From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id BC9FF6B003D for ; Wed, 18 Mar 2009 19:42:52 -0400 (EDT) Date: Wed, 18 Mar 2009 16:36:57 -0700 (PDT) From: Linus Torvalds Subject: Re: ftruncate-mmap: pages are lost after writing to mmaped file. In-Reply-To: <604427e00903181618t66020557kda533d37f51d7e7d@mail.gmail.com> Message-ID: References: <604427e00903181244w360c5519k9179d5c3e5cd6ab3@mail.gmail.com> <20090318151157.85109100.akpm@linux-foundation.org> <604427e00903181618t66020557kda533d37f51d7e7d@mail.gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Ying Han Cc: Andrew Morton , linux-kernel , linux-mm , guichaz@gmail.com, Alex Khesin , Mike Waychison , Rohit Seth , Nick Piggin , Peter Zijlstra List-ID: On Wed, 18 Mar 2009, Ying Han wrote: > > > > Can you say what filesystem, and what mount-flags you use? Iirc, last time > > we had MAP_SHARED lost writes it was at least partly triggered by the > > filesystem doing its own flushing independently of the VM (ie ext3 with > > "data=journal", I think), so that kind of thing does tend to matter. > > /etc/fstab > "/dev/hda1 / ext2 defaults 1 0" Sadly, /etc/fstab is not necessarily accurate for the root filesystem. At least Fedora will ignore the flags in it. What does /proc/mounts say? That should be a more reliable indication of what the kernel actually does. That said, I assume the ext2 part is accurate. Maybe that's why people haven't seen it - I guess most testing was done on ext3. It certainly was for me. > > Ying Han - since you're all set up for testing this and have reproduced it > > on multiple kernels, can you try it on a few more kernel versions? It > > would be interesting to both go further back in time (say 2.6.15-ish), > > _and_ check something like 2.6.21 which had the exact dirty accounting > > fix. Maybe it's not really an old bug - maybe we re-introduced a bug that > > was fixed for a while. > > I will give a try. Thanks, Linus -- 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