From mboxrd@z Thu Jan 1 00:00:00 1970 From: Artem Bokhan Subject: Re: [PATCH #upstream-fixes] sata_mv: don't issue two DMA commands concurrently Date: Thu, 14 Aug 2008 14:42:55 +0700 Message-ID: <48A3E1FF.4030502@ngs.ru> References: <489C19CE.6030708@ngs.ru> <489C4B6E.9070306@rtr.ca> <489C4F29.6020007@rtr.ca> <489C54D1.5080901@rtr.ca> <48A29E14.3090908@gmail.com> <48A2BBDC.2090201@ngs.ru> <48A2BC5D.5060801@gmail.com> <48A2C35C.7020400@ngs.ru> <48A2C460.6040504@gmail.com> <48A2C770.2040200@ngs.ru> <48A2CB1B.4000200@gmail.com> <48A2CE09.9090806@ngs.ru> <48A30920.5030803@rtr.ca> <48A33CDC.3000809@ngs.ru> <48A36FE5.5000706@rtr.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from smtpout1.ngs.ru ([195.93.186.195]:55798 "EHLO smtpout1.ngs.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752461AbYHNHmu (ORCPT ); Thu, 14 Aug 2008 03:42:50 -0400 In-Reply-To: <48A36FE5.5000706@rtr.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord , Tejun Heo , linux-ide@vger.kernel.org Mark Lord =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > > I only see two failures (eg. one retry) in the log you showed. Yes, I mean 2 tries, so 1 unnecessary rerty. > But it probably was not a retry, but rather a second I/O after > the first one. The filesystem layer often does that. > If kernel tries to read the same sector more then one time, I call that= =20 retry :) I found that it depend on vm someway... First 'dd if=3D/dev/sdb=20 of=3D/dev/null skip=3D300000 count=3D1' causes 2 failures (1 retry), bu= t next=20 'dd's only 1failure. After I drop vm cache 'sysctl vm.drop_caches=3D1',= I=20 get two failures again. running 'dd if=3D/dev/sdb of=3D/dev/null skip=3D300000 count=3D1 iflag=3D= direct'=20 always causes only 1 failure IMHO, looks like cavity somewhere... Any ideas? > Cheers