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 95C42C43603 for ; Wed, 18 Dec 2019 16:56:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C7CE2176D for ; Wed, 18 Dec 2019 16:56:53 +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="Cw3/cX10" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727504AbfLRQ4x (ORCPT ); Wed, 18 Dec 2019 11:56:53 -0500 Received: from mail-io1-f67.google.com ([209.85.166.67]:44217 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727021AbfLRQ4x (ORCPT ); Wed, 18 Dec 2019 11:56:53 -0500 Received: by mail-io1-f67.google.com with SMTP id b10so2678535iof.11 for ; Wed, 18 Dec 2019 08:56:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=rTEAWvowPGiFm5bG98LTp8ro86bKvhqp1ci3ULDNOxE=; b=Cw3/cX10PPDAUYUM5rAGyGOME6Qu+RzUqAQmtd25Lg/C2gnl1JKPerg/GIHijZIZt9 XhVJDbh2y/2QKLauB6fy2cvWemLqWd9Gq+64D27LSHQYbz/b7QMsQIeYkfYl8IubuZk9 a2MaJhq1ioT8tZ7vxwy9ulLODP/ASjy0CZSXVW2jZSFR1Tov9j8Rcez5kHAi3VnQJZwQ wOR1hvatDhTd4Wdoj6B241fKvUaoghBKN8S3fK8cO+sVjk6sgl503k/8I0AZqPCPLTRg r3l9SeeB3eybTXsugdhUtMF11A9i59bZFyDvqpK/VIthYXb3OtSb5unN9+g2zlbDKBEs 1TWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=rTEAWvowPGiFm5bG98LTp8ro86bKvhqp1ci3ULDNOxE=; b=Bxo2g+3uDy5NlJiLcBTeK/9/RYDJidFbRIiwcmSs5q/gep/o413v2y0jqsrJ7L+J66 j1YcYVmfIlmIkm9PrIvUNsn6JIObTzY6oaFvJIjeF2JXMMaaUIn9ryFibLbyVStFWraQ 6m5FslBRfhLtvyhQds2TeQ+3iD8U4RuJD6IkQq6PLv1KzJUe6loKUCv4PVrnVGLJ3afx VEdsqp6AbSKMuroihENZboL7IlTqgzpDh0xu+kjtheEjHctZQ0nTmf/FcKy+Jd3LpEDs Oi4U//EUejlqCUtbVPLHmNwxMYyeaF2oaXUDUG1Q1jdUXI7TViXRbcjIuNuK9v0x3bB2 dX0w== X-Gm-Message-State: APjAAAWrGab9woelgq/GQHyjYusPho7SNpFxusG2bZ2SYwPddo6W4rWD eX2FYwzOKN3P+eOEcabxoa2JWQ== X-Google-Smtp-Source: APXvYqw6HgfbjWrkvdzzoP8foDMwN38PPf5JRmq4JvAUC33lN7IwtCTqA7XbBuU8q9KC3+R9uWtO9Q== X-Received: by 2002:a05:6638:97c:: with SMTP id o28mr3342377jaj.8.1576688212169; Wed, 18 Dec 2019 08:56:52 -0800 (PST) Received: from [192.168.1.159] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id t15sm836936ili.50.2019.12.18.08.56.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 18 Dec 2019 08:56:51 -0800 (PST) Subject: Re: [PATCH v5] io_uring: don't wait when under-submitting To: Pavel Begunkov , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: <28aad565ed6c3a3a03975377aa62035b1b0a4d97.1576687827.git.asml.silence@gmail.com> From: Jens Axboe Message-ID: <7b684479-d0f9-4e74-b947-5ceba577734a@kernel.dk> Date: Wed, 18 Dec 2019 09:56:51 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <28aad565ed6c3a3a03975377aa62035b1b0a4d97.1576687827.git.asml.silence@gmail.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 12/18/19 9:53 AM, Pavel Begunkov wrote: > There is no reliable way to submit and wait in a single syscall, as > io_submit_sqes() may under-consume sqes (in case of an early error). > Then it will wait for not-yet-submitted requests, deadlocking the user > in most cases. > > Don't wait/poll if can't submit all sqes This looks great, thanks, applied. -- Jens Axboe