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=-5.1 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,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 1FDD6C433E0 for ; Fri, 29 May 2020 08:59:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E43AD20776 for ; Fri, 29 May 2020 08:59:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jY6t650K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725562AbgE2I7v (ORCPT ); Fri, 29 May 2020 04:59:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725306AbgE2I7v (ORCPT ); Fri, 29 May 2020 04:59:51 -0400 Received: from mail-wm1-x344.google.com (mail-wm1-x344.google.com [IPv6:2a00:1450:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A932CC03E969 for ; Fri, 29 May 2020 01:59:50 -0700 (PDT) Received: by mail-wm1-x344.google.com with SMTP id h4so2336708wmb.4 for ; Fri, 29 May 2020 01:59:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=to:cc:references:from:autocrypt:subject:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=wqlpNHf32+vSr/onlAfZWWc/BiqZixBWCu54HMPoOSs=; b=jY6t650KWyW1YiFswXHVCZwqcTIAgX60XhE/5AXO8T+JCfTlDricoznH+O3mnpnpD4 sGlvKAGMtVq2UiT2xmMtj0ftGN7zbHGAT4PrbiRyyFftJtNQf3cjpRpKWwEwjdSsQV9G HkoiwrjjX7n5N1EQfU3WDhYazNVA1aOv/VeIB5xb5QznZMAjaKfep6FDiWiGNrduqZB6 KP73+aV+aJ2KCdE1EJxnolv2bgBR1RifVqrl93qjMVLqv6phWDmmgYX0czeQCXKC27K4 XJgva8LPQIqU2H6PkyS5XHs8sCfRgQ/8ob2EVqHy5Cue1o3kVl3mg3DxtjMvxMc9Crn9 aAXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:references:from:autocrypt:subject :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=wqlpNHf32+vSr/onlAfZWWc/BiqZixBWCu54HMPoOSs=; b=raA6CbXVtoPmnhw9LhkPFQPaa3T4UfrgSfnbeVSTdGhD8JWm9pMXdzLwEc/An9inJ3 MisRIxz9uuxpruZs+aX5opXCXBb8VFwy7BWo4yPp23AqeFelERCI6WJTpObUN8cIb1xM JNBQzmB/E+TquSlmFsFl5OZF8R4DOfwoJtpqV9+3P9nWD0pinsXBQ1mt0Qv612Kn6Tu/ gzwd7tqJeLPzPfVST9aU8LXaFJtRB/LkoQqTaMbNjtJr0/GXZtdPWlCSSFk/ab5sks66 FH3p4Z1xhnyuq10TGSGSbVKhUV3x0sOJYw8j9yl7YDdVRsWUZrPAc8fxpGAh26jcQTok 85zw== X-Gm-Message-State: AOAM531nRw+SVRtEUTdUxy76XZsrIghKIaNpfFoTsGQGcdO7BoPdAER+ r3wGi0KB4PkdcNVt+iz9bOM95FyF X-Google-Smtp-Source: ABdhPJzdTWMhH+kgryTm+Ne/Mee/1U6+tyW0lulwttD1Ynf0d5ry6/d9ooLBL7PVRRLuJn6k5kCuWQ== X-Received: by 2002:a1c:c3d7:: with SMTP id t206mr7637917wmf.69.1590742789099; Fri, 29 May 2020 01:59:49 -0700 (PDT) Received: from [192.168.43.204] ([5.100.193.151]) by smtp.gmail.com with ESMTPSA id o20sm9326249wra.29.2020.05.29.01.59.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 29 May 2020 01:59:48 -0700 (PDT) To: Xiaoguang Wang , io-uring@vger.kernel.org Cc: axboe@kernel.dk, joseph.qi@linux.alibaba.com References: <20200528091550.3169-1-xiaoguang.wang@linux.alibaba.com> 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== Subject: Re: [PATCH v3 1/2] io_uring: avoid whole io_wq_work copy for requests completed inline Message-ID: Date: Fri, 29 May 2020 11:58:33 +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: <20200528091550.3169-1-xiaoguang.wang@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 28/05/2020 12:15, Xiaoguang Wang wrote: > If requests can be submitted and completed inline, we don't need to > initialize whole io_wq_work in io_init_req(), which is an expensive > operation, add a new 'REQ_F_WORK_INITIALIZED' to control whether > io_wq_work is initialized. It looks nicer. Especially if you'd add a helper as Jens supposed. The other thing, even though I hate treating a part of the fields differently from others, I don't like ->creds tossing either. Did you consider trying using only ->work.creds without adding req->creds? like in the untested incremental below. init_io_work() there is misleading, should be somehow played around better. diff --git a/fs/io_uring.c b/fs/io_uring.c index 4dd3295d74f6..4086561ce444 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -643,7 +643,6 @@ struct io_kiocb { unsigned int flags; refcount_t refs; struct task_struct *task; - const struct cred *creds; unsigned long fsize; u64 user_data; u32 result; @@ -894,8 +893,16 @@ static const struct file_operations io_uring_fops; static inline void init_io_work(struct io_kiocb *req, void (*func)(struct io_wq_work **)) { - req->work = (struct io_wq_work){ .func = func }; - req->flags |= REQ_F_WORK_INITIALIZED; + struct io_wq_work *work = &req->work; + + /* work->creds are already initialised by a user */ + work->list.next = NULL; + work->func = func; + work->files = NULL; + work->mm = NULL; + work->fs = NULL; + work->flags = REQ_F_WORK_INITIALIZED; + work->task_pid = 0; } struct sock *io_uring_get_socket(struct file *file) { @@ -1019,15 +1026,9 @@ static inline void io_req_work_grab_env(struct io_kiocb *req, mmgrab(current->mm); req->work.mm = current->mm; } + if (!req->work.creds) + req->work.creds = get_current_cred(); - if (!req->work.creds) { - if (!req->creds) - req->work.creds = get_current_cred(); - else { - req->work.creds = req->creds; - req->creds = NULL; - } - } if (!req->work.fs && def->needs_fs) { spin_lock(¤t->fs->lock); if (!current->fs->in_exec) { @@ -1044,6 +1045,12 @@ static inline void io_req_work_grab_env(struct io_kiocb *req, static inline void io_req_work_drop_env(struct io_kiocb *req) { + /* always init'ed, put before REQ_F_WORK_INITIALIZED check */ + if (req->work.creds) { + put_cred(req->work.creds); + req->work.creds = NULL; + } + if (!(req->flags & REQ_F_WORK_INITIALIZED)) return; @@ -1051,10 +1058,6 @@ static inline void io_req_work_drop_env(struct io_kiocb *req) mmdrop(req->work.mm); req->work.mm = NULL; } - if (req->work.creds) { - put_cred(req->work.creds); - req->work.creds = NULL; - } if (req->work.fs) { struct fs_struct *fs = req->work.fs; @@ -5901,12 +5904,12 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, id = READ_ONCE(sqe->personality); if (id) { - req->creds = idr_find(&ctx->personality_idr, id); - if (unlikely(!req->creds)) + req->work.creds = idr_find(&ctx->personality_idr, id); + if (unlikely(!req->work.creds)) return -EINVAL; - get_cred(req->creds); + get_cred(req->work.creds); } else - req->creds = NULL; + req->work.creds = NULL; /* same numerical values with corresponding REQ_F_*, safe to copy */ req->flags |= sqe_flags; -- Pavel Begunkov