From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266618AbUGPVCB (ORCPT ); Fri, 16 Jul 2004 17:02:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266620AbUGPVCB (ORCPT ); Fri, 16 Jul 2004 17:02:01 -0400 Received: from 216-54-166-5.gen.twtelecom.net ([216.54.166.5]:57503 "EHLO texas.encore.com") by vger.kernel.org with ESMTP id S266618AbUGPVBC (ORCPT ); Fri, 16 Jul 2004 17:01:02 -0400 Message-ID: <40F8420C.88E694F2@compro.net> Date: Fri, 16 Jul 2004 17:01:00 -0400 From: Mark Hounschell Reply-To: markh@compro.net X-Mailer: Mozilla 4.8 [en] (X11; U; Linux 2.4.26-ert i686) X-Accept-Language: en MIME-Version: 1.0 To: Andrew Morton Cc: linux-kernel@vger.kernel.org Subject: Re: mlockall and mmap of IO devices don't mix References: <20031003214411.GA25802@rudolph.ccur.com> <40ADE959.822F1C23@compro.net> <20040521191326.58100086.akpm@osdl.org> <20040525142728.GA10738@tsunami.ccur.com> <20040525124715.5f7e61b6.akpm@osdl.org> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > > Joe Korty wrote: > > > > On Fri, May 21, 2004 at 07:13:26PM -0700, Andrew Morton wrote: > > > Mark Hounschell wrote: > > > > > > > > Joe Korty wrote: > > > > > > > > > > 2.6.0-test6: the use of mlockall(2) in a process that has mmap(2)ed > > > > > the registers of an IO device will hang that process uninterruptibly. > > > > > The task runs in an infinite loop in get_user_pages(), invoking > > > > > follow_page() forever. > > > > > > > > > > Using binary search I discovered that the problem was introduced > > > > > in 2.5.14, specifically in ChangeSetKey > > > > > > > > > > zippel@linux-m68k.org|ChangeSet|20020503210330|37095 > > > > > > > > > > > > > I know this is an old thread but can anyone tell me if this problem is > > > > resolved in the current 2.6.6 kernel? > > > > > > > > > > There's an utterly ancient patch in -mm which might fix this. > > > > > > http://www.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.6/2.6.6-mm4/broken-out/get_user_pages-handle-VM_IO.patch > > > > [ 2nd send -- corporate email system in the throes of being scrambled / updated ] > > > > Andrew, > > I have been using this patch for ages. Any chance of it being forwared to > > the official tree? > > That patch had its first birthday last week. I wrote it in response to > some long-forgotten problem, failed to changelog it at the time then forgot > why I wrote it. I kept it in the hope that I'd remember why I wrote it. I > subsequently wrote a best-effort changelog but am unconvinced by it. Ho > hum. > > Let me genuflect a bit. I guess we can be reasonably confident it won't > break anything. Strange thing about this patch is "it doesn't seem to work on all machines". Originally it worked for me on a dual AMD1900 box. Now I'm trying to use it on a Dual P4 box and a dual Opteron in both 32 and 64 bit modes with no luck at all???? I guess I need to go back to my original AMD and reverify it's functionality. The user level code I'm using: status = mlockall(MCL_CURRENT | MCL_FUTURE); if (status < 0) perror("mlock all failure"); dhan = rtom_usec_map(&rtom_microseconds, 0); mmaps rtom usec timer ????? Regards Mark