From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752671AbbBKJpy (ORCPT ); Wed, 11 Feb 2015 04:45:54 -0500 Received: from casper.infradead.org ([85.118.1.10]:37211 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751418AbbBKJpv (ORCPT ); Wed, 11 Feb 2015 04:45:51 -0500 Date: Wed, 11 Feb 2015 10:45:41 +0100 From: Peter Zijlstra To: Alexei Starovoitov Cc: Steven Rostedt , Ingo Molnar , Namhyung Kim , Arnaldo Carvalho de Melo , Jiri Olsa , Masami Hiramatsu , Linux API , Network Development , LKML , Linus Torvalds , "Eric W. Biederman" Subject: Re: [PATCH v3 linux-trace 1/8] tracing: attach eBPF programs to tracepoints and syscalls Message-ID: <20150211094541.GO23123@twins.programming.kicks-ass.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 10, 2015 at 04:22:50PM -0800, Alexei Starovoitov wrote: > well, ->prio and ->pid are already printed by sched tracepoints > and their meaning depends on scheduler. So users taking that > into account. Right, so trace_events were/are root only, and root 'should' be in the root pid namespace, and therefore pid magically works. And I'm not sure, but I don't think the 'nested' root available from containers should have access to ftrace, so that should not be an issue. Perf tries real hard to present PERF_SAMPLE_PID data in the pid namespace of the task that created the event. As to prio; yes this is a prime example of suck, I would love to change that but cannot :-(. The only solace I have is that everybody who is relying on it is broken. There is a very good reason I'm against adding more tracepoints to the scheduler, its a nightmare. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH v3 linux-trace 1/8] tracing: attach eBPF programs to tracepoints and syscalls Date: Wed, 11 Feb 2015 10:45:41 +0100 Message-ID: <20150211094541.GO23123@twins.programming.kicks-ass.net> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Steven Rostedt , Ingo Molnar , Namhyung Kim , Arnaldo Carvalho de Melo , Jiri Olsa , Masami Hiramatsu , Linux API , Network Development , LKML , Linus Torvalds , "Eric W. Biederman" To: Alexei Starovoitov Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On Tue, Feb 10, 2015 at 04:22:50PM -0800, Alexei Starovoitov wrote: > well, ->prio and ->pid are already printed by sched tracepoints > and their meaning depends on scheduler. So users taking that > into account. Right, so trace_events were/are root only, and root 'should' be in the root pid namespace, and therefore pid magically works. And I'm not sure, but I don't think the 'nested' root available from containers should have access to ftrace, so that should not be an issue. Perf tries real hard to present PERF_SAMPLE_PID data in the pid namespace of the task that created the event. As to prio; yes this is a prime example of suck, I would love to change that but cannot :-(. The only solace I have is that everybody who is relying on it is broken. There is a very good reason I'm against adding more tracepoints to the scheduler, its a nightmare.