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 DB032C433EF for ; Thu, 10 Mar 2022 15:43:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229596AbiCJPoy (ORCPT ); Thu, 10 Mar 2022 10:44:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50258 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229475AbiCJPox (ORCPT ); Thu, 10 Mar 2022 10:44:53 -0500 Received: from mail-io1-xd31.google.com (mail-io1-xd31.google.com [IPv6:2607:f8b0:4864:20::d31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E844A184628 for ; Thu, 10 Mar 2022 07:43:52 -0800 (PST) Received: by mail-io1-xd31.google.com with SMTP id c23so6904697ioi.4 for ; Thu, 10 Mar 2022 07:43:52 -0800 (PST) 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 :references:from:in-reply-to:content-transfer-encoding; bh=3JIu9tzm5dKlKuyfvYx+Vl4iuiC9S4DyMD+M32fzD0Q=; b=ULMaM5cbJ8wx8E4T13nbmEOihjpOF2N5kU6c588eYd0xjcJB6WbMtKhV0pAn3uOASM ZGVoKinqlZRE/s2MNFWDTlU2fEOkoSO7lpi1EwikX0Aifzr+EmIUj4yEf9lmvoo9hzhz fv2Zl+/eUdllRRz/nJDLFWdJ2rG4xi8YLTCXxpTrc+5TB9LCK24pNPaqtZDPYGDsJN2C wuqNWS50tXnWUmm7OhErzRrIDT+U3SeXpULZcXfbhm41bGqZvM6jHgQQCcwrsgNVDS5M dunafg/kp1RuoqSWexjoKXjcOVf2saS2Rdy+D1MD+OJkrdpDHJg5N2u15U0uzDVCSukO lnQw== 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:references:from:in-reply-to :content-transfer-encoding; bh=3JIu9tzm5dKlKuyfvYx+Vl4iuiC9S4DyMD+M32fzD0Q=; b=ExImoZf25VVHZKdWBTIG8h3idl1LzOD1nyteB1WF4sDOKvz7YpIlTDrPqRffJ0yz7p +btQazRyFgtVdQQS0dWRz8oaPM7MgJc63jaVeUGjHtehJa3awtMs2z5b+TmDwYmVgJ3F 6azMGDlnNZGXkeiCPvGdZ3pSV5FL+ofzeNtkGT+6BiLgXGA8YtRT/c1L0JI/gOcLkkng xxSykM70J5eeJK1Ij2/cqC3syRT6arOCaxSqqvdrdvcCVJE8Z+c8yGc/njvOnS0IFblA 6s0ZWH+t5E+Y+9pxTT+mQ0WR1wbockk6CDWvs9fH0oRSXFv54MWDgMGcleoepXdBAN+e yL2A== X-Gm-Message-State: AOAM530PJmh6FnVJP0pu2TXSCtf/caIjCmRtSI+GxsnCcdto/L5lL7HU X7bvoE6Om+WtEzSDo8E17KDMQA== X-Google-Smtp-Source: ABdhPJxyzeG3VkOh7ClGnKIDn4DzwDNS+7sQhnHO+NOsdYgnNqeveZEHzrwfHxXn0KZ1l9rnInpZcA== X-Received: by 2002:a02:6a5e:0:b0:317:cb94:d0f7 with SMTP id m30-20020a026a5e000000b00317cb94d0f7mr4387071jaf.11.1646927032248; Thu, 10 Mar 2022 07:43:52 -0800 (PST) Received: from [192.168.1.172] ([207.135.234.126]) by smtp.gmail.com with ESMTPSA id t10-20020a056602140a00b00648b2f4d60esm597858iov.28.2022.03.10.07.43.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Mar 2022 07:43:51 -0800 (PST) Message-ID: <1bfafa03-8f5f-be7a-37a5-f3989596ff5a@kernel.dk> Date: Thu, 10 Mar 2022 08:43:51 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: Sending CQE to a different ring Content-Language: en-US To: Artyom Pavlov , io-uring@vger.kernel.org References: <478d1650-139b-f02b-bebf-7d54aa24eae2@kernel.dk> <9f8c753d-fed4-08ac-7b39-aee23b8ba04c@kernel.dk> <0cbbe6d4-048d-9acb-2ea4-599d41f8eb28@gmail.com> From: Jens Axboe In-Reply-To: <0cbbe6d4-048d-9acb-2ea4-599d41f8eb28@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 3/10/22 8:36 AM, Artyom Pavlov wrote: > After thinking about it a bit, I think this approach has one serious > disadvantage: you lose successful result value of the initial request. > Imagine we submit IORING_OP_READ and link IORING_OP_WAKEUP_RING to it. > If the request is completed successfully, both ring1 and ring2 will > lose number of read bytes. But you know what the result is, otherwise you would've gotten a cqe posted if it wasn't what you asked for. -- Jens Axboe