Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761158Ab3DBOYz (ORCPT ); Tue, 2 Apr 2013 10:24:55 -0400 Received: from mail-bk0-f49.google.com ([209.85.214.49]:42117 "EHLO mail-bk0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760885Ab3DBOYy (ORCPT ); Tue, 2 Apr 2013 10:24:54 -0400 Message-ID: <1364912689.3399.7.camel@host5.opentask.org> Subject: Re: [PATCH v2] wait while adding MMC host to ensure root mounts From: Sergey Yanovich To: Adrian Hunter Cc: Chris Ball , Ulf Hansson , Greg Kroah-Hartman , Linus Walleij , Jaehoon Chung , Namjae Jeon , linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org Date: Tue, 02 Apr 2013 18:24:49 +0400 In-Reply-To: <515ADEDE.3050707@intel.com> 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> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.2-0ubuntu0.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1183 Lines: 37 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? 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 > 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(); -- 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/