mm: factor out memory isolate functions

mm/page_alloc.c has some memory isolation functions but they are used only
when we enable CONFIG_{CMA|MEMORY_HOTPLUG|MEMORY_FAILURE}.  So let's make
it configurable by new CONFIG_MEMORY_ISOLATION so that it can reduce
binary size and we can check it simple by CONFIG_MEMORY_ISOLATION, not if
defined CONFIG_{CMA|MEMORY_HOTPLUG|MEMORY_FAILURE}.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 83 insertions, 78 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index 82fed4eb2b6f..d5c8019c6627 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -140,9 +140,13 @@ config ARCH_DISCARD_MEMBLOCK
 config NO_BOOTMEM
         boolean
 
+config MEMORY_ISOLATION
+        boolean
+
 # eventually, we can have this option just 'select SPARSEMEM'
 config MEMORY_HOTPLUG
         bool "Allow for memory hot-add"
+        select MEMORY_ISOLATION
         depends on SPARSEMEM || X86_64_ACPI_NUMA
         depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG
         depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390)
@@ -272,6 +276,7 @@ config MEMORY_FAILURE
         depends on MMU
         depends on ARCH_SUPPORTS_MEMORY_FAILURE
         bool "Enable recovery from hardware memory errors"
+        select MEMORY_ISOLATION
         help
           Enables code to recover from some memory failures on systems
           with MCA recovery. This allows a system to continue running
diff --git a/mm/Makefile b/mm/Makefile
index 290bbfe33698..92753e2d82da 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -15,8 +15,8 @@ obj-y			:= filemap.o mempool.o oom_kill.o fadvise.o \
                            maccess.o page_alloc.o page-writeback.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 \
-                           compaction.o slab_common.o $(mmu-y)
+                           mm_init.o mmu_context.o percpu.o slab_common.o \
+                           compaction.o $(mmu-y)
 
 obj-y += init-mm.o
 
@@ -56,3 +56,4 @@ obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o
 obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o
 obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o
 obj-$(CONFIG_CLEANCACHE) += cleancache.o
+obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 667338e80e94..228194728ccd 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -51,7 +51,6 @@
 #include <linux/page_cgroup.h>
 #include <linux/debugobjects.h>
 #include <linux/kmemleak.h>
-#include <linux/memory.h>
 #include <linux/compaction.h>
 #include <trace/events/kmem.h>
 #include <linux/ftrace_event.h>
@@ -219,7 +218,7 @@ EXPORT_SYMBOL(nr_online_nodes);
 
 int page_group_by_mobility_disabled __read_mostly;
 
-static void set_pageblock_migratetype(struct page *page, int migratetype)
+void set_pageblock_migratetype(struct page *page, int migratetype)
 {
 
         if (unlikely(page_group_by_mobility_disabled))
@@ -954,7 +953,7 @@ static int move_freepages(struct zone *zone,
         return pages_moved;
 }
 
-static int move_freepages_block(struct zone *zone, struct page *page,
+int move_freepages_block(struct zone *zone, struct page *page,
                                 int migratetype)
 {
         unsigned long start_pfn, end_pfn;
@@ -5463,8 +5462,7 @@ void set_pageblock_flags_group(struct page *page, unsigned long flags,
  * MIGRATE_MOVABLE block might include unmovable pages. It means you can't
  * expect this function should be exact.
  */
-static bool
-__has_unmovable_pages(struct zone *zone, struct page *page, int count)
+bool has_unmovable_pages(struct zone *zone, struct page *page, int count)
 {
         unsigned long pfn, iter, found;
         int mt;
@@ -5541,77 +5539,7 @@ bool is_pageblock_removable_nolock(struct page *page)
                         zone->zone_start_pfn + zone->spanned_pages <= pfn)
                 return false;
 
