Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932521Ab0GOGC7 (ORCPT ); Thu, 15 Jul 2010 02:02:59 -0400 Received: from arkanian.console-pimps.org ([212.110.184.194]:60299 "EHLO arkanian.console-pimps.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932499Ab0GOGC5 (ORCPT ); Thu, 15 Jul 2010 02:02:57 -0400 From: Matt Fleming To: Anton Vorontsov Cc: Andrew Morton , Wolfram Sang , Albert Herranz , Ben Dooks , Pierre Ossman , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org Subject: Re: [PATCH 0/8] sdhci: Move real work out of an atomic context In-Reply-To: <20100714130728.GA27339@oksana.dev.rtsoft.ru> References: <20100714130728.GA27339@oksana.dev.rtsoft.ru> User-Agent: Notmuch/0.3.1-61-g3f63bb6 (http://notmuchmail.org) Emacs/23.1.90.2 (x86_64-unknown-linux-gnu) Date: Thu, 15 Jul 2010 07:02:55 +0100 Message-ID: <87oce9z3hs.fsf@linux-g6p1.site> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1148 Lines: 26 On Wed, 14 Jul 2010 17:07:28 +0400, Anton Vorontsov wrote: > Hi all, > > Currently the sdhci driver does everything in the atomic context. > And what is worse, PIO transfers are made from the IRQ handler. > > This causes huge latencies (up to 120 ms). On some P2020 SOCs, > DMA and card detection is broken, which means that kernel polls > for the card via PIO transfers every second. Needless to say > that this is quite bad. > > So, this patch set reworks sdhci code to avoid atomic context, > almost completely. We only do two device memory operations > in the atomic context, and all the rest is threaded. > > I noticed no throughput drop neither with PIO transfers nor > with DMA (tested on MPC8569E CPU), while latencies should be > greatly improved. I haven't had time to read these patches in detail yet but they all seem to be sensible changes. A very nice series! -- 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/