1 files changed, 190 insertions, 135 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 780c8f023b28..23f5066bd4a5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -78,6 +78,34 @@
 #include "shuffle.h"
 #include "page_reporting.h"
 
+/* Free Page Internal flags: for internal, non-pcp variants of free_pages(). */
+typedef int __bitwise fpi_t;
+
+/* No special request */
+#define FPI_NONE		((__force fpi_t)0)
+
+/*
+ * Skip free page reporting notification for the (possibly merged) page.
+ * This does not hinder free page reporting from grabbing the page,
+ * reporting it and marking it "reported" -  it only skips notifying
+ * the free page reporting infrastructure about a newly freed page. For
+ * example, used when temporarily pulling a page from a freelist and
+ * putting it back unmodified.
+ */
+#define FPI_SKIP_REPORT_NOTIFY	((__force fpi_t)BIT(0))
+
+/*
+ * Place the (possibly merged) page to the tail of the freelist. Will ignore
+ * page shuffling (relevant code - e.g., memory onlining - is expected to
+ * shuffle the whole zone).
+ *
+ * Note: No code should rely on this flag for correctness - it's purely
+ *       to allow for optimizations when handing back either fresh pages
+ *       (memory onlining) or untouched pages (page isolation, free page
+ *       reporting).
+ */
+#define FPI_TO_TAIL		((__force fpi_t)BIT(1))
+
 /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
 static DEFINE_MUTEX(pcp_batch_high_lock);
 #define MIN_PERCPU_PAGELIST_FRACTION	(8)
@@ -156,16 +184,16 @@ static int __init early_init_on_alloc(char *buf)
 	int ret;
 	bool bool_result;
 
-	if (!buf)
-		return -EINVAL;
 	ret = kstrtobool(buf, &bool_result);
+	if (ret)
+		return ret;
 	if (bool_result && page_poisoning_enabled())
 		pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_alloc\n");
 	if (bool_result)
 		static_branch_enable(&init_on_alloc);
 	else
 		static_branch_disable(&init_on_alloc);
-	return ret;
+	return 0;
 }
 early_param("init_on_alloc", early_init_on_alloc);
 
@@ -174,16 +202,16 @@ static int __init early_init_on_free(char *buf)
 	int ret;
 	bool bool_result;
 
-	if (!buf)
-		return -EINVAL;
 	ret = kstrtobool(buf, &bool_result);
+	if (ret)
+		return ret;
 	if (bool_result && page_poisoning_enabled())
 		pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_free\n");
 	if (bool_result)
 		static_branch_enable(&init_on_free);
 	else
 		static_branch_disable(&init_on_free);
-	return ret;
+	return 0;
 }
 early_param("init_on_free", early_init_on_free);
 
@@ -247,7 +275,8 @@ bool pm_suspended_storage(void)
 unsigned int pageblock_order __read_mostly;
 #endif
 
-static void __free_pages_ok(struct page *page, unsigned int order);
+static void __free_pages_ok(struct page *page, unsigned int order,
+			    fpi_t fpi_flags);
 
 /*
  * results with 256, 32 in the lowmem_reserve sysctl:
@@ -659,7 +688,7 @@ out:
 void free_compound_page(struct page *page)
 {
 	mem_cgroup_uncharge(page);
-	__free_pages_ok(page, compound_order(page));
+	__free_pages_ok(page, compound_order(page), FPI_NONE);
 }
 
 void prep_compound_page(struct page *page, unsigned int order)
@@ -763,7 +792,7 @@ static inline void clear_page_guard(struct zone *zone, struct page *page,
 				unsigned int order, int migratetype) {}
 #endif
 
-static inline void set_page_order(struct page *page, unsigned int order)
+static inline void set_buddy_order(struct page *page, unsigned int order)
 {
 	set_page_private(page, order);
 	__SetPageBuddy(page);
@@ -788,7 +817,7 @@ static inline bool page_is_buddy(struct page *page, struct page *buddy,
 	if (!page_is_guard(buddy) && !PageBuddy(buddy))
 		return false;
 
-	if (page_order(buddy) != order)
+	if (buddy_order(buddy) != order)
 		return false;
 
 	/*
@@ -873,13 +902,17 @@ static inline void add_to_free_list_tail(struct page *page, struct zone *zone,
 	area->nr_free++;
 }
 