-        return !__has_unmovable_pages(zone, page, 0);
-}
-
-int set_migratetype_isolate(struct page *page)
-{
-        struct zone *zone;
-        unsigned long flags, pfn;
-        struct memory_isolate_notify arg;
-        int notifier_ret;
-        int ret = -EBUSY;
-
-        zone = page_zone(page);
-
-        spin_lock_irqsave(&zone->lock, flags);
-
-        pfn = page_to_pfn(page);
-        arg.start_pfn = pfn;
-        arg.nr_pages = pageblock_nr_pages;
-        arg.pages_found = 0;
-
-        /*
-         * It may be possible to isolate a pageblock even if the
-         * migratetype is not MIGRATE_MOVABLE. The memory isolation
-         * notifier chain is used by balloon drivers to return the
-         * number of pages in a range that are held by the balloon
-         * driver to shrink memory. If all the pages are accounted for
-         * by balloons, are free, or on the LRU, isolation can continue.
-         * Later, for example, when memory hotplug notifier runs, these
-         * pages reported as "can be isolated" should be isolated(freed)
-         * by the balloon driver through the memory notifier chain.
-         */
-        notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
-        notifier_ret = notifier_to_errno(notifier_ret);
-        if (notifier_ret)
-                goto out;
-        /*
-         * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
-         * We just check MOVABLE pages.
-         */
-        if (!__has_unmovable_pages(zone, page, arg.pages_found))
-                ret = 0;
-        /*
-         * Unmovable means "not-on-lru" pages. If Unmovable pages are
-         * larger than removable-by-driver pages reported by notifier,
-         * we'll fail.
-         */
-
-out:
-        if (!ret) {
-                set_pageblock_migratetype(page, MIGRATE_ISOLATE);
-                move_freepages_block(zone, page, MIGRATE_ISOLATE);
-        }
-
-        spin_unlock_irqrestore(&zone->lock, flags);
-        if (!ret)
-                drain_all_pages();
-        return ret;
-}
-
-void unset_migratetype_isolate(struct page *page, unsigned migratetype)
-{
-        struct zone *zone;
-        unsigned long flags;
-        zone = page_zone(page);
-        spin_lock_irqsave(&zone->lock, flags);
-        if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
-                goto out;
-        set_pageblock_migratetype(page, migratetype);
-        move_freepages_block(zone, page, migratetype);
-out:
-        spin_unlock_irqrestore(&zone->lock, flags);
+        return !has_unmovable_pages(zone, page, 0);
 }
 
 #ifdef CONFIG_CMA
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index c9f04774f2b8..fb482cf438da 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -5,8 +5,79 @@
 #include <linux/mm.h>
 #include <linux/page-isolation.h>
 #include <linux/pageblock-flags.h>
+#include <linux/memory.h>
 #include "internal.h"
 
+int set_migratetype_isolate(struct page *page)
+{
+        struct zone *zone;
+        unsigned long flags, pfn;
+        struct memory_isolate_notify arg;
+        int notifier_ret;
+        int ret = -EBUSY;
+
+        zone = page_zone(page);
+
+        spin_lock_irqsave(&zone->lock, flags);
+
+        pfn = page_to_pfn(page);
+        arg.start_pfn = pfn;
+        arg.nr_pages = pageblock_nr_pages;
+        arg.pages_found = 0;
+
+        /*
+         * It may be possible to isolate a pageblock even if the
+         * migratetype is not MIGRATE_MOVABLE. The memory isolation
+         * notifier chain is used by balloon drivers to return the
+         * number of pages in a range that are held by the balloon
+         * driver to shrink memory. If all the pages are accounted for
+         * by balloons, are free, or on the LRU, isolation can continue.
+         * Later, for example, when memory hotplug notifier runs, these
+         * pages reported as "can be isolated" should be isolated(freed)
+         * by the balloon driver through the memory notifier chain.
+         */
+        notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
+        notifier_ret = notifier_to_errno(notifier_ret);
+        if (notifier_ret)
+                goto out;
+        /*
+         * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
+         * We just check MOVABLE pages.
+         */
+        if (!has_unmovable_pages(zone, page, arg.pages_found))
+                ret = 0;
+
+        /*
+         * immobile means "not-on-lru" paes. If immobile is larger than
+         * removable-by-driver pages reported by notifier, we'll fail.
+         */
+
+out:
+        if (!ret) {
+                set_pageblock_migratetype(page, MIGRATE_ISOLATE);
+                move_freepages_block(zone, page, MIGRATE_ISOLATE);
+        }
+
+        spin_unlock_irqrestore(&zone->lock, flags);
+        if (!ret)
+                drain_all_pages();
+        return ret;
+}
+
+void unset_migratetype_isolate(struct page *page, unsigned migratetype)
+{
+        struct zone *zone;
+        unsigned long flags;
+        zone = page_zone(page);
+        spin_lock_irqsave(&zone->lock, flags);
+        if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
+                goto out;
+        set_pageblock_migratetype(page, migratetype);
+        move_freepages_block(zone, page, migratetype);
+out:
+        spin_unlock_irqrestore(&zone->lock, flags);
+}
+
 static inline struct page *
 __first_valid_page(unsigned long pfn, unsigned long nr_pages)
 {