On 3/28/23 11:39, Christian Brauner wrote:
I saw that the current cgroup code already have the can_fork, fork and
cancel_fork callbacks. Unfortunately such callbacks are not defined for
cpuset yet. That is why the cpu affinity isn't correctly updated. I can
post a patch to add those callback functions to cpuset which should then
able to correctly address this issue.
Giuseppe reported that the the affinity mask isn't updated when a
process is spawned directly into the target cgroup via
CLONE_INTO_CGROUP. However, migrating a process will cause the affinity
mask to be updated (see the repro at .
I took a quick look and the issue seems to be that we don't call the
various attach handlers during CLONE_INTO_CGROUP whereas we do for
migration. So the solution seems to roughly be that we need to call the
various attach handlers during CLONE_INTO_CGROUP as well when the
parent's cgroups is different from the child cgroup. I think we need to
call all of them, can, cancel and attach.
The plumbing here might be a bit intricate since the arguments that the
fork handlers take are different from the attach handlers.