-/* Used for pages which are on another list */
+/*
+ * Used for pages which are on another list. Move the pages to the tail
+ * of the list - so the moved pages won't immediately be considered for
+ * allocation again (e.g., optimization for memory onlining).
+ */
 static inline void move_to_free_list(struct page *page, struct zone *zone,
 				     unsigned int order, int migratetype)
 {
 	struct free_area *area = &zone->free_area[order];
 
-	list_move(&page->lru, &area->free_list[migratetype]);
+	list_move_tail(&page->lru, &area->free_list[migratetype]);
 }
 
 static inline void del_page_from_free_list(struct page *page, struct zone *zone,
@@ -952,7 +985,7 @@ buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn,
 static inline void __free_one_page(struct page *page,
 		unsigned long pfn,
 		struct zone *zone, unsigned int order,
-		int migratetype, bool report)
+		int migratetype, fpi_t fpi_flags)
 {
 	struct capture_control *capc = task_capc(zone);
 	unsigned long buddy_pfn;
@@ -1026,9 +1059,11 @@ continue_merging:
 	}
 
 done_merging:
-	set_page_order(page, order);
+	set_buddy_order(page, order);
 
-	if (is_shuffle_order(order))
+	if (fpi_flags & FPI_TO_TAIL)
+		to_tail = true;
+	else if (is_shuffle_order(order))
 		to_tail = shuffle_pick_tail();
 	else
 		to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order);
@@ -1039,7 +1074,7 @@ done_merging:
 		add_to_free_list(page, zone, order, migratetype);
 
 	/* Notify page reporting subsystem of freed page */
-	if (report)
+	if (!(fpi_flags & FPI_SKIP_REPORT_NOTIFY))
 		page_reporting_notify_free(order);
 }
 
@@ -1174,6 +1209,17 @@ static __always_inline bool free_pages_prepare(struct page *page,
 
 	trace_mm_page_free(page, order);
 
+	if (unlikely(PageHWPoison(page)) && !order) {
+		/*
+		 * Do not let hwpoison pages hit pcplists/buddy
+		 * Untie memcg state and reset page's owner
+		 */
+		if (memcg_kmem_enabled() && PageKmemcg(page))
+			__memcg_kmem_uncharge_page(page, order);
+		reset_page_owner(page, order);
+		return false;
+	}
+
 	/*
 	 * Check tail pages before head page information is cleared to
 	 * avoid checking PageCompound for order-0 pages.
@@ -1369,7 +1415,7 @@ static void free_pcppages_bulk(struct zone *zone, int count,
 		if (unlikely(isolated_pageblocks))
 			mt = get_pageblock_migratetype(page);
 
-		__free_one_page(page, page_to_pfn(page), zone, 0, mt, true);
+		__free_one_page(page, page_to_pfn(page), zone, 0, mt, FPI_NONE);
 		trace_mm_page_pcpu_drain(page, 0, mt);
 	}
 	spin_unlock(&zone->lock);
@@ -1378,14 +1424,14 @@ static void free_pcppages_bulk(struct zone *zone, int count,
 static void free_one_page(struct zone *zone,
 				struct page *page, unsigned long pfn,
 				unsigned int order,
-				int migratetype)
+				int migratetype, fpi_t fpi_flags)
 {
 	spin_lock(&zone->lock);
 	if (unlikely(has_isolate_pageblock(zone) ||
 		is_migrate_isolate(migratetype))) {
 		migratetype = get_pfnblock_migratetype(page, pfn);
 	}
-	__free_one_page(page, pfn, zone, order, migratetype, true);
+	__free_one_page(page, pfn, zone, order, migratetype, fpi_flags);
 	spin_unlock(&zone->lock);
 }
 
@@ -1463,7 +1509,8 @@ void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
 	}
 }
 
-static void __free_pages_ok(struct page *page, unsigned int order)
+static void __free_pages_ok(struct page *page, unsigned int order,
+			    fpi_t fpi_flags)
 {
 	unsigned long flags;
 	int migratetype;
@@ -1475,7 +1522,8 @@ static void __free_pages_ok(struct page *page, unsigned int order)
 	migratetype = get_pfnblock_migratetype(page, pfn);
 	local_irq_save(flags);
 	__count_vm_events(PGFREE, 1 << order);
-	free_one_page(page_zone(page), page, pfn, order, migratetype);
+	free_one_page(page_zone(page), page, pfn, order, migratetype,
+		      fpi_flags);
 	local_irq_restore(flags);
 }
 
