[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: Christoph 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: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/migrate.c b/mm/migrate.c
index 0903816..d3a1810 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -624,6 +624,15 @@
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 @@
*
* 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 @@
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 @@
if (!swapwrite)
current->flags &= ~PF_SWAPWRITE;
+ putback_lru_pages(from);
return nr_failed + retry;
}
@@ -702,11 +710,10 @@
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 @@
if (nr_pages > MIGRATE_CHUNK_SIZE)
break;
}
- err = migrate_pages(pagelist, &newlist, &moved, &failed);
+ err = migrate_pages(pagelist, &newlist);
- putback_lru_pages(&moved); /* Call release pages instead ?? */
-
- if (err >= 0 && 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);
+ if (err >= 0) {
+ nr_failed += err;
+ if (list_empty(&newlist) && !list_empty(pagelist))
+ goto redo;
}
- 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;
}
