From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754381AbcGLOJU (ORCPT ); Tue, 12 Jul 2016 10:09:20 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:57007 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754193AbcGLOJR (ORCPT ); Tue, 12 Jul 2016 10:09:17 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Peter Zijlstra Cc: Nikolay Borisov , Aravinda Prasad , linux-kernel@vger.kernel.org, rostedt@goodmis.org, mingo@redhat.com, paulus@samba.org, acme@kernel.org, hbathini@linux.vnet.ibm.com, ananth@in.ibm.com References: <20160614164530.4192.79560.stgit@aravindap> <20160614164951.4192.66724.stgit@aravindap> <20160627155002.GD30909@twins.programming.kicks-ass.net> <5784B7B9.5020901@linux.vnet.ibm.com> <20160712114734.GL30154@twins.programming.kicks-ass.net> <5784E586.5090904@kyup.com> <20160712130430.GQ30909@twins.programming.kicks-ass.net> Date: Tue, 12 Jul 2016 08:55:17 -0500 In-Reply-To: <20160712130430.GQ30909@twins.programming.kicks-ass.net> (Peter Zijlstra's message of "Tue, 12 Jul 2016 15:04:30 +0200") Message-ID: <8737nf55bu.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1bMyMc-00062x-Pa;;;mid=<8737nf55bu.fsf@x220.int.ebiederm.org>;;;hst=in01.mta.xmission.com;;;ip=67.3.204.119;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19HUUshwzt6LH0HhqSb5Ys9Tmo7sLf5OlY= X-SA-Exim-Connect-IP: 67.3.204.119 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.7 XMSubLong Long Subject * 1.5 XMNoVowels Alpha-numberic number with no vowels * 0.0 TVD_RCVD_IP Message was received from an IP address * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.5000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa07 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_01 4+ unique symbols in subject X-Spam-DCC: XMission; sa07 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: **;Peter Zijlstra X-Spam-Relay-Country: X-Spam-Timing: total 601 ms - load_scoreonly_sql: 0.04 (0.0%), signal_user_changed: 3.2 (0.5%), b_tie_ro: 2.3 (0.4%), parse: 1.02 (0.2%), extract_message_metadata: 17 (2.8%), get_uri_detail_list: 1.52 (0.3%), tests_pri_-1000: 4.3 (0.7%), tests_pri_-950: 1.62 (0.3%), tests_pri_-900: 1.37 (0.2%), tests_pri_-400: 26 (4.4%), check_bayes: 25 (4.1%), b_tokenize: 9 (1.5%), b_tok_get_all: 7 (1.1%), b_comp_prob: 3.1 (0.5%), b_tok_touch_all: 2.9 (0.5%), b_finish: 1.50 (0.2%), tests_pri_0: 401 (66.7%), check_dkim_signature: 0.73 (0.1%), check_dkim_adsp: 132 (21.9%), tests_pri_500: 141 (23.5%), poll_dns_idle: 135 (22.5%), rewrite_mail: 0.00 (0.0%) Subject: Re: [RFC PATCH 2/2] perf: Filter events based on perf-namespace X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Zijlstra writes: > On Tue, Jul 12, 2016 at 03:41:42PM +0300, Nikolay Borisov wrote: > >> Namespaces and cgroups are completely orthogonal to one another. > > Then how do you specify what your new 'root' is? Surely you must first > create a cgroup and then confine yourself to that? > >> Also in the v1 of cgroups it's possible to have a process member of >> more than 1 cgroup. > > Yeah, so? We only care about the perf controller obviously. I completely misread the description of this, or I would have something earlier. For some reason I thought he was talking about the perf controller. As I recall the tricky part of this was to have tracing that was safe and usable inside of a container. If you can align a per cgroup with your container that is probably sufficient for the select of processes. At the same time there is a real desire to have identifiers like pids translated into the appropriate form for inside of the container. Without that translation they are meaningless inside a container. Further it is necessary to be certain the trancing that is used is is safe for unprivileged users. I don't think I ever suggested or approved of the concept of a perf namespace and that sounds a bit dubious to me. Eric