@@ -1485,6 +1533,11 @@ void __free_pages_core(struct page *page, unsigned int order)
 	struct page *p = page;
 	unsigned int loop;
 
+	/*
+	 * When initializing the memmap, __init_single_page() sets the refcount
+	 * of all pages to 1 ("allocated"/"not free"). We have to set the
+	 * refcount of all involved pages to 0.
+	 */
 	prefetchw(p);
 	for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
 		prefetchw(p + 1);
@@ -1495,8 +1548,12 @@ void __free_pages_core(struct page *page, unsigned int order)
 	set_page_count(p, 0);
 
 	atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
-	set_page_refcounted(page);
-	__free_pages(page, order);
+
+	/*
+	 * Bypass PCP and place fresh pages right to the tail, primarily
+	 * relevant for memory onlining.
+	 */
+	__free_pages_ok(page, order, FPI_TO_TAIL);
 }
 
 #ifdef CONFIG_NEED_MULTIPLE_NODES
@@ -2121,7 +2178,7 @@ static inline void expand(struct zone *zone, struct page *page,
 			continue;
 
 		add_to_free_list(&page[size], zone, high, migratetype);
-		set_page_order(&page[size], high);
+		set_buddy_order(&page[size], high);
 	}
 }
 
@@ -2299,7 +2356,7 @@ static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
 #endif
 
 /*
- * Move the free pages in a range to the free lists of the requested type.
+ * Move the free pages in a range to the freelist tail of the requested type.
  * Note that start_page and end_pages are not aligned on a pageblock
  * boundary. If alignment is required, use move_freepages_block()
  */
@@ -2335,7 +2392,7 @@ static int move_freepages(struct zone *zone,
 		VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
 		VM_BUG_ON_PAGE(page_zone(page) != zone, page);
 
-		order = page_order(page);
+		order = buddy_order(page);
 		move_to_free_list(page, zone, order, migratetype);
 		page += 1 << order;
 		pages_moved += 1 << order;
@@ -2459,7 +2516,7 @@ static inline void boost_watermark(struct zone *zone)
 static void steal_suitable_fallback(struct zone *zone, struct page *page,
 		unsigned int alloc_flags, int start_type, bool whole_block)
 {
-	unsigned int current_order = page_order(page);
+	unsigned int current_order = buddy_order(page);
 	int free_pages, movable_pages, alike_pages;
 	int old_block_type;
 
@@ -3123,7 +3180,8 @@ static void free_unref_page_commit(struct page *page, unsigned long pfn)
 	 */
 	if (migratetype >= MIGRATE_PCPTYPES) {
 		if (unlikely(is_migrate_isolate(migratetype))) {
-			free_one_page(zone, page, pfn, 0, migratetype);
+			free_one_page(zone, page, pfn, 0, migratetype,
+				      FPI_NONE);
 			return;
 		}
 		migratetype = MIGRATE_MOVABLE;
@@ -3209,7 +3267,7 @@ void split_page(struct page *page, unsigned int order)
 
 	for (i = 1; i < (1 << order); i++)
 		set_page_refcounted(page + i);
-	split_page_owner(page, order);
+	split_page_owner(page, 1 << order);
 }
 EXPORT_SYMBOL_GPL(split_page);
 
@@ -3278,7 +3336,8 @@ void __putback_isolated_page(struct page *page, unsigned int order, int mt)
 	lockdep_assert_held(&zone->lock);
 
 	/* Return isolated page to tail of freelist. */
-	__free_one_page(page, page_to_pfn(page), zone, order, mt, false);
+	__free_one_page(page, page_to_pfn(page), zone, order, mt,
+			FPI_SKIP_REPORT_NOTIFY | FPI_TO_TAIL);
 }
 
 /*
@@ -3496,7 +3555,7 @@ static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
 
