[PATCH 2/5] mm: migrate: Change migrate_mode to support combination migration modes.

[Zi Yan]

From: Zi Yan <zi.yan@xxxxxxxxxxxxxx>

From: Zi Yan <ziy@xxxxxxxxxx>

No functionality is changed.

Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Zi Yan <zi.yan@xxxxxxxxxxxxxx>
---
 include/linux/migrate_mode.h |  6 +++---
 mm/compaction.c              | 20 ++++++++++----------
 mm/migrate.c                 | 14 +++++++-------
 3 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/include/linux/migrate_mode.h b/include/linux/migrate_mode.h
index ebf3d89..0e2deb8 100644
--- a/include/linux/migrate_mode.h
+++ b/include/linux/migrate_mode.h
@@ -8,9 +8,9 @@
  * MIGRATE_SYNC will block when migrating pages
  */
 enum migrate_mode {
-	MIGRATE_ASYNC,
-	MIGRATE_SYNC_LIGHT,
-	MIGRATE_SYNC,
+	MIGRATE_ASYNC		= 1<<0,
+	MIGRATE_SYNC_LIGHT	= 1<<1,
+	MIGRATE_SYNC		= 1<<2,
 };
 
 #endif		/* MIGRATE_MODE_H_INCLUDED */
diff --git a/mm/compaction.c b/mm/compaction.c
index 0409a4a..6606ded 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -296,7 +296,7 @@ static void update_pageblock_skip(struct compact_control *cc,
 	if (migrate_scanner) {
 		if (pfn > zone->compact_cached_migrate_pfn[0])
 			zone->compact_cached_migrate_pfn[0] = pfn;
-		if (cc->mode != MIGRATE_ASYNC &&
+		if (!(cc->mode & MIGRATE_ASYNC) &&
 		    pfn > zone->compact_cached_migrate_pfn[1])
 			zone->compact_cached_migrate_pfn[1] = pfn;
 	} else {
@@ -329,7 +329,7 @@ static void update_pageblock_skip(struct compact_control *cc,
 static bool compact_trylock_irqsave(spinlock_t *lock, unsigned long *flags,
 						struct compact_control *cc)
 {
-	if (cc->mode == MIGRATE_ASYNC) {
+	if (cc->mode & MIGRATE_ASYNC) {
 		if (!spin_trylock_irqsave(lock, *flags)) {
 			cc->contended = true;
 			return false;
@@ -370,7 +370,7 @@ static bool compact_unlock_should_abort(spinlock_t *lock,
 	}
 
 	if (need_resched()) {
-		if (cc->mode == MIGRATE_ASYNC) {
+		if (cc->mode & MIGRATE_ASYNC) {
 			cc->contended = true;
 			return true;
 		}
@@ -393,7 +393,7 @@ static inline bool compact_should_abort(struct compact_control *cc)
 {
 	/* async compaction aborts if contended */
 	if (need_resched()) {
-		if (cc->mode == MIGRATE_ASYNC) {
+		if (cc->mode & MIGRATE_ASYNC) {
 			cc->contended = true;
 			return true;
 		}
@@ -704,7 +704,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 	 */
 	while (unlikely(too_many_isolated(zone))) {
 		/* async migration should just abort */
-		if (cc->mode == MIGRATE_ASYNC)
+		if (cc->mode & MIGRATE_ASYNC)
 			return 0;
 
 		congestion_wait(BLK_RW_ASYNC, HZ/10);
@@ -716,7 +716,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 	if (compact_should_abort(cc))
 		return 0;
 
-	if (cc->direct_compaction && (cc->mode == MIGRATE_ASYNC)) {
+	if (cc->direct_compaction && (cc->mode & MIGRATE_ASYNC)) {
 		skip_on_failure = true;
 		next_skip_pfn = block_end_pfn(low_pfn, cc->order);
 	}
@@ -1204,7 +1204,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
 	struct page *page;
 	const isolate_mode_t isolate_mode =
 		(sysctl_compact_unevictable_allowed ? ISOLATE_UNEVICTABLE : 0) |
-		(cc->mode != MIGRATE_SYNC ? ISOLATE_ASYNC_MIGRATE : 0);
+		(!(cc->mode & MIGRATE_SYNC) ? ISOLATE_ASYNC_MIGRATE : 0);
 
