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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Shakeel Butt <shakeel.butt@linux.dev>
Cc: 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: Re: [PATCH v2] memcg: simple cleanup of stats update functions
Message-ID: <20240527152200.P1rU7FaG@linutronix.de>
References: <20240420232505.2768428-1-shakeel.butt@linux.dev>
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In-Reply-To: <20240420232505.2768428-1-shakeel.butt@linux.dev>

On 2024-04-20 16:25:05 [-0700], Shakeel Butt wrote:
> mod_memcg_lruvec_state() is never called from outside of memcontrol.c
> and with always irq disabled. So, replace it with the irq disabled
> version and add an assert that irq is disabled in the caller.

unless PREEMPT_RT is enabled. In that case IRQs are not disabled as part
of local_lock_irqsave(&memcg_stock.stock_lock, =E2=80=A6) leading to:

| ------------[ cut here ]------------
| WARNING: CPU: 0 PID: 1 at mm/memcontrol.c:3150 __mod_objcg_mlstate+0xc2/0=
x110
| CPU: 0 PID: 1 Comm: systemd Not tainted 6.10.0-rc1-rt0+ #17
| Call Trace:
|  <TASK>
|  mod_objcg_state+0x2b3/0x320
|  __memcg_slab_post_alloc_hook+0x13c/0x340
|  kmem_cache_alloc_lru_noprof+0x2bd/0x2e0
|  alloc_inode+0x59/0xc0
|  iget_locked+0xf0/0x290

suggestions?

Sebastian