 #endif /* CONFIG_FAIL_PAGE_ALLOC */
 
-static noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
+noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
 {
 	return __should_fail_alloc_page(gfp_mask, order);
 }
@@ -3741,8 +3800,8 @@ retry:
 	 */
 	no_fallback = alloc_flags & ALLOC_NOFRAGMENT;
 	z = ac->preferred_zoneref;
-	for_next_zone_zonelist_nodemask(zone, z, ac->zonelist,
-					ac->highest_zoneidx, ac->nodemask) {
+	for_next_zone_zonelist_nodemask(zone, z, ac->highest_zoneidx,
+					ac->nodemask) {
 		struct page *page;
 		unsigned long mark;
 
@@ -3986,8 +4045,10 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
 	 * success so it is time to admit defeat. We will skip the OOM killer
 	 * because it is very likely that the caller has a more reasonable
 	 * fallback than shooting a random task.
+	 *
+	 * The OOM killer may not free memory on a specific node.
 	 */
-	if (gfp_mask & __GFP_RETRY_MAYFAIL)
+	if (gfp_mask & (__GFP_RETRY_MAYFAIL | __GFP_THISNODE))
 		goto out;
 	/* The OOM killer does not needlessly kill tasks for lowmem */
 	if (ac->highest_zoneidx < ZONE_NORMAL)
@@ -4004,10 +4065,6 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
 	 * failures more gracefully we should just bail out here.
 	 */
 
-	/* The OOM killer may not free memory on a specific node */
-	if (gfp_mask & __GFP_THISNODE)
-		goto out;
-
 	/* Exhausted what can be done so it's blame time */
 	if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
 		*did_some_progress = 1;
@@ -4255,13 +4312,12 @@ EXPORT_SYMBOL_GPL(fs_reclaim_release);
 #endif
 
 /* Perform direct synchronous page reclaim */
-static int
+static unsigned long
 __perform_reclaim(gfp_t gfp_mask, unsigned int order,
 					const struct alloc_context *ac)
 {
-	int progress;
 	unsigned int noreclaim_flag;
-	unsigned long pflags;
+	unsigned long pflags, progress;
 
 	cond_resched();
 
@@ -4840,12 +4896,6 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
 
 	*alloc_flags = current_alloc_flags(gfp_mask, *alloc_flags);
 
-	return true;
-}
-
-/* Determine whether to spread dirty pages and what the first usable zone */
-static inline void finalise_ac(gfp_t gfp_mask, struct alloc_context *ac)
-{
 	/* Dirty zone balancing only done in the fast path */
 	ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
 
@@ -4856,6 +4906,8 @@ static inline void finalise_ac(gfp_t gfp_mask, struct alloc_context *ac)
 	 */
 	ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
 					ac->highest_zoneidx, ac->nodemask);
+
+	return true;
 }
 
 /*
@@ -4884,8 +4936,6 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
 	if (!prepare_alloc_pages(gfp_mask, order, preferred_nid, nodemask, &ac, &alloc_mask, &alloc_flags))
 		return NULL;
 
-	finalise_ac(gfp_mask, &ac);
-
 	/*
 	 * Forbid the first pass from falling back to types that fragment
 	 * memory until all local zones are considered.
@@ -4954,13 +5004,16 @@ static inline void free_the_page(struct page *page, unsigned int order)
 	if (order == 0)		/* Via pcp? */
 		free_unref_page(page);
 	else
-		__free_pages_ok(page, order);
+		__free_pages_ok(page, order, FPI_NONE);
 }
 
 void __free_pages(struct page *page, unsigned int order)
 {
 	if (put_page_testzero(page))
 		free_the_page(page, order);
+	else if (!PageHead(page))
+		while (order-- > 0)
+			free_the_page(page + (1 << order), order);
 }
 EXPORT_SYMBOL(__free_pages);
 
@@ -5651,7 +5704,6 @@ static int find_next_best_node(int node, nodemask_t *used_node_mask)
 	int n, val;
 	int min_val = INT_MAX;
 	int best_node = NUMA_NO_NODE;
-	const struct cpumask *tmp = cpumask_of_node(0);
 
 	/* Use the local node if we haven't already */
 	if (!node_isset(node, *used_node_mask)) {
@@ -5672,8 +5724,7 @@ static int find_next_best_node(int node, nodemask_t *used_node_mask)
 		val += (n < node);
 
 		/* Give preference to headless and unused nodes */
-		tmp = cpumask_of_node(n);
-		if (!cpumask_empty(tmp))
+		if (!cpumask_empty(cpumask_of_node(n)))
 			val += PENALTY_FOR_NODE_WITH_CPUS;
 
