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=-8.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 72423C433DF for ; Tue, 26 May 2020 07:39:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 42B5C20787 for ; Tue, 26 May 2020 07:39:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Mi+k/GZU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731617AbgEZHj6 (ORCPT ); Tue, 26 May 2020 03:39:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726736AbgEZHj5 (ORCPT ); Tue, 26 May 2020 03:39:57 -0400 Received: from mail-ej1-x644.google.com (mail-ej1-x644.google.com [IPv6:2a00:1450:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F323C061A0E; Tue, 26 May 2020 00:39:56 -0700 (PDT) Received: by mail-ej1-x644.google.com with SMTP id nr22so6370690ejb.6; Tue, 26 May 2020 00:39:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:autocrypt:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=skSMG6X/+WKS/bVjBD77N/pFg3Dhya72NQQT1usQTkk=; b=Mi+k/GZUtchNwfVbDjUj5E6CPwy77us5bbXMOw/Pkj6VWDfYfTspLOncUddCoSIYaH pmmZ/9gfhbnmzM1leOIddqbtvWeToj1tPpROZ/ENqcE44yayPWuIfKtsfFvYKOoMVKFt mK/ahUpkcgY3+DrPqdpYVfUOqwyvuPRSxBh8IpFelFruARbsAcCGIobFNe3iKXvQg+6G BJv8Q439LSstmfG9FIR8F9X+ubttsxFMuPX4SGge7w6uUZdy/PffZyL/VY1clQuiVg67 WZdVu8NnINm7TU+56VqIDTNvCfcQ5V+1slAm4CCWyTcHWME1fuSr8p7bJw3B/gOUlv/G o4Rg== 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:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=skSMG6X/+WKS/bVjBD77N/pFg3Dhya72NQQT1usQTkk=; b=nL7+hVwz7aDR2N8VkCt4+V6sY30UQcJL3othzFi6adfnxhfiJfZRYke6LfNJwkiYy2 kXRJLti2ruvg9JBp9T9XjVfsjJM42sYMdyRDRaBx7YRiXFVmGSYC5xABO7tvBRym0iSI FuSqNs/dgGeVp6xpa8AGYy2cypylOeatzbqqicFWNWAjYipxY14hC7f2jMyf5xH4Db/6 UURoFBEtGQFborXgUpq3c0ckI9Cr6zG5fbfqCC/D0CCuAldyJ6b5WyHcVXx48xDjtN71 2qsCzx3LD8lTxIo3+xxsg4/i/YUSdEDydYDBl0vK4E17RSirzSEQWiifS/4a8DK4cTE/ AXfg== X-Gm-Message-State: AOAM533OjZvUQxPYtnobZHDhPC6LReo8u5lge+fs6NslXfiKnWv2rI+g tnWV5zl4liQ652pU0XqcflQ= X-Google-Smtp-Source: ABdhPJyUJQLtuoRKDJxESdd3vHZdvtsDMFogWIKBb4hMwDgxOG2+203wQ3t2VB/jPhNDJPuV2D0NAA== X-Received: by 2002:a17:906:660f:: with SMTP id b15mr1675ejp.113.1590478795067; Tue, 26 May 2020 00:39:55 -0700 (PDT) Received: from [192.168.43.172] ([5.100.193.151]) by smtp.gmail.com with ESMTPSA id y17sm17471500edo.23.2020.05.26.00.39.