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Commit aaa994b3 authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
Browse files

[PATCH] page migration: handle freeing of pages in migrate_pages() 



Do not leave pages on the lists passed to migrate_pages().  Seems that we will
not need any postprocessing of pages.  This will simplify the handling of
pages by the callers of migrate_pages().

Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Jes Sorensen <jes@trained-monkey.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent e24f0b8f

include/linux/migrate.h

+3 −4
Original line number Diff line number Diff line
@@ -8,8 +8,7 @@ extern int isolate_lru_page(struct page *p, struct list_head *pagelist); 
extern int putback_lru_pages(struct list_head *l);

extern int migrate_page(struct address_space *,

			struct page *, struct page *);

extern int migrate_pages(struct list_head *l, struct list_head *t,

		struct list_head *moved, struct list_head *failed);

extern int migrate_pages(struct list_head *l, struct list_head *t);

extern int migrate_pages_to(struct list_head *pagelist,

			struct vm_area_struct *vma, int dest);

extern int fail_migrate_page(struct address_space *,
@@ -22,8 +21,8 @@ extern int migrate_prep(void); 
static inline int isolate_lru_page(struct page *p, struct list_head *list)

					{ return -ENOSYS; }

static inline int putback_lru_pages(struct list_head *l) { return 0; }

static inline int migrate_pages(struct list_head *l, struct list_head *t,

	struct list_head *moved, struct list_head *failed) { return -ENOSYS; }

static inline int migrate_pages(struct list_head *l, struct list_head *t)

					{ return -ENOSYS; }



static inline int migrate_pages_to(struct list_head *pagelist,

			struct vm_area_struct *vma, int dest) { return 0; }

mm/mempolicy.c

+1 −7
Original line number Diff line number Diff line
@@ -603,11 +603,8 @@ int migrate_to_node(struct mm_struct *mm, int source, int dest, int flags) 
	check_range(mm, mm->mmap->vm_start, TASK_SIZE, &nmask,

			flags | MPOL_MF_DISCONTIG_OK, &pagelist);



	if (!list_empty(&pagelist)) {

		err = migrate_pages_to(&pagelist, NULL, dest);

	if (!list_empty(&pagelist))

			putback_lru_pages(&pagelist);

	}

		err = migrate_pages_to(&pagelist, NULL, dest);

	return err;

}
@@ -773,9 +770,6 @@ long do_mbind(unsigned long start, unsigned long len, 
			err = -EIO;

	}



	if (!list_empty(&pagelist))

		putback_lru_pages(&pagelist);



	up_write(&mm->mmap_sem);

	mpol_free(new);

	return err;

mm/migrate.c

+23 −25
Original line number Diff line number Diff line
@@ -624,6 +624,15 @@ unlock: 
	unlock_page(page);

ret:

	if (rc != -EAGAIN) {

 		/*

 		 * A page that has been migrated has all references

 		 * removed and will be freed. A page that has not been

 		 * migrated will have kepts its references and be

 		 * restored.

 		 */

 		list_del(&page->lru);

 		move_to_lru(page);



		list_del(&newpage->lru);

		move_to_lru(newpage);

	}
@@ -640,12 +649,12 @@ ret: 
 *

 * The function returns after 10 attempts or if no pages

 * are movable anymore because to has become empty

 * or no retryable pages exist anymore.

 * or no retryable pages exist anymore. All pages will be

 * retruned to the LRU or freed.

 *

 * Return: Number of pages not migrated when "to" ran empty.

 * Return: Number of pages not migrated.

 */

int migrate_pages(struct list_head *from, struct list_head *to,

		  struct list_head *moved, struct list_head *failed)

int migrate_pages(struct list_head *from, struct list_head *to)

{

	int retry = 1;

	int nr_failed = 0;
@@ -675,11 +684,9 @@ int migrate_pages(struct list_head *from, struct list_head *to, 
				retry++;

				break;

			case 0:

				list_move(&page->lru, moved);

				break;

			default:

				/* Permanent failure */

				list_move(&page->lru, failed);

				nr_failed++;

				break;

			}
@@ -689,6 +696,7 @@ int migrate_pages(struct list_head *from, struct list_head *to, 
	if (!swapwrite)

		current->flags &= ~PF_SWAPWRITE;



	putback_lru_pages(from);

	return nr_failed + retry;

}
@@ -702,11 +710,10 @@ int migrate_pages_to(struct list_head *pagelist, 
			struct vm_area_struct *vma, int dest)

{

	LIST_HEAD(newlist);

	LIST_HEAD(moved);

	LIST_HEAD(failed);

	int err = 0;

	unsigned long offset = 0;

	int nr_pages;

	int nr_failed = 0;

	struct page *page;

	struct list_head *p;
@@ -740,26 +747,17 @@ redo: 
		if (nr_pages > MIGRATE_CHUNK_SIZE)

			break;

	}

	err = migrate_pages(pagelist, &newlist, &moved, &failed);



	putback_lru_pages(&moved);	/* Call release pages instead ?? */

	err = migrate_pages(pagelist, &newlist);



	if (err >= 0 && list_empty(&newlist) && !list_empty(pagelist))

	if (err >= 0) {

		nr_failed += err;

		if (list_empty(&newlist) && !list_empty(pagelist))

			goto redo;

out:

	/* Return leftover allocated pages */

	while (!list_empty(&newlist)) {

		page = list_entry(newlist.next, struct page, lru);

		list_del(&page->lru);

		__free_page(page);

	}

	list_splice(&failed, pagelist);

	if (err < 0)

		return err;

out:



	/* Calculate number of leftover pages */

	nr_pages = 0;

	list_for_each(p, pagelist)

		nr_pages++;

	return nr_pages;

		nr_failed++;

	return nr_failed;

}