 		/* Slight preference for less loaded node */
@@ -5969,7 +6020,7 @@ overlap_memmap_init(unsigned long zone, unsigned long *pfn)
 
 	if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
 		if (!r || *pfn >= memblock_region_memory_end_pfn(r)) {
-			for_each_memblock(memory, r) {
+			for_each_mem_region(r) {
 				if (*pfn < memblock_region_memory_end_pfn(r))
 					break;
 			}
@@ -5987,10 +6038,15 @@ overlap_memmap_init(unsigned long zone, unsigned long *pfn)
  * Initially all pages are reserved - free ones are freed
  * up by memblock_free_all() once the early boot process is
  * done. Non-atomic initialization, single-pass.
+ *
+ * All aligned pageblocks are initialized to the specified migratetype
+ * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
+ * zone stats (e.g., nr_isolate_pageblock) are touched.
  */
 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
-		unsigned long start_pfn, enum meminit_context context,
-		struct vmem_altmap *altmap)
+		unsigned long start_pfn,
+		enum meminit_context context,
+		struct vmem_altmap *altmap, int migratetype)
 {
 	unsigned long pfn, end_pfn = start_pfn + size;
 	struct page *page;
@@ -6034,19 +6090,12 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
 			__SetPageReserved(page);
 
 		/*
-		 * Mark the block movable so that blocks are reserved for
-		 * movable at startup. This will force kernel allocations
-		 * to reserve their blocks rather than leaking throughout
-		 * the address space during boot when many long-lived
-		 * kernel allocations are made.
-		 *
-		 * bitmap is created for zone's valid pfn range. but memmap
-		 * can be created for invalid pages (for alignment)
-		 * check here not to call set_pageblock_migratetype() against
-		 * pfn out of zone.
+		 * Usually, we want to mark the pageblock MIGRATE_MOVABLE,
+		 * such that unmovable allocations won't be scattered all
+		 * over the place during system boot.
 		 */
-		if (!(pfn & (pageblock_nr_pages - 1))) {
-			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
+		if (IS_ALIGNED(pfn, pageblock_nr_pages)) {
+			set_pageblock_migratetype(page, migratetype);
 			cond_resched();
 		}
 		pfn++;
@@ -6108,15 +6157,10 @@ void __ref memmap_init_zone_device(struct zone *zone,
 		 * the address space during boot when many long-lived
 		 * kernel allocations are made.
 		 *
-		 * bitmap is created for zone's valid pfn range. but memmap
-		 * can be created for invalid pages (for alignment)
-		 * check here not to call set_pageblock_migratetype() against
-		 * pfn out of zone.
-		 *
 		 * Please note that MEMINIT_HOTPLUG path doesn't clear memmap
 		 * because this is done early in section_activate()
 		 */
-		if (!(pfn & (pageblock_nr_pages - 1))) {
+		if (IS_ALIGNED(pfn, pageblock_nr_pages)) {
 			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
 			cond_resched();
 		}
@@ -6151,7 +6195,7 @@ void __meminit __weak memmap_init(unsigned long size, int nid,
 		if (end_pfn > start_pfn) {
 			size = end_pfn - start_pfn;
 			memmap_init_zone(size, nid, zone, start_pfn,
-					 MEMINIT_EARLY, NULL);
+					 MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
 		}
 	}
 }
@@ -6554,7 +6598,7 @@ static unsigned long __init zone_absent_pages_in_node(int nid,
 		unsigned long start_pfn, end_pfn;
 		struct memblock_region *r;
 
-		for_each_memblock(memory, r) {
+		for_each_mem_region(r) {
 			start_pfn = clamp(memblock_region_memory_base_pfn(r),
 					  zone_start_pfn, zone_end_pfn);
 			end_pfn = clamp(memblock_region_memory_end_pfn(r),
@@ -6998,8 +7042,7 @@ static void __init init_unavailable_mem(void)
 	 * Loop through unavailable ranges not covered by memblock.memory.
 	 */
 	pgcnt = 0;
-	for_each_mem_range(i, &memblock.memory, NULL,
-			NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) {
+	for_each_mem_range(i, &start, &end) {
 		if (next < start)
 			pgcnt += init_unavailable_range(PFN_DOWN(next),
 							PFN_UP(start));
@@ -7149,7 +7192,7 @@ static void __init find_zone_movable_pfns_for_nodes(void)
 	 * options.
 	 */
 	if (movable_node_is_enabled()) {
-		for_each_memblock(memory, r) {
+		for_each_mem_region(r) {
 			if (!memblock_is_hotpluggable(r))
 				continue;
 
