1 files changed, 37 insertions, 14 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a919ba5cb3c8..e95b5b7c9c3d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4061,17 +4061,6 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 	int reserve_flags;
 
 	/*
-	 * In the slowpath, we sanity check order to avoid ever trying to
-	 * reclaim >= MAX_ORDER areas which will never succeed. Callers may
-	 * be using allocators in order of preference for an area that is
-	 * too large.
-	 */
-	if (order >= MAX_ORDER) {
-		WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
-		return NULL;
-	}
-
-	/*
 	 * We also sanity check to catch abuse of atomic reserves being used by
 	 * callers that are not in atomic context.
 	 */
@@ -4364,6 +4353,15 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
 	gfp_t alloc_mask; /* The gfp_t that was actually used for allocation */
 	struct alloc_context ac = { };
 
+	/*
+	 * There are several places where we assume that the order value is sane
+	 * so bail out early if the request is out of bound.
+	 */
+	if (unlikely(order >= MAX_ORDER)) {
+		WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
+		return NULL;
+	}
+
 	gfp_mask &= gfp_allowed_mask;
 	alloc_mask = gfp_mask;
 	if (!prepare_alloc_pages(gfp_mask, order, preferred_nid, nodemask, &ac, &alloc_mask, &alloc_flags))
@@ -5544,6 +5542,18 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
 			cond_resched();
 		}
 	}
+#ifdef CONFIG_SPARSEMEM
+	/*
+	 * If the zone does not span the rest of the section then
+	 * we should at least initialize those pages. Otherwise we
+	 * could blow up on a poisoned page in some paths which depend
+	 * on full sections being initialized (e.g. memory hotplug).
+	 */
+	while (end_pfn % PAGES_PER_SECTION) {
+		__init_single_page(pfn_to_page(end_pfn), end_pfn, zone, nid);
+		end_pfn++;
+	}
+#endif
 }
 
 #ifdef CONFIG_ZONE_DEVICE
@@ -5815,8 +5825,10 @@ void __meminit init_currently_empty_zone(struct zone *zone,
 					unsigned long size)
 {
 	struct pglist_data *pgdat = zone->zone_pgdat;
+	int zone_idx = zone_idx(zone) + 1;
 
-	pgdat->nr_zones = zone_idx(zone) + 1;
+	if (zone_idx > pgdat->nr_zones)
+		pgdat->nr_zones = zone_idx;
 
 	zone->zone_start_pfn = zone_start_pfn;
 
@@ -7789,16 +7801,27 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
 			goto unmovable;
 
 		/*
+		 * If the zone is movable and we have ruled out all reserved
+		 * pages then it should be reasonably safe to assume the rest
+		 * is movable.
+		 */
+		if (zone_idx(zone) == ZONE_MOVABLE)
+			continue;
+
+		/*
 		 * Hugepages are not in LRU lists, but they're movable.
 		 * We need not scan over tail pages bacause we don't
 		 * handle each tail page individually in migration.
 		 */
 		if (PageHuge(page)) {
+			struct page *head = compound_head(page);
+			unsigned int skip_pages;
 
-			if (!hugepage_migration_supported(page_hstate(page)))
+			if (!hugepage_migration_supported(page_hstate(head)))
 				goto unmovable;
 
-			iter = round_up(iter + 1, 1<<compound_order(page)) - 1;
+			skip_pages = (1 << compound_order(head)) - (page - head);
+			iter += skip_pages - 1;
 			continue;
 		}