From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from magic.merlins.org ([209.81.13.136]:50131 "EHLO mail1.merlins.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756174AbaCTAUI (ORCPT ); Wed, 19 Mar 2014 20:20:08 -0400 Date: Wed, 19 Mar 2014 17:20:07 -0700 From: Marc MERLIN To: Chris Mason Cc: "linux-btrfs@vger.kernel.org" Subject: Re: btrfs-rmw-2: page allocation failure: order:1, mode:0x8020 Message-ID: <20140320002007.GY18959@merlins.org> References: <20140319223723.GU18959@merlins.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, Mar 20, 2014 at 12:13:36AM +0000, Chris Mason wrote: > >Should I double it? > > > >For now, I have the copy running again, and it's been going for 8 hours > >without failure on the old kernel but of course that doesn't mean my 2TB > >copy will complete without hitting the bug again. > > Sorry, I misspoke, you should bump /proc/sys/vm/min_free_kbytes. Honestly > though, itıs just a bug in the mvs driver. Atomic 8K allocations are > doomed to fail eventually. Gotcha polgara:/mnt/btrfs_backupcopy# cat /proc/sys/vm/min_free_kbytes 45056 polgara:/mnt/btrfs_backupcopy# echo 100000 > /proc/sys/vm/min_free_kbytes polgara:/mnt/btrfs_backupcopy# cat /proc/sys/vm/min_free_kbytes 100000 polgara:/mnt/btrfs_backupcopy# > The driver should either busy loop until the allocation completes (really > not a great choice), gracefully deal with the failure (looks tricky), or > preallocate the space (like the rest of the block layer). Gotcha. I'll report this to the folks maintaining the marvel driver. So just to make sure I got you right, although the page allocation failure was shown in btrfs, it's really the underlying marvel driver at fault here, and there isn't really anything to change on the btrfs side, correct? Thanks, Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/