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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 15BDDC433E0 for ; Fri, 12 Jun 2020 15:16:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E70012081A for ; Fri, 12 Jun 2020 15:16:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="kfBL7U52" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726257AbgFLPQV (ORCPT ); Fri, 12 Jun 2020 11:16:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34932 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726085AbgFLPQV (ORCPT ); Fri, 12 Jun 2020 11:16:21 -0400 Received: from mail-pj1-x1033.google.com (mail-pj1-x1033.google.com [IPv6:2607:f8b0:4864:20::1033]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C7922C03E96F for ; Fri, 12 Jun 2020 08:16:20 -0700 (PDT) Received: by mail-pj1-x1033.google.com with SMTP id ne5so3759013pjb.5 for ; Fri, 12 Jun 2020 08:16:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=UCrHdKLCx3hRMwZHAdg0DDwTbcc5Psxh1fcWsWBlr4E=; b=kfBL7U52bxTsCEDomkzMljEikamArlpMkVv31vbAhaB4fj90AmUkYbFxieHRK/zOQF 0CO5+rOrs+3Su6G9CzWgBDe/VE7HYLUUVF2t0tT7d6IxQPvzciU9d8ac0XOkcTvIvqqn uf7UL+7H6XyL8zjmDt/mkbhJvUYQXaG0856S0OmPoy7MyVLvtZGxpKroJQn2LnrtCLlF HIPeyQR23bCLcCsEOmgi+k/KqPmyNe/LR0HmlZaDuyrmfRBF5Pj11jWQyx6EHwQdNqMP z3ecEprjfSC5NB5Iczg95lYEVULCRbVISB9IsRb3U9tEtbFV1g5bOGEL4QylXOsP5t6O XAMg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=UCrHdKLCx3hRMwZHAdg0DDwTbcc5Psxh1fcWsWBlr4E=; b=P2Kb+y4xKxK6wyrrfBny/X3+Ww1o1SWUHNGwsgNf2JVzJzTSBxd8AIHVTe1r1F1k8P +DjfZm4WkRuz+QvIJdHII3WuAnt5319PPzDsVoyKswVQlAi/EIvZuC3K0Zv/JIiu/DZm wfNigPrWL3Z8qi2qht9L+heRH6WAug9eSXy/yUGHuGspR7ZJqiqSr6PaaxBTLKLO1GDJ y3i+c3F3iOJgey9OKsPsX+tkrZ5ccdxmuLCWxzBZ+nvN9iOU/BrPiNYQJGaziwwhYRs3 CDRc/ZF0f0jo4jARBwB7cl7xd69xHg5avUDD/vVsIg/2wcmdCvvA4jAdnjWVoSK+Mv88 +W/w== X-Gm-Message-State: AOAM531g+HPimMQwp9HfSfsXhiqZ0ooIHR2Yq21BrOgLYFcz2oI1yis7 0Jfa8ZQMNQqEyM323fb9vjGpnPNqFbjDrQ== X-Google-Smtp-Source: ABdhPJzjJ8yVH63e89kuuOD1q9znZi7pI5gKcCMW4zVTn+BnH3WX5HzlJvnL59AFyC3ViPxtkZbWoA== X-Received: by 2002:a17:90a:d206:: with SMTP id o6mr12237595pju.132.1591974979419; Fri, 12 Jun 2020 08:16:19 -0700 (PDT) Received: from [192.168.1.188] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id d22sm5777525pgh.64.2020.06.12.08.16.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 12 Jun 2020 08:16:18 -0700 (PDT) Subject: Re: [RFC 1/2] io_uring: disallow overlapping ranges for buffer registration To: Bijan Mottahedeh Cc: io-uring@vger.kernel.org References: <1591928617-19924-1-git-send-email-bijan.mottahedeh@oracle.com> <1591928617-19924-2-git-send-email-bijan.mottahedeh@oracle.com> From: Jens Axboe Message-ID: Date: Fri, 12 Jun 2020 09:16:17 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <1591928617-19924-2-git-send-email-bijan.mottahedeh@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 6/11/20 8:23 PM, Bijan Mottahedeh wrote: > Buffer registration is expensive in terms of cpu/mem overhead and there > seems no good reason to allow overlapping ranges. There's also no good reason to disallow it imho, so not sure we should be doing that. -- Jens Axboe