diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
index 047d64706f2a298157cf0d54305aa8e49f6f7837..d4cd2014fa6f5a18f03f1b0babfccb21fa3ac55f 100644
--- a/include/linux/page-isolation.h
+++ b/include/linux/page-isolation.h
@@ -33,10 +33,7 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
bool skip_hwpoisoned_pages);
void set_pageblock_migratetype(struct page *page, int migratetype);
int move_freepages_block(struct zone *zone, struct page *page,
- int migratetype);
-int move_freepages(struct zone *zone,
- struct page *start_page, struct page *end_page,
- int migratetype);
+ int migratetype, int *num_movable);
/*
* Changes migrate type in [start_pfn, end_pfn) to be MIGRATE_ISOLATE.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2f1118b4dda4096ce8e27bc91e6577c3c9e3665e..d90792addeb973514d1556d23aab99836afed24d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1832,9 +1832,9 @@ static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
* Note that start_page and end_pages are not aligned on a pageblock
* boundary. If alignment is required, use move_freepages_block()
*/
-int move_freepages(struct zone *zone,
+static int move_freepages(struct zone *zone,
struct page *start_page, struct page *end_page,
- int migratetype)
+ int migratetype, int *num_movable)
{
struct page *page;
unsigned int order;
@@ -1851,6 +1851,9 @@ int move_freepages(struct zone *zone,
VM_BUG_ON(page_zone(start_page) != page_zone(end_page));
#endif
+ if (num_movable)
+ *num_movable = 0;
+
for (page = start_page; page <= end_page;) {
if (!pfn_valid_within(page_to_pfn(page))) {
page++;
@@ -1861,6 +1864,15 @@ int move_freepages(struct zone *zone,
VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
if (!PageBuddy(page)) {
+ /*
+ * We assume that pages that could be isolated for
+ * migration are movable. But we don't actually try
+ * isolating, as that would be expensive.
+ */
+ if (num_movable &&
+ (PageLRU(page) || __PageMovable(page)))
+ (*num_movable)++;
+
page++;
continue;
}
@@ -1876,7 +1888,7 @@ int move_freepages(struct zone *zone,
}
int move_freepages_block(struct zone *zone, struct page *page,
- int migratetype)
+ int migratetype, int *num_movable)
{
unsigned long start_pfn, end_pfn;
struct page *start_page, *end_page;
@@ -1893,7 +1905,8 @@ int move_freepages_block(struct zone *zone, struct page *page,
if (!zone_spans_pfn(zone, end_pfn))
return 0;
- return move_freepages(zone, start_page, end_page, migratetype);
+ return move_freepages(zone, start_page, end_page, migratetype,
+ num_movable);
}
static void change_pageblock_range(struct page *pageblock_page,
@@ -1943,22 +1956,26 @@ static bool can_steal_fallback(unsigned int order, int start_mt)
/*
* This function implements actual steal behaviour. If order is large enough,
* we can steal whole pageblock. If not, we first move freepages in this
- * pageblock and check whether half of pages are moved or not. If half of
- * pages are moved, we can change migratetype of pageblock and permanently
- * use it's pages as requested migratetype in the future.
+ * pageblock to our migratetype and determine how many already-allocated pages
+ * are there in the pageblock with a compatible migratetype. If at least half
+ * of pages are free or compatible, we can change migratetype of the pageblock
+ * itself, so pages freed in the future will be put on the correct free list.
*/
static void steal_suitable_fallback(struct zone *zone, struct page *page,
int start_type, bool whole_block)
{
unsigned int current_order = page_order(page);
struct free_area *area;
- int pages;
+ int free_pages, movable_pages, alike_pages;
+ int old_block_type;
+
+ old_block_type = get_pageblock_migratetype(page);
/*
* This can happen due to races and we want to prevent broken
* highatomic accounting.
*/
- if (is_migrate_highatomic_page(page))
+ if (is_migrate_highatomic(old_block_type))
goto single_page;
/* Take ownership for orders >= pageblock_order */
@@ -1971,13 +1988,39 @@ static void steal_suitable_fallback(struct zone *zone, struct page *page,
if (!whole_block)
goto single_page;
- pages = move_freepages_block(zone, page, start_type);
+ free_pages = move_freepages_block(zone, page, start_type,
+ &movable_pages);
+ /*
+ * Determine how many pages are compatible with our allocation.
+ * For movable allocation, it's the number of movable pages which
+ * we just obtained. For other types it's a bit more tricky.
+ */
+ if (start_type == MIGRATE_MOVABLE) {
+ alike_pages = movable_pages;
+ } else {
+ /*
+ * If we are falling back a RECLAIMABLE or UNMOVABLE allocation
+ * to MOVABLE pageblock, consider all non-movable pages as
+ * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or
+ * vice versa, be conservative since we can't distinguish the
+ * exact migratetype of non-movable pages.
+ */
+ if (old_block_type == MIGRATE_MOVABLE)
+ alike_pages = pageblock_nr_pages
+ - (free_pages + movable_pages);
+ else
+ alike_pages = 0;
+ }
+
/* moving whole block can fail due to zone boundary conditions */
- if (!pages)
+ if (!free_pages)
goto single_page;
- /* Claim the whole block if over half of it is free */
- if (pages >= (1 << (pageblock_order-1)) ||
+ /*
+ * If a sufficient number of pages in the block are either free or of
+ * comparable migratability as our allocation, claim the whole block.
+ */
+ if (free_pages + alike_pages >= (1 << (pageblock_order-1)) ||
page_group_by_mobility_disabled)
set_pageblock_migratetype(page, start_type);
@@ -2055,7 +2098,7 @@ static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
&& !is_migrate_cma(mt)) {
zone->nr_reserved_highatomic += pageblock_nr_pages;
set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
- move_freepages_block(zone, page, MIGRATE_HIGHATOMIC);
+ move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL);
}
out_unlock:
@@ -2132,7 +2175,8 @@ static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
* may increase.
*/
set_pageblock_migratetype(page, ac->migratetype);
- ret = move_freepages_block(zone, page, ac->migratetype);
+ ret = move_freepages_block(zone, page, ac->migratetype,
+ NULL);
if (ret) {
spin_unlock_irqrestore(&zone->lock, flags);
return ret;
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 7927bbb54a4e3200e39fc098b787794f21f6c855..5092e4ef00c832fefb624a1d9d8f618402ad4402 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -66,7 +66,8 @@ static int set_migratetype_isolate(struct page *page,
set_pageblock_migratetype(page, MIGRATE_ISOLATE);
zone->nr_isolate_pageblock++;
- nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE);
+ nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE,
+ NULL);
__mod_zone_freepage_state(zone, -nr_pages, migratetype);
}
@@ -120,7 +121,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
* pageblock scanning for freepage moving.
*/
if (!isolated_page) {
- nr_pages = move_freepages_block(zone, page, migratetype);
+ nr_pages = move_freepages_block(zone, page, migratetype, NULL);
__mod_zone_freepage_state(zone, nr_pages, migratetype);
}
set_pageblock_migratetype(page, migratetype);