On Thu, Dec 2, 2010 at 7:07 PM, Colin Cross <ccross@xxxxxxxxxxx> wrote: >> Not in one case - if we create a new cgroup and try to move a thread >> into it, but the thread is exiting as we move it, we'll call >> put_css_set() on the new css_set, which will drop the refcount on the >> target cgroup back to 0. We wouldn't want the auto-release >> notification to kick in in that situation, I think. > > Clearing the CGRP_RELEASABLE bit any time after the tests in > check_for_release introduces a race if __css_get is called between the > check and clearing the bit - the cgroup will have an entry, but the > bit will not be set. Without additional locking in __css_get, I don't > see any way to safely clear CGRP_RELEASABLE. I don't quite follow your argument here. Are you saying that the problem is that you could end up spawning a release agent for a cgroup that was no longer releasable since it now had a process in it again? If so, then I don't think that's a problem - spurious release agent invocations for non-empty cgroups will always happen occasionally due to races between the kernel and userspace. But a failed move of a task into a previously-empty cgroup shouldn't trigger the agent. Paul _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
