I had a go at writing a patch, but I think it's possible already
without any patch.
After launch you can get the PID of the qemu subprocess:
guestfs_get_pid (g);
--> returns PID
You can use Linux to map this to a list of thread IDs:
ls /proc/$PID/task/
--> returns a list of thread IDs
[Yes, this is potentially racy, but in reality qemu has already
started up fully after guestfs_launch returns and is almost quiescent
when you're not issuing commands.]
Then you can assign the threads to the cgroup:
for tid in $(ls -1 /proc/$PID/task); do
echo $tid > /cgroup/blkio/$group/tasks
done
This is more cumbersome if you're using guestfish instead of some
scripting language, and it's difficult if you want to port to
non-Linux, but should work in the common case AFAICS. I've not tried
it though ...
Rich.
--
Richard Jones, Virtualization Group, Red Hat
http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines. Supports shell scripting,
bindings from many languages.
http://et.redhat.com/~rjones/libguestfs/
See what it can do:
http://et.redhat.com/~rjones/libguestfs/recipes.html