From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B9DDC54FCB for ; Mon, 27 Apr 2020 18:34:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1998F205C9 for ; Mon, 27 Apr 2020 18:34:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726562AbgD0Seq (ORCPT ); Mon, 27 Apr 2020 14:34:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:49114 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726213AbgD0Sep (ORCPT ); Mon, 27 Apr 2020 14:34:45 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7079D214AF; Mon, 27 Apr 2020 18:34:43 +0000 (UTC) Date: Mon, 27 Apr 2020 14:34:42 -0400 From: Steven Rostedt To: Adrian Hunter Cc: Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Masami Hiramatsu , Borislav Petkov , "H . Peter Anvin" , x86@kernel.org, Mark Rutland , Alexander Shishkin , Mathieu Poirier , Leo Yan , Jiri Olsa , linux-kernel@vger.kernel.org Subject: Re: [PATCH V6 08/15] ftrace: Add perf text poke events for ftrace trampolines Message-ID: <20200427143442.14d929f0@gandalf.local.home> In-Reply-To: <76de871f-fb0a-6918-68a9-94aa7b049d6b@intel.com> References: <20200405201327.7332-1-adrian.hunter@intel.com> <20200405201327.7332-9-adrian.hunter@intel.com> <20200421134504.GQ20730@hirez.programming.kicks-ass.net> <20200422114659.GE20730@hirez.programming.kicks-ass.net> <76de871f-fb0a-6918-68a9-94aa7b049d6b@intel.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 27 Apr 2020 10:23:05 +0300 Adrian Hunter wrote: > On 22/04/20 2:46 pm, Peter Zijlstra wrote: > > On Wed, Apr 22, 2020 at 10:39:06AM +0300, Adrian Hunter wrote: > >> On 21/04/20 4:45 pm, Peter Zijlstra wrote: > >>> On Sun, Apr 05, 2020 at 11:13:20PM +0300, Adrian Hunter wrote: > >>>> Add perf text poke events for ftrace trampolines when created and when > >>>> freed. > >>> > >>> Maybe also put in a little more detail on the various events. Because > >>> arch_ftrace_update_trampoline() can also generate text_poke_bp() events, > >>> to update an existing trampoline. > >>> > >>> A diagram, like with the kprobes thing perhaps. > >> > >> How about adding this: > >> > >> There can be 3 text_poke events for ftrace trampolines: > >> > >> 1. NULL -> trampoline > >> By ftrace_update_trampoline() when !ops->trampoline > >> Trampoline created > >> > >> 2. [e.g. on x86] CALL rel32 -> CALL rel32 > >> By arch_ftrace_update_trampoline() when ops->trampoline and > >> ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP > >> [e.g. on x86] via text_poke_bp() which generates text poke events > >> Trampoline-called function target updated > >> > >> 3. trampoline -> NULL > >> By ftrace_trampoline_free() when ops->trampoline and > >> ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP > >> Trampoline freed > > > > Yes, very nice. Thanks! > > Arnaldo, do you have this patchset on your radar? Arnaldo deals with the userspace perf code. This looks like it needs to go through the x86 tree. -- Steve