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[37.188.249.36]) by smtp.gmail.com with ESMTPSA id r14sm11330332wmb.2.2020.05.13.03.49.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 May 2020 03:49:40 -0700 (PDT) Date: Wed, 13 May 2020 12:49:38 +0200 From: Michal Hocko To: Petr Mladek Cc: Tetsuo Handa , Sergey Senozhatsky , Steven Rostedt , linux-kernel@vger.kernel.org, Dmitry Safonov , Yafang Shao Subject: Re: [PATCH] printk: Add loglevel for "do not print to consoles". Message-ID: <20200513104938.GW29153@dhcp22.suse.cz> References: <4dae86af-1d9a-f5a8-cff6-aa91ec038a79@i-love.sakura.ne.jp> <20200428121828.GP28637@dhcp22.suse.cz> <20200428154532.GU28637@dhcp22.suse.cz> <20200429142106.GG28637@dhcp22.suse.cz> <20200513062652.GM413@jagdpanzerIV.localdomain> <20200513100413.GH17734@linux-b0ei> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200513100413.GH17734@linux-b0ei> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 13-05-20 12:04:13, Petr Mladek wrote: > What is so special about OOM dump task so that it would deserve such > complications? Nothing really. Except for the potential amount of the output. But as you've said there are two ways around that. Disable this output if you do not need it or make it a lower loglevel. A completely different method of tagging messages just to distinguish different backends of the printk ring buffers sounds like a bad idea to me because it a) adds a policy to the kernel and b) it makes it incredibly hard to judge when to use such a feature. I simply cannot tell whether somebody considers dump_tasks an important information to be printed on consoles. If there is any need to control which messages should be routed to which backend then the proper solution would be to filter messages per log level per backend. But I have no idea how feasible this is for the existing infrastructure - or maybe it already exists... -- Michal Hocko SUSE Labs