mm, vmscan: release/reacquire lru_lock on pgdat change (785b99fe) · Commits · 戴 / test

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:

Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by:

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 */