There is just one code flow if two for-loops find proper area. So we don't
need to keep this logic in for-loops. Clean-up code to nderstand easily
what it does. It is for following patch.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8fcced7..a822389 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1013,10 +1013,10 @@ static void change_pageblock_range(struct page *pageblock_page,
static inline struct page *
__rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
{
- struct free_area * area;
+ struct free_area *area = NULL;
int current_order;
struct page *page;
- int migratetype, i;
+ int migratetype = 0, i;
/* Find the largest possible block of pages in the other list */
for (current_order = MAX_ORDER-1; current_order >= order;
@@ -1029,64 +1029,59 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
break;
area = &(zone->free_area[current_order]);
- if (list_empty(&area->free_list[migratetype]))
- continue;
+ if (!list_empty(&area->free_list[migratetype]))
+ goto found;
+ }
+ }
- page = list_entry(area->free_list[migratetype].next,
- struct page, lru);
- area->nr_free--;
+ return NULL;
- /*
- * 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 on different free lists. We don't
- * want unmovable pages to be allocated from
- * MIGRATE_CMA areas.
- */
- if (!is_migrate_cma(migratetype) &&
- (unlikely(current_order >= pageblock_order / 2) ||
- start_migratetype == MIGRATE_RECLAIMABLE ||
- page_group_by_mobility_disabled)) {
- int pages;
- pages = move_freepages_block(zone, page,
- start_migratetype);
-
- /* Claim the whole block if over half of it is free */
- if (pages >= (1 << (pageblock_order-1)) ||
- page_group_by_mobility_disabled)
- set_pageblock_migratetype(page,
- start_migratetype);
-
- migratetype = start_migratetype;
- }
+found:
+ page = list_entry(area->free_list[migratetype].next, struct page, lru);
+ area->nr_free--;
- /* Remove the page from the freelists */
- list_del(&page->lru);
- rmv_page_order(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 on different free lists. We don't
+ * want unmovable pages to be allocated from MIGRATE_CMA areas.
+ */
+ if (!is_migrate_cma(migratetype) &&
+ (unlikely(current_order >= pageblock_order / 2) ||
+ start_migratetype == MIGRATE_RECLAIMABLE ||
+ page_group_by_mobility_disabled)) {
+ int pages;
+ pages = move_freepages_block(zone, page, start_migratetype);
+
+ /* Claim the whole block if over half of it is free */
+ if (pages >= (1 << (pageblock_order-1)) ||
+ page_group_by_mobility_disabled)
+ set_pageblock_migratetype(page, start_migratetype);
+
+ migratetype = start_migratetype;
+ }
- /* Take ownership for orders >= pageblock_order */
- if (current_order >= pageblock_order &&
- !is_migrate_cma(migratetype))
- change_pageblock_range(page, current_order,
- start_migratetype);
+ /* Remove the page from the freelists */
+ list_del(&page->lru);
+ rmv_page_order(page);
- expand(zone, page, order, current_order, area,
- is_migrate_cma(migratetype)
- ? migratetype : start_migratetype);
+ /* Take ownership for orders >= pageblock_order */
+ if (current_order >= pageblock_order &&
+ !is_migrate_cma(migratetype))
+ change_pageblock_range(page, current_order, start_migratetype);
- trace_mm_page_alloc_extfrag(page, order, current_order,
- start_migratetype, migratetype);
+ expand(zone, page, order, current_order, area,
+ is_migrate_cma(migratetype)
+ ? migratetype : start_migratetype);
- return page;
- }
- }
+ trace_mm_page_alloc_extfrag(page, order, current_order,
+ start_migratetype, migratetype);
- return NULL;
+ return page;
}
/*
--
1.7.9.5
--
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