kernel 2.6.22 pdflush consumes ~90% cpu

[Dave Chinner]

On Mon, Jan 13, 2014 at 02:58:54PM +0000, Muralitharan Perumal wrote:
> Hi,
> 
> I am currently working on an embedded platform involving XFS as the
> preferred fs. Earlier, ext3 was used but now replaced with XFS. The unit
> is working fine with ext3 but after replacing with XFS, I am seeing a
> few issues:
> 
> a) Occassionally I am getting the following error when we write files to
> the fs:
> 
> attempt to access beyond end of device
> sda1: rw=0, want=10487141907480064, limit=9766912
> I/O error in filesystem ("sda1") meta-data dev sda1 block 0x254200001abdf8       ("xfs_trans_read_buf") error 5 buf count 4096
> attempt to access beyond end of device
> sda1: rw=0, want=10487141907480064, limit=9766912
> I/O error in filesystem ("sda1") meta-data dev sda1 block 0x254200001abdf8       ("xfs_trans_read_buf") error 5 buf count 4096

It's trying to write way beyond the end of the device, hence the
error. I'd suggest updating to xfsprogs 3.11 and running
xfs_repair -n /dev/sda1 on the device and seeing if it finds a
corrupt block map on an inode somewhere.

> b) After running for about 20 to 25 minutes, the pdflush consumes about 90% cpu and stuck there in D state:

It can't be stuck in an uninterruptible sleep (D state) and
consuming CPU at the same time....

> Is there any similar issue seen with kernel 2.6.22? Am I missing any XFS patches that could fix this?

That's a 6 year old kernel. I'd suggest that an upgrade to something
more recent might be in order...

Cheers,

Dave.
-- 
Dave Chinner
david at fromorbit.com