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 26 May 2020 00:39:54 -0700 (PDT) Subject: Re: [PATCH 12/12] io_uring: support true async buffered reads, if file provides it To: Jens Axboe , io-uring@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20200523185755.8494-1-axboe@kernel.dk> <20200523185755.8494-13-axboe@kernel.dk> From: Pavel Begunkov Autocrypt: addr=asml.silence@gmail.com; prefer-encrypt=mutual; keydata= mQINBFmKBOQBEAC76ZFxLAKpDw0bKQ8CEiYJRGn8MHTUhURL02/7n1t0HkKQx2K1fCXClbps bdwSHrhOWdW61pmfMbDYbTj6ZvGRvhoLWfGkzujB2wjNcbNTXIoOzJEGISHaPf6E2IQx1ik9 6uqVkK1OMb7qRvKH0i7HYP4WJzYbEWVyLiAxUj611mC9tgd73oqZ2pLYzGTqF2j6a/obaqha +hXuWTvpDQXqcOZJXIW43atprH03G1tQs7VwR21Q1eq6Yvy2ESLdc38EqCszBfQRMmKy+cfp W3U9Mb1w0L680pXrONcnlDBCN7/sghGeMHjGKfNANjPc+0hzz3rApPxpoE7HC1uRiwC4et83 CKnncH1l7zgeBT9Oa3qEiBlaa1ZCBqrA4dY+z5fWJYjMpwI1SNp37RtF8fKXbKQg+JuUjAa9 Y6oXeyEvDHMyJYMcinl6xCqCBAXPHnHmawkMMgjr3BBRzODmMr+CPVvnYe7BFYfoajzqzq+h EyXSl3aBf0IDPTqSUrhbmjj5OEOYgRW5p+mdYtY1cXeK8copmd+fd/eTkghok5li58AojCba jRjp7zVOLOjDlpxxiKhuFmpV4yWNh5JJaTbwCRSd04sCcDNlJj+TehTr+o1QiORzc2t+N5iJ NbILft19Izdn8U39T5oWiynqa1qCLgbuFtnYx1HlUq/HvAm+kwARAQABtDFQYXZlbCBCZWd1 bmtvdiAoc2lsZW5jZSkgPGFzbWwuc2lsZW5jZUBnbWFpbC5jb20+iQJOBBMBCAA4FiEE+6Ju PTjTbx479o3OWt5b1Glr+6UFAlmKBOQCGwMFCwkIBwIGFQgJCgsCBBYCAwECHgECF4AACgkQ Wt5b1Glr+6WxZA//QueaKHzgdnOikJ7NA/Vq8FmhRlwgtP0+E+w93kL+ZGLzS/cUCIjn2f4Q Mcutj2Neg0CcYPX3b2nJiKr5Vn0rjJ/suiaOa1h1KzyNTOmxnsqE5fmxOf6C6x+NKE18I5Jy xzLQoktbdDVA7JfB1itt6iWSNoOTVcvFyvfe5ggy6FSCcP+m1RlR58XxVLH+qlAvxxOeEr/e aQfUzrs7gqdSd9zQGEZo0jtuBiB7k98t9y0oC9Jz0PJdvaj1NZUgtXG9pEtww3LdeXP/TkFl HBSxVflzeoFaj4UAuy8+uve7ya/ECNCc8kk0VYaEjoVrzJcYdKP583iRhOLlZA6HEmn/+Gh9 4orG67HNiJlbFiW3whxGizWsrtFNLsSP1YrEReYk9j1SoUHHzsu+ZtNfKuHIhK0sU07G1OPN 2rDLlzUWR9Jc22INAkhVHOogOcc5ajMGhgWcBJMLCoi219HlX69LIDu3Y34uIg9QPZIC2jwr 24W0kxmK6avJr7+n4o8m6sOJvhlumSp5TSNhRiKvAHB1I2JB8Q1yZCIPzx+w1ALxuoWiCdwV M/azguU42R17IuBzK0S3hPjXpEi2sK/k4pEPnHVUv9Cu09HCNnd6BRfFGjo8M9kZvw360gC1 reeMdqGjwQ68o9x0R7NBRrtUOh48TDLXCANAg97wjPoy37dQE7e5Ag0EWYoE5AEQAMWS+aBV IJtCjwtfCOV98NamFpDEjBMrCAfLm7wZlmXy5I6o7nzzCxEw06P2rhzp1hIqkaab1kHySU7g dkpjmQ7Jjlrf6KdMP87mC/Hx4+zgVCkTQCKkIxNE76Ff3O9uTvkWCspSh9J0qPYyCaVta2D1 Sq5HZ8WFcap71iVO1f2/FEHKJNz/YTSOS/W7dxJdXl2eoj3gYX2UZNfoaVv8OXKaWslZlgqN jSg9wsTv1K73AnQKt4fFhscN9YFxhtgD/SQuOldE5Ws4UlJoaFX/yCoJL3ky2kC0WFngzwRF Yo6u/KON/o28yyP+alYRMBrN0Dm60FuVSIFafSqXoJTIjSZ6olbEoT0u17Rag8BxnxryMrgR dkccq272MaSS0eOC9K2rtvxzddohRFPcy/8bkX+t2iukTDz75KSTKO+chce62Xxdg62dpkZX xK+HeDCZ7gRNZvAbDETr6XI63hPKi891GeZqvqQVYR8e+V2725w+H1iv3THiB1tx4L2bXZDI DtMKQ5D2RvCHNdPNcZeldEoJwKoA60yg6tuUquvsLvfCwtrmVI2rL2djYxRfGNmFMrUDN1Xq F3xozA91q3iZd9OYi9G+M/OA01husBdcIzj1hu0aL+MGg4Gqk6XwjoSxVd4YT41kTU7Kk+/I 5/Nf+i88ULt6HanBYcY/+Daeo/XFABEBAAGJAjYEGAEIACAWIQT7om49ONNvHjv2jc5a3lvU aWv7pQUCWYoE5AIbDAAKCRBa3lvUaWv7pfmcEACKTRQ28b1y5ztKuLdLr79+T+LwZKHjX++P 4wKjEOECCcB6KCv3hP+J2GCXDOPZvdg/ZYZafqP68Yy8AZqkfa4qPYHmIdpODtRzZSL48kM8 LRzV8Rl7J3ItvzdBRxf4T/Zseu5U6ELiQdCUkPGsJcPIJkgPjO2ROG/ZtYa9DvnShNWPlp+R uPwPccEQPWO/NP4fJl2zwC6byjljZhW5kxYswGMLBwb5cDUZAisIukyAa8Xshdan6C2RZcNs rB3L7vsg/R8UCehxOH0C+NypG2GqjVejNZsc7bgV49EOVltS+GmGyY+moIzxsuLmT93rqyII 5rSbbcTLe6KBYcs24XEoo49Zm9oDA3jYvNpeYD8rDcnNbuZh9kTgBwFN41JHOPv0W2FEEWqe JsCwQdcOQ56rtezdCJUYmRAt3BsfjN3Jn3N6rpodi4Dkdli8HylM5iq4ooeb5VkQ7UZxbCWt UVMKkOCdFhutRmYp0mbv2e87IK4erwNHQRkHUkzbsuym8RVpAZbLzLPIYK/J3RTErL6Z99N2 m3J6pjwSJY/zNwuFPs9zGEnRO4g0BUbwGdbuvDzaq6/3OJLKohr5eLXNU3JkT+3HezydWm3W OPhauth7W0db74Qd49HXK0xe/aPrK+Cp+kU1HRactyNtF8jZQbhMCC8vMGukZtWaAwpjWiiH bA== Message-ID: <9c2cc031-e4ce-4c5f-5e14-21ea48c327f6@gmail.com> Date: Tue, 26 May 2020 10:38:40 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: <20200523185755.8494-13-axboe@kernel.dk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/05/2020 21:57, Jens Axboe wrote: > If the file is flagged with FMODE_BUF_RASYNC, then we don't have to punt > the buffered read to an io-wq worker. Instead we can rely on page > unlocking callbacks to support retry based async IO. This is a lot more > efficient than doing async thread offload. > > The retry is done similarly to how we handle poll based retry. From > the unlock callback, we simply queue the retry to a task_work based > handler. > > Signed-off-by: Jens Axboe > --- > fs/io_uring.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 99 insertions(+) > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index e95481c552ff..dd532d2634c2 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -498,6 +498,8 @@ struct io_async_rw { > struct iovec *iov; > ssize_t nr_segs; > ssize_t size; > + struct wait_page_queue wpq; > + struct callback_head task_work; > }; > > struct io_async_ctx { > @@ -2568,6 +2570,99 @@ static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, > return 0; > } > > +static void io_async_buf_cancel(struct callback_head *cb) > +{ > + struct io_async_rw *rw; > + struct io_ring_ctx *ctx; > + struct io_kiocb *req; > + > + rw = container_of(cb, struct io_async_rw, task_work); > + req = rw->wpq.wait.private; > + ctx = req->ctx; > + > + spin_lock_irq(&ctx->completion_lock); > + io_cqring_fill_event(req, -ECANCELED); It seems like it should go through kiocb_done()/io_complete_rw_common(). My concern is missing io_put_kbuf(). > + io_commit_cqring(ctx); > + spin_unlock_irq(&ctx->completion_lock); > + > + io_cqring_ev_posted(ctx); > + req_set_fail_links(req); > + io_double_put_req(req); > +} -- Pavel Begunkov