Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

47 files changed, 2974 insertions, 2724 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index 1b5a95f0fa01..3e9977a9d657 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -134,6 +134,9 @@ config HAVE_MEMBLOCK
 config HAVE_MEMBLOCK_NODE_MAP
 	boolean
 
+config HAVE_MEMBLOCK_PHYS_MAP
+	boolean
+
 config ARCH_DISCARD_MEMBLOCK
 	boolean
 
@@ -264,6 +267,9 @@ config MIGRATION
 	  pages as migration can relocate pages to satisfy a huge page
 	  allocation instead of reclaiming.
 
+config ARCH_ENABLE_HUGEPAGE_MIGRATION
+	boolean
+
 config PHYS_ADDR_T_64BIT
 	def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
 
@@ -430,16 +436,6 @@ choice
 	  benefit.
 endchoice
 
-config CROSS_MEMORY_ATTACH
-	bool "Cross Memory Support"
-	depends on MMU
-	default y
-	help
-	  Enabling this option adds the system calls process_vm_readv and
-	  process_vm_writev which allow a process with the correct privileges
-	  to directly read from or write to to another process's address space.
-	  See the man page for more details.
-
 #
 # UP and nommu archs use km based percpu allocator
 #
@@ -555,7 +551,7 @@ config MEM_SOFT_DIRTY
 	  See Documentation/vm/soft-dirty.txt for more details.
 
 config ZSMALLOC
-	bool "Memory allocator for compressed pages"
+	tristate "Memory allocator for compressed pages"
 	depends on MMU
 	default n
 	help
diff --git a/mm/Makefile b/mm/Makefile
index b484452dac57..4064f3ec145e 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -3,7 +3,7 @@
 #
 
 mmu-y			:= nommu.o
-mmu-$(CONFIG_MMU)	:= fremap.o highmem.o madvise.o memory.o mincore.o \
+mmu-$(CONFIG_MMU)	:= fremap.o gup.o highmem.o madvise.o memory.o mincore.o \
 			   mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \
 			   vmalloc.o pagewalk.o pgtable-generic.o
 
