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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 547E9C070C3 for ; Fri, 14 Sep 2018 06:19:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0679E20866 for ; Fri, 14 Sep 2018 06:19:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0679E20866 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727710AbeINLcJ (ORCPT ); Fri, 14 Sep 2018 07:32:09 -0400 Received: from mga07.intel.com ([134.134.136.100]:36159 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726891AbeINLcJ (ORCPT ); Fri, 14 Sep 2018 07:32:09 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Sep 2018 23:19:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,372,1531810800"; d="scan'208";a="83431493" Received: from ahunter-desktop.fi.intel.com (HELO [10.237.72.98]) ([10.237.72.98]) by orsmga003.jf.intel.com with ESMTP; 13 Sep 2018 23:18:59 -0700 Subject: Re: [PATCH RFC] scsi: ufs: Disable blk-mq for now To: Ming Lei Cc: "Martin K . Petersen" , "James E . J . Bottomley" , Jens Axboe , Christoph Hellwig , Johannes Thumshirn , Bart Van Assche , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Stanislav Nijnikov , Evan Green , Vinayak Holikatti , Janek Kotas , Vivek Gautam , Asutosh Das , Subhash Jadavani , Sayali Lokhande , Li Wei , Bjorn Andersson , Jaegeuk Kim , Alim Akhtar , Alex Lemberg References: <20180913112848.7807-1-adrian.hunter@intel.com> <20180913120459.GA4965@ming.t460p> <20180914015237.GC11059@ming.t460p> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: <2fdfc038-5b86-243c-9b0a-f294d281e5c0@intel.com> Date: Fri, 14 Sep 2018 09:17:14 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180914015237.GC11059@ming.t460p> 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 14/09/18 04:52, Ming Lei wrote: > On Thu, Sep 13, 2018 at 03:15:39PM +0300, Adrian Hunter wrote: >> On 13/09/18 15:05, Ming Lei wrote: >>> On Thu, Sep 13, 2018 at 02:28:48PM +0300, Adrian Hunter wrote: >>>> blk-mq does not support runtime pm, so disable blk-mq support for now. >>> >>> So could you describe a bit what the issue you are trying to fix? >> >> UFS is a low-power solution, so we must be able to runtime suspend. >> >>> >>> This is host level runtime PM you are trying to address, and if blk-mq >>> runtime isn't enabled, I guess the host won't be runtime suspended at all >>> because some of its descendant are always active. >>> >>> So seems we need to do nothing for preventing the host controller from >>> entering runtime suspend. >> >> We don't want to prevent the host controller from runtime suspending, quite >> the opposite. > > OK, got it. > > However, in previous discussion, it is strongly objected to use > per-driver/device .use_blk_mq switch, so not sure if this way can > be accepted. It is only needed for 4.19 so far. Otherwise just revert d5038a13eca7 ("scsi: core: switch to scsi-mq by default") > > BTW, I just posted the runtime PM enablement patches[1] for blk-mq, > and I verified that it works fine and passed blktests & xfstest & my > other sanity tests, could you try it on UFS? > > [1] https://marc.info/?l=linux-block&m=153684095523409&w=2 I will give it a go. Obviously, if those patches go in, we wouldn't need to disable blk-mq anymore, but that isn't until 4.20 at least. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [PATCH RFC] scsi: ufs: Disable blk-mq for now Date: Fri, 14 Sep 2018 09:17:14 +0300 Message-ID: <2fdfc038-5b86-243c-9b0a-f294d281e5c0@intel.com> References: <20180913112848.7807-1-adrian.hunter@intel.com> <20180913120459.GA4965@ming.t460p> <20180914015237.GC11059@ming.t460p> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180914015237.GC11059@ming.t460p> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Ming Lei Cc: "Martin K . Petersen" , "James E . J . Bottomley" , Jens Axboe , Christoph Hellwig , Johannes Thumshirn , Bart Van Assche , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Stanislav Nijnikov , Evan Green , Vinayak Holikatti , Janek Kotas , Vivek Gautam , Asutosh Das , Subhash Jadavani , Sayali Lokhande , Li Wei , Bjorn Andersson , Jaegeuk Kim List-Id: linux-scsi@vger.kernel.org On 14/09/18 04:52, Ming Lei wrote: > On Thu, Sep 13, 2018 at 03:15:39PM +0300, Adrian Hunter wrote: >> On 13/09/18 15:05, Ming Lei wrote: >>> On Thu, Sep 13, 2018 at 02:28:48PM +0300, Adrian Hunter wrote: >>>> blk-mq does not support runtime pm, so disable blk-mq support for now. >>> >>> So could you describe a bit what the issue you are trying to fix? >> >> UFS is a low-power solution, so we must be able to runtime suspend. >> >>> >>> This is host level runtime PM you are trying to address, and if blk-mq >>> runtime isn't enabled, I guess the host won't be runtime suspended at all >>> because some of its descendant are always active. >>> >>> So seems we need to do nothing for preventing the host controller from >>> entering runtime suspend. >> >> We don't want to prevent the host controller from runtime suspending, quite >> the opposite. > > OK, got it. > > However, in previous discussion, it is strongly objected to use > per-driver/device .use_blk_mq switch, so not sure if this way can > be accepted. It is only needed for 4.19 so far. Otherwise just revert d5038a13eca7 ("scsi: core: switch to scsi-mq by default") > > BTW, I just posted the runtime PM enablement patches[1] for blk-mq, > and I verified that it works fine and passed blktests & xfstest & my > other sanity tests, could you try it on UFS? > > [1] https://marc.info/?l=linux-block&m=153684095523409&w=2 I will give it a go. Obviously, if those patches go in, we wouldn't need to disable blk-mq anymore, but that isn't until 4.20 at least.