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Commit 3db65812 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
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Revert "mm, vmscan: account for skipped pages as a partial scan" 

This reverts commit d7f05528.

Now that reclaimability of a node is no longer based on the ratio
between pages scanned and theoretically reclaimable pages, we can remove
accounting tricks for pages skipped due to zone constraints.

Link: http://lkml.kernel.org/r/20170228214007.5621-9-hannes@cmpxchg.org


Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarHillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Jia He <hejianet@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c822f622

mm/vmscan.c

+4 −18
Original line number Diff line number Diff line
@@ -1472,12 +1472,12 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, 
	unsigned long nr_taken = 0;

	unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 };

	unsigned long nr_skipped[MAX_NR_ZONES] = { 0, };

	unsigned long skipped = 0, total_skipped = 0;

	unsigned long skipped = 0;

	unsigned long scan, nr_pages;

	LIST_HEAD(pages_skipped);



	for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan &&

					!list_empty(src);) {

					!list_empty(src); scan++) {

		struct page *page;



		page = lru_to_page(src);
@@ -1491,12 +1491,6 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, 
			continue;

		}



		/*

		 * Account for scanned and skipped separetly to avoid the pgdat

		 * being prematurely marked unreclaimable by pgdat_reclaimable.

		 */

		scan++;



		switch (__isolate_lru_page(page, mode)) {

		case 0:

			nr_pages = hpage_nr_pages(page);
@@ -1525,6 +1519,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, 
	if (!list_empty(&pages_skipped)) {

		int zid;



		list_splice(&pages_skipped, src);

		for (zid = 0; zid < MAX_NR_ZONES; zid++) {

			if (!nr_skipped[zid])

				continue;
@@ -1532,17 +1527,8 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, 
			__count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]);

			skipped += nr_skipped[zid];

		}



		/*

		 * Account skipped pages as a partial scan as the pgdat may be

		 * close to unreclaimable. If the LRU list is empty, account

		 * skipped pages as a full scan.

		 */

		total_skipped = list_empty(src) ? skipped : skipped >> 2;



		list_splice(&pages_skipped, src);

	}

	*nr_scanned = scan + total_skipped;

	*nr_scanned = scan;

	trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan,

				    scan, skipped, nr_taken, mode, lru);

	update_lru_sizes(lruvec, lru, nr_zone_taken);