1 files changed, 59 insertions, 47 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 84d9da1..1b1c39e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -511,7 +511,7 @@ static inline int free_pages_check(struct page *page)
 }
 
 /*
- * Frees a list of pages. 
+ * Frees a number of pages from the PCP lists
  * Assumes all pages on list are in same zone, and of same order.
  * count is the number of pages to free.
  *
@@ -521,23 +521,36 @@ static inline int free_pages_check(struct page *page)
  * And clear the zone's pages_scanned counter, to hold off the "all pages are
  * pinned" detection logic.
  */
-static void free_pages_bulk(struct zone *zone, int count,
-					struct list_head *list, int order)
+static void free_pcppages_bulk(struct zone *zone, int count,
+					struct per_cpu_pages *pcp)
 {
+	int migratetype = 0;
+
 	spin_lock(&zone->lock);
 	zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
 	zone->pages_scanned = 0;
 
-	__mod_zone_page_state(zone, NR_FREE_PAGES, count << order);
+	__mod_zone_page_state(zone, NR_FREE_PAGES, count);
 	while (count--) {
 		struct page *page;
+		struct list_head *list;
+
+		/*
+		 * Remove pages from lists in a round-robin fashion. This spinning
+		 * around potentially empty lists is bloody awful, alternatives that
+		 * don't suck are welcome
+		 */
+		do {
+			if (++migratetype == MIGRATE_PCPTYPES)
+				migratetype = 0;
+			list = &pcp->lists[migratetype];
+		} while (list_empty(list));
 
-		VM_BUG_ON(list_empty(list));
 		page = list_entry(list->prev, struct page, lru);
 		/* have to delete it as __free_one_page list manipulates */
 		list_del(&page->lru);
-		trace_mm_page_pcpu_drain(page, order, page_private(page));
-		__free_one_page(page, zone, order, page_private(page));
+		trace_mm_page_pcpu_drain(page, 0, migratetype);
+		__free_one_page(page, zone, 0, migratetype);
 	}
 	spin_unlock(&zone->lock);
 }
@@ -953,7 +966,7 @@ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
 		to_drain = pcp->batch;
 	else
 		to_drain = pcp->count;
-	free_pages_bulk(zone, to_drain, &pcp->list, 0);
+	free_pcppages_bulk(zone, to_drain, pcp);
 	pcp->count -= to_drain;
 	local_irq_restore(flags);
 }
@@ -979,7 +992,7 @@ static void drain_pages(unsigned int cpu)
 
 		pcp = &pset->pcp;
 		local_irq_save(flags);
-		free_pages_bulk(zone, pcp->count, &pcp->list, 0);
+		free_pcppages_bulk(zone, pcp->count, pcp);
 		pcp->count = 0;
 		local_irq_restore(flags);
 	}
@@ -1045,6 +1058,7 @@ static void free_hot_cold_page(struct page *page, int cold)
 	struct zone *zone = page_zone(page);
 	struct per_cpu_pages *pcp;
 	unsigned long flags;
+	int migratetype;
 	int wasMlocked = __TestClearPageMlocked(page);
 
 	kmemcheck_free_shadow(page, 0);
@@ -1062,21 +1076,39 @@ static void free_hot_cold_page(struct page *page, int cold)
 	kernel_map_pages(page, 1, 0);
 
 	pcp = &zone_pcp(zone, get_cpu())->pcp;
-	set_page_private(page, get_pageblock_migratetype(page));
+	migratetype = get_pageblock_migratetype(page);
+	set_page_private(page, migratetype);
 	local_irq_save(flags);
 	if (unlikely(wasMlocked))
 		free_page_mlock(page);
 	__count_vm_event(PGFREE);
 
