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 DA853C61DA4 for ; Wed, 15 Mar 2023 19:10:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232625AbjCOTKe (ORCPT ); Wed, 15 Mar 2023 15:10:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232237AbjCOTKd (ORCPT ); Wed, 15 Mar 2023 15:10:33 -0400 Received: from mail-il1-x132.google.com (mail-il1-x132.google.com [IPv6:2607:f8b0:4864:20::132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0060B570B7 for ; Wed, 15 Mar 2023 12:10:28 -0700 (PDT) Received: by mail-il1-x132.google.com with SMTP id l9so7802386iln.1 for ; Wed, 15 Mar 2023 12:10:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; t=1678907428; x=1681499428; 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=FqIUWL49gOnBQOdYINMYdbzx0C9jJ4cqoE/J1/KRSUw=; b=oYYwwldYHC7TBk82xDbOuoDVKGbkRqnhpnQuu8n+RMNqKKKSp08E2HPGYf/yOWHMYq MkKlgIvtv5608qyQDds4vvisg0YCh1Bfn+LSZ3uGQ1DVBl9mtgT4Ka3cR4XdaywOeR8f YRMf0KBAamjwkOM2rVu2CFKdR4tp2qjkJYraqMT5uYg2kO9dt0ydv792YMY8fPKCraAG NfmGVk/lyjAa3xGkGw4ELAXHQF28nvpPj8vnOKmWIBMgqugUPgy6Mg55UP/1zIV4UcCc 0zlMnhMl9laH6+X+fTJ1DcH0ZRszzJlR13u8gNknffRYpGi2Xs/GoDXdR2lfOQRA0dfl N0SQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678907428; x=1681499428; 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=FqIUWL49gOnBQOdYINMYdbzx0C9jJ4cqoE/J1/KRSUw=; b=PtDu6iNj+pQ4nrkK+j/tIEkRx1MPR7RifCfAAVm8Cu0L6rYcbhq2sIbu2OsR9XZA2C oPv45yICcIFVBHg8sD/M3fcD3yzotzFz30pOkMcfCjtnCq8dywIOdMnG/am+yJSj69a9 Th0EnLHAC1xzn5Kb5+klLEDhw1R86tam7pOPmKJ3VxffnSw9B33YHAUxlZVHRr6eEb4w oV8MK992OucOfF02oeubul1q+3n2jipap+E6YFUy/Wu1x2hohyzqGNyJE4wCzgJkk4QJ R+D+9LNKaqkwYQPspH43e81FmD6mGaNmvvx9TxwHUquGfn5DPksKkL97Pi4gTkQGCu1K pkxw== X-Gm-Message-State: AO0yUKVlwmb+ohOCUQ0CZWZgiIWrgHNwZM5jHTfP5DLp3zSLLWHtkSIQ 2jX9ZoH1POVIK4cbjnS3q2Frrg== X-Google-Smtp-Source: AK7set8J26niHNh/3V/fslXVnCiDAuLHDWPShiSCV4pJIh9snXib4NM+TeRPcJUNZRJ4X0aDKEosoA== X-Received: by 2002:a05:6e02:1a88:b0:316:67be:1b99 with SMTP id k8-20020a056e021a8800b0031667be1b99mr2730516ilv.0.1678907428255; Wed, 15 Mar 2023 12:10:28 -0700 (PDT) Received: from [192.168.1.94] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id v5-20020a02b905000000b003f8765183cesm1892370jan.87.2023.03.15.12.10.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 15 Mar 2023 12:10:27 -0700 (PDT) Message-ID: Date: Wed, 15 Mar 2023 13:10:26 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: Resizing io_uring SQ/CQ? Content-Language: en-US To: Stefan Hajnoczi Cc: Ming Lei , io-uring@vger.kernel.org References: <20230309134808.GA374376@fedora> <2f928d56-a2ff-39ef-f7ae-b6cc1da4fc42@kernel.dk> <20230310134400.GB464073@fedora> <20230315151524.GA14895@fedora> <20230315190147.GA7517@fedora> From: Jens Axboe In-Reply-To: <20230315190147.GA7517@fedora> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 3/15/23 1:01?PM, Stefan Hajnoczi wrote: > On Wed, Mar 15, 2023 at 09:19:39AM -0600, Jens Axboe wrote: >> On 3/15/23 9:15?AM, Stefan Hajnoczi wrote: >>> Hi Ming and Jens, >>> It would be great if you have time to clarify whether deadlocks can >>> occur or not. If you have any questions about the scenario I was >>> describing, please let me know. >> >> I don't believe there is. In anything not ancient, you are always >> allowed to submit and the documentation should be updated to >> describe that correctly. We don't return -EBUSY for submits with >> overflow pending. > > Thank you both for the discussion! It has helped. Would like to add that while I don't think ring resizing is necessary because of any potential deadlocks, I do think CQ ring resizing would be a useful addition to avoid networked applications using giant CQ ring sizes by default... If we had that, you could start smaller and make it larger if you ran into overflows. -- Jens Axboe