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Commit 66635629 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

vmscan: set up pagevec as late as possible in shrink_inactive_list() 



shrink_inactive_list() sets up a pagevec to release unfreeable pages.  It
uses significant amounts of stack doing this.  This patch splits
shrink_inactive_list() to take the stack usage out of the main path so
that callers to writepage() do not contain an unused pagevec on the stack.

Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
Reviewed-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michael Rubin <mrubin@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d4debc66

mm/vmscan.c

+56 −43
Original line number Diff line number Diff line
@@ -1132,20 +1132,66 @@ static int too_many_isolated(struct zone *zone, int file, 
	return isolated > inactive;

}



/*

 * TODO: Try merging with migrations version of putback_lru_pages

 */

static noinline_for_stack void

putback_lru_pages(struct zone *zone, struct zone_reclaim_stat *reclaim_stat,

				unsigned long nr_anon, unsigned long nr_file,

				struct list_head *page_list)

{

	struct page *page;

	struct pagevec pvec;



	pagevec_init(&pvec, 1);



	/*

	 * Put back any unfreeable pages.

	 */

	spin_lock(&zone->lru_lock);

	while (!list_empty(page_list)) {

		int lru;

		page = lru_to_page(page_list);

		VM_BUG_ON(PageLRU(page));

		list_del(&page->lru);

		if (unlikely(!page_evictable(page, NULL))) {

			spin_unlock_irq(&zone->lru_lock);

			putback_lru_page(page);

			spin_lock_irq(&zone->lru_lock);

			continue;

		}

		SetPageLRU(page);

		lru = page_lru(page);

		add_page_to_lru_list(zone, page, lru);

		if (is_active_lru(lru)) {

			int file = is_file_lru(lru);

			reclaim_stat->recent_rotated[file]++;

		}

		if (!pagevec_add(&pvec, page)) {

			spin_unlock_irq(&zone->lru_lock);

			__pagevec_release(&pvec);

			spin_lock_irq(&zone->lru_lock);

		}

	}

	__mod_zone_page_state(zone, NR_ISOLATED_ANON, -nr_anon);

	__mod_zone_page_state(zone, NR_ISOLATED_FILE, -nr_file);



	spin_unlock_irq(&zone->lru_lock);

	pagevec_release(&pvec);

}



/*

 * shrink_inactive_list() is a helper for shrink_zone().  It returns the number

 * of reclaimed pages

 */

static unsigned long shrink_inactive_list(unsigned long nr_to_scan,

			struct zone *zone, struct scan_control *sc,

			int priority, int file)

static noinline_for_stack unsigned long

shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone,

			struct scan_control *sc, int priority, int file)

{

	LIST_HEAD(page_list);

	struct pagevec pvec;

	unsigned long nr_scanned;

	unsigned long nr_reclaimed = 0;

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

	struct page *page;

	unsigned long nr_taken;

	unsigned long nr_active;

	unsigned int count[NR_LRU_LISTS] = { 0, };
@@ -1161,8 +1207,6 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan, 
	}





	pagevec_init(&pvec, 1);



	lru_add_drain();

	spin_lock_irq(&zone->lru_lock);
@@ -1192,8 +1236,10 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan, 
		 */

	}



	if (nr_taken == 0)

		goto done;

	if (nr_taken == 0) {

		spin_unlock_irq(&zone->lru_lock);

		return 0;

	}



	nr_active = clear_active_flags(&page_list, count);

	__count_vm_events(PGDEACTIVATE, nr_active);
@@ -1244,40 +1290,7 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan, 
		__count_vm_events(KSWAPD_STEAL, nr_reclaimed);

	__count_zone_vm_events(PGSTEAL, zone, nr_reclaimed);



	spin_lock(&zone->lru_lock);

	/*

	 * Put back any unfreeable pages.

	 */

	while (!list_empty(&page_list)) {

		int lru;

		page = lru_to_page(&page_list);

		VM_BUG_ON(PageLRU(page));

		list_del(&page->lru);

		if (unlikely(!page_evictable(page, NULL))) {

			spin_unlock_irq(&zone->lru_lock);

			putback_lru_page(page);

			spin_lock_irq(&zone->lru_lock);

			continue;

		}

		SetPageLRU(page);

		lru = page_lru(page);

		add_page_to_lru_list(zone, page, lru);

		if (is_active_lru(lru)) {

			int file = is_file_lru(lru);

			reclaim_stat->recent_rotated[file]++;

		}

		if (!pagevec_add(&pvec, page)) {

			spin_unlock_irq(&zone->lru_lock);

			__pagevec_release(&pvec);

			spin_lock_irq(&zone->lru_lock);

		}

	}

	__mod_zone_page_state(zone, NR_ISOLATED_ANON, -nr_anon);

	__mod_zone_page_state(zone, NR_ISOLATED_FILE, -nr_file);



done:

	spin_unlock_irq(&zone->lru_lock);

	pagevec_release(&pvec);

	putback_lru_pages(zone, reclaim_stat, nr_anon, nr_file, &page_list);

	return nr_reclaimed;

}