@@ -7170,7 +7213,7 @@ static void __init find_zone_movable_pfns_for_nodes(void)
 	if (mirrored_kernelcore) {
 		bool mem_below_4gb_not_mirrored = false;
 
-		for_each_memblock(memory, r) {
+		for_each_mem_region(r) {
 			if (memblock_is_mirror(r))
 				continue;
 
@@ -8234,14 +8277,7 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
 {
 	unsigned long iter = 0;
 	unsigned long pfn = page_to_pfn(page);
-
-	/*
-	 * TODO we could make this much more efficient by not checking every
-	 * page in the range if we know all of them are in MOVABLE_ZONE and
-	 * that the movable zone guarantees that pages are migratable but
-	 * the later is not the case right now unfortunatelly. E.g. movablecore
-	 * can still lead to having bootmem allocations in zone_movable.
-	 */
+	unsigned long offset = pfn % pageblock_nr_pages;
 
 	if (is_migrate_cma_page(page)) {
 		/*
@@ -8255,12 +8291,18 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
 		return page;
 	}
 
-	for (; iter < pageblock_nr_pages; iter++) {
+	for (; iter < pageblock_nr_pages - offset; iter++) {
 		if (!pfn_valid_within(pfn + iter))
 			continue;
 
 		page = pfn_to_page(pfn + iter);
 
+		/*
+		 * Both, bootmem allocations and memory holes are marked
+		 * PG_reserved and are unmovable. We can even have unmovable
+		 * allocations inside ZONE_MOVABLE, for example when
+		 * specifying "movablecore".
+		 */
 		if (PageReserved(page))
 			return page;
 
@@ -8302,7 +8344,7 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
 		 */
 		if (!page_ref_count(page)) {
 			if (PageBuddy(page))
-				iter += (1 << page_order(page)) - 1;
+				iter += (1 << buddy_order(page)) - 1;
 			continue;
 		}
 
@@ -8334,14 +8376,6 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
 		 * it.  But now, memory offline itself doesn't call
 		 * shrink_node_slabs() and it still to be fixed.
 		 */
-		/*
-		 * If the page is not RAM, page_count()should be 0.
-		 * we don't need more check. This is an _used_ not-movable page.
-		 *
-		 * The problematic thing here is PG_reserved pages. PG_reserved
-		 * is set to both of a memory hole page and a _used_ kernel
-		 * page at boot.
-		 */
 		return page;
 	}
 	return NULL;
@@ -8475,7 +8509,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
 
 	ret = start_isolate_page_range(pfn_max_align_down(start),
 				       pfn_max_align_up(end), migratetype, 0);
-	if (ret < 0)
+	if (ret)
 		return ret;
 
 	/*
@@ -8523,7 +8557,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
 	}
 
 	if (outer_start != start) {
-		order = page_order(pfn_to_page(outer_start));
+		order = buddy_order(pfn_to_page(outer_start));
 
 		/*
 		 * outer_start page could be small order buddy page and
@@ -8711,35 +8745,21 @@ void zone_pcp_reset(struct zone *zone)
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
 /*
- * All pages in the range must be in a single zone and isolated
- * before calling this.
+ * All pages in the range must be in a single zone, must not contain holes,
+ * must span full sections, and must be isolated before calling this function.
  */
-unsigned long
-__offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
+void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
 {
+	unsigned long pfn = start_pfn;
 	struct page *page;
 	struct zone *zone;
 	unsigned int order;
-	unsigned long pfn;
 	unsigned long flags;
-	unsigned long offlined_pages = 0;
-
-	/* find the first valid pfn */
-	for (pfn = start_pfn; pfn < end_pfn; pfn++)
-		if (pfn_valid(pfn))
-			break;
-	if (pfn == end_pfn)
-		return offlined_pages;
 
