Depends on https://github.com/containerd/go-runc/pull/24
The is currently a race with the reaper where you could miss some exit
events from processes.
The problem before and why the reaper was so complex was because
processes could fork, getting a pid, and then fail on an execve before
we would have time to register the process with the reaper. This could
cause pids to fill up in a map as a way to reduce the race.
This changes makes the reaper handle multiple subscribers so that the
caller can handle locking, for when they want to wait for a specific
pid, without affecting other callers using the reaper code.
Exit events are broadcast to multiple subscribers, in the case, the runc
commands and container pids that we get from a pid-file. Locking while
the entire container stats no longs affects runc commands where you want
to call `runc create` and wait until that has been completed.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
6b4c4a2937