From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754634AbdBPLaE (ORCPT ); Thu, 16 Feb 2017 06:30:04 -0500 Received: from out02.mta.xmission.com ([166.70.13.232]:58598 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754505AbdBPLaC (ORCPT ); Thu, 16 Feb 2017 06:30:02 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Hari Bathini Cc: ast@fb.com, peterz@infradead.org, lkml , acme@kernel.org, alexander.shishkin@linux.intel.com, mingo@redhat.com, daniel@iogearbox.net, rostedt@goodmis.org, Ananth N Mavinakayanahalli , sargun@sargun.me, Aravinda Prasad , brendan.d.gregg@gmail.com, jolsa@redhat.com References: <148654265580.27983.8822211570127163843.stgit@hbathini.in.ibm.com> <148654268436.27983.5340774362600828412.stgit@hbathini.in.ibm.com> Date: Fri, 17 Feb 2017 00:25:27 +1300 In-Reply-To: <148654268436.27983.5340774362600828412.stgit@hbathini.in.ibm.com> (Hari Bathini's message of "Wed, 08 Feb 2017 14:01:24 +0530") Message-ID: <87zihmtm1k.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1ceKG7-0005q2-BB;;;mid=<87zihmtm1k.fsf@xmission.com>;;;hst=in01.mta.xmission.com;;;ip=101.100.131.232;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19QdUuo5JbXQcmKqheR0Np3W+L7WxP/kN8= X-SA-Exim-Connect-IP: 101.100.131.232 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 * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * -0.0 BAYES_40 BODY: Bayes spam probability is 20 to 40% * [score: 0.2416] * -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: ;Hari Bathini X-Spam-Relay-Country: X-Spam-Timing: total 544 ms - load_scoreonly_sql: 0.07 (0.0%), signal_user_changed: 3.2 (0.6%), b_tie_ro: 2.1 (0.4%), parse: 1.16 (0.2%), extract_message_metadata: 3.3 (0.6%), get_uri_detail_list: 0.83 (0.2%), tests_pri_-1000: 4.0 (0.7%), tests_pri_-950: 1.23 (0.2%), tests_pri_-900: 1.02 (0.2%), tests_pri_-400: 18 (3.2%), check_bayes: 17 (3.0%), b_tokenize: 5.0 (0.9%), b_tok_get_all: 5 (1.0%), b_comp_prob: 1.84 (0.3%), b_tok_touch_all: 2.6 (0.5%), b_finish: 0.69 (0.1%), tests_pri_0: 495 (91.0%), check_dkim_signature: 0.52 (0.1%), check_dkim_adsp: 3.1 (0.6%), tests_pri_500: 6 (1.2%), rewrite_mail: 0.00 (0.0%) Subject: Re: [PATCH v6 1/3] perf: add PERF_RECORD_NAMESPACES to include namespaces related info 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 > +/* > + * The maximum size of the name of each namespace > + */ > +#define NS_NAME_SIZE 8 > + > +struct perf_ns_link_info { > + char name[NS_NAME_SIZE]; > + __u64 dev; > + __u64 ino; > +}; Ugh. I missed the name the first time around. That really looks like useless clutter. You already know the index so the name doesn't add any information, so unless I am missing something that name will just slow down the perf kernel implementation with useless work. The userspace reader can have the information just as reliably by looking at the index and indexing into a table. The set of namespaces changes slowly enough that this is not likely to be a problem in practice. Especially as perf is released with the kernel. Plus who knows how long the name of the next namespace is going to be. Eric