[qubes-users] blkback errors in dmesg

Mailing Lists qubes-users
1

Occasionally, when my system is under heavy load, it will freeze for a
few seconds. During this time, the pointer is still reasonably
responsive, but nothing else is. When the freeze ends, I get these
entries in dmesg:

    Feb 16 13:37:23 dom0 kernel: xen-blkback: Scheduled work from previous purge is still busy, cannot purge list
    Feb 16 13:37:23 dom0 kernel: xen-blkback: Scheduled work from previous purge is still busy, cannot purge list

What is the meaning of these entries? Is it a red herring?
- --
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab

2

My guess is that the relation of block I/O requests to block device speed is bad (i.e.: to much I/O for the slow disk). If the I/O is caused by paging (swap), you might want more RAM or trim down your VMs to use less RAM.

Despite of that I think there was a recent Xen change limiting block queues (or something like that).

Regards,
Ulrich