 	offline_mem_sections(pfn, end_pfn);
 	zone = page_zone(pfn_to_page(pfn));
 	spin_lock_irqsave(&zone->lock, flags);
-	pfn = start_pfn;
 	while (pfn < end_pfn) {
-		if (!pfn_valid(pfn)) {
-			pfn++;
-			continue;
-		}
 		page = pfn_to_page(pfn);
 		/*
 		 * The HWPoisoned page may be not in buddy system, and
@@ -8747,7 +8767,6 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
 		 */
 		if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
 			pfn++;
-			offlined_pages++;
 			continue;
 		}
 		/*
@@ -8758,20 +8777,16 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
 			BUG_ON(page_count(page));
 			BUG_ON(PageBuddy(page));
 			pfn++;
-			offlined_pages++;
 			continue;
 		}
 
 		BUG_ON(page_count(page));
 		BUG_ON(!PageBuddy(page));
-		order = page_order(page);
-		offlined_pages += 1 << order;
+		order = buddy_order(page);
 		del_page_from_free_list(page, zone, order);
 		pfn += (1 << order);
 	}
 	spin_unlock_irqrestore(&zone->lock, flags);
-
-	return offlined_pages;
 }
 #endif
 
@@ -8786,7 +8801,7 @@ bool is_free_buddy_page(struct page *page)
 	for (order = 0; order < MAX_ORDER; order++) {
 		struct page *page_head = page - (pfn & ((1 << order) - 1));
 
-		if (PageBuddy(page_head) && page_order(page_head) >= order)
+		if (PageBuddy(page_head) && buddy_order(page_head) >= order)
 			break;
 	}
 	spin_unlock_irqrestore(&zone->lock, flags);
@@ -8796,30 +8811,70 @@ bool is_free_buddy_page(struct page *page)
 
 #ifdef CONFIG_MEMORY_FAILURE
 /*
- * Set PG_hwpoison flag if a given page is confirmed to be a free page.  This
- * test is performed under the zone lock to prevent a race against page
- * allocation.
+ * Break down a higher-order page in sub-pages, and keep our target out of
+ * buddy allocator.
+ */
+static void break_down_buddy_pages(struct zone *zone, struct page *page,
+				   struct page *target, int low, int high,
+				   int migratetype)
+{
+	unsigned long size = 1 << high;
+	struct page *current_buddy, *next_page;
+
+	while (high > low) {
+		high--;
+		size >>= 1;
+
+		if (target >= &page[size]) {
+			next_page = page + size;
+			current_buddy = page;
+		} else {
+			next_page = page;
+			current_buddy = page + size;
+		}
+
+		if (set_page_guard(zone, current_buddy, high, migratetype))
+			continue;
+
+		if (current_buddy != target) {
+			add_to_free_list(current_buddy, zone, high, migratetype);
+			set_buddy_order(current_buddy, high);
+			page = next_page;
+		}
+	}
+}
+
+/*
+ * Take a page that will be marked as poisoned off the buddy allocator.
  */
-bool set_hwpoison_free_buddy_page(struct page *page)
+bool take_page_off_buddy(struct page *page)
 {
 	struct zone *zone = page_zone(page);
 	unsigned long pfn = page_to_pfn(page);
 	unsigned long flags;
 	unsigned int order;
-	bool hwpoisoned = false;
+	bool ret = false;
 
 	spin_lock_irqsave(&zone->lock, flags);
 	for (order = 0; order < MAX_ORDER; order++) {
 		struct page *page_head = page - (pfn & ((1 << order) - 1));
+		int page_order = buddy_order(page_head);
 
-		if (PageBuddy(page_head) && page_order(page_head) >= order) {
-			if (!TestSetPageHWPoison(page))
-				hwpoisoned = true;
+		if (PageBuddy(page_head) && page_order >= order) {
+			unsigned long pfn_head = page_to_pfn(page_head);
+			int migratetype = get_pfnblock_migratetype(page_head,
+								   pfn_head);
+
+			del_page_from_free_list(page_head, zone, page_order);
+			break_down_buddy_pages(zone, page_head, page, 0,
+						page_order, migratetype);
+			ret = true;
 			break;
 		}
+		if (page_count(page_head) > 0)
+			break;
 	}
 	spin_unlock_irqrestore(&zone->lock, flags);
-
-	return hwpoisoned;
+	return ret;
 }
 #endif