@@ -30,7 +30,6 @@ endif
 
 obj-$(CONFIG_HAVE_MEMBLOCK) += memblock.o
 
-obj-$(CONFIG_BOUNCE)	+= bounce.o
 obj-$(CONFIG_SWAP)	+= page_io.o swap_state.o swapfile.o
 obj-$(CONFIG_FRONTSWAP)	+= frontswap.o
 obj-$(CONFIG_ZSWAP)	+= zswap.o
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 09d9591b7708..1706cbbdf5f0 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -557,7 +557,7 @@ void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
 	bit = sync ? BDI_sync_congested : BDI_async_congested;
 	if (test_and_clear_bit(bit, &bdi->state))
 		atomic_dec(&nr_bdi_congested[sync]);
-	smp_mb__after_clear_bit();
+	smp_mb__after_atomic();
 	if (waitqueue_active(wqh))
 		wake_up(wqh);
 }
diff --git a/mm/bounce.c b/mm/bounce.c
deleted file mode 100644
index 523918b8c6dc..000000000000
--- a/mm/bounce.c
+++ /dev/null
@@ -1,287 +0,0 @@
-/* bounce buffer handling for block devices
- *
- * - Split from highmem.c
- */
-
-#include <linux/mm.h>
-#include <linux/export.h>
-#include <linux/swap.h>
-#include <linux/gfp.h>
-#include <linux/bio.h>
-#include <linux/pagemap.h>
-#include <linux/mempool.h>
-#include <linux/blkdev.h>
-#include <linux/init.h>
-#include <linux/hash.h>
-#include <linux/highmem.h>
-#include <linux/bootmem.h>
-#include <asm/tlbflush.h>
-
-#include <trace/events/block.h>
-
-#define POOL_SIZE	64
-#define ISA_POOL_SIZE	16
-
-static mempool_t *page_pool, *isa_page_pool;
-
-#if defined(CONFIG_HIGHMEM) || defined(CONFIG_NEED_BOUNCE_POOL)
-static __init int init_emergency_pool(void)
-{
-#if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG)
-	if (max_pfn <= max_low_pfn)
-		return 0;
-#endif
-
-	page_pool = mempool_create_page_pool(POOL_SIZE, 0);
-	BUG_ON(!page_pool);
-	printk("bounce pool size: %d pages\n", POOL_SIZE);
-
-	return 0;
-}
-
-__initcall(init_emergency_pool);
-#endif
-
-#ifdef CONFIG_HIGHMEM
-/*
- * highmem version, map in to vec
- */
-static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
-{
-	unsigned long flags;
-	unsigned char *vto;
-
-	local_irq_save(flags);
-	vto = kmap_atomic(to->bv_page);
-	memcpy(vto + to->bv_offset, vfrom, to->bv_len);
-	kunmap_atomic(vto);
-	local_irq_restore(flags);
-}
-
-#else /* CONFIG_HIGHMEM */
-
-#define bounce_copy_vec(to, vfrom)	\
-	memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
-
-#endif /* CONFIG_HIGHMEM */
-
-/*
- * allocate pages in the DMA region for the ISA pool
- */
-static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data)
-{
-	return mempool_alloc_pages(gfp_mask | GFP_DMA, data);
-}
-
-/*
- * gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
- * as the max address, so check if the pool has already been created.
- */
-int init_emergency_isa_pool(void)
-{
-	if (isa_page_pool)
-		return 0;
-
-	isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
-				       mempool_free_pages, (void *) 0);
-	BUG_ON(!isa_page_pool);
-
-	printk("isa bounce pool size: %d pages\n", ISA_POOL_SIZE);
-	return 0;
-}
-
-/*
- * Simple bounce buffer support for highmem pages. Depending on the
- * queue gfp mask set, *to may or may not be a highmem page. kmap it
- * always, it will do the Right Thing
- */
-static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
-{
-	unsigned char *vfrom;
-	struct bio_vec tovec, *fromvec = from->bi_io_vec;
-	struct bvec_iter iter;
-
-	bio_for_each_segment(tovec, to, iter) {
-		if (tovec.bv_page != fromvec->bv_page) {
-			/*
-			 * fromvec->bv_offset and fromvec->bv_len might have
-			 * been modified by the block layer, so use the original
-			 * copy, bounce_copy_vec already uses tovec->bv_len
-			 */
-			vfrom = page_address(fromvec->bv_page) +
-				tovec.bv_offset;
-
-			bounce_copy_vec(&tovec, vfrom);
-			flush_dcache_page(tovec.bv_page);
-		}
-
-		fromvec++;
-	}
-}
-
-static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
-{
-	struct bio *bio_orig = bio->bi_private;
-	struct bio_vec *bvec, *org_vec;
-	int i;
-
-	if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
