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 39339C77B73 for ; Thu, 27 Apr 2023 23:01:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344373AbjD0XBL (ORCPT ); Thu, 27 Apr 2023 19:01:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229912AbjD0XBH (ORCPT ); Thu, 27 Apr 2023 19:01:07 -0400 Received: from mail-pf1-x42c.google.com (mail-pf1-x42c.google.com [IPv6:2607:f8b0:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C421B212F for ; Thu, 27 Apr 2023 16:01:06 -0700 (PDT) Received: by mail-pf1-x42c.google.com with SMTP id d2e1a72fcca58-63b7b18a336so2059785b3a.1 for ; Thu, 27 Apr 2023 16:01:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20221208.gappssmtp.com; s=20221208; t=1682636466; x=1685228466; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=yEIv0mpPqT6iAHQ12FfnifyqYoeAQW4rrtrDxVFk1U8=; b=Do9/pqSIjG1lwOjGDZ90CWJjHVOBweqpeo0Zs/cqh502uf8tNs+7ry8nJci/0hYzvw VxTLFS1CaC7cfPWLwL7Xn1IwAEM7cahAGBIvx6/NEtqeGvjDeZ68+eed7WpYXGFxl7ec 4EWirWJfUxVNUh5CXYuucg0SDYJtmd9L6HJfkNc6XtcQeWpAirjDxNi5M9+K1JmccXCO vPpn8p+5DT/LzB9Y+UZE8sL4aWzSnR5E24wTwMqmXmN6IZYznyDvlFnFO8MvajagvmmD pf3GY4yYkBH6jVSoq2VQaqdS7gMYynCinRL/cnQ+gZRNMuFi1oOMRqOdhxuzzqlp0zfI 45BQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682636466; x=1685228466; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=yEIv0mpPqT6iAHQ12FfnifyqYoeAQW4rrtrDxVFk1U8=; b=UcWnywCtGolnFbDNJTyysUaeo1Nta0eFLW0B4OVlSAzJYWhCx991PeOZgyfk1NpV7J b5KlQurphUGWJ/KRx78OVDEUZJVmqrV2gYCgqs6eAd2aW3ykx4L2Nlk79keWmdUU2VDn uPhXrmiYOZSgLxUYlOfTQDRUA96pK0eEhoEJou61PLd/giDJGVHNQvMt9YAI1sRkeWr6 H5h1/MEIz0ropiidukPmw02ctbua1LX5TGmUNB0crOD21Q9yQs0f2urTpREE5otjtl2k c1GB9Bmom+42xf8JXfK/Xch95PjjRc8Q3ZQDbWfjjoluej08J/WfyOjQQM1Auq0LK8eG 6ktA== X-Gm-Message-State: AC+VfDxzW1AtPrWIZmFhmdt3PUnYRnuX8msSqDzHVar8wgneIKLKe/r1 shSgadgY6vCa2aGwA+ih17AsLg== X-Google-Smtp-Source: ACHHUZ4agbOrasu1chzWjy354jO+EEIA67oWUAcf7l6h4rFBDwFZ9No+KBZyh7mgI5P40TQdekIg6Q== X-Received: by 2002:a05:6a20:440d:b0:f8:ea21:7c4f with SMTP id ce13-20020a056a20440d00b000f8ea217c4fmr3472983pzb.5.1682636466237; Thu, 27 Apr 2023 16:01:06 -0700 (PDT) Received: from [192.168.1.136] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id f17-20020a63f751000000b00502ecb91940sm11903029pgk.55.2023.04.27.16.01.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 27 Apr 2023 16:01:05 -0700 (PDT) Message-ID: <3decbaf1-250b-9b73-70fd-4cb9a204c452@kernel.dk> Date: Thu, 27 Apr 2023 17:01:04 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH] nvmet: Reorder fields in 'struct nvmet_ns' Content-Language: en-US To: Chaitanya Kulkarni , Christophe JAILLET Cc: "linux-kernel@vger.kernel.org" , Sagi Grimberg , Christoph Hellwig , "kernel-janitors@vger.kernel.org" , "linux-nvme@lists.infradead.org" References: From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/27/23 4:59?PM, Chaitanya Kulkarni wrote: > On 4/27/23 12:47, Christophe JAILLET wrote: >> Group some variables based on their sizes to reduce holes. >> On x86_64, this shrinks the size of 'struct nvmet_ns' from 520 to 512 >> bytes. >> > > Although this looks good, we at least need to document what > happens on other arch(s) which are not mentioned in the > commit log ? is there a possibility that someone might come > up with the contradictory data in future for the arch(s) which > arch that are not mentioned here ? The change is certainly not going to make things _worse_ for any arch, so I think that's somewhat of a pointless exercise and an unreasonable ask for something that makes sense on 64-bit arm/x86 and saves half the space. -- Jens Axboe