From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 25 Aug 2022 18:41:28 +0200
Subject: [PATCH 5/8] mm/memcontrol: Replace the PREEMPT_RT conditionals

Use VM_WARN_ON_IRQS_ENABLED() and preempt_disable/enable_nested() to
replace the CONFIG_PREEMPT_RT #ifdeffery.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220825164131.402717-6-bigeasy@linutronix.de
---
 mm/memcontrol.c |   19 ++++++-------------
 1 file changed, 6 insertions(+), 13 deletions(-)

--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -597,25 +597,18 @@ static u64 flush_next_time;
  */
 static void memcg_stats_lock(void)
 {
-#ifdef CONFIG_PREEMPT_RT
-      preempt_disable();
-#else
-      VM_BUG_ON(!irqs_disabled());
-#endif
+	preempt_disable_nested();
+	VM_WARN_ON_IRQS_ENABLED();
 }
 
 static void __memcg_stats_lock(void)
 {
-#ifdef CONFIG_PREEMPT_RT
-      preempt_disable();
-#endif
+	preempt_disable_nested();
 }
 
 static void memcg_stats_unlock(void)
 {
-#ifdef CONFIG_PREEMPT_RT
-      preempt_enable();
-#endif
+	preempt_enable_nested();
 }
 
 static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
@@ -715,7 +708,7 @@ void __mod_memcg_lruvec_state(struct lru
 	 * interrupt context while other caller need to have disabled interrupt.
 	 */
 	__memcg_stats_lock();
-	if (IS_ENABLED(CONFIG_DEBUG_VM) && !IS_ENABLED(CONFIG_PREEMPT_RT)) {
+	if (IS_ENABLED(CONFIG_DEBUG_VM)) {
 		switch (idx) {
 		case NR_ANON_MAPPED:
 		case NR_FILE_MAPPED:
@@ -725,7 +718,7 @@ void __mod_memcg_lruvec_state(struct lru
 			WARN_ON_ONCE(!in_task());
 			break;
 		default:
-			WARN_ON_ONCE(!irqs_disabled());
+			VM_WARN_ON_IRQS_ENABLED();
 		}
 	}