-		set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);
-
-	/*
-	 * free up bounce indirect pages used
-	 */
-	bio_for_each_segment_all(bvec, bio, i) {
-		org_vec = bio_orig->bi_io_vec + i;
-		if (bvec->bv_page == org_vec->bv_page)
-			continue;
-
-		dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
-		mempool_free(bvec->bv_page, pool);
-	}
-
-	bio_endio(bio_orig, err);
-	bio_put(bio);
-}
-
-static void bounce_end_io_write(struct bio *bio, int err)
-{
-	bounce_end_io(bio, page_pool, err);
-}
-
-static void bounce_end_io_write_isa(struct bio *bio, int err)
-{
-
-	bounce_end_io(bio, isa_page_pool, err);
-}
-
-static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err)
-{
-	struct bio *bio_orig = bio->bi_private;
-
-	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
-		copy_to_high_bio_irq(bio_orig, bio);
-
-	bounce_end_io(bio, pool, err);
-}
-
-static void bounce_end_io_read(struct bio *bio, int err)
-{
-	__bounce_end_io_read(bio, page_pool, err);
-}
-
-static void bounce_end_io_read_isa(struct bio *bio, int err)
-{
-	__bounce_end_io_read(bio, isa_page_pool, err);
-}
-
-#ifdef CONFIG_NEED_BOUNCE_POOL
-static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
-{
-	if (bio_data_dir(bio) != WRITE)
-		return 0;
-
-	if (!bdi_cap_stable_pages_required(&q->backing_dev_info))
-		return 0;
-
-	return test_bit(BIO_SNAP_STABLE, &bio->bi_flags);
-}
-#else
-static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
-{
-	return 0;
-}
-#endif /* CONFIG_NEED_BOUNCE_POOL */
-
-static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
-			       mempool_t *pool, int force)
-{
-	struct bio *bio;
-	int rw = bio_data_dir(*bio_orig);
-	struct bio_vec *to, from;
-	struct bvec_iter iter;
-	unsigned i;
-
-	if (force)
-		goto bounce;
-	bio_for_each_segment(from, *bio_orig, iter)
-		if (page_to_pfn(from.bv_page) > queue_bounce_pfn(q))
-			goto bounce;
-
-	return;
-bounce:
-	bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);
-
-	bio_for_each_segment_all(to, bio, i) {
-		struct page *page = to->bv_page;
-
-		if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force)
-			continue;
-
-		inc_zone_page_state(to->bv_page, NR_BOUNCE);
-		to->bv_page = mempool_alloc(pool, q->bounce_gfp);
-
-		if (rw == WRITE) {
-			char *vto, *vfrom;
-
-			flush_dcache_page(page);
-
-			vto = page_address(to->bv_page) + to->bv_offset;
-			vfrom = kmap_atomic(page) + to->bv_offset;
-			memcpy(vto, vfrom, to->bv_len);
-			kunmap_atomic(vfrom);
-		}
-	}
-
-	trace_block_bio_bounce(q, *bio_orig);
-
-	bio->bi_flags |= (1 << BIO_BOUNCED);
-
-	if (pool == page_pool) {
-		bio->bi_end_io = bounce_end_io_write;
-		if (rw == READ)
-			bio->bi_end_io = bounce_end_io_read;
-	} else {
-		bio->bi_end_io = bounce_end_io_write_isa;
-		if (rw == READ)
-			bio->bi_end_io = bounce_end_io_read_isa;
-	}
-
-	bio->bi_private = *bio_orig;
-	*bio_orig = bio;
-}
-
-void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
-{
-	int must_bounce;
-	mempool_t *pool;
-
-	/*
-	 * Data-less bio, nothing to bounce
-	 */
-	if (!bio_has_data(*bio_orig))
-		return;
-
-	must_bounce = must_snapshot_stable_pages(q, *bio_orig);
-
-	/*
-	 * for non-isa bounce case, just check if the bounce pfn is equal
-	 * to or bigger than the highest pfn in the system -- in that case,
-	 * don't waste time iterating over bio segments
-	 */
-	if (!(q->bounce_gfp & GFP_DMA)) {
-		if (queue_bounce_pfn(q) >= blk_max_pfn && !must_bounce)
-			return;
-		pool = page_pool;
-	} else {
-		BUG_ON(!isa_page_pool);
-		pool = isa_page_pool;
-	}
-
-	/*
-	 * slow path
-	 */
-	__blk_queue_bounce(q, bio_orig, pool, must_bounce);
-}
-
-EXPORT_SYMBOL(blk_queue_bounce);
diff --git a/mm/compaction.c b/mm/compaction.c
index 627dc2e4320f..21bf292b642a 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -89,7 +89,8 @@ static void __reset_isolation_suitable(struct zone *zone)
 	unsigned long end_pfn = zone_end_pfn(zone);
 	unsigned long pfn;
 
