From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Muchun Song <muchun.song@linux.dev>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH] memcg: Remove the lockdep assert from __mod_objcg_mlstate().
Date: Tue, 28 May 2024 14:19:28 +0200 [thread overview]
Message-ID: <20240528121928.i-Gu7Jvg@linutronix.de> (raw)
The assert was introduced in the commit cited below as an insurance that
the semantic is the same after the local_irq_save() has been removed and
the function has been made static.
The original requirement to disable interrupt was due the modification
of per-CPU counters which require interrupts to be disabled because the
counter update operation is not atomic and some of the counters are
updated from interrupt context.
All callers of __mod_objcg_mlstate() acquire a lock
(memcg_stock.stock_lock) which disables interrupts on !PREEMPT_RT and
the lockdep assert is satisfied. On PREEMPT_RT the interrupts are not
disabled and the assert triggers.
The safety of the counter update is already ensured by
VM_WARN_ON_IRQS_ENABLED() which is part of memcg_stats_lock() and does
not require yet another check.
Remove the lockdep assert from __mod_objcg_mlstate().
Fixes: 91882c1617c15 ("memcg: simple cleanup of stats update functions")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
mm/memcontrol.c | 2 --
1 file changed, 2 deletions(-)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3147,8 +3147,6 @@ static inline void __mod_objcg_mlstate(s
struct mem_cgroup *memcg;
struct lruvec *lruvec;
- lockdep_assert_irqs_disabled();
-
rcu_read_lock();
memcg = obj_cgroup_memcg(objcg);
lruvec = mem_cgroup_lruvec(memcg, pgdat);
next reply other threads:[~2024-05-28 12:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-28 12:19 Sebastian Andrzej Siewior [this message]
2024-05-28 12:34 ` Vlastimil Babka (SUSE)
2024-05-28 13:40 ` Sebastian Andrzej Siewior
2024-05-28 13:44 ` Vlastimil Babka (SUSE)
2024-05-28 14:13 ` [PATCH v2] " Sebastian Andrzej Siewior
2024-05-28 14:19 ` Vlastimil Babka (SUSE)
2024-05-28 14:59 ` Shakeel Butt
2024-05-28 15:07 ` Vlastimil Babka (SUSE)
2024-05-28 16:21 ` Shakeel Butt
2024-05-28 15:08 ` Sebastian Andrzej Siewior
2024-05-28 16:20 ` Shakeel Butt
2024-05-28 16:21 ` Shakeel Butt
2024-05-29 9:16 ` Michal Hocko
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