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Fri, 28 Jun 2024 16:09:02 +0800 Message-ID: <0e44be2c-7039-710b-202f-c452bfc3f1ad@huawei.com> Date: Fri, 28 Jun 2024 16:09:02 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.5.1 Subject: Re: [PATCH -next] mm: memcg: adjust the warning when seq_buf overflows Content-Language: en-US To: Michal Hocko CC: , , , , , , , References: <20240628072333.2496527-1-xiujianfeng@huawei.com> From: xiujianfeng In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.110.112] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpeml500023.china.huawei.com (7.185.36.114) X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 31EA0120019 X-Stat-Signature: pfq1cw3sdoj5nni1h9ub3korp1m8usxb X-Rspam-User: X-HE-Tag: 1719562146-251631 X-HE-Meta: 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 OL5r9hlf sNbhJMO9O8Op43UoXVyjCPco8ixsJ5h81+mNJcRPVecyQdku1rrHibecoj+wRM6qlnzv95DoJ7+4iiFVhNzLzuJP7761PUkY8+OKKWZBw3EhLhx1RIIx3npF3lC0sMsK7Epk69OV/nvoiYNgDRLTJQbU3R1E1AfMU5bLXxLhl0ELDsOW/Y7Vz+ClQznLbUg2IthT/JVNJvwIWZV2k7v9dCyMGRyOzmHz8J1oEUIQrfbDbirCYQ+QyR8iIrJ2brgefdtfF X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2024/6/28 15:45, Michal Hocko wrote: > On Fri 28-06-24 07:23:33, Xiu Jianfeng wrote: >> Currently it uses WARN_ON_ONCE() if seq_buf overflows when user reads >> memory.stat, the only advantage of WARN_ON_ONCE is that the splat is >> so verbose that it gets noticed. And also it panics the system if >> panic_on_warn is enabled. It seems like the warning is just an over >> reaction and a simple pr_warn should just achieve the similar effect. >> >> Suggested-by: Michal Hocko >> Signed-off-by: Xiu Jianfeng > > Acked-by: Michal Hocko > > I would just squash this with other patch removing it from > memcg_stat_format. But this is up to you. Sorry, I might have misunderstood, if you can squash them, it looks good to me, thanks. > > Thanks! > >> --- >> mm/memcontrol.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >> index c251bbe35f4b..8e5590ac43d7 100644 >> --- a/mm/memcontrol.c >> +++ b/mm/memcontrol.c >> @@ -1484,7 +1484,8 @@ static void memory_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) >> memcg_stat_format(memcg, s); >> else >> memcg1_stat_format(memcg, s); >> - WARN_ON_ONCE(seq_buf_has_overflowed(s)); >> + if (seq_buf_has_overflowed(s)) >> + pr_warn("%s: Warning, stat buffer overflow, please report\n", __func__); >> } >> >> /** >> -- >> 2.34.1 >> >