[PATCH v4 23/31] mm: do not open-code lruvec lock

[Qi Zheng <qi.zheng@linux.dev>]

From: Qi Zheng <zhengqi.arch@bytedance.com>

Now we have lruvec_unlock(), lruvec_unlock_irq() and
lruvec_unlock_irqrestore(), but no the paired lruvec_lock(),
lruvec_lock_irq() and lruvec_lock_irqsave().

There is currently no use case for lruvec_lock_irqsave(), so only
introduce lruvec_lock_irq(), and change all open-code places to use
this helper function. This looks cleaner and prepares for reparenting
LRU pages, preventing user from missing RCU lock calls due to
open-code lruvec lock.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Muchun Song <muchun.song@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
---
 include/linux/memcontrol.h |  5 +++++
 mm/vmscan.c                | 38 +++++++++++++++++++-------------------
 2 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f1556759d0d3f..4b6f20dc694ba 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1499,6 +1499,11 @@ static inline struct lruvec *parent_lruvec(struct lruvec *lruvec)
 	return mem_cgroup_lruvec(memcg, lruvec_pgdat(lruvec));
 }
 
+static inline void lruvec_lock_irq(struct lruvec *lruvec)
+{
+	spin_lock_irq(&lruvec->lru_lock);
+}
+
 static inline void lruvec_unlock(struct lruvec *lruvec)
 {
 	spin_unlock(&lruvec->lru_lock);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6a7eacd39bc5f..f904231e33ec0 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2003,7 +2003,7 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
 
 	lru_add_drain();
 
-	spin_lock_irq(&lruvec->lru_lock);
+	lruvec_lock_irq(lruvec);
 
 	nr_taken = isolate_lru_folios(nr_to_scan, lruvec, &folio_list,
 				     &nr_scanned, sc, lru);
@@ -2015,7 +2015,7 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
 	count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned);
 	__count_vm_events(PGSCAN_ANON + file, nr_scanned);
 
-	spin_unlock_irq(&lruvec->lru_lock);
+	lruvec_unlock_irq(lruvec);
 
 	if (nr_taken == 0)
 		return 0;
@@ -2034,7 +2034,7 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
 	count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed);
 	count_vm_events(PGSTEAL_ANON + file, nr_reclaimed);
 
-	spin_lock_irq(&lruvec->lru_lock);
+	lruvec_lock_irq(lruvec);
 	lru_note_cost_unlock_irq(lruvec, file, stat.nr_pageout,
 					nr_scanned - nr_reclaimed);
 
@@ -2113,7 +2113,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 
 	lru_add_drain();
 
-	spin_lock_irq(&lruvec->lru_lock);
+	lruvec_lock_irq(lruvec);
 
 	nr_taken = isolate_lru_folios(nr_to_scan, lruvec, &l_hold,
 				     &nr_scanned, sc, lru);
@@ -2124,7 +2124,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 		__count_vm_events(PGREFILL, nr_scanned);
 	count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned);
 
-	spin_unlock_irq(&lruvec->lru_lock);
+	lruvec_unlock_irq(lruvec);
 
 	while (!list_empty(&l_hold)) {
 		struct folio *folio;
@@ -2180,7 +2180,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 	count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate);
 	mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
 
-	spin_lock_irq(&lruvec->lru_lock);
+	lruvec_lock_irq(lruvec);
 	lru_note_cost_unlock_irq(lruvec, file, 0, nr_rotated);
 	trace_mm_vmscan_lru_shrink_active(pgdat->node_id, nr_taken, nr_activate,
 			nr_deactivate, nr_rotated, sc->priority, file);
@@ -3801,9 +3801,9 @@ static void walk_mm(struct mm_struct *mm, struct lru_gen_mm_walk *walk)
 		}
 
 		if (walk->batched) {
-			spin_lock_irq(&lruvec->lru_lock);
+			lruvec_lock_irq(lruvec);
 			reset_batch_size(walk);
-			spin_unlock_irq(&lruvec->lru_lock);
+			lruvec_unlock_irq(lruvec);
 		}
 
 		cond_resched();
@@ -3962,7 +3962,7 @@ static bool inc_max_seq(struct lruvec *lruvec, unsigned long seq, int swappiness
 	if (seq < READ_ONCE(lrugen->max_seq))
 		return false;
 
