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mm, compaction: fix NR_ISOLATED_* stats for pfn based migration

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Since commit bda807d444 ("mm: migrate: support non-lru movable page
migration") isolate_migratepages_block) can isolate !PageLRU pages which
would acct_isolated account as NR_ISOLATED_*.  Accounting these non-lru
pages NR_ISOLATED_{ANON,FILE} doesn't make any sense and it can misguide
heuristics based on those counters such as pgdat_reclaimable_pages resp.
too_many_isolated which would lead to unexpected stalls during the
direct reclaim without any good reason.  Note that
__alloc_contig_migrate_range can isolate a lot of pages at once.

On mobile devices such as 512M ram android Phone, it may use a big zram
swap.  In some cases zram(zsmalloc) uses too many non-lru but
migratedable pages, such as:

      MemTotal: 468148 kB
      Normal free:5620kB
      Free swap:4736kB
      Total swap:409596kB
      ZRAM: 164616kB(zsmalloc non-lru pages)
      active_anon:60700kB
      inactive_anon:60744kB
      active_file:34420kB
      inactive_file:37532kB

Fix this by only accounting lru pages to NR_ISOLATED_* in
isolate_migratepages_block right after they were isolated and we still
know they were on LRU.  Drop acct_isolated because it is called after
the fact and we've lost that information.  Batching per-cpu counter
doesn't make much improvement anyway.  Also make sure that we uncharge
only LRU pages when putting them back on the LRU in
putback_movable_pages resp.  when unmap_and_move migrates the page.

[mhocko@suse.com: replace acct_isolated() with direct counting]
Fixes: bda807d444 ("mm: migrate: support non-lru movable page migration")
Link: http://lkml.kernel.org/r/20161019080240.9682-1-mhocko@kernel.org
Signed-off-by: Ming Ling <ming.ling@spreadtrum.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ming Ling 2016-12-12 16:42:26 -08:00 committed by Linus Torvalds
parent 6d8409580b
commit 6afcf8ef0c
2 changed files with 14 additions and 26 deletions
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25
mm/compaction.c
View File

@ -634,22 +634,6 @@ isolate_freepages_range(struct compact_control *cc,
return pfn;
}
/* Update the number of anon and file isolated pages in the zone */
static void acct_isolated(struct zone *zone, struct compact_control *cc)
{
struct page *page;
unsigned int count[2] = { 0, };
if (list_empty(&cc->migratepages))
return;
list_for_each_entry(page, &cc->migratepages, lru)
count[!!page_is_file_cache(page)]++;
mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_ANON, count[0]);
mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE, count[1]);
}
/* Similar to reclaim, but different enough that they don't share logic */
static bool too_many_isolated(struct zone *zone)
{
@ -866,6 +850,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
/* Successfully isolated */
del_page_from_lru_list(page, lruvec, page_lru(page));
inc_node_page_state(page,
NR_ISOLATED_ANON + page_is_file_cache(page));
isolate_success:
list_add(&page->lru, &cc->migratepages);
@ -902,7 +888,6 @@ isolate_fail:
spin_unlock_irqrestore(zone_lru_lock(zone), flags);
locked = false;
}
acct_isolated(zone, cc);
putback_movable_pages(&cc->migratepages);
cc->nr_migratepages = 0;
cc->last_migrated_pfn = 0;
@ -988,7 +973,6 @@ isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn,
if (cc->nr_migratepages == COMPACT_CLUSTER_MAX)
break;
}
acct_isolated(cc->zone, cc);
return pfn;
}
@ -1258,10 +1242,8 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
low_pfn = isolate_migratepages_block(cc, low_pfn,
block_end_pfn, isolate_mode);
if (!low_pfn || cc->contended) {
acct_isolated(zone, cc);
if (!low_pfn || cc->contended)
return ISOLATE_ABORT;
}
/*
* Either we isolated something and proceed with migration. Or
@ -1271,7 +1253,6 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
break;
}
acct_isolated(zone, cc);
/* Record where migration scanner will be restarted. */
cc->migrate_pfn = low_pfn;

11
mm/migrate.c
View File

@ -168,8 +168,6 @@ void putback_movable_pages(struct list_head *l)
continue;
}
list_del(&page->lru);
dec_node_page_state(page, NR_ISOLATED_ANON +
page_is_file_cache(page));
/*
* We isolated non-lru movable page so here we can use
* __PageMovable because LRU page's mapping cannot have
@ -186,6 +184,8 @@ void putback_movable_pages(struct list_head *l)
put_page(page);
} else {
putback_lru_page(page);
dec_node_page_state(page, NR_ISOLATED_ANON +
page_is_file_cache(page));
}
}
}
@ -1121,6 +1121,13 @@ out:
* restored.
*/
list_del(&page->lru);
/*
* Compaction can migrate also non-LRU pages which are
* not accounted to NR_ISOLATED_*. They can be recognized
* as __PageMovable
*/
if (likely(!__PageMovable(page)))
dec_node_page_state(page, NR_ISOLATED_ANON +
page_is_file_cache(page));
}