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-rw-r--r--mm/page_alloc.c62
1 files changed, 29 insertions, 33 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b7a881019352..7c44b49cec40 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1125,33 +1125,18 @@ static void change_pageblock_range(struct page *pageblock_page,
/*
* If breaking a large block of pages, move all free pages to the preferred
* allocation list. If falling back for a reclaimable kernel allocation, be
- * more aggressive about taking ownership of free pages.
- *
- * On the other hand, never change migration type of MIGRATE_CMA pageblocks
- * nor move CMA pages to different free lists. We don't want unmovable pages
- * to be allocated from MIGRATE_CMA areas.
- *
- * Returns the allocation migratetype if free pages were stolen, or the
- * fallback migratetype if it was decided not to steal.
+ * more aggressive about taking ownership of free pages. If we claim more than
+ * half of the pageblock, change pageblock's migratetype as well.
*/
-static int try_to_steal_freepages(struct zone *zone, struct page *page,
+static void try_to_steal_freepages(struct zone *zone, struct page *page,
int start_type, int fallback_type)
{
int current_order = page_order(page);
- /*
- * When borrowing from MIGRATE_CMA, we need to release the excess
- * buddy pages to CMA itself. We also ensure the freepage_migratetype
- * is set to CMA so it is returned to the correct freelist in case
- * the page ends up being not actually allocated from the pcp lists.
- */
- if (is_migrate_cma(fallback_type))
- return fallback_type;
-
/* Take ownership for orders >= pageblock_order */
if (current_order >= pageblock_order) {
change_pageblock_range(page, current_order, start_type);
- return start_type;
+ return;
}
if (current_order >= pageblock_order / 2 ||
@@ -1165,11 +1150,7 @@ static int try_to_steal_freepages(struct zone *zone, struct page *page,
if (pages >= (1 << (pageblock_order-1)) ||
page_group_by_mobility_disabled)
set_pageblock_migratetype(page, start_type);
-
- return start_type;
}
-
- return fallback_type;
}
/* Remove an element from the buddy allocator from the fallback list */
@@ -1179,14 +1160,15 @@ __rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype)
struct free_area *area;
unsigned int current_order;
struct page *page;
- int migratetype, new_type, i;
/* Find the largest possible block of pages in the other list */
for (current_order = MAX_ORDER-1;
current_order >= order && current_order <= MAX_ORDER-1;
--current_order) {
+ int i;
for (i = 0;; i++) {
- migratetype = fallbacks[start_migratetype][i];
+ int migratetype = fallbacks[start_migratetype][i];
+ int buddy_type = start_migratetype;
/* MIGRATE_RESERVE handled later if necessary */
if (migratetype == MIGRATE_RESERVE)
@@ -1200,22 +1182,36 @@ __rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype)
struct page, lru);
area->nr_free--;
- new_type = try_to_steal_freepages(zone, page,
- start_migratetype,
- migratetype);
+ if (!is_migrate_cma(migratetype)) {
+ try_to_steal_freepages(zone, page,
+ start_migratetype,
+ migratetype);
+ } else {
+ /*
+ * When borrowing from MIGRATE_CMA, we need to
+ * release the excess buddy pages to CMA
+ * itself, and we do not try to steal extra
+ * free pages.
+ */
+ buddy_type = migratetype;
+ }
/* Remove the page from the freelists */
list_del(&page->lru);
rmv_page_order(page);
expand(zone, page, order, current_order, area,
- new_type);
- /* The freepage_migratetype may differ from pageblock's
+ buddy_type);
+
+ /*
+ * The freepage_migratetype may differ from pageblock's
* migratetype depending on the decisions in
- * try_to_steal_freepages. This is OK as long as it does
- * not differ for MIGRATE_CMA type.
+ * try_to_steal_freepages(). This is OK as long as it
+ * does not differ for MIGRATE_CMA pageblocks. For CMA
+ * we need to make sure unallocated pages flushed from
+ * pcp lists are returned to the correct freelist.
*/
- set_freepage_migratetype(page, new_type);
+ set_freepage_migratetype(page, buddy_type);
trace_mm_page_alloc_extfrag(page, order, current_order,
start_migratetype, migratetype);