From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756613Ab1LBNQ6 (ORCPT ); Fri, 2 Dec 2011 08:16:58 -0500 Received: from mailhub.sw.ru ([195.214.232.25]:15814 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755095Ab1LBNQ4 (ORCPT ); Fri, 2 Dec 2011 08:16:56 -0500 Message-ID: <4ED8CFC4.5010804@parallels.com> Date: Fri, 02 Dec 2011 17:16:52 +0400 From: Pavel Emelyanov User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc15 Thunderbird/3.1.10 MIME-Version: 1.0 To: Pedro Alves CC: KAMEZAWA Hiroyuki , Cyrill Gorcunov , "linux-kernel@vger.kernel.org" , Andrew Morton , Tejun Heo , Andrew Vagin , Serge Hallyn , Vasiliy Kulikov Subject: Re: [rfc 2/3] fs, proc: Introduce the Children: line in /proc//status References: <20111129191252.769160532@openvz.org> <201112021241.04471.pedro@codesourcery.com> <4ED8C7DE.4050107@parallels.com> <201112021258.04197.pedro@codesourcery.com> In-Reply-To: <201112021258.04197.pedro@codesourcery.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/02/2011 04:58 PM, Pedro Alves wrote: > On Friday 02 December 2011 12:43:10, Pavel Emelyanov wrote: > >>>> Yes, I like /children file. other points seems to be pointed out by other >>>> reviewers. >>> >>> Any reason this is a file instead of a directory like /proc/PID/task/ ? >>> >>> $ sudo ls /proc/8167/task/ >>> 8167 854 855 856 857 858 859 >>> $ sudo ls /proc/8167/task/855/ >>> attr clear_refs cpuset exe io loginuid mountinfo oom_adj pagemap sched smaps statm wchan >>> auxv cmdline cwd fd latency maps mounts oom_score personality schedstat stack status >>> cgroup comm environ fdinfo limits mem numa_maps oom_score_adj root sessionid stat syscall >>> >>> Much easier to follow the chain from the command line this way. >> >> What do you propose to put into these directories? Another directories named with >> children pid-s? > > Yes, just like the task/ dir gives you directories named with the > processes's thread ids. Opening /proc/PID/children/PID-CHILD1/ would get > you the same as opening /proc/PID-CHILD1/. Just like > opening /proc/PID/task/PID-CHILD1/ gets you (almost) the same as opening > /proc/PID-CHILD1/. You cannot make the dentry named /proc//children/ be a hardlink on the /proc/. Thus you have to make arbitrary amount of inodes to point to a single task. This brings unnecessary complexity and memory usage (by dentries and proc inodes). I'd accept the symbolic links, but how would they look like? Like this: # ls -l /proc/123/children 234 -> ../../234 ? Thanks, Pavel