It appears that briefly thawing the cgroup while freezing
greatly increases its chances to freeze successfully.
The test case I used is doing runc exec in a look parallel with runc
pause/resume in another loop, and the failure to freeze rate reduced
from 40 to 0 per minute (tested inside a VM using a busybox container
running sleep 1h, doing about 1500 pause/resumes and 650 execs per
minute), with max retries being 150 (of 1000).
This is still a game of chances, so failures are possible.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Kir Kolyshkin
d1007b08a3