linux-kernel - [PATCH 2/4] mm/compaction: use "spinlock_t *" to record held lock in isolate_migratepages

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Message-Id: <20230719113001.2023703-3-shikemeng@huaweicloud.com>
Date:   Wed, 19 Jul 2023 19:29:59 +0800
From:   Kemeng Shi <shikemeng@...weicloud.com>
To:     akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Cc:     shikemeng@...weicloud.com
Subject: [PATCH 2/4] mm/compaction: use "spinlock_t *" to record held lock in isolate_migratepages_block

Use "spinlock_t *" instead of "struct lruvec *" to record held lock in
isolate_migratepages_block.
This is a preparation to use compact_unlock_should_abort in
isolate_migratepages_block to remove repeat code.

Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
---
 mm/compaction.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index dfef14d3ef78..638146a49e89 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -840,7 +840,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 	unsigned long nr_scanned = 0, nr_isolated = 0;
 	struct lruvec *lruvec;
 	unsigned long flags = 0;
-	struct lruvec *locked = NULL;
+	spinlock_t *locked = NULL;
 	struct folio *folio = NULL;
 	struct page *page = NULL, *valid_page = NULL;
 	struct address_space *mapping;
@@ -911,7 +911,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 		 */
 		if (!(low_pfn % COMPACT_CLUSTER_MAX)) {
 			if (locked) {
-				unlock_page_lruvec_irqrestore(locked, flags);
+				spin_unlock_irqrestore(locked, flags);
 				locked = NULL;
 			}
 
@@ -946,7 +946,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 
 		if (PageHuge(page) && cc->alloc_contig) {
 			if (locked) {
-				unlock_page_lruvec_irqrestore(locked, flags);
+				spin_unlock_irqrestore(locked, flags);
 				locked = NULL;
 			}
 
@@ -1035,7 +1035,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 			if (unlikely(__PageMovable(page)) &&
 					!PageIsolated(page)) {
 				if (locked) {
-					unlock_page_lruvec_irqrestore(locked, flags);
+					spin_unlock_irqrestore(locked, flags);
 					locked = NULL;
 				}
 
@@ -1120,12 +1120,11 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 		lruvec = folio_lruvec(folio);
 
 		/* If we already hold the lock, we can skip some rechecking */
-		if (lruvec != locked) {
+		if (&lruvec->lru_lock != locked) {
 			if (locked)
-				unlock_page_lruvec_irqrestore(locked, flags);
+				spin_unlock_irqrestore(locked, flags);
 
-			compact_lock_irqsave(&lruvec->lru_lock, &flags, cc);
-			locked = lruvec;
+			locked = compact_lock_irqsave(&lruvec->lru_lock, &flags, cc);
 
 			lruvec_memcg_debug(lruvec, folio);
 
@@ -1188,7 +1187,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 isolate_fail_put:
 		/* Avoid potential deadlock in freeing page under lru_lock */
 		if (locked) {
-			unlock_page_lruvec_irqrestore(locked, flags);
+			spin_unlock_irqrestore(locked, flags);
 			locked = NULL;
 		}
 		folio_put(folio);
@@ -1204,7 +1203,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 		 */
 		if (nr_isolated) {
 			if (locked) {
-				unlock_page_lruvec_irqrestore(locked, flags);
+				spin_unlock_irqrestore(locked, flags);
 				locked = NULL;
 			}
 			putback_movable_pages(&cc->migratepages);
@@ -1236,7 +1235,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 
 isolate_abort:
 	if (locked)
-		unlock_page_lruvec_irqrestore(locked, flags);
+		spin_unlock_irqrestore(locked, flags);
 	if (folio) {
 		folio_set_lru(folio);
 		folio_put(folio);
-- 
2.30.0