From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [patch for 2.6.33? 1/1] ata: call flush_dcache_page() around PIO data transfers in libata-aff.c Date: Wed, 03 Feb 2010 12:52:34 -0500 Message-ID: <4B69B7E2.4070808@pobox.com> References: <1265151518.2800.715.camel@mulgrave.site> <20100202150537.0f6a01c0.akpm@linux-foundation.org> <4B68B1E0.4090004@pobox.com> <20100202.152140.216335166.davem@davemloft.net> <1265153568.2800.815.camel@mulgrave.site> <1265192325.1970.28.camel@pc1117.cambridge.arm.com> <1265215254.2873.201.camel@mulgrave.site> <4B69ABCA.1030507@pobox.com> <20100203090631.44753f3b.akpm@linux-foundation.org> <4B69AF42.5050508@pobox.com> <20100203174620.0fba7837@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-yw0-f198.google.com ([209.85.211.198]:57505 "EHLO mail-yw0-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932788Ab0BCRwi (ORCPT ); Wed, 3 Feb 2010 12:52:38 -0500 Received: by ywh36 with SMTP id 36so1507112ywh.15 for ; Wed, 03 Feb 2010 09:52:37 -0800 (PST) In-Reply-To: <20100203174620.0fba7837@lxorguk.ukuu.org.uk> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: Andrew Morton , James Bottomley , Catalin Marinas , David Miller , jeff@garzik.org, linux-ide@vger.kernel.org, stable@kernel.org, tj@kernel.org On 02/03/2010 12:46 PM, Alan Cox wrote: > And indeed there was a patch I proposed in 2008 for this bounce > buffer latency: See the archive > > Date: Fri, 29 Feb 2008 13:51:06 +0000 > From: Alan Cox > To: linux-ide@vger.kernel.org, jeff@garzik.org > Subject: [RFC PATCH] libata: PIO via bounce buffer > > although it doesn't deal with the dcache coherency issue and seems to > need a little tweaking to apply due to other changes Yeah, I definitely liked the idea. I wonder if we could do the allocation during port_start rather than at the time of bounce? One maximally-sized buffer per device should not be too punishing on the system, IMO. In any case, it is a nice approach to pursue. Jeff