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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 2A222C4360F for ; Tue, 2 Apr 2019 13:13:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 032B4206B8 for ; Tue, 2 Apr 2019 13:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730819AbfDBNNx (ORCPT ); Tue, 2 Apr 2019 09:13:53 -0400 Received: from mga14.intel.com ([192.55.52.115]:46880 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729732AbfDBNNw (ORCPT ); Tue, 2 Apr 2019 09:13:52 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Apr 2019 06:13:51 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,300,1549958400"; d="scan'208";a="147363778" Received: from ahunter-desktop.fi.intel.com (HELO [10.237.72.198]) ([10.237.72.198]) by orsmga002.jf.intel.com with ESMTP; 02 Apr 2019 06:13:48 -0700 Subject: Re: [PATCH v2 1/8] mmc: sdhci: Get rid of finish_tasklet To: Faiz Abbas , Ulf Hansson Cc: Linux Kernel Mailing List , DTML , "linux-mmc@vger.kernel.org" , linux-omap , Rob Herring , Mark Rutland , Kishon , Chunyan Zhang , Grygorii Strashko References: <20190215192033.24203-1-faiz_abbas@ti.com> <20190215192033.24203-2-faiz_abbas@ti.com> <65f24027-005a-4372-8819-45e6a360bfce@intel.com> <987a3616-8530-7247-ce00-6513a6c2d4bc@ti.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: <99e1b9cb-8eef-9ef2-4caa-3d5c98e9c6f3@intel.com> Date: Tue, 2 Apr 2019 16:12:29 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <987a3616-8530-7247-ce00-6513a6c2d4bc@ti.com> 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 2/04/19 10:59 AM, Faiz Abbas wrote: > Hi Adrian, > > On 26/03/19 1:03 PM, Adrian Hunter wrote: >> On 18/03/19 11:33 AM, Ulf Hansson wrote: >>> + Arnd, Grygorii >>> >>> On Fri, 15 Feb 2019 at 20:17, Faiz Abbas wrote: >>>> >>>> sdhci.c has two bottom halves implemented. A threaded_irq for handling >>>> card insert/remove operations and a tasklet for finishing mmc requests. >>>> With the addition of external dma support, dmaengine APIs need to >>>> terminate in non-atomic context before unmapping the dma buffers. >>>> >>>> To facilitate this, remove the finish_tasklet and move the call of >>>> sdhci_request_done() to the threaded_irq() callback. Also move the >>>> interrupt result variable to sdhci_host so it can be populated from >>>> anywhere inside the sdhci_irq handler. >>>> >>>> Signed-off-by: Faiz Abbas >>> >>> Adrian, I think it makes sense to apply this patch, even if there is >>> very minor negative impact throughput wise. >>> >>> To me, it doesn't seems like MMC/SD/SDIO has good justification for >>> using tasklets, besides from the legacy point of view, of course. >>> Instead, I think we should try to move all mmc hosts into using >>> threaded IRQs. >>> >>> So, what do you think? Can you overlook the throughput drop and >>> instead we can try to recover this on top with other optimizations? >> >> I tend to favour good results as expressed here: >> >> https://lkml.org/lkml/2007/6/22/360 >> >> So I want to do optimization first. >> >> But performance is not the only problem with the patch. Give me a few >> days and I will see what I can come up with. >> > > Gentle ping on this. Working on it :-)