Re: [libvirt] Is it a workqueue related issue in 2.6.37 (Was: Re: blkio cgroup [solved])
Hi
> This was taken with 2.6.37 plus the patch you mentioned on a Dell
R815
> with 2 12 core AMD Opteron 6174 CPUs. If you need any more information,
> please let me know.
Hmmm... well, I have no idea what you were trying to do
Long story short: I have a couple of virtual machines. Some of them have
blkio throttle configured, some don't. To simulate whether the
throttling works, I start
dd if=/dev/zero of=testfile bs=1M count=1500
in each guest simultaneously.
The result is that from that point, no i/o is happening any more. You
see the result in the trace.
With 2.6.37 (also tried .1 and .2) it does not work but end up like I
documented. With 2.6.38-rc1, it does work. With deadline scheduler, it
also works in 2.6.37.
I am in bisect run 2 currently to find the changeset that fixed it.
Will let you know as soon as I do.
Regards
Dominik
ps. I am by no means a kernel hacker and none of the rest of your email
made any sense to me. Sorry.
but here are
some info which might be helpful.
* queue_work happens when the work item is queued.
* activate_work happens when the work item becomes eligible for
execution. e.g. If the workqueue's @max_active is limited and
maximum number of work items are already in flight, a new item will
only get activated after one of the in flight ones retires.
* execute_start marks the actual starting of execution.
* execute_end marks the end of execution.
So, I would look for the matching work function and then try to follow
what happens to it after being scheduled and if it doesn't get
executed what's going on with the target workqueue.
Thanks.