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Tue, 08 Aug 2023 05:08:48 -0700 (PDT) MIME-Version: 1.0 References: <20230808022229.1560559-1-xiongwei.song@windriver.com> In-Reply-To: From: Xiongwei Song Date: Tue, 8 Aug 2023 20:08:26 +0800 Message-ID: Subject: Re: [PATCH] mm/memcontrol: add tips for kmem.slabinfo To: Michal Hocko Cc: Roman Gushchin , xiongwei.song@windriver.com, hannes@cmpxchg.org, shakeelb@google.com, muchun.song@linux.dev, akpm@linux-foundation.org, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 473BA1C001A X-Stat-Signature: cg5n8imkzj3aw38zzfbioxwjt8fzsgtd X-Rspam-User: X-HE-Tag: 1691496529-660137 X-HE-Meta: U2FsdGVkX1/3agJfi9cv1CAqG9vYQPrerKeaA96/sc0+SzhqW8dMeoxlgvufc6fO+6VxcBUL7AomYSWdCY1SKMHH+k7MpzImOX6IJNOhMdie/8AVAVuHmTzOD6TxNpmmhuKrEqiC+CKrs+6DdNO+KRA1UKNeDnrxCdlFV4eBS3CY5pualEAmkvN8/DAH/FfsgTC8pVmDMuejHlQuh53IZSqSXFQEBbFO++bfyk3u6aq50vGtjGRk53P8u6Ap35kV/SvFXmQdqK2NqrUexVHKK/KYDJU+/haPGXArwdSQoUh8qi396kJZy/GlPt+8d2nB6LIpO7tJ2GRQ1NTrxlWFwqdEyu7XWNkzV5XiGWLYuk2609EDQ+PPzVq9pI3JhfwbcN1rVudluchfwxmD0lrSo4uWWV0dj5s3S3k0+DIxpA8lkdTRmjnJzEEmObAcD6vJTfZlGl2DUjQf4uSt6P4EAtMYnRwlKUJK5pUXaoo5xUR0xSwSMuxxQ/7UJMrF5VHCNC2O7+CwA1GK0PpcvpMgf7+ZEuL8i+kn6yhAnO+uygF+pJG9Bu0G7sWF+ODk3g3CKnGC/kD9oZNEuCrBQTYVjwGGEgxUG81Z+lMbNFUul4dlcvKKQO+vLPhN92LlpQ3h96tMlkpUln/Lfv2UXsEoDjKT5ZZormWtG29Die1VA/35ttiQABeeY0BbkV+YXQWIxhv57dt9VNvWreLcuav1CsXo5UnjFvtev8Qd3lAhgZvsy93IM/n2kP20w7N1fjjQdpYWJ9XMExswOogEtSYJinM024LEiVUDjdv/z9wHonsKTHrThLu/gCYV9yGGYqlkT2IyJAENxRgxWBPchRwM5NRY8tU1JUcFqxuHiVIjSdsZ4aecPzSxPO6cCn2moSDOh5kE9p8AzeN9+YDtw+BEqa6mnZJA6iQVwV7oNXuMS+1DT9uJkvlk7rD/f8qFsMm6gev97lSPscmRXPGGZXI K9q9KU/w mogP6dvi5aKJFOsLn43PftBqc7TPmjzSkqi0KhGWi+sZq7mb5aSdpUe+Fj41S4y8033RVr+eF5dBzQdDMQx4dCmW/Y4H7BXuGWTWlW4JW70Bdb2+r2qTrQgj5JTM516Ih4cYelD+ItUjWTjcjUVmkFMIiIQATDxDl2eWisZEei217TkJ13ofcGU7PfDGPL1BcWume+SGgea0lh+nXp8Ubw+DQiCUgSDLBft1++gd9vJBHvaFIXK1OEb9Ru+AxlEz0lnPoVHeWyf4QeSUnYodOI3RYY/5MiYra2kHTpr4d+r3uHfqGrbq0nEQupqVNowTu27RaSPnY5h4aw1HWVxdd88ARsbaO4hJ9OI8P0YV3DIdSmTmYCftXV1g4yzI8wjRx3SjJK26gmeMasgvbzNOAP1UkoaTQESkMYjppl3QfEFOd9MdN7mtTwMj28UHiXNmFGBZGs8FV+QvRIQW12vcKkI/CmQ== 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: On Tue, Aug 8, 2023 at 3:30=E2=80=AFPM Michal Hocko wrote= : > > On Mon 07-08-23 20:59:59, Roman Gushchin wrote: > > On Tue, Aug 08, 2023 at 10:22:29AM +0800, xiongwei.song@windriver.com w= rote: > > > From: Xiongwei Song > > > > > > No any output from kmem.slabinfo, which is not friendly. Adding > > > tips for it. > > > > > > Signed-off-by: Xiongwei Song > > > --- > > > mm/memcontrol.c | 6 ++---- > > > 1 file changed, 2 insertions(+), 4 deletions(-) > > > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > > index e8ca4bdcb03c..58d3bd93890b 100644 > > > --- a/mm/memcontrol.c > > > +++ b/mm/memcontrol.c > > > @@ -5002,10 +5002,8 @@ static ssize_t memcg_write_event_control(struc= t kernfs_open_file *of, > > > #if defined(CONFIG_MEMCG_KMEM) && (defined(CONFIG_SLAB) || defined(C= ONFIG_SLUB_DEBUG)) > > > static int mem_cgroup_slab_show(struct seq_file *m, void *p) > > > { > > > - /* > > > - * Deprecated. > > > - * Please, take a look at tools/cgroup/memcg_slabinfo.py . > > > - */ > > > + seq_puts(m, "This file is deprecated.\n" > > > + "Please use tools/cgroup/memcg_slabinfo.py, which is in k= ernel source.\n"); > > > > It'll break the ABI. > > Agreed > > > The only possible option here is to use WARN_ON_ONCE(), which will prin= t once to dmesg. > > But honestly I'm not sure we need it. > > There are systems with panic_on_warn configured. I do not think we want > those to go down just becasue some random tool tries to read this file. Thank you for the comments. > -- > Michal Hocko > SUSE Labs >