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[2620:137:e000::1:20]) by mx.google.com with ESMTP id z24-20020a170906945800b0098e0739532fsi2263469ejx.732.2023.07.11.07.21.19; Tue, 11 Jul 2023 07:21:43 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=LqyzUctD; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231208AbjGKNe6 (ORCPT + 99 others); Tue, 11 Jul 2023 09:34:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230513AbjGKNe4 (ORCPT ); Tue, 11 Jul 2023 09:34:56 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41B45E6F; Tue, 11 Jul 2023 06:34:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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=+BmIGfZ8mUxPdweCAo3LBuoEvRT/aOTQDEICBJuQjnQ=; b=LqyzUctD7qNU+lRe3xpcVLzJXL lyynTs8AalGWPmlguziXZ3eYQuuuRmVeRZoDZm4kSNAVdK8tm1Kb7M1fYzHLG/BHfGiobLsfXJQ0G EEqKDLvd33Cbkzrlvtr8plnm2pSMVs87m4F17jLPlzJFGD9my+8zlDwXFqPPW/vKv00ju5QCbOW64 J/nFMFi+Uo6dJo7zRaMxErfQduotAqFnvUJ7k33Gn66EOtEaxOitTAABrkID8f9BwOmALB7sqv1es TomKmuBQWf5DUntx2sHabJ7LZBA+/I4qoIVLippGZzqwVTM7gtbaQFNFKWpGSp1iUREYtcrkTez4W jb03/mLg==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qJDVh-00Fl0B-2f; Tue, 11 Jul 2023 13:34:33 +0000 Date: Tue, 11 Jul 2023 14:34:33 +0100 From: Matthew Wilcox To: Zehao Zhang Cc: linkinjeon@kernel.org, sj1557.seo@samsung.com, rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH v2] exfat: Add ftrace support for exfat and add some tracepoints Message-ID: References: <20230711122208.65020-1-zhangzehao@vivo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230711122208.65020-1-zhangzehao@vivo.com> X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 11, 2023 at 08:22:08PM +0800, Zehao Zhang wrote: > Add ftrace support for exFAT file system, > and add some tracepoints: Why? I don't believe these are useful. Because if you actually had use for them, you would have noticed that you're missing 99% of the reads issued to the filesystem from the VFS -- through exfat_readahead(), which you didn't instrument. So what do you actually want to know, and why can't you get that information already?