vmscan: low order lumpy reclaim also should use PAGEOUT_IO_SYNC (78dc583d) · Commits · 戴 / test

Commit ("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 . 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 . 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:

Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rik van Riel <riel@redhat.com> Signed-off-by:

KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by:

Minchan Kim <Minchan.kim@gmail.com> Reviewed-by:

Mel Gorman <mel@csn.ul.ie> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

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);

		/*

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