Merge commit 'v3.6-rc1' into linux-next

* commit 'v3.6-rc1': (9532 commits)
  Linux 3.6-rc1
  mm: remove node_start_pfn checking in new WARN_ON for now
  ARM: mmp: add missing irqs.h
  arm: mvebu: fix typo in .dtsi comment for Armada XP SoCs
  ARM: PRIMA2: delete redundant codes to restore LATCHED when timer resumes
  libceph: fix crypto key null deref, memory leak
  ceph: simplify+fix atomic_open
  sh: explicitly include sh_dma.h in setup-sh7722.c
  um: Add arch/x86/um to MAINTAINERS
  um: pass siginfo to guest process
  um: fix ubd_file_size for read-only files
  md/dm-raid: DM_RAID should select MD_RAID10
  md/raid1: submit IO from originating thread instead of md thread.
  raid5: raid5d handle stripe in batch way
  raid5: make_request use batch stripe release
  um: pull interrupt_end() into userspace()
  um: split syscall_trace(), pass pt_regs to it
  um: switch UPT_SET_RETURN_VALUE and regs_return_value to pt_regs
  MIPS: Loongson 2: Sort out clock managment.
  locks: remove unused lm_release_private
  ...

1 files changed, 62 insertions, 6 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 7ea259d82a99..e78cb9688421 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -422,6 +422,17 @@ static void isolate_freepages(struct zone *zone,
 					pfn -= pageblock_nr_pages) {
 		unsigned long isolated;
 
+		/*
+		 * Skip ahead if another thread is compacting in the area
+		 * simultaneously. If we wrapped around, we can only skip
+		 * ahead if zone->compact_cached_free_pfn also wrapped to
+		 * above our starting point.
+		 */
+		if (cc->order > 0 && (!cc->wrapped ||
+				      zone->compact_cached_free_pfn >
+				      cc->start_free_pfn))
+			pfn = min(pfn, zone->compact_cached_free_pfn);
+
 		if (!pfn_valid(pfn))
 			continue;
 
@@ -461,8 +472,11 @@ static void isolate_freepages(struct zone *zone,
 		 * looking for free pages, the search will restart here as
 		 * page migration may have returned some pages to the allocator
 		 */
-		if (isolated)
+		if (isolated) {
 			high_pfn = max(high_pfn, pfn);
+			if (cc->order > 0)
+				zone->compact_cached_free_pfn = high_pfn;
+		}
 	}
 
 	/* split_free_page does not map the pages */
@@ -556,6 +570,20 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
 	return ISOLATE_SUCCESS;
 }
 
+/*
+ * Returns the start pfn of the last page block in a zone.  This is the starting
+ * point for full compaction of a zone.  Compaction searches for free pages from
+ * the end of each zone, while isolate_freepages_block scans forward inside each
+ * page block.
+ */
+static unsigned long start_free_pfn(struct zone *zone)
+{
+	unsigned long free_pfn;
+	free_pfn = zone->zone_start_pfn + zone->spanned_pages;
+	free_pfn &= ~(pageblock_nr_pages-1);
+	return free_pfn;
+}
+
 static int compact_finished(struct zone *zone,
 			    struct compact_control *cc)
 {
@@ -565,8 +593,26 @@ static int compact_finished(struct zone *zone,
 	if (fatal_signal_pending(current))
 		return COMPACT_PARTIAL;
 
-	/* Compaction run completes if the migrate and free scanner meet */
-	if (cc->free_pfn <= cc->migrate_pfn)
+	/*
+	 * A full (order == -1) compaction run starts at the beginning and
+	 * end of a zone; it completes when the migrate and free scanner meet.
+	 * A partial (order > 0) compaction can start with the free scanner
+	 * at a random point in the zone, and may have to restart.
+	 */
+	if (cc->free_pfn <= cc->migrate_pfn) {
+		if (cc->order > 0 && !cc->wrapped) {
+			/* We started partway through; restart at the end. */
+			unsigned long free_pfn = start_free_pfn(zone);
+			zone->compact_cached_free_pfn = free_pfn;
+			cc->free_pfn = free_pfn;
+			cc->wrapped = 1;
+			return COMPACT_CONTINUE;
+		}
+		return COMPACT_COMPLETE;
+	}
+
+	/* We wrapped around and ended up where we started. */
+	if (cc->wrapped && cc->free_pfn <= cc->start_free_pfn)
 		return COMPACT_COMPLETE;
 
 	/*
@@ -664,8 +710,15 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 
 	/* Setup to move all movable pages to the end of the zone */
 	cc->migrate_pfn = zone->zone_start_pfn;
-	cc->free_pfn = cc->migrate_pfn + zone->spanned_pages;
-	cc->free_pfn &= ~(pageblock_nr_pages-1);
+
+	if (cc->order > 0) {
+		/* Incremental compaction. Start where the last one stopped. */
+		cc->free_pfn = zone->compact_cached_free_pfn;
+		cc->start_free_pfn = cc->free_pfn;
+	} else {
+		/* Order == -1 starts at the end of the zone. */
+		cc->free_pfn = start_free_pfn(zone);
+	}
 
 	migrate_prep_local();
 
@@ -701,8 +754,11 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 		if (err) {
 			putback_lru_pages(&cc->migratepages);
 			cc->nr_migratepages = 0;
+			if (err == -ENOMEM) {
+				ret = COMPACT_PARTIAL;
+				goto out;
+			}
 		}
-
 	}
 
 out: