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=-2.3 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 4D5AEC35242 for ; Tue, 11 Feb 2020 20:06:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 28CF620842 for ; Tue, 11 Feb 2020 20:06:04 +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="KRHyrqNS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728211AbgBKUGD (ORCPT ); Tue, 11 Feb 2020 15:06:03 -0500 Received: from mail-io1-f54.google.com ([209.85.166.54]:44197 "EHLO mail-io1-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727762AbgBKUGD (ORCPT ); Tue, 11 Feb 2020 15:06:03 -0500 Received: by mail-io1-f54.google.com with SMTP id z16so13205665iod.11 for ; Tue, 11 Feb 2020 12:06:03 -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=FpfPq3R5BrbBpww0mfOuGDw22fVDFzP/524w9CLu6mQ=; b=KRHyrqNSDxIMsZdwtDfUcrGNHZX8fO5+AMBBp77tQ3BImF8myvb9Tlg5pGaGwQXaMe 7Z6QAGZrkxn1EAvFgKDrRNiPPsQAvD2kS8VGHyeJJSsSRgg47fnXny2Sys72PdKn8DyM F8nMer356fLFhGFu9PEStq5NEQYBGvOBpNF3ntireRy+DKjyBRvvznmnRAJmoVsZzlwD e8JjeznJrSf0G7TgKKZ/16espGwF4ngs4rvBicb2gIGlJp7RWp6Lggse4BUkBVFq1pel x70gbS/2wUZ8Pmq8HMkwf8Wu6BjpKnHwoGgDhF4fSjebREYgvuGUC7UF0bdyxeYxgjDS lvwQ== 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=FpfPq3R5BrbBpww0mfOuGDw22fVDFzP/524w9CLu6mQ=; b=Z2xYvCg22eO8XeldLK+3jrZFf7vUxiHTNOcOuRLvAyyv1RCC0xNFczBdrEGVUy2Eqh xZvF/JXC7Tu7m9oSMiZ/XER4fwkiTvnzebzgdD+92fKXmzMzq4dxxTZFNnaJhUj7Xs4T WnitC2/2Pkhd19EypUqEOHIA2jPREUfHd344jhcuk42753zcmaxV+N7ND2dXyBe/qbJK JEjS8DRiC4wIxDEjkQ/2sh+KoBz/x2DA91SZ/E91rUR8PJ5XLMWqpPy7aKp3Z5vo0XkA nj3e5aZ0O0L89U/5jZqXSSz6mJf97C7bdzZbzNJUlO2Lm8oMEQ6wqpy93SZAIIrb0W5B +gIg== X-Gm-Message-State: APjAAAWLy7z0V+F/RfmsLTGq6K0pVbjfc09R1+p9K/i6rBDGqGGoBb8z rgZMbGrMT/T8Yy6l+xD8fcYjqlwFelU= X-Google-Smtp-Source: APXvYqxVxu/yxM3wBRIjOc54AlbRq5Iqa4VCNcxvPsMIP8KrZ84ouSrPOHT529K1Ogdp83RpAOPeQw== X-Received: by 2002:a6b:e601:: with SMTP id g1mr14593759ioh.55.1581451562546; Tue, 11 Feb 2020 12:06:02 -0800 (PST) Received: from [192.168.1.159] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id a21sm1289717ioh.29.2020.02.11.12.06.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 11 Feb 2020 12:06:02 -0800 (PST) Subject: Re: [PATCHSET 0/3] io_uring: make POLL_ADD support multiple waitqs To: Pavel Begunkov , io-uring@vger.kernel.org References: <20200210205650.14361-1-axboe@kernel.dk> From: Jens Axboe Message-ID: <692a561c-9176-63fa-3c48-7f37a8214057@kernel.dk> Date: Tue, 11 Feb 2020 13:06:00 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: 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 2/11/20 1:01 PM, Pavel Begunkov wrote: > On 10/02/2020 23:56, Jens Axboe wrote: >> As mentioned in the previous email, here are the three patches that add >> support for multiple waitqueues for polling with io_uring. >> >> Patches 1-2 are just basic prep patches, and should not have any >> functional changes in them. Patch 3 adds support for allocating a new >> io_poll_iocb unit if we get multiple additions through our queue proc >> for the wait queues. This new 'poll' addition is queued up as well, and >> it grabs a reference to the original poll request. >> >> Please do review, would love to get this (long standing) issue fixed as >> it's a real problem for various folks. >> > > I need to dig a bit deeper into poll to understand some moments, but there is a > question: don't we won't to support arbitrary number of waitqueues then? In theory, probably. But in practice, don't think anything exists with > 2 waitqueues. As mentioned, even the 2 waitqueue case is limited to less than a handful of users. But the patch should for sure check this, and -EINVAL if we get a third entry attempted. -- Jens Axboe