Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763638Ab3DDGal (ORCPT ); Thu, 4 Apr 2013 02:30:41 -0400 Received: from mga11.intel.com ([192.55.52.93]:22807 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763424Ab3DDGak (ORCPT ); Thu, 4 Apr 2013 02:30:40 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,405,1363158000"; d="scan'208";a="313415653" Message-ID: <515D1F4E.1080306@intel.com> Date: Thu, 04 Apr 2013 09:35:58 +0300 From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Sergey Yanovich CC: Chris Ball , Ulf Hansson , Greg Kroah-Hartman , Linus Walleij , Jaehoon Chung , Namjae Jeon , linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org Subject: Re: [PATCH v2] wait while adding MMC host to ensure root mounts References: <1363223183-3772-1-git-send-email-ynvich@gmail.com> <1363224194-7366-1-git-send-email-ynvich@gmail.com> <87620jmkoe.fsf@octavius.laptop.org> <87ppylf429.fsf@octavius.laptop.org> <515ADEDE.3050707@intel.com> <1364912689.3399.7.camel@host5.opentask.org> In-Reply-To: <1364912689.3399.7.camel@host5.opentask.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1434 Lines: 50 On 02/04/13 17:24, Sergey Yanovich wrote: > On Tue, 2013-04-02 at 16:36 +0300, Adrian Hunter wrote: >> On my system it is significant: >> >> Before the patch: >> >> [ 1.625623] VFS: Mounted root (ext4 filesystem) readonly on device 179:2. >> >> After the patch: >> >> [ 1.935851] VFS: Mounted root (ext4 filesystem) readonly on device 179:2. >> >> That is an addition of 310 ms which is 19% performance degradation. > > Are you sure the delay is caused by mmc? Yes > > On my intel laptop (userspace is Debian/unstable): > [ 1.542339] EXT4-fs (sda2): mounted filesystem with ordered data mode. Opts: (null) > ... > [ 2.735851] mmc0: new high speed SD card at address e624 > [ 2.742289] mmcblk0: mmc0:e624 SU02G 1.84 GiB > [ 2.752317] mmcblk0: p1 No, I am booting from eMMC. > >> Please revert the patch. > > Chris, could provide a pointer on how to improve the patch? > > Maybe introduce mmc_is_hosting_root() and do something like: > > - mmc_flush_scheduled_work(); > + if (mmc_is_hosting_root()) > + mmc_flush_scheduled_work(); No, I am booting from eMMC. Perhaps a host capability: if (host->caps2 & MMC_CAP2_ROOTWAIT) mmc_flush_scheduled_work(); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/