3 files changed, 191 insertions, 173 deletions

diff --git a/mm/Makefile b/mm/Makefile
index 50ec00ef2a0e..8aada89efbbb 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -13,7 +13,7 @@ obj-y			:= filemap.o mempool.o oom_kill.o fadvise.o \
                            readahead.o swap.o truncate.o vmscan.o shmem.o \
                            prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
                            page_isolation.o mm_init.o mmu_context.o percpu.o \
-                           $(mmu-y)
+                           compaction.o $(mmu-y)
 obj-y += init-mm.o
 
 ifdef CONFIG_NO_BOOTMEM
@@ -32,7 +32,6 @@ obj-$(CONFIG_NUMA) 	+= mempolicy.o
 obj-$(CONFIG_SPARSEMEM) += sparse.o
 obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o
 obj-$(CONFIG_SLOB) += slob.o
-obj-$(CONFIG_COMPACTION) += compaction.o
 obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o
 obj-$(CONFIG_KSM) += ksm.o
 obj-$(CONFIG_PAGE_POISONING) += debug-pagealloc.o
diff --git a/mm/compaction.c b/mm/compaction.c
index 06b198fa9abe..7a92e418a187 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -16,30 +16,11 @@
 #include <linux/sysfs.h>
 #include "internal.h"
 
+#if defined CONFIG_COMPACTION || defined CONFIG_CMA
+
 #define CREATE_TRACE_POINTS
 #include <trace/events/compaction.h>
 
-/*
- * compact_control is used to track pages being migrated and the free pages
- * they are being migrated to during memory compaction. The free_pfn starts
- * at the end of a zone and migrate_pfn begins at the start. Movable pages
- * are moved to the end of a zone during a compaction run and the run
- * completes when free_pfn <= migrate_pfn
- */
-struct compact_control {
-        struct list_head freepages;     /* List of free pages to migrate to */
-        struct list_head migratepages;  /* List of pages being migrated */
-        unsigned long nr_freepages;     /* Number of isolated free pages */
-        unsigned long nr_migratepages;  /* Number of pages to migrate */
-        unsigned long free_pfn;         /* isolate_freepages search base */
-        unsigned long migrate_pfn;      /* isolate_migratepages search base */
-        bool sync;                      /* Synchronous migration */
-
-        int order;                      /* order a direct compactor needs */
-        int migratetype;                /* MOVABLE, RECLAIMABLE etc */
-        struct zone *zone;
-};
-
 static unsigned long release_freepages(struct list_head *freelist)
 {
         struct page *page, *next;
@@ -54,6 +35,16 @@ static unsigned long release_freepages(struct list_head *freelist)
         return count;
 }
 
+static void map_pages(struct list_head *list)
+{
+        struct page *page;
+
+        list_for_each_entry(page, list, lru) {
+                arch_alloc_page(page, 0);
+                kernel_map_pages(page, 1, 1);
+        }
+}
+
 /*
  * Isolate free pages onto a private freelist. Caller must hold zone->lock.
  * If @strict is true, will abort returning 0 on any invalid PFNs or non-free
@@ -122,7 +113,7 @@ static unsigned long isolate_freepages_block(unsigned long blockpfn,
  * (which may be greater then end_pfn if end fell in a middle of
  * a free page).
  */
-static unsigned long
+unsigned long
 isolate_freepages_range(unsigned long start_pfn, unsigned long end_pfn)
 {
         unsigned long isolated, pfn, block_end_pfn, flags;
@@ -176,127 +167,6 @@ isolate_freepages_range(unsigned long start_pfn, unsigned long end_pfn)
         return pfn;
 }
 
