[PATCH v5 8/8] mm/lru: debug checking for page memcg moving and lock_page_memcg

[Alex Shi]

The extra irq disable/enable and BUG_ON checking costs 5% readtwice
performance on a 2 socket * 26 cores * HT box.

Need to remove them later?

Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: cgroups@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 mm/compaction.c |  4 ++++
 mm/memcontrol.c | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/mm/compaction.c b/mm/compaction.c
index 0907eec3db84..7f750a9100af 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -972,6 +972,10 @@ static bool too_many_isolated(pg_data_t *pgdat)
 			compact_lock_irqsave(&lruvec->lru_lock, &flags, cc);
 			locked_lruvec = lruvec;
 
+#ifdef	CONFIG_MEMCG
+			if (!mem_cgroup_disabled())
+				VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != page->mem_cgroup, page);
+#endif
 			/* Try get exclusive access under lock */
 			if (!skip_updated) {
 				skip_updated = true;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 4a92689c37d6..833df0ce1bc1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1255,6 +1255,10 @@ struct lruvec *lock_page_lruvec_irq(struct page *page)
 	lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
 	spin_lock_irq(&lruvec->lru_lock);
 
+#ifdef CONFIG_MEMCG
+	if (!mem_cgroup_disabled())
+		VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != page->mem_cgroup, page);
+#endif
 	return lruvec;
 }
 
@@ -1267,6 +1271,10 @@ struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
 	lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
 	spin_lock_irqsave(&lruvec->lru_lock, *flags);
 
+#ifdef CONFIG_MEMCG
+	if (!mem_cgroup_disabled())
+		VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != page->mem_cgroup, page);
+#endif
 	return lruvec;
 }
 
@@ -2015,6 +2023,11 @@ struct mem_cgroup *lock_page_memcg(struct page *page)
 	if (unlikely(!memcg))
 		return NULL;
 
+	/* temporary lockdep checking, need remove */
+	local_irq_save(flags);
+	might_lock(&memcg->move_lock);
+	local_irq_restore(flags);
+
 	if (atomic_read(&memcg->moving_account) <= 0)
 		return memcg;
 
-- 
1.8.3.1