-	zone->compact_cached_migrate_pfn = start_pfn;
+	zone->compact_cached_migrate_pfn[0] = start_pfn;
+	zone->compact_cached_migrate_pfn[1] = start_pfn;
 	zone->compact_cached_free_pfn = end_pfn;
 	zone->compact_blockskip_flush = false;
 
@@ -131,9 +132,10 @@ void reset_isolation_suitable(pg_data_t *pgdat)
  */
 static void update_pageblock_skip(struct compact_control *cc,
 			struct page *page, unsigned long nr_isolated,
-			bool migrate_scanner)
+			bool set_unsuitable, bool migrate_scanner)
 {
 	struct zone *zone = cc->zone;
+	unsigned long pfn;
 
 	if (cc->ignore_skip_hint)
 		return;
@@ -141,20 +143,32 @@ static void update_pageblock_skip(struct compact_control *cc,
 	if (!page)
 		return;
 
-	if (!nr_isolated) {
-		unsigned long pfn = page_to_pfn(page);
+	if (nr_isolated)
+		return;
+
+	/*
+	 * Only skip pageblocks when all forms of compaction will be known to
+	 * fail in the near future.
+	 */
+	if (set_unsuitable)
 		set_pageblock_skip(page);
 
-		/* Update where compaction should restart */
-		if (migrate_scanner) {
-			if (!cc->finished_update_migrate &&
-			    pfn > zone->compact_cached_migrate_pfn)
-				zone->compact_cached_migrate_pfn = pfn;
-		} else {
-			if (!cc->finished_update_free &&
-			    pfn < zone->compact_cached_free_pfn)
-				zone->compact_cached_free_pfn = pfn;
-		}
+	pfn = page_to_pfn(page);
+
+	/* Update where async and sync compaction should restart */
+	if (migrate_scanner) {
+		if (cc->finished_update_migrate)
+			return;
+		if (pfn > zone->compact_cached_migrate_pfn[0])
+			zone->compact_cached_migrate_pfn[0] = pfn;
+		if (cc->mode != MIGRATE_ASYNC &&
+		    pfn > zone->compact_cached_migrate_pfn[1])
+			zone->compact_cached_migrate_pfn[1] = pfn;
+	} else {
+		if (cc->finished_update_free)
+			return;
+		if (pfn < zone->compact_cached_free_pfn)
+			zone->compact_cached_free_pfn = pfn;
 	}
 }
 #else
@@ -166,7 +180,7 @@ static inline bool isolation_suitable(struct compact_control *cc,
 
 static void update_pageblock_skip(struct compact_control *cc,
 			struct page *page, unsigned long nr_isolated,
-			bool migrate_scanner)
+			bool set_unsuitable, bool migrate_scanner)
 {
 }
 #endif /* CONFIG_COMPACTION */
@@ -195,7 +209,7 @@ static bool compact_checklock_irqsave(spinlock_t *lock, unsigned long *flags,
 		}
 
 		/* async aborts if taking too long or contended */
-		if (!cc->sync) {
+		if (cc->mode == MIGRATE_ASYNC) {
 			cc->contended = true;
 			return false;
 		}
@@ -208,10 +222,28 @@ static bool compact_checklock_irqsave(spinlock_t *lock, unsigned long *flags,
 	return true;
 }
 
-static inline bool compact_trylock_irqsave(spinlock_t *lock,
-			unsigned long *flags, struct compact_control *cc)
+/*
+ * Aside from avoiding lock contention, compaction also periodically checks
+ * need_resched() and either schedules in sync compaction or aborts async
+ * compaction. This is similar to what compact_checklock_irqsave() does, but
+ * is used where no lock is concerned.
+ *
+ * Returns false when no scheduling was needed, or sync compaction scheduled.
+ * Returns true when async compaction should abort.
+ */
+static inline bool compact_should_abort(struct compact_control *cc)
 {
-	return compact_checklock_irqsave(lock, flags, false, cc);
+	/* async compaction aborts if contended */
+	if (need_resched()) {
+		if (cc->mode == MIGRATE_ASYNC) {
+			cc->contended = true;
+			return true;
+		}
+
+		cond_resched();
+	}
+
+	return false;
 }
 
 /* Returns true if the page is within a block suitable for migration to */
@@ -329,7 +361,8 @@ isolate_fail:
 
 	/* Update the pageblock-skip if the whole pageblock was scanned */
 	if (blockpfn == end_pfn)
-		update_pageblock_skip(cc, valid_page, total_isolated, false);
+		update_pageblock_skip(cc, valid_page, total_isolated, true,
+				      false);
 
 	count_compact_events(COMPACTFREE_SCANNED, nr_scanned);
 	if (total_isolated)
@@ -464,8 +497,9 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 	unsigned long flags;
 	bool locked = false;
 	struct page *page = NULL, *valid_page = NULL;
-	bool skipped_async_unsuitable = false;
-	const isolate_mode_t mode = (!cc->sync ? ISOLATE_ASYNC_MIGRATE : 0) |
+	bool set_unsuitable = true;
+	const isolate_mode_t mode = (cc->mode == MIGRATE_ASYNC ?
+					ISOLATE_ASYNC_MIGRATE : 0) |
 				    (unevictable ? ISOLATE_UNEVICTABLE : 0);
 
