Johannes Weiner 2016-07-13 12:28 ` Johannes Weiner 2016-07-08 9:34 ` [PATCH 13/34] mm, vmscan: make shrink_node decisions more node-centric Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 14:32 ` Johannes Weiner 2016-07-12 14:32 ` Johannes Weiner 2016-07-13 8:48 ` Mel Gorman 2016-07-13 8:48 ` Mel Gorman 2016-07-08 9:34 ` [PATCH 14/34] mm, memcg: move memcg limit enforcement from zones to nodes Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 14:38 ` Johannes Weiner 2016-07-12 14:38 ` Johannes Weiner 2016-07-08 9:34 ` [PATCH 15/34] mm, workingset: make working set detection node-aware Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-08 9:34 ` [PATCH 16/34] mm, page_alloc: consider dirtyable memory in terms of nodes Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-08 9:34 ` [PATCH 17/34] mm: move page mapped accounting to the node Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 14:42 ` Johannes Weiner 2016-07-12 14:42 ` Johannes Weiner 2016-07-08 9:34 ` [PATCH 18/34] mm: rename NR_ANON_PAGES to NR_ANON_MAPPED Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 14:58 ` Johannes Weiner 2016-07-12 14:58 ` Johannes Weiner 2016-07-13 8:55 ` Mel Gorman 2016-07-13 8:55 ` Mel Gorman 2016-07-13 13:04 ` Johannes Weiner 2016-07-13 13:04 ` Johannes Weiner 2016-07-13 13:37 ` Mel Gorman 2016-07-13 13:37 ` Mel Gorman 2016-07-13 21:13 ` Andrew Morton 2016-07-13 21:13 ` Andrew Morton 2016-07-15 10:46 ` Mel Gorman 2016-07-15 10:46 ` Mel Gorman 2016-07-15 22:35 ` Andrew Morton 2016-07-15 22:35 ` Andrew Morton 2016-07-18 13:34 ` Johannes Weiner 2016-07-18 13:34 ` Johannes Weiner 2016-07-14 1:27 ` Minchan Kim 2016-07-14 1:27 ` Minchan Kim 2016-07-08 9:34 ` [PATCH 19/34] mm: move most file-based accounting to the node Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 15:11 ` Johannes Weiner 2016-07-12 15:11 ` Johannes Weiner 2016-07-08 9:34 ` [PATCH 20/34] mm: move vmscan writes and file write " Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 15:15 ` Johannes Weiner 2016-07-12 15:15 ` Johannes Weiner 2016-07-08 9:34 ` [PATCH 21/34] mm, vmscan: only wakeup kswapd once per node for the requested classzone Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 17:18 ` Johannes Weiner 2016-07-12 17:18 ` Johannes Weiner 2016-07-08 9:34 ` [PATCH 22/34] mm, page_alloc: wake kswapd based on the highest eligible zone Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 17:24 ` Johannes Weiner 2016-07-12 17:24 ` Johannes Weiner 2016-07-14 10:05 ` Vlastimil Babka 2016-07-14 10:05 ` Vlastimil Babka 2016-07-08 9:34 ` [PATCH 23/34] mm: convert zone_reclaim to node_reclaim Mel Gorman 2016-07-08 9:34 ` Mel Gorman 2016-07-12 17:28 ` Johannes Weiner 2016-07-12 17:28 ` Johannes Weiner 2016-07-08 9:35 ` [PATCH 24/34] mm, vmscan: avoid passing in classzone_idx unnecessarily to shrink_node Mel Gorman 2016-07-08 9:35 ` Mel Gorman 2016-07-12 17:31 ` Johannes Weiner 2016-07-12 17:31 ` Johannes Weiner 2016-07-14 10:09 ` Vlastimil Babka 2016-07-14 10:09 ` Vlastimil Babka 2016-07-08 