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Commit 0dabec93 authored by Minchan Kim's avatar Minchan Kim Committed by Linus Torvalds
Browse files

mm: migration: clean up unmap_and_move() 



unmap_and_move() is one a big messy function.  Clean it up.

Signed-off-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Reviewed-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f80c0673

mm/migrate.c

+40 −35
Original line number Diff line number Diff line
@@ -621,38 +621,18 @@ static int move_to_new_page(struct page *newpage, struct page *page, 
	return rc;

}



/*

 * Obtain the lock on page, remove all ptes and migrate the page

 * to the newly allocated page in newpage.

 */

static int unmap_and_move(new_page_t get_new_page, unsigned long private,

			struct page *page, int force, bool offlining, bool sync)

static int __unmap_and_move(struct page *page, struct page *newpage,

				int force, bool offlining, bool sync)

{

	int rc = 0;

	int *result = NULL;

	struct page *newpage = get_new_page(page, private, &result);

	int rc = -EAGAIN;

	int remap_swapcache = 1;

	int charge = 0;

	struct mem_cgroup *mem;

	struct anon_vma *anon_vma = NULL;



	if (!newpage)

		return -ENOMEM;



	if (page_count(page) == 1) {

		/* page was freed from under us. So we are done. */

		goto move_newpage;

	}

	if (unlikely(PageTransHuge(page)))

		if (unlikely(split_huge_page(page)))

			goto move_newpage;



	/* prepare cgroup just returns 0 or -ENOMEM */

	rc = -EAGAIN;



	if (!trylock_page(page)) {

		if (!force || !sync)

			goto move_newpage;

			goto out;



		/*

		 * It's not safe for direct compaction to call lock_page.
@@ -668,7 +648,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, 
		 * altogether.

		 */

		if (current->flags & PF_MEMALLOC)

			goto move_newpage;

			goto out;



		lock_page(page);

	}
@@ -785,8 +765,35 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, 
		mem_cgroup_end_migration(mem, page, newpage, rc == 0);

unlock:

	unlock_page(page);

out:

	return rc;

}



move_newpage:

/*

 * Obtain the lock on page, remove all ptes and migrate the page

 * to the newly allocated page in newpage.

 */

static int unmap_and_move(new_page_t get_new_page, unsigned long private,

			struct page *page, int force, bool offlining, bool sync)

{

	int rc = 0;

	int *result = NULL;

	struct page *newpage = get_new_page(page, private, &result);



	if (!newpage)

		return -ENOMEM;



	if (page_count(page) == 1) {

		/* page was freed from under us. So we are done. */

		goto out;

	}



	if (unlikely(PageTransHuge(page)))

		if (unlikely(split_huge_page(page)))

			goto out;



	rc = __unmap_and_move(page, newpage, force, offlining, sync);

out:

	if (rc != -EAGAIN) {

		/*

		 * A page that has been migrated has all references
@@ -799,13 +806,11 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, 
				page_is_file_cache(page));

		putback_lru_page(page);

	}



	/*

	 * Move the new page to the LRU. If migration was not successful

	 * then this will free the page.

	 */

	putback_lru_page(newpage);



	if (result) {

		if (rc)

			*result = rc;