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 91E3CC77B7A for ; Wed, 17 May 2023 18:23:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229633AbjEQSXd (ORCPT ); Wed, 17 May 2023 14:23:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229525AbjEQSXa (ORCPT ); Wed, 17 May 2023 14:23:30 -0400 Received: from mail-pl1-f181.google.com (mail-pl1-f181.google.com [209.85.214.181]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E0D4AD26; Wed, 17 May 2023 11:23:16 -0700 (PDT) Received: by mail-pl1-f181.google.com with SMTP id d9443c01a7336-1ae3fe67980so12194915ad.3; Wed, 17 May 2023 11:23:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684347796; x=1686939796; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=yBzWQWarXz9+zZ2Mc7G87KcpNXJGB6yUDNeKIXNCtSA=; b=UkskJbNeTvAcm426IjPFfI97COAA4aWhhnz5GPsmfnfuh/V7HtzmqytwwVvC4p/Tos w0pofK8JW2hn+YZh6oeoVEj/hHFeNrC1dT1JPnG0U7AG9IHcZyf5alG+G9h/PKKN95jb 3cVwtm0bUFt2tqK/d89M/bz4nfc1KrCmji6NkbA+mghmXaZjqmIJjO1uUJ4vFCmk6YwJ c1MNQrcQEmj7+pk1R9LQnuh2HN2R+3FoTQtHUAZXbi04OXBRzQ1P3CjypNbzMYoieU47 ybiaO95UMmH0gudjsDFmuxGAMFsGjzwIDOtbuMPbRDjpo2RtDCLfEqcSwp2J4injT1Am W6EQ== X-Gm-Message-State: AC+VfDwG/R1fmlKcif8Lul9X6RNPzOMJvI2XLrE37cAm9SBb8CULFwEt Zs7Y3UNVWEQ/GWSdv7S8Rbg= X-Google-Smtp-Source: ACHHUZ4YGGTWAES+ifNoAmfqzMuyp7rgF6Rhkiiru7ruMgSKKpN7kzpCCSfJrIQ7EJbOmjWIGpTfVQ== X-Received: by 2002:a17:903:124f:b0:1ac:451d:34a with SMTP id u15-20020a170903124f00b001ac451d034amr54880269plh.33.1684347796297; Wed, 17 May 2023 11:23:16 -0700 (PDT) Received: from [192.168.51.14] ([98.51.102.78]) by smtp.gmail.com with ESMTPSA id b9-20020a170902650900b001a6dc4f4a8csm18010196plk.73.2023.05.17.11.23.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 May 2023 11:23:15 -0700 (PDT) Message-ID: <097caed2-10b3-7cd1-7c06-90f983e5c720@acm.org> Date: Wed, 17 May 2023 11:23:13 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH 2/2] ufs: don't use the fair tag sharings Content-Language: en-US To: Yu Kuai , Christoph Hellwig Cc: Ed Tsai , axboe@kernel.dk, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, martin.petersen@oracle.com, stanley.chu@mediatek.com, peter.wang@mediatek.com, chun-hung.wu@mediatek.com, alice.chao@mediatek.com, powen.kao@mediatek.com, naomi.chu@mediatek.com, wsd_upstream@mediatek.com, "yukuai (C)" References: <20230509065230.32552-1-ed.tsai@mediatek.com> <20230509065230.32552-3-ed.tsai@mediatek.com> <2740ee82-e35f-1cbf-f5d0-373f94eb14a5@acm.org> <86065501-ab2e-09b4-71cd-c0b18ede00ed@acm.org> From: Bart Van Assche In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/17/23 00:49, Yu Kuai wrote: > 在 2023/05/16 23:12, Bart Van Assche 写道: >> I propose that we switch to one of these two approaches: > > How about a smoothing method that the device with more io will share > more tag, and each device will get at least one tag? Hi Yu, hctx_may_queue() is called from the hot path (blk_mq_get_tag()). I'm pretty sure that adding any nontrivial code in that path will cause a performance (IOPS) regression. So I don't think that adding a smoothing method in hctx_may_queue() is a realistic option. Thanks, Bart.