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 35A2FC433EF for ; Fri, 20 May 2022 15:11:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350667AbiETPLp (ORCPT ); Fri, 20 May 2022 11:11:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238626AbiETPLn (ORCPT ); Fri, 20 May 2022 11:11:43 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A1DEB27FD1 for ; Fri, 20 May 2022 08:11:41 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id 31so7963896pgp.8 for ; Fri, 20 May 2022 08:11:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=wxiN51YttqZ6z8fn+6Jl5O1G3wTtjehvYfZKGeCzivo=; b=Y+pGUbnBoLUnlLA1uF2J2yJF+IOMvaOD2i4b6UV4fT0xQqtLbMIAoHur1VUew3lM97 akpMrzQF+E5fE+Rv5zvFa4gT2QovZe8xXeyQsSU76A/FBvZHOCH54/z0Xjfykd8eT8Ly 4UFHrZP/vFnjKTzlPZvGamifckr3W6vgMz7OmMfzdIwjQcOPJ5Yh26mKbo7ZfqaudznU fKGGORUaU2+g9DICqxTdAXkWu/uZatg6zNr565w7g+o82mErYRZtrU+5E29MA/+sTiBB d16zObHt2h0tuaY53fY3OCK10uhnRsnDHDE6vXIzHMeEUsTq/JjytmcXFrCFTzkpBvaB frpQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=wxiN51YttqZ6z8fn+6Jl5O1G3wTtjehvYfZKGeCzivo=; b=FB8Jy8FCADwYQQzMWx3OKvilQhrzmsGc865aMOQmSdGakS30w3tSZmBf+297ly7Gwl bXSGbUYgK9vlrviZV55Xy0eRCU7ltDuI9SgQjd+YF/BsAZxZC5QjcszOMqal7amr3apN 7jK2x09oS1RBf5GV9I9QtCE93H7edjnRsb81uvkR4Sj1laegkqQ/X1ECwIof+zMc66ny melpLmwLaqN7TYOvT2GalPvagEpkiT1GAzrNif0mcNDglcqfIJKIByG2VE7a5pPJknCn TL+gTsQnROLkvY+BgRpRepqj+xyow7r6Dv0xR4L+Un1zox7trN7GLjtlF6hsUdZ6qo4S rgFA== X-Gm-Message-State: AOAM533sWSAW8XzW0GX7g1iWLAgDU5nHoswrRzzgB7tpI6b1rJJREtbY WXwADy/n5OaIUtl1RDXVEuZTNXwx2pKvBw== X-Google-Smtp-Source: ABdhPJwRV1X63bl22cDKl3x/sUYr059BW2U+nCt9VcX4EsGouTekPNDfERRgA6Uw3hIIXVjzsM/HeA== X-Received: by 2002:a05:6a00:ad2:b0:4f1:2734:a3d9 with SMTP id c18-20020a056a000ad200b004f12734a3d9mr10475427pfl.61.1653059501102; Fri, 20 May 2022 08:11:41 -0700 (PDT) Received: from [192.168.1.100] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id k22-20020a170902761600b001614cd997a8sm5803656pll.236.2022.05.20.08.11.40 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 20 May 2022 08:11:40 -0700 (PDT) Message-ID: Date: Fri, 20 May 2022 09:11:39 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH] char/mem: only use {read,write}_iter, not the old {read,write} functions Content-Language: en-US To: Al Viro , "Jason A. Donenfeld" Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org References: <20220520135030.166831-1-Jason@zx2c4.com> 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 5/20/22 9:09 AM, Al Viro wrote: > On Fri, May 20, 2022 at 03:50:30PM +0200, Jason A. Donenfeld wrote: >> Currently mem.c implements both the {read,write}_iter functions and the >> {read,write} functions. But with {read,write} going away at some point >> in the future, > > Not likely to happen, unfortunately. > >> and most kernel code made to prefer {read,write}_iter, >> there's no point in keeping around the old code. > > Profile and you'll see ;-/ Weren't you working on bits to get us to performance parity there? What's the status of that? It really is an unfortunate situation we're currently in with two methods for either read or write, with one being greatly preferred as we can pass in non-file associated state (like IOCB_NOWAIT, etc) but the older variant being a bit faster. It lives us in a bad place, imho. -- Jens Axboe