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Commit abe4c3b5 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

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



shrink_page_list() sets up a pagevec to release pages as according as they
are free.  It uses significant amounts of stack on the pagevec.  This
patch adds pages to be freed via pagevec to a linked list which is then
freed en-masse at the end.  This avoids using stack in the main path that
potentially calls writepage().

Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
Reviewed-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 66635629

mm/vmscan.c

+28 −8
Original line number Diff line number Diff line
@@ -622,6 +622,24 @@ static enum page_references page_check_references(struct page *page, 
	return PAGEREF_RECLAIM;

}



static noinline_for_stack void free_page_list(struct list_head *free_pages)

{

	struct pagevec freed_pvec;

	struct page *page, *tmp;



	pagevec_init(&freed_pvec, 1);



	list_for_each_entry_safe(page, tmp, free_pages, lru) {

		list_del(&page->lru);

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

			__pagevec_free(&freed_pvec);

			pagevec_reinit(&freed_pvec);

		}

	}



	pagevec_free(&freed_pvec);

}



/*

 * shrink_page_list() returns the number of reclaimed pages

 */
@@ -630,13 +648,12 @@ static unsigned long shrink_page_list(struct list_head *page_list, 
					enum pageout_io sync_writeback)

{

	LIST_HEAD(ret_pages);

	struct pagevec freed_pvec;

	LIST_HEAD(free_pages);

	int pgactivate = 0;

	unsigned long nr_reclaimed = 0;



	cond_resched();



	pagevec_init(&freed_pvec, 1);

	while (!list_empty(page_list)) {

		enum page_references references;

		struct address_space *mapping;
@@ -811,10 +828,12 @@ static unsigned long shrink_page_list(struct list_head *page_list, 
		__clear_page_locked(page);

free_it:

		nr_reclaimed++;

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

			__pagevec_free(&freed_pvec);

			pagevec_reinit(&freed_pvec);

		}



		/*

		 * Is there need to periodically free_page_list? It would

		 * appear not as the counts should be low

		 */

		list_add(&page->lru, &free_pages);

		continue;



cull_mlocked:
@@ -837,9 +856,10 @@ static unsigned long shrink_page_list(struct list_head *page_list, 
		list_add(&page->lru, &ret_pages);

		VM_BUG_ON(PageLRU(page) || PageUnevictable(page));

	}



	free_page_list(&free_pages);



	list_splice(&ret_pages, page_list);

	if (pagevec_count(&freed_pvec))

		__pagevec_free(&freed_pvec);

	count_vm_events(PGACTIVATE, pgactivate);

	return nr_reclaimed;

}