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bh=lpA4KdrK70TL2Etj3PL1Cfra8aJL0LqY3fuNb0fiTvc=; b=mgZVAibaY3lnvIFmOTTHRMtxp3t7qQKh8BnOSevYzZfKQ9ODixCurYGn0FceCkXYyYsp0+ RvsA+wkdqZohpaqPEn1MlNCQFu0gtGvRAx4qDNx3uVWO++I0kqwdfjEmJD+LpiPmQNnfxG pO3CeZANL2wZKxSHtzxRki9EQbPlmFg= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 37BD813451; Tue, 8 Aug 2023 07:29:55 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 2xkkCvPu0WTBXwAAMHmgww (envelope-from ); Tue, 08 Aug 2023 07:29:55 +0000 Date: Tue, 8 Aug 2023 09:29:54 +0200 From: Michal Hocko To: Roman Gushchin Cc: 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 Subject: Re: [PATCH] mm/memcontrol: add tips for kmem.slabinfo Message-ID: References: <20230808022229.1560559-1-xiongwei.song@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 09576180004 X-Stat-Signature: enf1siw9gpwwbm38ihwxjgg4gegdxxgi X-HE-Tag: 1691479796-142818 X-HE-Meta: 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 a6j9jPRY kGQ9hMqI7J/W0g1e2XrxyVAMWtB703pk2rQdekMGTCNTQXeI3vrzSyqHbKOjBlzRWxACJYdg0av4BSchNJh/DMaq/77LbwcaOmjGlYulB0NwRcRn1V+IGcyK/UJJ20Vhxt+Se7Uy4frChmhAq9dLSZgzLhBIV7KODwzVccZ2EFvFu79iRffbjXZ4ZMv0Vkk0U8Hs4EpxNRUOtWps= 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 Mon 07-08-23 20:59:59, Roman Gushchin wrote: > On Tue, Aug 08, 2023 at 10:22:29AM +0800, xiongwei.song@windriver.com wrote: > > 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(struct kernfs_open_file *of, > > #if defined(CONFIG_MEMCG_KMEM) && (defined(CONFIG_SLAB) || defined(CONFIG_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 kernel source.\n"); > > It'll break the ABI. Agreed > The only possible option here is to use WARN_ON_ONCE(), which will print 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. -- Michal Hocko SUSE Labs