-/* Returns true if the page is within a block suitable for migration to */
-static bool suitable_migration_target(struct page *page)
-{
-
-        int migratetype = get_pageblock_migratetype(page);
-
-        /* Don't interfere with memory hot-remove or the min_free_kbytes blocks */
-        if (migratetype == MIGRATE_ISOLATE || migratetype == MIGRATE_RESERVE)
-                return false;
-
-        /* If the page is a large free page, then allow migration */
-        if (PageBuddy(page) && page_order(page) >= pageblock_order)
-                return true;
-
-        /* If the block is MIGRATE_MOVABLE, allow migration */
-        if (migratetype == MIGRATE_MOVABLE)
-                return true;
-
-        /* Otherwise skip the block */
-        return false;
-}
-
-static void map_pages(struct list_head *list)
-{
-        struct page *page;
-
-        list_for_each_entry(page, list, lru) {
-                arch_alloc_page(page, 0);
-                kernel_map_pages(page, 1, 1);
-        }
-}
-
-/*
- * Based on information in the current compact_control, find blocks
- * suitable for isolating free pages from and then isolate them.
- */
-static void isolate_freepages(struct zone *zone,
-                                struct compact_control *cc)
-{
-        struct page *page;
-        unsigned long high_pfn, low_pfn, pfn, zone_end_pfn, end_pfn;
-        unsigned long flags;
-        int nr_freepages = cc->nr_freepages;
-        struct list_head *freelist = &cc->freepages;
-
-        /*
-         * Initialise the free scanner. The starting point is where we last
-         * scanned from (or the end of the zone if starting). The low point
-         * is the end of the pageblock the migration scanner is using.
-         */
-        pfn = cc->free_pfn;
-        low_pfn = cc->migrate_pfn + 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);
-
-        zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
-
-        /*
-         * 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) {
-                unsigned long isolated;
-
-                if (!pfn_valid(pfn))
-                        continue;
-
-                /*
-                 * Check for overlapping nodes/zones. It's possible on some
-                 * configurations to have a setup like
-                 * node0 node1 node0
-                 * 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);
-                if (page_zone(page) != zone)
-                        continue;
-
-                /* Check the block is suitable for migration */
-                if (!suitable_migration_target(page))
-                        continue;
-
-                /*
-                 * Found a block suitable for isolating free pages from. Now
-                 * we disabled interrupts, double check things are ok and
-                 * isolate the pages. This is to minimise the time IRQs
-                 * are disabled
-                 */
-                isolated = 0;
-                spin_lock_irqsave(&zone->lock, flags);
-                if (suitable_migration_target(page)) {
-                        end_pfn = min(pfn + pageblock_nr_pages, zone_end_pfn);
-                        isolated = isolate_freepages_block(pfn, end_pfn,
-                                                           freelist, false);
-                        nr_freepages += isolated;
-                }
-                spin_unlock_irqrestore(&zone->lock, flags);
-
-                /*
-                 * 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
-                 */
-                if (isolated)
-                        high_pfn = max(high_pfn, pfn);
-        }
-
-        /* split_free_page does not map the pages */
-        map_pages(freelist);
-
-        cc->free_pfn = high_pfn;
-        cc->nr_freepages = nr_freepages;
-}
-
 /* Update the number of anon and file isolated pages in the zone */
 static void acct_isolated(struct zone *zone, struct compact_control *cc)
 {
@@ -325,13 +195,6 @@ static bool too_many_isolated(struct zone *zone)
         return isolated > (inactive + active) / 2;
 }
 
-/* possible outcome of isolate_migratepages */
-typedef enum {
-        ISOLATE_ABORT,          /* Abort compaction now */
-        ISOLATE_NONE,           /* No pages isolated, continue scanning */
-        ISOLATE_SUCCESS,        /* Pages isolated, migrate */
-} isolate_migrate_t;
-
 /**
  * isolate_migratepages_range() - isolate all migrate-able pages in range.
  * @zone:       Zone pages are in.
@@ -351,7 +214,7 @@ typedef enum {
  * does not modify any cc's fields, in particular it does not modify
  * (or read for that matter) cc->migrate_pfn.
  */
-static unsigned long
+unsigned long
 isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
                            unsigned long low_pfn, unsigned long end_pfn)
 {
@@ -487,35 +350,118 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
         return low_pfn;
 }
 
+#endif /* CONFIG_COMPACTION || CONFIG_CMA */
+#ifdef CONFIG_COMPACTION
+
+/* Returns true if the page is within a block suitable for migration to */
+static bool suitable_migration_target(struct page *page)
+{
+
+        int migratetype = get_pageblock_migratetype(page);
+
+        /* Don't interfere with memory hot-remove or the min_free_kbytes blocks */
+        if (migratetype == MIGRATE_ISOLATE || migratetype == MIGRATE_RESERVE)
+                return false;
+
+        /* If the page is a large free page, then allow migration */
+        if (PageBuddy(page) && page_order(page) >= pageblock_order)
+                return true;
+
+        /* If the block is MIGRATE_MOVABLE, allow migration */
+        if (migratetype == MIGRATE_MOVABLE)
+                return true;
+
+        /* Otherwise skip the block */
+        return false;
+}
+
 /*
- * Isolate all pages that can be migrated from the block pointed to by
- * the migrate scanner within compact_control.
+ * Based on information in the current compact_control, find blocks
+ * suitable for isolating free pages from and then isolate them.
  */
-static isolate_migrate_t isolate_migratepages(struct zone *zone,
-                                        struct compact_control *cc)
+static void isolate_freepages(struct zone *zone,
+                                struct compact_control *cc)
 {
-        unsigned long low_pfn, end_pfn;
+        struct page *page;
+        unsigned long high_pfn, low_pfn, pfn, zone_end_pfn, end_pfn;
+        unsigned long flags;
+        int nr_freepages = cc->nr_freepages;
+        struct list_head *freelist = &cc->freepages;
 
-        /* Do not scan outside zone boundaries */
-        low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn);
+        /*
+         * Initialise the free scanner. The starting point is where we last
+         * scanned from (or the end of the zone if starting). The low point
+         * is the end of the pageblock the migration scanner is using.
+         */
+        pfn = cc->free_pfn;
+        low_pfn = cc->migrate_pfn + pageblock_nr_pages;
 
-        /* Only scan within a pageblock boundary */
-        end_pfn = ALIGN(low_pfn + pageblock_nr_pages, 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);
 
-        /* Do not cross the free scanner or scan within a memory hole */
-        if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) {
-                cc->migrate_pfn = end_pfn;
-                return ISOLATE_NONE;
-        }
+        zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
 
