On 7/28/22 11:23, Michal Koutný wrote:
On Thu, Jul 28, 2022 at 10:59:01AM -0400, Waiman Long <longman@xxxxxxxxxx> wrote:
Cgroup v1 doesn't have this problem.
v1 analogy would be:
echo 2-3 >$dst/cpuset.cpus
# job runs in $dst
# one task T in $dst sets affinity just to one cpu
# I rethink my config, I want to allow $dst more space
echo 2-5 >$dst/cpuset.cpus
Most tasks in $dst happily utilize the new cpus but it breaks affinity
for T -- this must have been broken since ever.
(Or I'd argue that per-thread affinities are just recommendations, if I
have a task for nohz CPU, I should enforce its placement with cpuset
from the beginning.)
I should have clarified that what I meant is systemd on a cgroup v1
environment doesn't cause this cpu list reset to happen. It doesn't mean
that cgroup v1 has no similar problem. Sorry for the confusion.
Cheers,
Longman
