Merge branch 'akpm' (patches from Andrew)

Merge updates from Andrew Morton:

 - A few misc subsystems: kthread, scripts, ntfs, ocfs2, block, and vfs

 - Most the MM patches which precede the patches in Willy's tree: kasan,
   pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap,
   sparsemem, vmalloc, pagealloc, memory-failure, mlock, hugetlb,
   userfaultfd, vmscan, compaction, mempolicy, oom-kill, migration, thp,
   cma, autonuma, psi, ksm, page-poison, madvise, memory-hotplug, rmap,
   zswap, uaccess, ioremap, highmem, cleanups, kfence, hmm, and damon.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (227 commits)
  mm/damon/sysfs: remove repeat container_of() in damon_sysfs_kdamond_release()
  Docs/ABI/testing: add DAMON sysfs interface ABI document
  Docs/admin-guide/mm/damon/usage: document DAMON sysfs interface
  selftests/damon: add a test for DAMON sysfs interface
  mm/damon/sysfs: support DAMOS stats
  mm/damon/sysfs: support DAMOS watermarks
  mm/damon/sysfs: support schemes prioritization
  mm/damon/sysfs: support DAMOS quotas
  mm/damon/sysfs: support DAMON-based Operation Schemes
  mm/damon/sysfs: support the physical address space monitoring
  mm/damon/sysfs: link DAMON for virtual address spaces monitoring
  mm/damon: implement a minimal stub for sysfs-based DAMON interface
  mm/damon/core: add number of each enum type values
  mm/damon/core: allow non-exclusive DAMON start/stop
  Docs/damon: update outdated term 'regions update interval'
  Docs/vm/damon/design: update DAMON-Idle Page Tracking interference handling
  Docs/vm/damon: call low level monitoring primitives the operations
  mm/damon: remove unnecessary CONFIG_DAMON option
  mm/damon/paddr,vaddr: remove damon_{p,v}a_{target_valid,set_operations}()
  mm/damon/dbgfs-test: fix is_target_id() change
  ...

1 files changed, 15 insertions, 10 deletions

diff --git a/mm/swap.c b/mm/swap.c
index bcf3ac288b56..754520bab299 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -425,7 +425,7 @@ void folio_mark_accessed(struct folio *folio)
 		/*
 		 * Unevictable pages are on the "LRU_UNEVICTABLE" list. But,
 		 * this list is never rotated or maintained, so marking an
-		 * evictable page accessed has no effect.
+		 * unevictable page accessed has no effect.
 		 */
 	} else if (!folio_test_active(folio)) {
 		/*
@@ -831,8 +831,7 @@ inline void __lru_add_drain_all(bool force_all_cpus)
 	for_each_online_cpu(cpu) {
 		struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
 
-		if (force_all_cpus ||
-		    pagevec_count(&per_cpu(lru_pvecs.lru_add, cpu)) ||
+		if (pagevec_count(&per_cpu(lru_pvecs.lru_add, cpu)) ||
 		    data_race(pagevec_count(&per_cpu(lru_rotate.pvec, cpu))) ||
 		    pagevec_count(&per_cpu(lru_pvecs.lru_deactivate_file, cpu)) ||
 		    pagevec_count(&per_cpu(lru_pvecs.lru_deactivate, cpu)) ||
@@ -876,15 +875,21 @@ atomic_t lru_disable_count = ATOMIC_INIT(0);
 void lru_cache_disable(void)
 {
 	atomic_inc(&lru_disable_count);
-#ifdef CONFIG_SMP
 	/*
-	 * lru_add_drain_all in the force mode will schedule draining on
-	 * all online CPUs so any calls of lru_cache_disabled wrapped by
-	 * local_lock or preemption disabled would be ordered by that.
-	 * The atomic operation doesn't need to have stronger ordering
-	 * requirements because that is enforced by the scheduling
-	 * guarantees.
+	 * Readers of lru_disable_count are protected by either disabling
+	 * preemption or rcu_read_lock:
+	 *
+	 * preempt_disable, local_irq_disable  [bh_lru_lock()]
+	 * rcu_read_lock		       [rt_spin_lock CONFIG_PREEMPT_RT]
+	 * preempt_disable		       [local_lock !CONFIG_PREEMPT_RT]
+	 *
+	 * Since v5.1 kernel, synchronize_rcu() is guaranteed to wait on
+	 * preempt_disable() regions of code. So any CPU which sees
+	 * lru_disable_count = 0 will have exited the critical
+	 * section when synchronize_rcu() returns.
 	 */
+	synchronize_rcu();
+#ifdef CONFIG_SMP
 	__lru_add_drain_all(true);
 #else
 	lru_add_and_bh_lrus_drain();