From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f49.google.com (mail-pa0-f49.google.com [209.85.220.49]) by kanga.kvack.org (Postfix) with ESMTP id 8D1906B0253 for ; Wed, 2 Dec 2015 19:12:00 -0500 (EST) Received: by pacdm15 with SMTP id dm15so54564702pac.3 for ; Wed, 02 Dec 2015 16:12:00 -0800 (PST) Received: from mail-pf0-x230.google.com (mail-pf0-x230.google.com. [2607:f8b0:400e:c00::230]) by mx.google.com with ESMTPS id he9si7866004pac.102.2015.12.02.16.11.59 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Dec 2015 16:11:59 -0800 (PST) Received: by pfu207 with SMTP id 207so2716865pfu.2 for ; Wed, 02 Dec 2015 16:11:59 -0800 (PST) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.0 \(3094\)) Subject: Re: [PATCH 1/2] mm, printk: introduce new format string for flags From: yalin wang In-Reply-To: <565F5CD9.9080301@suse.cz> Date: Wed, 2 Dec 2015 16:11:58 -0800 Content-Transfer-Encoding: quoted-printable Message-Id: <1F60C207-1CC2-4B28-89AC-58C72D95A39D@gmail.com> References: <20151125143010.GI27283@dhcp22.suse.cz> <1448899821-9671-1-git-send-email-vbabka@suse.cz> <4EAD2C33-D0E4-4DEB-92E5-9C0457E8635C@gmail.com> <565F5CD9.9080301@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: "open list:MEMORY MANAGEMENT" , linux-kernel , Andrew Morton , Joonsoo Kim , Minchan Kim , Sasha Levin , "Kirill A. Shutemov" , Mel Gorman , Michal Hocko , Rasmus Villemoes > On Dec 2, 2015, at 13:04, Vlastimil Babka wrote: >=20 > On 12/02/2015 06:40 PM, yalin wang wrote: >=20 > (please trim your reply next time, no need to quote whole patch here) >=20 >> 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 {=20 >> unsigned long flag; >> structtrace_print_flags *flags; >> unsigned long option; } flag_sec; >> flag_sec my_flag; >> in printk we only pass like this : >> printk(=E2=80=9C%pg\n=E2=80=9D, &my_flag) ; >> then it can print any flags defined by user . >> more useful for other drivers to use . >=20 > 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? this can be avoided by provide a macro in header file . we can add a new struct to declare trace_print_flags : for example: #define DECLARE_FLAG_PRINTK_FMT(name, flags_array) flag_spec name =3D = { .flags =3D flags_array}; #define FLAG_PRINTK_FMT(name, flag) ({ name.flag =3D flag; &name}) in source code : DECLARE_FLAG_PRINTK_FMT(my_flag, vmaflags_names); printk(=E2=80=9C%pg\n=E2=80=9D, FLAG_PRINTK_FMT(my_flag, vma->flag)); i am not if DECLARE_FLAG_PRINTK_FMT and FLAG_PRINTK_FMT macro=20 can be defined into one macro ? maybe need some trick here . is it possible ? 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