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Commit 76395d37 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
Browse files

[PATCH] shrink_all_memory(): fix lru_pages handling 



At the end of shrink_all_memory() we forget to recalculate lru_pages: it can
be zero.

Fix that up, and add a helper function for this operation too.

Also, recalculate lru_pages each time around the inner loop to get the
balancing correct.

Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent d63b7090

mm/vmscan.c

+16 −17
Original line number Diff line number Diff line
@@ -1406,6 +1406,16 @@ static unsigned long shrink_all_zones(unsigned long nr_pages, int prio, 
	return ret;

}



static unsigned long count_lru_pages(void)

{

	struct zone *zone;

	unsigned long ret = 0;



	for_each_zone(zone)

		ret += zone->nr_active + zone->nr_inactive;

	return ret;

}



/*

 * Try to free `nr_pages' of memory, system-wide, and return the number of

 * freed pages.
@@ -1420,7 +1430,6 @@ unsigned long shrink_all_memory(unsigned long nr_pages) 
	unsigned long ret = 0;

	int pass;

	struct reclaim_state reclaim_state;

	struct zone *zone;

	struct scan_control sc = {

		.gfp_mask = GFP_KERNEL,

		.may_swap = 0,
@@ -1431,10 +1440,7 @@ unsigned long shrink_all_memory(unsigned long nr_pages) 


	current->reclaim_state = &reclaim_state;



	lru_pages = 0;

	for_each_zone(zone)

		lru_pages += zone->nr_active + zone->nr_inactive;



	lru_pages = count_lru_pages();

	nr_slab = global_page_state(NR_SLAB_RECLAIMABLE);

	/* If slab caches are huge, it's better to hit them first */

	while (nr_slab >= lru_pages) {
@@ -1461,13 +1467,6 @@ unsigned long shrink_all_memory(unsigned long nr_pages) 
	for (pass = 0; pass < 5; pass++) {

		int prio;



		/* Needed for shrinking slab caches later on */

		if (!lru_pages)

			for_each_zone(zone) {

				lru_pages += zone->nr_active;

				lru_pages += zone->nr_inactive;

			}



		/* Force reclaiming mapped pages in the passes #3 and #4 */

		if (pass > 2) {

			sc.may_swap = 1;
@@ -1483,7 +1482,8 @@ unsigned long shrink_all_memory(unsigned long nr_pages) 
				goto out;



			reclaim_state.reclaimed_slab = 0;

			shrink_slab(sc.nr_scanned, sc.gfp_mask, lru_pages);

			shrink_slab(sc.nr_scanned, sc.gfp_mask,

					count_lru_pages());

			ret += reclaim_state.reclaimed_slab;

			if (ret >= nr_pages)

				goto out;
@@ -1491,20 +1491,19 @@ unsigned long shrink_all_memory(unsigned long nr_pages) 
			if (sc.nr_scanned && prio < DEF_PRIORITY - 2)

				congestion_wait(WRITE, HZ / 10);

		}



		lru_pages = 0;

	}



	/*

	 * If ret = 0, we could not shrink LRUs, but there may be something

	 * in slab caches

	 */

	if (!ret)

	if (!ret) {

		do {

			reclaim_state.reclaimed_slab = 0;

			shrink_slab(nr_pages, sc.gfp_mask, lru_pages);

			shrink_slab(nr_pages, sc.gfp_mask, count_lru_pages());

			ret += reclaim_state.reclaimed_slab;

		} while (ret < nr_pages && reclaim_state.reclaimed_slab > 0);

	}



out:

	current->reclaim_state = NULL;