 	/*
@@ -475,7 +509,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 	 */
 	while (unlikely(too_many_isolated(zone))) {
 		/* async migration should just abort */
-		if (!cc->sync)
+		if (cc->mode == MIGRATE_ASYNC)
 			return 0;
 
 		congestion_wait(BLK_RW_ASYNC, HZ/10);
@@ -484,8 +518,10 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 			return 0;
 	}
 
+	if (compact_should_abort(cc))
+		return 0;
+
 	/* Time to isolate some pages for migration */
-	cond_resched();
 	for (; low_pfn < end_pfn; low_pfn++) {
 		/* give a chance to irqs before checking need_resched() */
 		if (locked && !(low_pfn % SWAP_CLUSTER_MAX)) {
@@ -540,9 +576,9 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 			 * the minimum amount of work satisfies the allocation
 			 */
 			mt = get_pageblock_migratetype(page);
-			if (!cc->sync && !migrate_async_suitable(mt)) {
-				cc->finished_update_migrate = true;
-				skipped_async_unsuitable = true;
+			if (cc->mode == MIGRATE_ASYNC &&
+			    !migrate_async_suitable(mt)) {
+				set_unsuitable = false;
 				goto next_pageblock;
 			}
 		}
@@ -646,11 +682,10 @@ next_pageblock:
 	/*
 	 * Update the pageblock-skip information and cached scanner pfn,
 	 * if the whole pageblock was scanned without isolating any page.
-	 * This is not done when pageblock was skipped due to being unsuitable
-	 * for async compaction, so that eventual sync compaction can try.
 	 */
-	if (low_pfn == end_pfn && !skipped_async_unsuitable)
-		update_pageblock_skip(cc, valid_page, nr_isolated, true);
+	if (low_pfn == end_pfn)
+		update_pageblock_skip(cc, valid_page, nr_isolated,
+				      set_unsuitable, true);
 
 	trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
 
@@ -671,7 +706,9 @@ static void isolate_freepages(struct zone *zone,
 				struct compact_control *cc)
 {
 	struct page *page;
-	unsigned long high_pfn, low_pfn, pfn, z_end_pfn;
+	unsigned long block_start_pfn;	/* start of current pageblock */
+	unsigned long block_end_pfn;	/* end of current pageblock */
+	unsigned long low_pfn;	     /* lowest pfn scanner is able to scan */
 	int nr_freepages = cc->nr_freepages;
 	struct list_head *freelist = &cc->freepages;
 
@@ -679,41 +716,38 @@ static void isolate_freepages(struct zone *zone,
 	 * Initialise the free scanner. The starting point is where we last
 	 * successfully isolated from, zone-cached value, or the end of the
 	 * zone when isolating for the first time. We need this aligned to
-	 * the pageblock boundary, because we do pfn -= pageblock_nr_pages
-	 * in the for loop.
+	 * the pageblock boundary, because we do
+	 * block_start_pfn -= pageblock_nr_pages in the for loop.
+	 * For ending point, take care when isolating in last pageblock of a
+	 * a zone which ends in the middle of a pageblock.
 	 * The low boundary is the end of the pageblock the migration scanner
 	 * is using.
 	 */
-	pfn = cc->free_pfn & ~(pageblock_nr_pages-1);
+	block_start_pfn = cc->free_pfn & ~(pageblock_nr_pages-1);
+	block_end_pfn = min(block_start_pfn + pageblock_nr_pages,
+						zone_end_pfn(zone));
 	low_pfn = ALIGN(cc->migrate_pfn + 1, pageblock_nr_pages);
 
 	/*
-	 * Take care that if the migration scanner is at the end of the zone
-	 * that the free scanner does not accidentally move to the next zone
-	 * in the next isolation cycle.
-	 */
-	high_pfn = min(low_pfn, pfn);
-
-	z_end_pfn = zone_end_pfn(zone);
-
-	/*
 	 * Isolate free pages until enough are available to migrate the
 	 * pages on cc->migratepages. We stop searching if the migrate
 	 * and free page scanners meet or enough free pages are isolated.
 	 */
-	for (; pfn >= low_pfn && cc->nr_migratepages > nr_freepages;
-					pfn -= pageblock_nr_pages) {
+	for (; block_start_pfn >= low_pfn && cc->nr_migratepages > nr_freepages;
+				block_end_pfn = block_start_pfn,
+				block_start_pfn -= pageblock_nr_pages) {
 		unsigned long isolated;
-		unsigned long end_pfn;
 
