From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e4.ny.us.ibm.com (8.13.8/8.12.11) with ESMTP id kAFIHL2f029037 for ; Wed, 15 Nov 2006 13:17:21 -0500 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay04.pok.ibm.com (8.13.6/8.13.6/NCO v8.1.1) with ESMTP id kAFIGoHH123122 for ; Wed, 15 Nov 2006 13:16:58 -0500 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id kAFIGo87011360 for ; Wed, 15 Nov 2006 13:16:50 -0500 Message-ID: <455B5990.7080808@us.ibm.com> Date: Wed, 15 Nov 2006 10:16:48 -0800 From: Badari Pulavarty MIME-Version: 1.0 Subject: Re: pagefault in generic_file_buffered_write() causing deadlock References: <1163606265.7662.8.camel@dyn9047017100.beaverton.ibm.com> <20061115090005.c9ec6db5.akpm@osdl.org> In-Reply-To: <20061115090005.c9ec6db5.akpm@osdl.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: linux-mm , ext4 , lkml List-ID: Andrew Morton wrote: > On Wed, 15 Nov 2006 07:57:45 -0800 > Badari Pulavarty wrote: > > >> We are looking at a customer situation (on 2.6.16-based distro) - where >> system becomes almost useless while running some java & stress tests. >> >> Root cause seems to be taking a pagefault in generic_file_buffered_write >> () after calling prepare_write. I am wondering >> >> 1) Why & How this can happen - since we made sure to fault the user >> buffer before prepare write. >> > > When using writev() we only fault in the first segment of the iovec. If > the second or succesive segment isn't mapped into pagetables we're > vulnerable to the deadlock. > Yes. I remember this change. Thank you. > >> 2) If this is already fixed in current mainline (I can't see how). >> > > It was fixed in 2.6.17. > > You'll need 6527c2bdf1f833cc18e8f42bd97973d583e4aa83 and > 81b0c8713385ce1b1b9058e916edcf9561ad76d6 > I will try to get this change into customer :( Thanks, Badari -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org