-	spin_lock_irq(&lruvec->lru_lock);
+	lruvec_lock_irq(lruvec);
 
 	VM_WARN_ON_ONCE(!seq_is_valid(lruvec));
 
@@ -3977,7 +3977,7 @@ static bool inc_max_seq(struct lruvec *lruvec, unsigned long seq, int swappiness
 		if (inc_min_seq(lruvec, type, swappiness))
 			continue;
 
-		spin_unlock_irq(&lruvec->lru_lock);
+		lruvec_unlock_irq(lruvec);
 		cond_resched();
 		goto restart;
 	}
@@ -4012,7 +4012,7 @@ static bool inc_max_seq(struct lruvec *lruvec, unsigned long seq, int swappiness
 	/* make sure preceding modifications appear */
 	smp_store_release(&lrugen->max_seq, lrugen->max_seq + 1);
 unlock:
-	spin_unlock_irq(&lruvec->lru_lock);
+	lruvec_unlock_irq(lruvec);
 
 	return success;
 }
@@ -4708,7 +4708,7 @@ static int evict_folios(unsigned long nr_to_scan, struct lruvec *lruvec,
 	struct mem_cgroup *memcg = lruvec_memcg(lruvec);
 	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 
-	spin_lock_irq(&lruvec->lru_lock);
+	lruvec_lock_irq(lruvec);
 
 	scanned = isolate_folios(nr_to_scan, lruvec, sc, swappiness, &type, &list);
 
@@ -4717,7 +4717,7 @@ static int evict_folios(unsigned long nr_to_scan, struct lruvec *lruvec,
 	if (evictable_min_seq(lrugen->min_seq, swappiness) + MIN_NR_GENS > lrugen->max_seq)
 		scanned = 0;
 
-	spin_unlock_irq(&lruvec->lru_lock);
+	lruvec_unlock_irq(lruvec);
 
 	if (list_empty(&list))
 		return scanned;
@@ -4755,9 +4755,9 @@ static int evict_folios(unsigned long nr_to_scan, struct lruvec *lruvec,
 	walk = current->reclaim_state->mm_walk;
 	if (walk && walk->batched) {
 		walk->lruvec = lruvec;
-		spin_lock_irq(&lruvec->lru_lock);
+		lruvec_lock_irq(lruvec);
 		reset_batch_size(walk);
-		spin_unlock_irq(&lruvec->lru_lock);
+		lruvec_unlock_irq(lruvec);
 	}
 
 	mod_lruvec_state(lruvec, PGDEMOTE_KSWAPD + reclaimer_offset(sc),
@@ -5195,7 +5195,7 @@ static void lru_gen_change_state(bool enabled)
 		for_each_node(nid) {
 			struct lruvec *lruvec = get_lruvec(memcg, nid);
 
-			spin_lock_irq(&lruvec->lru_lock);
+			lruvec_lock_irq(lruvec);
 
 			VM_WARN_ON_ONCE(!seq_is_valid(lruvec));
 			VM_WARN_ON_ONCE(!state_is_valid(lruvec));
@@ -5203,12 +5203,12 @@ static void lru_gen_change_state(bool enabled)
 			lruvec->lrugen.enabled = enabled;
 
 			while (!(enabled ? fill_evictable(lruvec) : drain_evictable(lruvec))) {
-				spin_unlock_irq(&lruvec->lru_lock);
+				lruvec_unlock_irq(lruvec);
 				cond_resched();
-				spin_lock_irq(&lruvec->lru_lock);
+				lruvec_lock_irq(lruvec);
 			}
 
-			spin_unlock_irq(&lruvec->lru_lock);
+			lruvec_unlock_irq(lruvec);
 		}
 
 		cond_resched();
-- 
2.20.1