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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 D3EA7C55189 for ; Wed, 22 Apr 2020 11:47:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD9D120784 for ; Wed, 22 Apr 2020 11:47:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="natgqUeB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727911AbgDVLrK (ORCPT ); Wed, 22 Apr 2020 07:47:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48590 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726061AbgDVLrJ (ORCPT ); Wed, 22 Apr 2020 07:47:09 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF091C03C1A8 for ; Wed, 22 Apr 2020 04:47:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=5c36qYY3DsYBZqhdm79liDlMg19bbaAYWX92R1Gw6eU=; b=natgqUeBA6dgCiDbTbPcUIlXX4 SwaEKqzAYYHwPR0vlt0gJZt/Pmi5IMy1nHFTXSVAXq1eHJ5e/84PSvH1hFk7pRvopHB+6hwhxB8Tm j5fknpXYs+qizeLjU2zHv65TQBeAa349ck/MCGhfpazI0ujLHkzzZ+Pq3QOQt/R3heHUCMbsDNdW/ PUFub2fddHUbnOl9jIFW2+Din4OiDuryB6nrnn8w0yyw+ytp4ObeHOwv9JJr2EwNT1VQfvZCzSHH4 NUE4DoQCuynSdNhEHZNyGFm8p44eEGwzvde0HzubAnE1KQADrQDH75JjGIQVp3jCMftyxRxPB//FL MMGhvdFg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jRDqH-0001jV-FH; Wed, 22 Apr 2020 11:47:01 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 43D95306064; Wed, 22 Apr 2020 13:46:59 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 2ACB6203AA837; Wed, 22 Apr 2020 13:46:59 +0200 (CEST) Date: Wed, 22 Apr 2020 13:46:59 +0200 From: Peter Zijlstra To: Adrian Hunter Cc: Ingo Molnar , Masami Hiramatsu , Steven Rostedt , Borislav Petkov , "H . Peter Anvin" , x86@kernel.org, Mark Rutland , Alexander Shishkin , Mathieu Poirier , Leo Yan , Arnaldo Carvalho de Melo , Jiri Olsa , linux-kernel@vger.kernel.org Subject: Re: [PATCH V6 08/15] ftrace: Add perf text poke events for ftrace trampolines Message-ID: <20200422114659.GE20730@hirez.programming.kicks-ass.net> References: <20200405201327.7332-1-adrian.hunter@intel.com> <20200405201327.7332-9-adrian.hunter@intel.com> <20200421134504.GQ20730@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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!