From: Josef Bacik <jbacik@fusionio.com>
To: <dsterba@suse.cz>, Tomasz Chmielewski <mangoo@wpkg.org>,
"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: btrfs: qgroup scan failed with -12
Date: Mon, 23 Sep 2013 13:43:48 -0400 [thread overview]
Message-ID: <20130923174348.GC18681@localhost.localdomain> (raw)
In-Reply-To: <20130923171905.GR6810@twin.jikos.cz>
On Mon, Sep 23, 2013 at 07:19:06PM +0200, David Sterba wrote:
> On Mon, Sep 23, 2013 at 07:43:44AM +0700, Tomasz Chmielewski wrote:
> > Not sure if it's anything interesting - I had the following entry in
> > dmesg a few days ago, on a server with 32 GB RAM. The system is still working fine.
>
> Yes this is interesting of course.
> >
> > [1878432.675210] btrfs-qgroup-re: page allocation failure: order:5, mode:0x104050
>
> Order 5 allocation, not guaranteed to succeed.
>
> > [1878432.675319] CPU: 5 PID: 22251 Comm: btrfs-qgroup-re Not tainted 3.11.0-rc7 #2
> > [1878432.676204] [<ffffffff810bde12>] krealloc+0x52/0x8c
> > [1878432.676324] [<ffffffffa036bcf0>] find_parent_nodes+0x49c/0x5a5 [btrfs]
> > [1878432.676383] [<ffffffffa036be75>] btrfs_find_all_roots+0x7c/0xd7 [btrfs]
> > [1878432.676441] [<ffffffffa036d6e1>] ? qgroup_account_ref_step1+0xea/0x102 [btrfs]
> > [1878432.676542] [<ffffffffa036d915>] btrfs_qgroup_rescan_worker+0x21c/0x516 [btrfs]
>
> 220 new_nodes = krealloc(old, sizeof(*new_nodes) * new_alloced,
> 221 gfp_mask);
> 222 if (!new_nodes)
> 223 return -ENOMEM;
>
> The requested size is between 64k and 128k, with 40 bytes of ulist_node
> it's 1638 to 3276 elements. So, lots of things going on during the
> rescan, quite expectable.
>
> I don't know if krealloc can be replaced with something more friendly to
> allocator, eg. a list of page-sized blocks instead of one contiguous
> array.
>
I've done that with a patch in bugzilla, hopefully that will fix it. I've not
had time to try and reproduce myself, but I assume if you do something like
create a random file, then create 100000 snapshots and then defrag it will
probably hit the same problem. Thanks,
Josef
next prev parent reply other threads:[~2013-09-23 17:43 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-23 0:43 btrfs: qgroup scan failed with -12 Tomasz Chmielewski
2013-09-23 13:00 ` Wang Shilong
2013-09-23 14:57 ` Josef Bacik
2013-09-23 17:19 ` David Sterba
2013-09-23 17:43 ` Josef Bacik [this message]
2013-09-25 10:11 ` David Sterba
2013-09-25 11:30 ` Tomasz Chmielewski
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