From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756822AbbLBVLH (ORCPT ); Wed, 2 Dec 2015 16:11:07 -0500 Received: from mx2.suse.de ([195.135.220.15]:38585 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755975AbbLBVE2 (ORCPT ); Wed, 2 Dec 2015 16:04:28 -0500 Subject: Re: [PATCH 1/2] mm, printk: introduce new format string for flags To: yalin wang References: <20151125143010.GI27283@dhcp22.suse.cz> <1448899821-9671-1-git-send-email-vbabka@suse.cz> <4EAD2C33-D0E4-4DEB-92E5-9C0457E8635C@gmail.com> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Joonsoo Kim , Minchan Kim , Sasha Levin , "Kirill A. Shutemov" , Mel Gorman , Michal Hocko , Rasmus Villemoes From: Vlastimil Babka X-Enigmail-Draft-Status: N1110 Message-ID: <565F5CD9.9080301@suse.cz> Date: Wed, 2 Dec 2015 22:04:25 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <4EAD2C33-D0E4-4DEB-92E5-9C0457E8635C@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/02/2015 06:40 PM, yalin wang wrote: (please trim your reply next time, no need to quote whole patch here) > i am thinking why not make %pg* to be more generic ? > not restricted to only GFP / vma flags / page flags . > so could we change format like this ? > define a flag spec struct to include flag and trace_print_flags and some other option : > typedef struct { > unsigned long flag; > struct trace_print_flags *flags; > unsigned long option; } flag_sec; > flag_sec my_flag; > in printk we only pass like this : > printk(“%pg\n”, &my_flag) ; > then it can print any flags defined by user . > more useful for other drivers to use . I don't know, it sounds quite complicated given that we had no flags printing for years and now there's just three kinds of them. The extra struct flag_sec is IMHO nuissance. No other printk format needs such thing AFAIK? For example, if I were to print page flags from several places, each would have to define the struct flag_sec instance, or some header would have to provide it? I could maybe accept passing a flag value and trace_print_flags * as two separate parameters, but I guess that breaks an ancient invariant of one parameter per format string... > Thanks > > > > > > > > > > > > > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f43.google.com (mail-wm0-f43.google.com [74.125.82.43]) by kanga.kvack.org (Postfix) with ESMTP id D295E6B0038 for ; Wed, 2 Dec 2015 16:04:28 -0500 (EST) Received: by wmww144 with SMTP id w144so74353229wmw.0 for ; Wed, 02 Dec 2015 13:04:28 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id o8si6827055wjy.224.2015.12.02.13.04.27 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 02 Dec 2015 13:04:27 -0800 (PST) Subject: Re: [PATCH 1/2] mm, printk: introduce new format string for flags References: <20151125143010.GI27283@dhcp22.suse.cz> <1448899821-9671-1-git-send-email-vbabka@suse.cz> <4EAD2C33-D0E4-4DEB-92E5-9C0457E8635C@gmail.com> From: Vlastimil Babka Message-ID: <565F5CD9.9080301@suse.cz> Date: Wed, 2 Dec 2015 22:04:25 +0100 MIME-Version: 1.0 In-Reply-To: <4EAD2C33-D0E4-4DEB-92E5-9C0457E8635C@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: yalin wang Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Joonsoo Kim , Minchan Kim , Sasha Levin , "Kirill A. Shutemov" , Mel Gorman , Michal Hocko , Rasmus Villemoes On 12/02/2015 06:40 PM, yalin wang wrote: (please trim your reply next time, no need to quote whole patch here) > i am thinking why not make %pg* to be more generic ? > not restricted to only GFP / vma flags / page flags . > so could we change format like this ? > define a flag spec struct to include flag and trace_print_flags and some other option : > typedef struct { > unsigned long flag; > struct trace_print_flags *flags; > unsigned long option; } flag_sec; > flag_sec my_flag; > in printk we only pass like this : > printk(a??%pg\na??, &my_flag) ; > then it can print any flags defined by user . > more useful for other drivers to use . I don't know, it sounds quite complicated given that we had no flags printing for years and now there's just three kinds of them. The extra struct flag_sec is IMHO nuissance. No other printk format needs such thing AFAIK? For example, if I were to print page flags from several places, each would have to define the struct flag_sec instance, or some header would have to provide it? I could maybe accept passing a flag value and trace_print_flags * as two separate parameters, but I guess that breaks an ancient invariant of one parameter per format string... > Thanks > > > > > > > > > > > > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org