 		/*
 		 * This can iterate a massively long zone without finding any
 		 * suitable migration targets, so periodically check if we need
-		 * to schedule.
+		 * to schedule, or even abort async compaction.
 		 */
-		cond_resched();
+		if (!(block_start_pfn % (SWAP_CLUSTER_MAX * pageblock_nr_pages))
+						&& compact_should_abort(cc))
+			break;
 
-		if (!pfn_valid(pfn))
+		if (!pfn_valid(block_start_pfn))
 			continue;
 
 		/*
@@ -723,7 +757,7 @@ static void isolate_freepages(struct zone *zone,
 		 * i.e. it's possible that all pages within a zones range of
 		 * pages do not belong to a single zone.
 		 */
-		page = pfn_to_page(pfn);
+		page = pfn_to_page(block_start_pfn);
 		if (page_zone(page) != zone)
 			continue;
 
@@ -736,26 +770,26 @@ static void isolate_freepages(struct zone *zone,
 			continue;
 
 		/* Found a block suitable for isolating free pages from */
-		isolated = 0;
+		cc->free_pfn = block_start_pfn;
+		isolated = isolate_freepages_block(cc, block_start_pfn,
+					block_end_pfn, freelist, false);
+		nr_freepages += isolated;
 
 		/*
-		 * Take care when isolating in last pageblock of a zone which
-		 * ends in the middle of a pageblock.
+		 * Set a flag that we successfully isolated in this pageblock.
+		 * In the next loop iteration, zone->compact_cached_free_pfn
+		 * will not be updated and thus it will effectively contain the
+		 * highest pageblock we isolated pages from.
 		 */
-		end_pfn = min(pfn + pageblock_nr_pages, z_end_pfn);
-		isolated = isolate_freepages_block(cc, pfn, end_pfn,
-						   freelist, false);
-		nr_freepages += isolated;
+		if (isolated)
+			cc->finished_update_free = true;
 
 		/*
-		 * Record the highest PFN we isolated pages from. When next
-		 * looking for free pages, the search will restart here as
-		 * page migration may have returned some pages to the allocator
+		 * isolate_freepages_block() might have aborted due to async
+		 * compaction being contended
 		 */
-		if (isolated) {
-			cc->finished_update_free = true;
-			high_pfn = max(high_pfn, pfn);
-		}
+		if (cc->contended)
+			break;
 	}
 
 	/* split_free_page does not map the pages */
@@ -765,10 +799,9 @@ static void isolate_freepages(struct zone *zone,
 	 * If we crossed the migrate scanner, we want to keep it that way
 	 * so that compact_finished() may detect this
 	 */
-	if (pfn < low_pfn)
-		cc->free_pfn = max(pfn, zone->zone_start_pfn);
-	else
-		cc->free_pfn = high_pfn;
+	if (block_start_pfn < low_pfn)
+		cc->free_pfn = cc->migrate_pfn;
+
 	cc->nr_freepages = nr_freepages;
 }
 
@@ -783,9 +816,13 @@ static struct page *compaction_alloc(struct page *migratepage,
 	struct compact_control *cc = (struct compact_control *)data;
 	struct page *freepage;
 
-	/* Isolate free pages if necessary */
+	/*
+	 * Isolate free pages if necessary, and if we are not aborting due to
+	 * contention.
+	 */
 	if (list_empty(&cc->freepages)) {
-		isolate_freepages(cc->zone, cc);
+		if (!cc->contended)
+			isolate_freepages(cc->zone, cc);
 
 		if (list_empty(&cc->freepages))
 			return NULL;
@@ -799,23 +836,16 @@ static struct page *compaction_alloc(struct page *migratepage,
 }
 
 /*
- * We cannot control nr_migratepages and nr_freepages fully when migration is
- * running as migrate_pages() has no knowledge of compact_control. When<