Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756726AbaF3Stw (ORCPT ); Mon, 30 Jun 2014 14:49:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11625 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753896AbaF3Stv (ORCPT ); Mon, 30 Jun 2014 14:49:51 -0400 Date: Mon, 30 Jun 2014 20:48:28 +0200 From: Oleg Nesterov To: Namhyung Kim Cc: Steven Rostedt , Masami Hiramatsu , Srikar Dronamraju , Tom Zanussi , "zhangwei(Jovi)" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/4] tracing/uprobes: Revert "Support mix of ftrace and perf" Message-ID: <20140630184828.GA24594@redhat.com> References: <20140627170116.GA18298@redhat.com> <20140627170136.GA18319@redhat.com> <87k37z54lu.fsf@sejong.aot.lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87k37z54lu.fsf@sejong.aot.lge.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Namhyung, On 06/30, Namhyung Kim wrote: > > On Fri, 27 Jun 2014 19:01:36 +0200, Oleg Nesterov wrote: > > > > This would be easy to fix, but there are other reasons why it is not > > simple to mix ftrace and perf. If nothing else, they can't share the > > same ->consumer.filter. This is fixable too, but probably we need to > > fix the poorly designed uprobe_register() interface first. At least > > "register" and "apply" should be clearly separated. > > Hmm.. right. It seems the current filter logic only cares about the > perf. If ftrace comes after perf, it might not see some events due to > the filter, right? Yes. Or vice versa, ftrace can miss the events because perf can return UPROBE_HANDLER_REMOVE. Or ftrace can come after perf, but in this case it should call uprobe_apply() or it won't add the new breakpoints. Actually, I'll probably try to make the patch tomorrow. It looks simple enough, the main complication is CONFIG_PERF. And, to keep this patch simple, I won't try to optimize (say) the TP_FLAG_TRACE-comes-first case which could avoid uprobe_apply(). Yes, I still think it would be better to change the register/unregister API first, but I do not know when I do this ;) > > Cc: stable@vger.kernel.org # v3.14 > > Signed-off-by: Oleg Nesterov > > Acked-by: Namhyung Kim Thanks! Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/