linux-kernel - [PATCH v6 08/10] mm/lru: debug checking for page memcg moving and lock_page

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Date:   Mon, 16 Dec 2019 17:26:24 +0800
From:   Alex Shi <alex.shi@...ux.alibaba.com>
To:     cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, akpm@...ux-foundation.org,
        mgorman@...hsingularity.net, tj@...nel.org, hughd@...gle.com,
        khlebnikov@...dex-team.ru, daniel.m.jordan@...cle.com,
        yang.shi@...ux.alibaba.com, willy@...radead.org,
        shakeelb@...gle.com, hannes@...xchg.org
Cc:     Alex Shi <alex.shi@...ux.alibaba.com>,
        Michal Hocko <mhocko@...nel.org>,
        Vladimir Davydov <vdavydov.dev@...il.com>
Subject: [PATCH v6 08/10] mm/lru: debug checking for page memcg moving and lock_page_memcg

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@...ux.alibaba.com>
Cc: Johannes Weiner <hannes@...xchg.org>
Cc: Michal Hocko <mhocko@...nel.org>
Cc: Vladimir Davydov <vdavydov.dev@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: cgroups@...r.kernel.org
Cc: linux-mm@...ck.org
Cc: linux-kernel@...r.kernel.org
---
 mm/compaction.c |  4 ++++
 mm/memcontrol.c | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/mm/compaction.c b/mm/compaction.c
index 8c0a2da217d8..f47820355b66 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -971,6 +971,10 @@ 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 f5d41ccd30e0..138f298b694f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1247,6 +1247,10 @@ 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;
 }
 
@@ -1259,6 +1263,10 @@ 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;
 }
 
@@ -2014,6 +2022,11 @@ 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