Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:

 - a bit more MM

 - procfs updates

 - dynamic-debug fixes

 - lib/ updates

 - checkpatch

 - epoll

 - nilfs2

 - signals

 - rapidio

 - PID management cleanup and optimization

 - kcov updates

 - sysvipc updates

 - quite a few misc things all over the place

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (94 commits)
  EXPERT Kconfig menu: fix broken EXPERT menu
  include/asm-generic/topology.h: remove unused parent_node() macro
  arch/tile/include/asm/topology.h: remove unused parent_node() macro
  arch/sparc/include/asm/topology_64.h: remove unused parent_node() macro
  arch/sh/include/asm/topology.h: remove unused parent_node() macro
  arch/ia64/include/asm/topology.h: remove unused parent_node() macro
  drivers/pcmcia/sa1111_badge4.c: avoid unused function warning
  mm: add infrastructure for get_user_pages_fast() benchmarking
  sysvipc: make get_maxid O(1) again
  sysvipc: properly name ipc_addid() limit parameter
  sysvipc: duplicate lock comments wrt ipc_addid()
  sysvipc: unteach ids->next_id for !CHECKPOINT_RESTORE
  initramfs: use time64_t timestamps
  drivers/watchdog: make use of devm_register_reboot_notifier()
  kernel/reboot.c: add devm_register_reboot_notifier()
  kcov: update documentation
  Makefile: support flag -fsanitizer-coverage=trace-cmp
  kcov: support comparison operands collection
  kcov: remove pointless current != NULL check
  kernel/panic.c: add TAINT_AUX
  ...

1 files changed, 35 insertions, 13 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 85395dc6eb13..10cd757f1006 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -219,6 +219,24 @@ static void reset_cached_positions(struct zone *zone)
 }
 
 /*
+ * Compound pages of >= pageblock_order should consistenly be skipped until
+ * released. It is always pointless to compact pages of such order (if they are
+ * migratable), and the pageblocks they occupy cannot contain any free pages.
+ */
+static bool pageblock_skip_persistent(struct page *page)
+{
+	if (!PageCompound(page))
+		return false;
+
+	page = compound_head(page);
+
+	if (compound_order(page) >= pageblock_order)
+		return true;
+
+	return false;
+}
+
+/*
  * This function is called to clear all cached information on pageblocks that
  * should be skipped for page isolation when the migrate and free page scanner
  * meet.
@@ -242,6 +260,8 @@ static void __reset_isolation_suitable(struct zone *zone)
 			continue;
 		if (zone != page_zone(page))
 			continue;
+		if (pageblock_skip_persistent(page))
+			continue;
 
 		clear_pageblock_skip(page);
 	}
@@ -275,7 +295,7 @@ static void update_pageblock_skip(struct compact_control *cc,
 	struct zone *zone = cc->zone;
 	unsigned long pfn;
 
-	if (cc->ignore_skip_hint)
+	if (cc->no_set_skip_hint)
 		return;
 
 	if (!page)
@@ -307,7 +327,12 @@ static inline bool isolation_suitable(struct compact_control *cc,
 	return true;
 }
 
-static void update_pageblock_skip(struct compact_control *cc,
+static inline bool pageblock_skip_persistent(struct page *page)
+{
+	return false;
+}
+
+static inline void update_pageblock_skip(struct compact_control *cc,
 			struct page *page, unsigned long nr_isolated,
 			bool migrate_scanner)
 {
@@ -449,13 +474,12 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 		 * and the only danger is skipping too much.
 		 */
 		if (PageCompound(page)) {
-			unsigned int comp_order = compound_order(page);
+			const unsigned int order = compound_order(page);
 
-			if (likely(comp_order < MAX_ORDER)) {
-				blockpfn += (1UL << comp_order) - 1;
-				cursor += (1UL << comp_order) - 1;
+			if (likely(order < MAX_ORDER)) {
+				blockpfn += (1UL << order) - 1;
+				cursor += (1UL << order) - 1;
 			}
-
 			goto isolate_fail;
 		}
 
@@ -772,11 +796,10 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 		 * danger is skipping too much.
 		 */
 		if (PageCompound(page)) {
-			unsigned int comp_order = compound_order(page);
-
-			if (likely(comp_order < MAX_ORDER))
-				low_pfn += (1UL << comp_order) - 1;
+			const unsigned int order = compound_order(page);
 
+			if (likely(order < MAX_ORDER))
+				low_pfn += (1UL << order) - 1;
 			goto isolate_fail;
 		}
 
@@ -1928,9 +1951,8 @@ static void kcompactd_do_work(pg_data_t *pgdat)
 		.total_free_scanned = 0,
 		.classzone_idx = pgdat->kcompactd_classzone_idx,
 		.mode = MIGRATE_SYNC_LIGHT,
-		.ignore_skip_hint = true,
+		.ignore_skip_hint = false,
 		.gfp_mask = GFP_KERNEL,
-
 	};
 	trace_mm_compaction_kcompactd_wake(pgdat->node_id, cc.order,
 							cc.classzone_idx);