From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756544Ab0ANLXt (ORCPT ); Thu, 14 Jan 2010 06:23:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756403Ab0ANLXs (ORCPT ); Thu, 14 Jan 2010 06:23:48 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:39944 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756375Ab0ANLXr (ORCPT ); Thu, 14 Jan 2010 06:23:47 -0500 Subject: Re: [RFC] [PATCH 7/7] Ftrace plugin for Uprobes From: Peter Zijlstra To: Srikar Dronamraju Cc: Ingo Molnar , Arnaldo Carvalho de Melo , Ananth N Mavinakayanahalli , utrace-devel , Jim Keniston , Frederic Weisbecker , Masami Hiramatsu , Maneesh Soni , Mark Wielaard , LKML In-Reply-To: <20100111122608.22050.94088.sendpatchset@srikar.in.ibm.com> References: <20100111122521.22050.3654.sendpatchset@srikar.in.ibm.com> <20100111122608.22050.94088.sendpatchset@srikar.in.ibm.com> Content-Type: text/plain; charset="UTF-8" Date: Thu, 14 Jan 2010 12:23:11 +0100 Message-ID: <1263468191.4244.300.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2010-01-11 at 17:56 +0530, Srikar Dronamraju wrote: > This patch implements ftrace plugin for uprobes. Right, like others have said, trace events is a much saner interface. So the easiest way I can see that working is to register uprobes against a file (not a pid). Then on creation it uses rmap to find all current maps of that file and install the probe if there is a consumer for that map. Then for each new mmap() of that file, we also need to check if there's a consumer ready and install the probe. The existence of the uprobe trace-event would keep a ref on the dentry/inode, ensuring it remains around or something. Consumers could be some utrace thing (currently called uprobe -- which is a misnomer imo), or perf, or ftrace like.