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=-14.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 5CADBC64E8A for ; Thu, 3 Dec 2020 12:10:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 00C8122201 for ; Thu, 3 Dec 2020 12:10:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388092AbgLCMKS (ORCPT ); Thu, 3 Dec 2020 07:10:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46656 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387983AbgLCMKR (ORCPT ); Thu, 3 Dec 2020 07:10:17 -0500 Received: from mail-wr1-x441.google.com (mail-wr1-x441.google.com [IPv6:2a00:1450:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A58B3C061A4F for ; Thu, 3 Dec 2020 04:09:36 -0800 (PST) Received: by mail-wr1-x441.google.com with SMTP id r3so1648097wrt.2 for ; Thu, 03 Dec 2020 04:09:36 -0800 (PST) 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=OCau6oXg+hbo5fJT9AdjUS3+erlq6n4fyJwsTvZG488=; b=uiL2W88i7rChbgRLAeb+6raRQpm10s5reG5LChrKJ2jntK0mwXqD6+dTvv8ls+YkXd +DXeGMIQygZH1U7TVK+p5a8NDTivjf3EkYFXZkSGBYq195cn/kuUwAcPl2eeRAepqXgs ERmrNsJAwB4nwyiCYe7yi9Rc6V8FYl4QpDKjKmQRHwdbJTL1uIS1ygaCPMOkYdX0BhTg 8M9OKhsDnawIhxwYxBVio7HzhNBmsWSAIxsNEl1PmGzh/HR1RHM76ktTMfToz8GMzKzN 66dmCnjDh2v6VBek/+PcsyKUF6RQ/msEZCvtz1RJ79TTNtDqoxUQoPfCheKGNDT2iWlA 0HwA== 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=OCau6oXg+hbo5fJT9AdjUS3+erlq6n4fyJwsTvZG488=; b=AV889DzQF2tzb/Od3Qh9AWQ8iL64U7W6001SoHIwnvH3d1I1hhbjRpjy1UId5MZ3bb CpyBIe2+PB9w1l57MRkutOjhl1LU8d8d3Ud6s9MX8fj4ngyXIJPASGGKmXPWmgOsx2Qf YqrtUMRgJXtugPTkU5L0+vTxf7GHzejhs9I21luh9TiwTl96xcnI3J0faTUv+bxoZa4h llRiYBcRCryJgCXfl3G3IBl/BGI0bV1WhG2MJOkf+PxCKWj6trqDYRNUIBDtSJIUeCqf VtpwI47TS3GNIJVQpf9q6SL4lArVbJWP0eRnIttARvOMSKBok2jt4Qhe77ZC+DhQuE/y Js8w== X-Gm-Message-State: AOAM5321mNE8/NvSClmiuyV+adVWo1XqwDTObdJJ7Ex8XghxKrGBMCd1 ltxZkBETIeN6SU1/8ufYiY5UwHNqeD9Wlw== X-Google-Smtp-Source: ABdhPJwC6WxUgn3RISx1+sadw/1e6iqShf3xCvHf0BGMwYZF1xkkvtgMsVbrNkHfW8bmveRytolaKg== X-Received: by 2002:adf:ea47:: with SMTP id j7mr3378241wrn.126.1606997375089; Thu, 03 Dec 2020 04:09:35 -0800 (PST) Received: from [192.168.1.59] (host109-152-100-189.range109-152.btcentralplus.com. [109.152.100.189]) by smtp.gmail.com with ESMTPSA id u23sm1255994wmc.32.2020.12.03.04.09.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 03 Dec 2020 04:09:34 -0800 (PST) To: Ming Lei Cc: Jens Axboe , linux-block@vger.kernel.org References: <20201203064931.GB629758@T590> 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 1/3] blk-mq: use right tag offset after wait Message-ID: <0997fd49-5d8c-375f-14be-d2d19b3cd8ee@gmail.com> Date: Thu, 3 Dec 2020 12:06:20 +0000 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: <20201203064931.GB629758@T590> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 03/12/2020 06:49, Ming Lei wrote: > On Mon, Nov 30, 2020 at 01:36:25AM +0000, Pavel Begunkov wrote: >> blk_mq_get_tag() selects tag_offset in the beginning and doesn't update >> it even though the tag set it may have changed hw queue during waiting. >> >> Signed-off-by: Pavel Begunkov >> --- >> block/blk-mq-tag.c | 7 +++++-- >> 1 file changed, 5 insertions(+), 2 deletions(-) >> >> diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c >> index 9c92053e704d..dbbf11edf9a6 100644 >> --- a/block/blk-mq-tag.c >> +++ b/block/blk-mq-tag.c >> @@ -101,10 +101,8 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) >> return BLK_MQ_NO_TAG; >> } >> bt = tags->breserved_tags; >> - tag_offset = 0; >> } else { >> bt = tags->bitmap_tags; >> - tag_offset = tags->nr_reserved_tags; >> } >> >> tag = __blk_mq_get_tag(data, bt); >> @@ -167,6 +165,11 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) >> sbitmap_finish_wait(bt, ws, &wait); >> >> found_tag: >> + if (data->flags & BLK_MQ_REQ_RESERVED) >> + tag_offset = 0; >> + else >> + tag_offset = tags->nr_reserved_tags; >> + > > So far, the tag offset is tag-set wide, and 'tag_offset' is same for all tags, > looks no need to add the extra check. Thanks for clearing that. I still think that's a good thing to do as more apparent to me and shouldn't be slower -- it unconditionally stores offset on-stack, even for no-wait path (gcc 9.2). With it's optimised more like if (!(data->flags & BLK_MQ_REQ_RESERVED)) tag += tags->nr_reserved_tags; I like assembly a bit more, but not like that matters much. -- Pavel Begunkov