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Commit 6e08a369 authored by Wu Fengguang's avatar Wu Fengguang Committed by Linus Torvalds
Browse files

vmscan: cleanup the scan batching code 



The vmscan batching logic is twisting.  Move it into a standalone function
nr_scan_try_batch() and document it.  No behavior change.

Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 56e49d21

include/linux/mmzone.h

+2 −2
Original line number Original line Diff line number Diff line
@@ -334,9 +334,9 @@ struct zone { 




	/* Fields commonly accessed by the page reclaim scanner */

	/* Fields commonly accessed by the page reclaim scanner */

	spinlock_t		lru_lock;	

	spinlock_t		lru_lock;	

	struct {

	struct zone_lru {

		struct list_head list;

		struct list_head list;

		unsigned long nr_scan;

		unsigned long nr_saved_scan;	/* accumulated for batching */

	} lru[NR_LRU_LISTS];

	} lru[NR_LRU_LISTS];





	struct zone_reclaim_stat reclaim_stat;

	struct zone_reclaim_stat reclaim_stat;

mm/page_alloc.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -3657,7 +3657,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat, 
		zone_pcp_init(zone);

		zone_pcp_init(zone);

		for_each_lru(l) {

		for_each_lru(l) {

			INIT_LIST_HEAD(&zone->lru[l].list);

			INIT_LIST_HEAD(&zone->lru[l].list);

			zone->lru[l].nr_scan = 0;

			zone->lru[l].nr_saved_scan = 0;

		}

		}

		zone->reclaim_stat.recent_rotated[0] = 0;

		zone->reclaim_stat.recent_rotated[0] = 0;

		zone->reclaim_stat.recent_rotated[1] = 0;

		zone->reclaim_stat.recent_rotated[1] = 0;

mm/vmscan.c

+28 −11
Original line number Original line Diff line number Diff line
@@ -1492,6 +1492,26 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc, 
	percent[1] = 100 - percent[0];

	percent[1] = 100 - percent[0];

}

}





/*

 * Smallish @nr_to_scan's are deposited in @nr_saved_scan,

 * until we collected @swap_cluster_max pages to scan.

 */

static unsigned long nr_scan_try_batch(unsigned long nr_to_scan,

				       unsigned long *nr_saved_scan,

				       unsigned long swap_cluster_max)

{

	unsigned long nr;



	*nr_saved_scan += nr_to_scan;

	nr = *nr_saved_scan;



	if (nr >= swap_cluster_max)

		*nr_saved_scan = 0;

	else

		nr = 0;



	return nr;

}





/*

/*

 * This is a basic per-zone page freer.  Used by both kswapd and direct reclaim.

 * This is a basic per-zone page freer.  Used by both kswapd and direct reclaim.
@@ -1517,14 +1537,11 @@ static void shrink_zone(int priority, struct zone *zone, 
			scan >>= priority;

			scan >>= priority;

			scan = (scan * percent[file]) / 100;

			scan = (scan * percent[file]) / 100;

		}

		}

		if (scanning_global_lru(sc)) {

		if (scanning_global_lru(sc))

			zone->lru[l].nr_scan += scan;

			nr[l] = nr_scan_try_batch(scan,

			nr[l] = zone->lru[l].nr_scan;

						  &zone->lru[l].nr_saved_scan,

			if (nr[l] >= swap_cluster_max)

						  swap_cluster_max);

				zone->lru[l].nr_scan = 0;

		else

		else

				nr[l] = 0;

		} else

			nr[l] = scan;

			nr[l] = scan;

	}

	}
@@ -2124,11 +2141,11 @@ static void shrink_all_zones(unsigned long nr_pages, int prio, 
						l == LRU_ACTIVE_FILE))

						l == LRU_ACTIVE_FILE))

				continue;

				continue;





			zone->lru[l].nr_scan += (lru_pages >> prio) + 1;

			zone->lru[l].nr_saved_scan += (lru_pages >> prio) + 1;

			if (zone->lru[l].nr_scan >= nr_pages || pass > 3) {

			if (zone->lru[l].nr_saved_scan >= nr_pages || pass > 3) {

				unsigned long nr_to_scan;

				unsigned long nr_to_scan;





				zone->lru[l].nr_scan = 0;

				zone->lru[l].nr_saved_scan = 0;

				nr_to_scan = min(nr_pages, lru_pages);

				nr_to_scan = min(nr_pages, lru_pages);

				nr_reclaimed += shrink_list(l, nr_to_scan, zone,

				nr_reclaimed += shrink_list(l, nr_to_scan, zone,

								sc, prio);

								sc, prio);

mm/vmstat.c

+4 −4
Original line number Original line Diff line number Diff line
@@ -718,10 +718,10 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat, 
		   low_wmark_pages(zone),

		   low_wmark_pages(zone),

		   high_wmark_pages(zone),

		   high_wmark_pages(zone),

		   zone->pages_scanned,

		   zone->pages_scanned,

		   zone->lru[LRU_ACTIVE_ANON].nr_scan,

		   zone->lru[LRU_ACTIVE_ANON].nr_saved_scan,

		   zone->lru[LRU_INACTIVE_ANON].nr_scan,

		   zone->lru[LRU_INACTIVE_ANON].nr_saved_scan,

		   zone->lru[LRU_ACTIVE_FILE].nr_scan,

		   zone->lru[LRU_ACTIVE_FILE].nr_saved_scan,

		   zone->lru[LRU_INACTIVE_FILE].nr_scan,

		   zone->lru[LRU_INACTIVE_FILE].nr_saved_scan,

		   zone->spanned_pages,

		   zone->spanned_pages,

		   zone->present_pages);

		   zone->present_pages);