From: Mel Gorman <mgorman@techsingularity.net>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>, Rik van Riel <riel@surriel.com>,
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 34/34] mm, vmstat: remove zone and node double accounting by approximating retries
Date: Fri, 15 Jul 2016 08:48:59 +0100 [thread overview]
Message-ID: <20160715074859.GM9806@techsingularity.net> (raw)
In-Reply-To: <bd515668-2d1f-e70e-f419-7a55189757f7@suse.cz>
On Thu, Jul 14, 2016 at 03:40:11PM +0200, Vlastimil Babka wrote:
> >@@ -4,6 +4,26 @@
> > #include <linux/huge_mm.h>
> > #include <linux/swap.h>
> >
> >+#ifdef CONFIG_HIGHMEM
> >+extern atomic_t highmem_file_pages;
> >+
> >+static inline void acct_highmem_file_pages(int zid, enum lru_list lru,
> >+ int nr_pages)
> >+{
> >+ if (is_highmem_idx(zid) && is_file_lru(lru)) {
> >+ if (nr_pages > 0)
>
> This seems like a unnecessary branch, atomic_add should handle negative
> nr_pages just fine?
>
On x86 it would but the interface makes no guarantees it'll handle
signed types properly on all architectures.
> >@@ -1456,14 +1461,27 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
> > unsigned long available;
> > enum compact_result compact_result;
> >
> >+ if (last_pgdat == zone->zone_pgdat)
> >+ continue;
> >+
> >+ /*
> >+ * This over-estimates the number of pages available for
> >+ * reclaim/compaction but walking the LRU would take too
> >+ * long. The consequences are that compaction may retry
> >+ * longer than it should for a zone-constrained allocation
> >+ * request.
>
> The comment above says that we don't retry zone-constrained at all. Is this
> an obsolete comment, or does it refer to the ZONE_NORMAL constraint? (as
> opposed to HIGHMEM, MOVABLE etc?).
>
It can still over-estimate the amount of memory available if
ZONE_MOVABLE exists even if the request is not zone-constrained.
> >@@ -3454,6 +3455,15 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
> > return false;
> >
> > /*
> >+ * Blindly retry lowmem allocation requests that are often ignored by
> >+ * the OOM killer up to MAX_RECLAIM_RETRIES as we not have a reliable
> >+ * and fast means of calculating reclaimable, dirty and writeback pages
> >+ * in eligible zones.
> >+ */
> >+ if (ac->high_zoneidx < ZONE_NORMAL)
> >+ goto out;
>
> A goto inside two nested for cycles? Is there no hope for sanity? :(
>
None, hand it in at the door.
It can be pulled out and put past the "return false" at the end. It's
just not necessarily any better.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2016-07-15 7:49 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
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 [this message]
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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