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Commit 78dc583d authored by KOSAKI Motohiro's avatar KOSAKI Motohiro Committed by Linus Torvalds
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vmscan: low order lumpy reclaim also should use PAGEOUT_IO_SYNC 



Commit 33c120ed ("more aggressively use
lumpy reclaim") increased how aggressive lumpy reclaim was by isolating
both active and inactive pages for asynchronous lumpy reclaim on
costly-high-order pages and for cheap-high-order when memory pressure is
high.  However, if the system is under heavy pressure and there are dirty
pages, asynchronous IO may not be sufficient to reclaim a suitable page in
time.

This patch causes the caller to enter synchronous lumpy reclaim for
costly-high-order pages and for cheap-high-order pages when under memory
pressure.

Minchan.kim@gmail.com said:

Andy added synchronous lumpy reclaim with
c661b078.  At that time, lumpy reclaim is
not agressive.  His intension is just for high-order users.(above
PAGE_ALLOC_COSTLY_ORDER).

After some time, Rik added aggressive lumpy reclaim with
33c120ed.  His intention was to do lumpy
reclaim when high-order users and trouble getting a small set of
contiguous pages.

So we also have to add synchronous pageout for small set of contiguous
pages.

Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: default avatarMinchan Kim <Minchan.kim@gmail.com>
Reviewed-by: default avatarMel Gorman <mel@csn.ul.ie>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d2bf6be8

mm/vmscan.c

+15 −14
Original line number Diff line number Diff line
@@ -1061,6 +1061,19 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, 
	unsigned long nr_scanned = 0;

	unsigned long nr_reclaimed = 0;

	struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);

	int lumpy_reclaim = 0;



	/*

	 * If we need a large contiguous chunk of memory, or have

	 * trouble getting a small set of contiguous pages, we

	 * will reclaim both active and inactive pages.

	 *

	 * We use the same threshold as pageout congestion_wait below.

	 */

	if (sc->order > PAGE_ALLOC_COSTLY_ORDER)

		lumpy_reclaim = 1;

	else if (sc->order && priority < DEF_PRIORITY - 2)

		lumpy_reclaim = 1;



	pagevec_init(&pvec, 1);
@@ -1073,19 +1086,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, 
		unsigned long nr_freed;

		unsigned long nr_active;

		unsigned int count[NR_LRU_LISTS] = { 0, };

		int mode = ISOLATE_INACTIVE;



		/*

		 * If we need a large contiguous chunk of memory, or have

		 * trouble getting a small set of contiguous pages, we

		 * will reclaim both active and inactive pages.

		 *

		 * We use the same threshold as pageout congestion_wait below.

		 */

		if (sc->order > PAGE_ALLOC_COSTLY_ORDER)

			mode = ISOLATE_BOTH;

		else if (sc->order && priority < DEF_PRIORITY - 2)

			mode = ISOLATE_BOTH;

		int mode = lumpy_reclaim ? ISOLATE_BOTH : ISOLATE_INACTIVE;



		nr_taken = sc->isolate_pages(sc->swap_cluster_max,

			     &page_list, &nr_scan, sc->order, mode,
@@ -1122,7 +1123,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, 
		 * but that should be acceptable to the caller

		 */

		if (nr_freed < nr_taken && !current_is_kswapd() &&

					sc->order > PAGE_ALLOC_COSTLY_ORDER) {

		    lumpy_reclaim) {

			congestion_wait(WRITE, HZ/10);



			/*