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>

1 files changed, 4 insertions, 76 deletions

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