 	/*
 	 * Start at where we last stopped, or beginning of the zone as
@@ -1250,7 +1250,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
 		 * Async compaction is optimistic to see if the minimum amount
 		 * of work satisfies the allocation.
 		 */
-		if (cc->mode == MIGRATE_ASYNC &&
+		if ((cc->mode & MIGRATE_ASYNC) &&
 		    !migrate_async_suitable(get_pageblock_migratetype(page)))
 			continue;
 
@@ -1493,7 +1493,7 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro
 	unsigned long start_pfn = zone->zone_start_pfn;
 	unsigned long end_pfn = zone_end_pfn(zone);
 	const int migratetype = gfpflags_to_migratetype(cc->gfp_mask);
-	const bool sync = cc->mode != MIGRATE_ASYNC;
+	const bool sync = !(cc->mode & MIGRATE_ASYNC);
 
 	ret = compaction_suitable(zone, cc->order, cc->alloc_flags,
 							cc->classzone_idx);
@@ -1589,7 +1589,7 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro
 			 * order-aligned block, so skip the rest of it.
 			 */
 			if (cc->direct_compaction &&
-						(cc->mode == MIGRATE_ASYNC)) {
+						(cc->mode & MIGRATE_ASYNC)) {
 				cc->migrate_pfn = block_end_pfn(
 						cc->migrate_pfn - 1, cc->order);
 				/* Draining pcplists is useless in this case */
diff --git a/mm/migrate.c b/mm/migrate.c
index bc6c1c4..4a4cf48 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -394,7 +394,7 @@ static bool buffer_migrate_lock_buffers(struct buffer_head *head,
 	struct buffer_head *bh = head;
 
 	/* Simple case, sync compaction */
-	if (mode != MIGRATE_ASYNC) {
+	if (!(mode & MIGRATE_ASYNC)) {
 		do {
 			get_bh(bh);
 			lock_buffer(bh);
@@ -495,7 +495,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
 	 * the mapping back due to an elevated page count, we would have to
 	 * block waiting on other references to be dropped.
 	 */
-	if (mode == MIGRATE_ASYNC && head &&
+	if ((mode & MIGRATE_ASYNC) && head &&
 			!buffer_migrate_lock_buffers(head, mode)) {
 		page_ref_unfreeze(page, expected_count);
 		spin_unlock_irq(&mapping->tree_lock);
@@ -779,7 +779,7 @@ int buffer_migrate_page(struct address_space *mapping,
 	 * with an IRQ-safe spinlock held. In the sync case, the buffers
 	 * need to be locked now
 	 */
-	if (mode != MIGRATE_ASYNC)
+	if (!(mode & MIGRATE_ASYNC))
 		BUG_ON(!buffer_migrate_lock_buffers(head, mode));
 
 	ClearPagePrivate(page);
@@ -861,7 +861,7 @@ static int fallback_migrate_page(struct address_space *mapping,
 {
 	if (PageDirty(page)) {
 		/* Only writeback pages in full synchronous migration */
-		if (mode != MIGRATE_SYNC)
+		if (!(mode & MIGRATE_SYNC))
 			return -EBUSY;
 		return writeout(mapping, page);
 	}
@@ -970,7 +970,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
 	bool is_lru = !__PageMovable(page);
 
 	if (!trylock_page(page)) {
-		if (!force || mode == MIGRATE_ASYNC)
+		if (!force || (mode & MIGRATE_ASYNC))
 			goto out;
 
 		/*
@@ -999,7 +999,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
 		 * the retry loop is too short and in the sync-light case,
 		 * the overhead of stalling is too much
 		 */
-		if (mode != MIGRATE_SYNC) {
+		if (!(mode & MIGRATE_SYNC)) {
 			rc = -EBUSY;
 			goto out_unlock;
 		}
@@ -1262,7 +1262,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
 		return -ENOMEM;
 
 	if (!trylock_page(hpage)) {
-		if (!force || mode != MIGRATE_SYNC)
+		if (!force || !(mode & MIGRATE_SYNC))
 			goto out;
 		lock_page(hpage);
 	}
-- 
2.10.2