-        /* Perform the isolation */
-        low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn);
-        if (!low_pfn)
-                return ISOLATE_ABORT;
+        /*
+         * 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) {
+                unsigned long isolated;
 
-        cc->migrate_pfn = low_pfn;
+                if (!pfn_valid(pfn))
+                        continue;
 
-        return ISOLATE_SUCCESS;
+                /*
+                 * Check for overlapping nodes/zones. It's possible on some
+                 * configurations to have a setup like
+                 * node0 node1 node0
+                 * 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);
+                if (page_zone(page) != zone)
+                        continue;
+
+                /* Check the block is suitable for migration */
+                if (!suitable_migration_target(page))
+                        continue;
+
+                /*
+                 * Found a block suitable for isolating free pages from. Now
+                 * we disabled interrupts, double check things are ok and
+                 * isolate the pages. This is to minimise the time IRQs
+                 * are disabled
+                 */
+                isolated = 0;
+                spin_lock_irqsave(&zone->lock, flags);
+                if (suitable_migration_target(page)) {
+                        end_pfn = min(pfn + pageblock_nr_pages, zone_end_pfn);
+                        isolated = isolate_freepages_block(pfn, end_pfn,
+                                                           freelist, false);
+                        nr_freepages += isolated;
+                }
+                spin_unlock_irqrestore(&zone->lock, flags);
+
+                /*
+                 * 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
+                 */
+                if (isolated)
+                        high_pfn = max(high_pfn, pfn);
+        }
+
+        /* split_free_page does not map the pages */
+        map_pages(freelist);
+
+        cc->free_pfn = high_pfn;
+        cc->nr_freepages = nr_freepages;
 }
 
 /*
@@ -564,6 +510,44 @@ static void update_nr_listpages(struct compact_control *cc)
         cc->nr_freepages = nr_freepages;
 }
 
+/* possible outcome of isolate_migratepages */
+typedef enum {
+        ISOLATE_ABORT,          /* Abort compaction now */
+        ISOLATE_NONE,           /* No pages isolated, continue scanning */
+        ISOLATE_SUCCESS,        /* Pages isolated, migrate */
+} isolate_migrate_t;
+
+/*
+ * Isolate all pages that can be migrated from the block pointed to by
+ * the migrate scanner within compact_control.
+ */
+static isolate_migrate_t isolate_migratepages(struct zone *zone,
+                                        struct compact_control *cc)
+{
+        unsigned long low_pfn, end_pfn;
+
+        /* Do not scan outside zone boundaries */
+        low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn);
+
+        /* Only scan within a pageblock boundary */
+        end_pfn = ALIGN(low_pfn + pageblock_nr_pages, pageblock_nr_pages);
+
+        /* Do not cross the free scanner or scan within a memory hole */
+        if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) {
+                cc->migrate_pfn = end_pfn;
+                return ISOLATE_NONE;
+        }
+
+        /* Perform the isolation */
+        low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn);
+        if (!low_pfn)
+                return ISOLATE_ABORT;
+
+        cc->migrate_pfn = low_pfn;
+
+        return ISOLATE_SUCCESS;
+}
+
 static int compact_finished(struct zone *zone,
                             struct compact_control *cc)
 {
@@ -910,3 +894,5 @@ void compaction_unregister_node(struct node *node)
         return device_remove_file(&node->dev, &dev_attr_compact);
 }
 #endif /* CONFIG_SYSFS && CONFIG_NUMA */
+
+#endif /* CONFIG_COMPACTION */
diff --git a/mm/internal.h b/mm/internal.h
index 2189af491783..aee4761cf9a9 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -100,6 +100,39 @@ extern void prep_compound_page(struct page *page, unsigned long order);
 extern bool is_free_buddy_page(struct page *page);
 #endif
 
+#if defined CONFIG_COMPACTION || defined CONFIG_CMA
+
+/*
+ * in mm/compaction.c
+ */
+/*
+ * compact_control is used to track pages being migrated and the free pages
+ * they are being migrated to during memory compaction. The free_pfn starts
+ * at the end of a zone and migrate_pfn begins at the start. Movable pages
+ * are moved to the end of a zone during a compaction run and the run
+ * completes when free_pfn <= migrate_pfn
+ */
+struct compact_control {
+        struct list_head freepages;     /* List of free pages to migrate to */
+        struct list_head migratepages;  /* List of pages being migrated */
+        unsigned long nr_freepages;     /* Number of isolated free pages */
+        unsigned long nr_migratepages;  /* Number of pages to migrate */
+        unsigned long free_pfn;         /* isolate_freepages search base */
+        unsigned long migrate_pfn;      /* isolate_migratepages search base */
+        bool sync;                      /* Synchronous migration */
+
+        int order;                      /* order a direct compactor needs */
+        int migratetype;                /* MOVABLE, RECLAIMABLE etc */
+        struct zone *zone;
+};
+
+unsigned long
+isolate_freepages_range(unsigned long start_pfn, unsigned long end_pfn);
+unsigned long
+isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
+                           unsigned long low_pfn, unsigned long end_pfn);
+
+#endif
 
 /*
  * function for dealing with page's order in buddy system.