From: Balbir Singh <bsingharora@gmail.com>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Balbir Singh <bsingharora@gmail.com>,
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>
Subject: Re: [PATCH 02/34] mm, vmscan: move lru_lock to the node
Date: Wed, 13 Jul 2016 15:50:39 +1000 [thread overview]
Message-ID: <20160713055039.GA23860@350D> (raw)
In-Reply-To: <20160712111805.GD9806@techsingularity.net>
On Tue, Jul 12, 2016 at 12:18:05PM +0100, Mel Gorman wrote:
> On Tue, Jul 12, 2016 at 09:06:04PM +1000, Balbir Singh wrote:
> > > diff --git a/Documentation/cgroup-v1/memory.txt b/Documentation/cgroup-v1/memory.txt
> > > index b14abf217239..946e69103cdd 100644
> > > --- a/Documentation/cgroup-v1/memory.txt
> > > +++ b/Documentation/cgroup-v1/memory.txt
> > > @@ -267,11 +267,11 @@ When oom event notifier is registered, event will be delivered.
> > > Other lock order is following:
> > > PG_locked.
> > > mm->page_table_lock
> > > - zone->lru_lock
> > > + zone_lru_lock
> >
> > zone_lru_lock is a little confusing, can't we just call it
> > node_lru_lock?
> >
>
> It's a matter of perspective. People familiar with the VM already expect
> a zone lock so will be looking for it. I can do a rename if you insist
> but it may not actually help.
I don't want to insist, but zone_ in the name can be confusing, as to
leading us to think that the lru_lock is still in the zone
If the rest of the reviewers are fine with, we don't need to rename
>
> > > @@ -496,7 +496,6 @@ struct zone {
> > > /* Write-intensive fields used by page reclaim */
> > >
> > > /* Fields commonly accessed by the page reclaim scanner */
> > > - spinlock_t lru_lock;
> > > struct lruvec lruvec;
> > >
> > > /*
> > > @@ -690,6 +689,9 @@ typedef struct pglist_data {
> > > /* Number of pages migrated during the rate limiting time interval */
> > > unsigned long numabalancing_migrate_nr_pages;
> > > #endif
> > > + /* Write-intensive fields used by page reclaim */
> > > + ZONE_PADDING(_pad1_)a
> >
> > I thought this was to have zone->lock and zone->lru_lock in different
> > cachelines, do we still need the padding here?
> >
>
> The zone padding current keeps the page lock wait tables, page allocator
> lists, compaction and vmstats on separate cache lines. They're still
> fine.
>
> The node padding may not be necessary. It currently ensures that zonelists
> and numa balancing are separate from the LRU lock but there is no guarantee
> the current arrangement is optimal. It would depend on both the kernel
> config and the workload but it may be necessary in the future to split
> node into read-mostly sections and then different write-intensive sections
> similar to what has happened to struct zone in the past.
>
Fair enough
Balbir Singh.
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next prev parent reply other threads:[~2016-07-13 5:50 UTC|newest]
Thread overview: 109+ 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 ` [PATCH 01/34] mm, vmstat: add infrastructure for per-node vmstats Mel Gorman
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
2016-07-12 11:06 ` Balbir Singh
2016-07-12 11:18 ` Mel Gorman
2016-07-13 5:50 ` Balbir Singh [this message]
2016-07-13 8:39 ` Vlastimil Babka
2016-07-08 9:34 ` [PATCH 03/34] mm, vmscan: move LRU lists to node Mel Gorman
2016-08-04 20:59 ` James Hogan
2016-08-05 8:41 ` Mel Gorman
2016-08-05 10:52 ` James Hogan
2016-08-05 11:55 ` Mel Gorman
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
2016-07-12 13:49 ` Johannes Weiner
2016-07-08 9:34 ` [PATCH 05/34] mm, vmscan: begin reclaiming pages on a per-node basis Mel Gorman
2016-07-12 13:54 ` Johannes Weiner
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
2016-07-12 14:05 ` Johannes Weiner
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
2016-08-29 9:38 ` Srikar Dronamraju
2016-08-30 12:07 ` Mel Gorman
2016-08-30 14:25 ` Srikar Dronamraju
2016-08-30 15:00 ` Mel Gorman
2016-08-31 6:09 ` Srikar Dronamraju
2016-08-31 8:49 ` Mel Gorman
2016-08-31 11:09 ` Michal Hocko
2016-08-31 12:46 ` Mel Gorman
2016-08-31 17:33 ` Srikar Dronamraju
2016-07-08 9:34 ` [PATCH 08/34] mm, vmscan: remove balance gap Mel Gorman
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 ` [PATCH 10/34] mm, vmscan: by default have direct reclaim only shrink once per node Mel Gorman
2016-07-08 9:34 ` [PATCH 11/34] mm, vmscan: remove duplicate logic clearing node congestion and dirty state Mel Gorman
2016-07-12 14:22 ` Johannes Weiner
2016-07-13 8:40 ` Mel Gorman
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
2016-07-12 14:29 ` Johannes Weiner
2016-07-13 8:47 ` Mel Gorman
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
2016-07-12 14:32 ` Johannes Weiner
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
2016-07-12 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 ` [PATCH 16/34] mm, page_alloc: consider dirtyable memory in terms of nodes Mel Gorman
2016-07-08 9:34 ` [PATCH 17/34] mm: move page mapped accounting to the node Mel Gorman
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
2016-07-12 14:58 ` Johannes Weiner
2016-07-13 8:55 ` Mel Gorman
2016-07-13 13:04 ` Johannes Weiner
2016-07-13 13:37 ` Mel Gorman
2016-07-13 21:13 ` Andrew Morton
2016-07-15 10:46 ` Mel Gorman
2016-07-15 22:35 ` Andrew Morton
2016-07-18 13:34 ` Johannes Weiner
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
2016-07-12 15:11 ` Johannes Weiner
2016-07-08 9:34 ` [PATCH 20/34] mm: move vmscan writes and file write " Mel Gorman
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
2016-07-12 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
2016-07-12 17:24 ` Johannes Weiner
2016-07-14 10:05 ` Vlastimil Babka
2016-07-08 9:34 ` [PATCH 23/34] mm: convert zone_reclaim to node_reclaim Mel Gorman
2016-07-12 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
2016-07-12 17:31 ` Johannes Weiner
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
2016-07-12 18:01 ` Johannes Weiner
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
2016-07-12 18:06 ` Johannes Weiner
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
2016-07-12 18:10 ` Johannes Weiner
2016-07-14 12:54 ` Vlastimil Babka
2016-07-08 9:35 ` [PATCH 28/34] mm, vmscan: add classzone information to tracepoints Mel Gorman
2016-07-12 18:13 ` Johannes Weiner
2016-07-08 9:35 ` [PATCH 29/34] mm, page_alloc: remove fair zone allocation policy Mel Gorman
2016-07-12 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
2016-07-12 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
2016-07-12 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
2016-07-12 19:06 ` Johannes Weiner
2016-07-08 9:35 ` [PATCH 33/34] mm, vmstat: print node-based stats in zoneinfo file Mel Gorman
2016-07-12 19:18 ` Johannes Weiner
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
2016-07-14 13:40 ` Vlastimil Babka
2016-07-15 7:48 ` Mel Gorman
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 13:23 ` Vlastimil Babka
2016-08-19 13:55 ` Andrea Arcangeli
2016-08-19 14:53 ` Mel Gorman
2016-08-19 15:32 ` Andrea Arcangeli
2016-08-19 15:55 ` Mel Gorman
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