linux-toradex.git/kernel/cgroup/cpuset.c, branch v6.5

cgroup/cpuset: remove unneeded header files

2023-06-12T16:52:04+00:00

Remove some unnecessary header files. No functional change intended.

Signed-off-by: Miaohe Lin 
Signed-off-by: Tejun Heo

cgroup/cpuset: remove unneeded header files

2023-05-21T02:21:49+00:00

Remove some unnecessary header files. No functional change intended.

Signed-off-by: Miaohe Lin 
Signed-off-by: Tejun Heo

cgroup/cpuset: Free DL BW in case can_attach() fails

2023-05-08T23:22:33+00:00

cpuset_can_attach() can fail. Postpone DL BW allocation until all tasks
have been checked. DL BW is not allocated per-task but as a sum over
all DL tasks migrating.

If multiple controllers are attached to the cgroup next to the cpuset
controller a non-cpuset can_attach() can fail. In this case free DL BW
in cpuset_cancel_attach().

Finally, update cpuset DL task count (nr_deadline_tasks) only in
cpuset_attach().

Suggested-by: Waiman Long 
Signed-off-by: Dietmar Eggemann 
Signed-off-by: Juri Lelli 
Reviewed-by: Waiman Long 
Signed-off-by: Tejun Heo

cgroup/cpuset: Iterate only if DEADLINE tasks are present

2023-05-08T23:22:33+00:00

update_tasks_root_domain currently iterates over all tasks even if no
DEADLINE task is present on the cpuset/root domain for which bandwidth
accounting is being rebuilt. This has been reported to introduce 10+ ms
delays on suspend-resume operations.

Skip the costly iteration for cpusets that don't contain DEADLINE tasks.

Reported-by: Qais Yousef 
Link: https://lore.kernel.org/lkml/20230206221428.2125324-1-qyousef@layalina.io/
Signed-off-by: Juri Lelli 
Reviewed-by: Waiman Long 
Signed-off-by: Tejun Heo

sched/cpuset: Keep track of SCHED_DEADLINE task in cpusets

2023-05-08T23:22:33+00:00

Qais reported that iterating over all tasks when rebuilding root domains
for finding out which ones are DEADLINE and need their bandwidth
correctly restored on such root domains can be a costly operation (10+
ms delays on suspend-resume).

To fix the problem keep track of the number of DEADLINE tasks belonging
to each cpuset and then use this information (followup patch) to only
perform the above iteration if DEADLINE tasks are actually present in
the cpuset for which a corresponding root domain is being rebuilt.

Reported-by: Qais Yousef 
Link: https://lore.kernel.org/lkml/20230206221428.2125324-1-qyousef@layalina.io/
Signed-off-by: Juri Lelli 
Reviewed-by: Waiman Long 
Signed-off-by: Tejun Heo

sched/cpuset: Bring back cpuset_mutex

2023-05-08T23:22:33+00:00

Turns out percpu_cpuset_rwsem - commit 1243dc518c9d ("cgroup/cpuset:
Convert cpuset_mutex to percpu_rwsem") - wasn't such a brilliant idea,
as it has been reported to cause slowdowns in workloads that need to
change cpuset configuration frequently and it is also not implementing
priority inheritance (which causes troubles with realtime workloads).

Convert percpu_cpuset_rwsem back to regular cpuset_mutex. Also grab it
only for SCHED_DEADLINE tasks (other policies don't care about stable
cpusets anyway).

Signed-off-by: Juri Lelli 
Reviewed-by: Waiman Long 
Signed-off-by: Tejun Heo

cgroup/cpuset: Rename functions dealing with DEADLINE accounting

2023-05-08T23:22:33+00:00

rebuild_root_domains() and update_tasks_root_domain() have neutral
names, but actually deal with DEADLINE bandwidth accounting.

Rename them to use 'dl_' prefix so that intent is more clear.

No functional change.

Suggested-by: Qais Yousef 
Signed-off-by: Juri Lelli 
Reviewed-by: Waiman Long 
Signed-off-by: Tejun Heo

Merge tag 'cgroup-for-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2023-04-29T17:05:22+00:00

Pull cgroup updates from Tejun Heo:

 - cpuset changes including the fix for an incorrect interaction with
   CPU hotplug and an optimization

 - Other doc and cosmetic changes

* tag 'cgroup-for-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  docs: cgroup-v1/cpusets: update libcgroup project link
  cgroup/cpuset: Minor updates to test_cpuset_prs.sh
  cgroup/cpuset: Include offline CPUs when tasks' cpumasks in top_cpuset are updated
  cgroup/cpuset: Skip task update if hotplug doesn't affect current cpuset
  cpuset: Clean up cpuset_node_allowed
  cgroup: bpf: use cgroup_lock()/cgroup_unlock() wrappers

cgroup/cpuset: Make cpuset_attach_task() skip subpartitions CPUs for top_cpuset

2023-04-12T18:23:58+00:00

It is found that attaching a task to the top_cpuset does not currently
ignore CPUs allocated to subpartitions in cpuset_attach_task(). So the
code is changed to fix that.

Signed-off-by: Waiman Long 
Reviewed-by: Michal Koutný 
Signed-off-by: Tejun Heo

cgroup/cpuset: Add cpuset_can_fork() and cpuset_cancel_fork() methods

2023-04-12T18:23:58+00:00

In the case of CLONE_INTO_CGROUP, not all cpusets are ready to accept
new tasks. It is too late to check that in cpuset_fork(). So we need
to add the cpuset_can_fork() and cpuset_cancel_fork() methods to
pre-check it before we can allow attachment to a different cpuset.

We also need to set the attach_in_progress flag to alert other code
that a new task is going to be added to the cpuset.

Fixes: ef2c41cf38a7 ("clone3: allow spawning processes into cgroups")
Suggested-by: Michal Koutný 
Signed-off-by: Waiman Long 
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Tejun Heo