From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Safonov Subject: Re: [PATCH 00/50] Add log level to show_stack() Date: Wed, 13 Nov 2019 02:41:50 +0000 Message-ID: References: <20191106030542.868541-1-dima@arista.com> <20191106083538.z5nlpuf64cigxigh@pathway.suse.cz> <20191108103719.GB175344@google.com> <20191108130447.h3wfgo4efjkto56f@pathway.suse.cz> <20191111012336.GA85185@google.com> <13e72b62-c842-8ed5-5b41-bc1692b28f53@arista.com> <20191112021747.GA68506@google.com> <25cb9647-007a-9c18-4784-49c0aef4f54b@arista.com> <20191112042546.GA119579@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=rLh7Q3GdiOOnXztTmb+NTAb+Wh+Y3hEa8ZnAFymAzVc=; b=RAeQL7WJnGNv4+ GVRE3f6r+ph8NVKKzr7TopfFmQ+hGX116RGQTwPjZx/hgpiFoDX6ur/kYP41Ae4ncHawPS8+qVUq5 RFjHfwVt4jkjzp0VG0Pa8dOmbBVwEQtD/H5S4nlWz/07fyYhL92tMprdPt6KOKsb0bpidNGts1Pdm S/6OixtTCSoaUDNZKXSLRW8xvNXNTSRvcwSNeaFqD8Jwfrrhj7FL+2mfnRw6M18HDrjt1PYp3HY1s hAouTcL7YlssVNeciEZlYhpzk8Af0BFgXUUXxbbq8xEgEyp3X1LkzIR4c56LQjmkGwpmDfIseVFLH v2syWlxIQYsk6R0NkP6A==; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=9ewNkq+k7WzF7N7FeKsJZWJsQUcIf4AaWPjf05A0Fco=; b=httZFalB2VvN+DAYr6xQfb8CS2lpW4CgtAeEsAWgjkvbyyGvCmjTLAPAEMfF/JCr7/ c8P9raTPSqNexy65EPzsFOdG6kVk1K592cMDIy0cHhBebJPWF8fQ9egPpzwWXfBWSrCz Jk1zAXvG+gTTHY9iuktiuKZH9vWWl//5vaZrlx7ppzhO4sTAZlX2C/T/kVZYDrElUqcN VIOq5oDXrk5HHYGKLT0+ff2WZ+LnUZTUWEqoGOOJeX0XdIUXtb1PCt6iQWGnVWpEOeHv 9p5PFEhwRvitpIH0ba4n5ClWOCwYigDV+TgMORDfM82fnMfxgxqmD7OSd4a8lnQJEp7K YgYw== In-Reply-To: <20191112042546.GA119579@google.com> Content-Language: en-US List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+glpr-linux-riscv=m.gmane.org@lists.infradead.org To: Sergey Senozhatsky Cc: Juri Lelli , linux-sh@vger.kernel.org, Catalin Marinas , Ben Segall , Guo Ren , Pavel Machek , Vincent Guittot , Paul Burton , Michael Ellerman , Geert Uytterhoeven , Mel Gorman , Jiri Slaby , Matt Turner , uclinux-h8-devel@lists.sourceforge.jp, Len Brown , linux-pm@vger.kernel.org, Heiko Carstens , linux-um@lists.infradead.org, Thomas Gleixner , Dietmar Eggemann , Richard Henderson , Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, Ralf Baechle On 11/12/19 4:25 AM, Sergey Senozhatsky wrote: > On (19/11/12 02:40), Dmitry Safonov wrote: > [..] >> In my point of view the cost of one-time [mostly build] testing every >> architecture is cheaper than introducing some new smart code that will >> live forever. > > Well, there may be the need to pass loglevel deeper due to "hey __show_stack() > on that arch invokes bar(), which invokes foo() and now foo() does printk(), > but we don't see it". The context which decided to backtaraces decided > to do so for a reason, probably, so I guess we can look at it as "a special > error reporting code block". > > The proposed patch set passes loglevel via slightly unusual channel - > via sprintf(). We probably can do it, but I would prefer to minimize > the number of such printk-s in the kernel. The code snippet which I > posted also does pretty unusual thing w.r.t loglevel. Both approaches > are "non-standard" from that POV. I don't strongly disagree, but if you look at those results: git grep 'printk("%s.*", \(lvl\|level\)' it seems to be used in quite a few places. Thanks, Dmitry