xfs
[Top] [All Lists]

Re: XFS unhappy with large holey loopback and syncs

To: David Chinner <dgc@xxxxxxx>
Subject: Re: XFS unhappy with large holey loopback and syncs
From: Andi Kleen <ak@xxxxxxx>
Date: Tue, 29 Nov 2005 10:13:02 +0100
Cc: Andi Kleen <ak@xxxxxxx>, linux-xfs@xxxxxxxxxxx
In-reply-to: <20051129032937.GZ501696@xxxxxxxxxxxxxxxxx>
References: <20051129003611.GF7209@xxxxxxxxxxxxxx> <20051129032937.GZ501696@xxxxxxxxxxxxxxxxx>
Sender: linux-xfs-bounce@xxxxxxxxxxx
On Tue, Nov 29, 2005 at 02:29:37PM +1100, David Chinner wrote:
> On Tue, Nov 29, 2005 at 01:36:11AM +0100, Andi Kleen wrote:
> > 
> > I just found an new exciting way to break XFS. Or rather the 
> > version that's in 2.6.13. But might be a interesting try anyways.
> 
> So I just ran this on a handy altix I had lying about between other
> testing ;)
> 
> It's currently not running 2.6.13, but I'm going to run this again
> against 2.6.14 just to make sure it's not a regression. I suspect that
> the problem is that you're generating a highly fragmented file
> which requires high-order memory allocations to hold the extent list.

Hmm - i didn't see any of the processes blocking in the memory
allocator, but maybe I just didn't look closely enough.

> budgie:/usr/local/aspen/loadgen # xfs_bmap -v /mnt/dgc/stripe/LARGE |wc -l
> 217708
> budgie:/usr/local/aspen/loadgen # 
> 
> Which is what makes me think you're having problems with high order
> memory allocations at substantially lower numbers of extents. You're
> testing on a machine with 4k pages, right?

Yep - on x86-64. But the machine had 8GB of RAM, so if even that
runs out of memory something is wrong imho. How large allocations
would it need?

-Andi


<Prev in Thread] Current Thread [Next in Thread>