9:35 ` [PATCH 25/34] mm, vmscan: avoid passing in classzone_idx unnecessarily to compaction_ready Mel Gorman 2016-07-08 9:35 ` Mel Gorman 2016-07-12 18:01 ` Johannes Weiner 2016-07-12 18:01 ` Johannes Weiner 2016-07-14 12:12 ` Vlastimil Babka 2016-07-14 12:12 ` Vlastimil Babka 2016-07-08 9:35 ` [PATCH 26/34] mm, vmscan: avoid passing in remaining unnecessarily to prepare_kswapd_sleep Mel Gorman 2016-07-08 9:35 ` Mel Gorman 2016-07-12 18:06 ` Johannes Weiner 2016-07-12 18:06 ` Johannes Weiner 2016-07-14 12:48 ` Vlastimil Babka 2016-07-14 12:48 ` Vlastimil Babka 2016-07-08 9:35 ` [PATCH 27/34] mm, vmscan: Have kswapd reclaim from all zones if reclaiming and buffer_heads_over_limit Mel Gorman 2016-07-08 9:35 ` Mel Gorman 2016-07-12 18:10 ` Johannes Weiner 2016-07-12 18:10 ` Johannes Weiner 2016-07-14 12:54 ` Vlastimil Babka 2016-07-14 12:54 ` Vlastimil Babka 2016-07-08 9:35 ` [PATCH 28/34] mm, vmscan: add classzone information to tracepoints Mel Gorman 2016-07-08 9:35 ` Mel Gorman 2016-07-12 18:13 ` Johannes Weiner 2016-07-12 18:13 ` Johannes Weiner 2016-07-08 9:35 ` [PATCH 29/34] mm, page_alloc: remove fair zone allocation policy Mel Gorman 2016-07-08 9:35 ` Mel Gorman 2016-07-12 18:18 ` Johannes Weiner 2016-07-12 18:18 ` Johannes Weiner 2016-07-08 9:35 ` [PATCH 30/34] mm: page_alloc: cache the last node whose dirty limit is reached Mel Gorman 2016-07-08 9:35 ` Mel Gorman 2016-07-12 18:43 ` Johannes Weiner 2016-07-12 18:43 ` Johannes Weiner 2016-07-08 9:35 ` [PATCH 31/34] mm: vmstat: replace __count_zone_vm_events with a zone id equivalent Mel Gorman 2016-07-08 9:35 ` Mel Gorman 2016-07-12 19:10 ` Johannes Weiner 2016-07-12 19:10 ` Johannes Weiner 2016-07-08 9:35 ` [PATCH 32/34] mm: vmstat: account per-zone stalls and pages skipped during reclaim Mel Gorman 2016-07-08 9:35 ` Mel Gorman 2016-07-12 19:06 ` Johannes Weiner 2016-07-12 19:06 ` Johannes Weiner 2016-07-08 9:35 ` [PATCH 33/34] mm, vmstat: print node-based stats in zoneinfo file Mel Gorman 2016-07-08 9:35 ` Mel Gorman 2016-07-12 19:18 ` Johannes Weiner 2016-07-12 19:18 ` Johannes Weiner 2016-07-14 12:56 ` Vlastimil Babka 2016-07-14 12:56 ` Vlastimil Babka 2016-07-08 9:35 ` [PATCH 34/34] mm, vmstat: remove zone and node double accounting by approximating retries Mel Gorman 2016-07-08 9:35 ` Mel Gorman 2016-07-14 13:40 ` Vlastimil Babka 2016-07-14 13:40 ` Vlastimil Babka 2016-07-15 7:48 ` Mel Gorman 2016-07-15 7:48 ` Mel Gorman 2016-07-15 12:20 ` Vlastimil Babka 2016-07-15 12:20 ` Vlastimil Babka 2016-08-19 13:12 ` [PATCH 00/34] Move LRU page reclaim from zones to nodes v9 Andrea Arcangeli 2016-08-19 13:12 ` Andrea Arcangeli 2016-08-19 13:23 ` Vlastimil Babka 2016-08-19 13:23 ` Vlastimil Babka 2016-08-19 13:55 ` Andrea Arcangeli 2016-08-19 13:55 ` Andrea Arcangeli 2016-08-19 14:53 ` Mel Gorman 2016-08-19 14:53 ` Mel Gorman 2016-08-19 15:32 ` Andrea Arcangeli 2016-08-19 15:32 ` Andrea Arcangeli 2016-08-19 15:55 ` Mel Gorman 2016-08-19 15:55 ` Mel Gorman
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