+ mm-workingset-replace-irq-off-check-with-a-lockdep-assert.patch added to -mm tree

+ mm-workingset-replace-irq-off-check-with-a-lockdep-assert.patch added to -mm tree

[Andrew Morton]

The patch titled
     Subject: mm: workingset: replace IRQ-off check with a lockdep assert.
has been added to the -mm tree.  Its filename is
     mm-workingset-replace-irq-off-check-with-a-lockdep-assert.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-workingset-replace-irq-off-check-with-a-lockdep-assert.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-workingset-replace-irq-off-check-with-a-lockdep-assert.patch

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------------------------------------------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: mm: workingset: replace IRQ-off check with a lockdep assert.

Commit 68d48e6a2df57 ("mm: workingset: add vmstat counter for shadow
nodes") introduced an IRQ-off check to ensure that a lock is held which
also disabled interrupts.  This does not work the same way on PREEMPT_RT
because none of the locks, that are held, disable interrupts.

Replace this check with a lockdep assert which ensures that the lock is
held.

Link: https://lkml.kernel.org/r/20220301122143.1521823-3-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/workingset.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/mm/workingset.c~mm-workingset-replace-irq-off-check-with-a-lockdep-assert
+++ a/mm/workingset.c
@@ -433,6 +433,8 @@ static struct list_lru shadow_nodes;
 
 void workingset_update_node(struct xa_node *node)
 {
+	struct address_space *mapping;
+
 	/*
 	 * Track non-empty nodes that contain only shadow entries;
 	 * unlink those that contain pages or are being freed.
@@ -441,7 +443,8 @@ void workingset_update_node(struct xa_no
 	 * already where they should be. The list_empty() test is safe
 	 * as node->private_list is protected by the i_pages lock.
 	 */
-	VM_WARN_ON_ONCE(!irqs_disabled());  /* For __inc_lruvec_page_state */
+	mapping = container_of(node->array, struct address_space, i_pages);
+	lockdep_assert_held(&mapping->i_pages.xa_lock);
 
 	if (node->count && node->count == node->nr_values) {
 		if (list_empty(&node->private_list)) {
_

Patches currently in -mm which might be from bigeasy@linutronix.de are

mm-memcg-disable-threshold-event-handlers-on-preempt_rt.patch
mm-memcg-protect-per-cpu-counter-by-disabling-preemption-on-preempt_rt-where-needed.patch
mm-memcg-protect-memcg_stock-with-a-local_lock_t.patch
mm-memcg-disable-migration-instead-of-preemption-in-drain_all_stock.patch
cgroup-use-irqsave-in-cgroup_rstat_flush_locked.patch
mm-workingset-replace-irq-off-check-with-a-lockdep-assert.patch