+	/*
+	 * We only track unmovable, reclaimable and movable on pcp lists.
+	 * Free ISOLATE pages back to the allocator because they are being
+	 * offlined but treat RESERVE as movable pages so we can get those
+	 * areas back if necessary. Otherwise, we may have to free
+	 * excessively into the page allocator
+	 */
+	if (migratetype >= MIGRATE_PCPTYPES) {
+		if (unlikely(migratetype == MIGRATE_ISOLATE)) {
+			free_one_page(zone, page, 0, migratetype);
+			goto out;
+		}
+		migratetype = MIGRATE_MOVABLE;
+	}
+
 	if (cold)
-		list_add_tail(&page->lru, &pcp->list);
+		list_add_tail(&page->lru, &pcp->lists[migratetype]);
 	else
-		list_add(&page->lru, &pcp->list);
+		list_add(&page->lru, &pcp->lists[migratetype]);
 	pcp->count++;
 	if (pcp->count >= pcp->high) {
-		free_pages_bulk(zone, pcp->batch, &pcp->list, 0);
+		free_pcppages_bulk(zone, pcp->batch, pcp);
 		pcp->count -= pcp->batch;
 	}
+
+out:
 	local_irq_restore(flags);
 	put_cpu();
 }
@@ -1134,46 +1166,24 @@ again:
 	cpu  = get_cpu();
 	if (likely(order == 0)) {
 		struct per_cpu_pages *pcp;
+		struct list_head *list;
 
 		pcp = &zone_pcp(zone, cpu)->pcp;
+		list = &pcp->lists[migratetype];
 		local_irq_save(flags);
-		if (!pcp->count) {
-			pcp->count = rmqueue_bulk(zone, 0,
-					pcp->batch, &pcp->list,
-					migratetype, cold);
-			if (unlikely(!pcp->count))
-				goto failed;
-		}
-
-		/* Find a page of the appropriate migrate type */
-		if (cold) {
-			list_for_each_entry_reverse(page, &pcp->list, lru)
-				if (page_private(page) == migratetype)
-					break;
-		} else {
-			list_for_each_entry(page, &pcp->list, lru)
-				if (page_private(page) == migratetype)
-					break;
-		}
-
-		/* Allocate more to the pcp list if necessary */
-		if (unlikely(&page->lru == &pcp->list)) {
-			int get_one_page = 0;
-
+		if (list_empty(list)) {
 			pcp->count += rmqueue_bulk(zone, 0,
-					pcp->batch, &pcp->list,
+					pcp->batch, list,
 					migratetype, cold);
-			list_for_each_entry(page, &pcp->list, lru) {
-				if (get_pageblock_migratetype(page) !=
-					    MIGRATE_ISOLATE) {
-					get_one_page = 1;
-					break;
-				}
-			}
-			if (!get_one_page)
+			if (unlikely(list_empty(list)))
 				goto failed;
 		}
 
+		if (cold)
+			page = list_entry(list->prev, struct page, lru);
+		else
+			page = list_entry(list->next, struct page, lru);
+
 		list_del(&page->lru);
 		pcp->count--;
 	} else {
@@ -3024,6 +3034,7 @@ static int zone_batchsize(struct zone *zone)
 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
 {
 	struct per_cpu_pages *pcp;
+	int migratetype;
 
 	memset(p, 0, sizeof(*p));
 
@@ -3031,7 +3042,8 @@ static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
 	pcp->count = 0;
 	pcp->high = 6 * batch;
 	pcp->batch = max(1UL, 1 * batch);
-	INIT_LIST_HEAD(&pcp->list);
+	for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
+		INIT_LIST_HEAD(&pcp->lists[migratetype]);
 }
 
 /*
@@ -3223,7 +3235,7 @@ static int __zone_pcp_update(void *data)
 		pcp = &pset->pcp;
 
 		local_irq_save(flags);
-		free_pages_bulk(zone, pcp->count, &pcp->list, 0);
+		free_pcppages_bulk(zone, pcp->count, pcp);
 		setup_pageset(pset, batch);
 		local_irq_restore(flags);
 	}