Move free pages between lists on steal
When a fallback occurs, there will be free pages for one allocation type
stored on the list for another. When a large steal occurs, this patch will
move all the free pages within one list to the other.
[y-goto@jp.fujitsu.com: fix BUG_ON check at move_freepages()]
[apw@shadowen.org: Move to using pfn_valid_within()]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andy Whitcroft <andyw@uk.ibm.com>
Cc: Bob Picco <bob.picco@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index aa7e5d2..d575a3e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -680,6 +680,72 @@
[MIGRATE_MOVABLE] = { MIGRATE_UNMOVABLE },
};
+/*
+ * Move the free pages in a range to the free lists of the requested type.
+ * Note that start_page and end_pages are not aligned in a MAX_ORDER_NR_PAGES
+ * boundary. If alignment is required, use move_freepages_block()
+ */
+int move_freepages(struct zone *zone,
+ struct page *start_page, struct page *end_page,
+ int migratetype)
+{
+ struct page *page;
+ unsigned long order;
+ int blocks_moved = 0;
+
+#ifndef CONFIG_HOLES_IN_ZONE
+ /*
+ * page_zone is not safe to call in this context when
+ * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
+ * anyway as we check zone boundaries in move_freepages_block().
+ * Remove at a later date when no bug reports exist related to
+ * CONFIG_PAGE_GROUP_BY_MOBILITY
+ */
+ BUG_ON(page_zone(start_page) != page_zone(end_page));
+#endif
+
+ for (page = start_page; page <= end_page;) {
+ if (!pfn_valid_within(page_to_pfn(page))) {
+ page++;
+ continue;
+ }
+
+ if (!PageBuddy(page)) {
+ page++;
+ continue;
+ }
+
+ order = page_order(page);
+ list_del(&page->lru);
+ list_add(&page->lru,
+ &zone->free_area[order].free_list[migratetype]);
+ page += 1 << order;
+ blocks_moved++;
+ }
+
+ return blocks_moved;
+}
+
+int move_freepages_block(struct zone *zone, struct page *page, int migratetype)
+{
+ unsigned long start_pfn, end_pfn;
+ struct page *start_page, *end_page;
+
+ start_pfn = page_to_pfn(page);
+ start_pfn = start_pfn & ~(MAX_ORDER_NR_PAGES-1);
+ start_page = pfn_to_page(start_pfn);
+ end_page = start_page + MAX_ORDER_NR_PAGES - 1;
+ end_pfn = start_pfn + MAX_ORDER_NR_PAGES - 1;
+
+ /* Do not cross zone boundaries */
+ if (start_pfn < zone->zone_start_pfn)
+ start_page = page;
+ if (end_pfn >= zone->zone_start_pfn + zone->spanned_pages)
+ return 0;
+
+ return move_freepages(zone, start_page, end_page, migratetype);
+}
+
/* Remove an element from the buddy allocator from the fallback list */
static struct page *__rmqueue_fallback(struct zone *zone, int order,
int start_migratetype)
@@ -704,11 +770,13 @@
area->nr_free--;
/*
- * If breaking a large block of pages, place the buddies
- * on the preferred allocation list
+ * If breaking a large block of pages, move all free
+ * pages to the preferred allocation list
*/
- if (unlikely(current_order >= MAX_ORDER / 2))
+ if (unlikely(current_order >= MAX_ORDER / 2)) {
migratetype = start_migratetype;
+ move_freepages_block(zone, page, migratetype);
+ }
/* Remove the page from the freelists */
list_del(&page->lru);