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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B400FC04FDF for ; Fri, 21 Jul 2023 17:25:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230411AbjGURZF convert rfc822-to-8bit (ORCPT ); Fri, 21 Jul 2023 13:25:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229902AbjGURZA (ORCPT ); Fri, 21 Jul 2023 13:25:00 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 968F026BF; Fri, 21 Jul 2023 10:24:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 312D461D5E; Fri, 21 Jul 2023 17:24:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17FEDC433C7; Fri, 21 Jul 2023 17:24:55 +0000 (UTC) Date: Fri, 21 Jul 2023 13:24:54 -0400 From: Steven Rostedt To: Nadav Amit Cc: Ajay Kaher , "shuah@kernel.org" , "mhiramat@kernel.org" , Ching-lin Yu , Linux Kernel Mailing List , "linux-kselftest@vger.kernel.org" , "linux-trace-kernel@vger.kernel.org" , kernel test robot , "oe-lkp@lists.linux.dev" , Alexey Makhalov , "er.ajay.kaher@gmail.com" , "srivatsa@csail.mit.edu" , Tapas Kundu , Vasavi Sirnapalli Subject: Re: [PATCH v4 00/10] tracing: introducing eventfs Message-ID: <20230721132454.07d6c8b2@gandalf.local.home> In-Reply-To: <66DACCE8-1C57-4A30-8ACF-D88179CA6381@vmware.com> References: <1689248004-8158-1-git-send-email-akaher@vmware.com> <20230714185824.62556254@gandalf.local.home> <883F9774-3E76-4346-9988-2788FAF0D55E@vmware.com> <20230718094005.32516161@gandalf.local.home> <2CD72098-08E2-4CAA-B74D-D8C44D318117@vmware.com> <20230719102310.552d3356@gandalf.local.home> <899D0823-A1B2-4A6F-A5BA-0D707F41C3D4@vmware.com> <20230719144046.746af82e@gandalf.local.home> <20230721084839.4a97a595@gandalf.local.home> <20230721091947.0df9fd73@gandalf.local.home> <66DACCE8-1C57-4A30-8ACF-D88179CA6381@vmware.com> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org On Fri, 21 Jul 2023 17:17:24 +0000 Nadav Amit wrote: > > I also added a "is_freed" field that is part of the union and is set if > > list elements have content. Note, since the union was criticized before, I > > will state the entire purpose of doing this patch set is to save memory. > > This structure will be used for every event file. What's the point of > > getting rid of dentries if we are replacing it with something just as big? > > Anyway, struct dentry does the exact same thing! > > Hey, don’t shoot me… ;-) > > [And admittedly, I didn’t review the whole series after v1.] > > I understand your position, but I think that at least is_freed should not > be in the union, and you can just put it after umode_t. > > Even for the matter of size, it should not matter in most architectures > since umode_t is 16-bit, as natural alignment is at least 32-bits. My new code I'm working on removes the umode_t and will require this then. I rather have that part tested before adding other drastic changes. -- Steve > > [ And “bool" is clearer type for is_freed. ] >