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Commit 785b99fe authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

mm, vmscan: release/reacquire lru_lock on pgdat change 

With node-lru, the locking is based on the pgdat.  As Minchan pointed
out, there is an opportunity to reduce LRU lock release/acquire in
check_move_unevictable_pages by only changing lock on a pgdat change.

[mgorman@techsingularity.net: remove double initialisation]
  Link: http://lkml.kernel.org/r/20160719074835.GC10438@techsingularity.net
Link: http://lkml.kernel.org/r/1468853426-12858-3-git-send-email-mgorman@techsingularity.net


Signed-off-by: default avatarMel Gorman <mgorman@techsingularity.net>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 22fecdf5

mm/vmscan.c

+10 −11
Original line number Diff line number Diff line
@@ -3774,24 +3774,23 @@ int page_evictable(struct page *page) 
void check_move_unevictable_pages(struct page **pages, int nr_pages)

{

	struct lruvec *lruvec;

	struct zone *zone = NULL;

	struct pglist_data *pgdat = NULL;

	int pgscanned = 0;

	int pgrescued = 0;

	int i;



	for (i = 0; i < nr_pages; i++) {

		struct page *page = pages[i];

		struct zone *pagezone;

		struct pglist_data *pagepgdat = page_pgdat(page);



		pgscanned++;

		pagezone = page_zone(page);

		if (pagezone != zone) {

			if (zone)

				spin_unlock_irq(zone_lru_lock(zone));

			zone = pagezone;

			spin_lock_irq(zone_lru_lock(zone));

		if (pagepgdat != pgdat) {

			if (pgdat)

				spin_unlock_irq(&pgdat->lru_lock);

			pgdat = pagepgdat;

			spin_lock_irq(&pgdat->lru_lock);

		}

		lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);

		lruvec = mem_cgroup_page_lruvec(page, pgdat);



		if (!PageLRU(page) || !PageUnevictable(page))

			continue;
@@ -3807,10 +3806,10 @@ void check_move_unevictable_pages(struct page **pages, int nr_pages) 
		}

	}



	if (zone) {

	if (pgdat) {

		__count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued);

		__count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned);

		spin_unlock_irq(zone_lru_lock(zone));

		spin_unlock_irq(&pgdat->lru_lock);

	}

}

#endif /* CONFIG_SHMEM */