Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759497AbcLPIVB (ORCPT ); Fri, 16 Dec 2016 03:21:01 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:53644 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752944AbcLPIUx (ORCPT ); Fri, 16 Dec 2016 03:20:53 -0500 Date: Fri, 16 Dec 2016 08:57:03 +0100 From: Peter Zijlstra To: Hari Bathini Cc: ast@fb.com, lkml , acme@kernel.org, alexander.shishkin@linux.intel.com, mingo@redhat.com, daniel@iogearbox.net, rostedt@goodmis.org, Ananth N Mavinakayanahalli , ebiederm@xmission.com, sargun@sargun.me, Aravinda Prasad , brendan.d.gregg@gmail.com Subject: Re: [PATCH v4 1/3] perf: add PERF_RECORD_NAMESPACES to include namespaces related info Message-ID: <20161216075703.GE3124@twins.programming.kicks-ass.net> References: <148182699546.5314.279803283347257825.stgit@hbathini.in.ibm.com> <148182702692.5314.556699668213767056.stgit@hbathini.in.ibm.com> <20161215184646.GP3107@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1422 Lines: 52 On Fri, Dec 16, 2016 at 11:57:47AM +0530, Hari Bathini wrote: > > > On Friday 16 December 2016 12:16 AM, Peter Zijlstra wrote: > >On Fri, Dec 16, 2016 at 12:07:06AM +0530, Hari Bathini wrote: > >>+struct perf_ns_link_info { > >>+ __u64 dev; > >>+ __u64 ino; > >>+}; > >>+ > >>+enum { > >>+ NET_NS_INDEX = 0, > >>+ UTS_NS_INDEX = 1, > >>+ IPC_NS_INDEX = 2, > >>+ PID_NS_INDEX = 3, > >>+ USER_NS_INDEX = 4, > >>+ MNT_NS_INDEX = 5, > >>+ CGROUP_NS_INDEX = 6, > >>+ > >>+ NAMESPACES_MAX, /* maximum available namespaces */ > >>+}; > >>+ > >> enum perf_event_type { > >> /* > >>@@ -862,6 +880,17 @@ enum perf_event_type { > >> */ > >> PERF_RECORD_SWITCH_CPU_WIDE = 15, > >>+ /* > >>+ * struct { > >>+ * struct perf_event_header header; > >>+ * u32 pid; > >>+ * u32 tid; > >>+ * struct namespace_link_info link_info[NAMESPACES_MAX]; > >>+ * struct sample_id sample_id; > >>+ * }; > >>+ */ > >>+ PERF_RECORD_NAMESPACES = 16, > >>+ > >> PERF_RECORD_MAX, /* non-ABI */ > >> }; > >What happens if a future kernel adds another namespace? > > > > No impact unless NAMESPACES_MAX in include/uapi/linux/perf_event.h is > updated to accommodate that.. > And if it is updated, the corresponding change is expected in perf-tool as > well.. And what happens if you try and process old data files with the new tools or the other way around? You must not expect lock-step updates for this to work.