Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 22 Mar 2023 14:18:47 +0100 | Subject | Re: [RFC PATCH 2/3] sched/cpuset: Keep track of SCHED_DEADLINE tasks in cpusets | From | Dietmar Eggemann <> |
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On 15/03/2023 18:14, Juri Lelli wrote: > On 15/03/23 11:46, Waiman Long wrote: >> >> On 3/15/23 08:18, Juri Lelli wrote:
[...]
>>> @@ -2472,6 +2492,11 @@ static int cpuset_can_attach(struct cgroup_taskset *tset) >>> ret = security_task_setscheduler(task); >>> if (ret) >>> goto out_unlock; >>> + >>> + if (dl_task(task)) { >>> + cs->nr_deadline_tasks++; >>> + cpuset_attach_old_cs->nr_deadline_tasks--; >>> + } >>> } >> >> Any one of the tasks in the cpuset can cause the test to fail and abort the >> attachment. I would suggest that you keep a deadline task transfer count in >> the loop and then update cs and cpouset_attach_old_cs only after all the >> tasks have been iterated successfully. > > Right, Dietmar I think commented pointing out something along these > lines. Think though we already have this problem with current > task_can_attach -> dl_cpu_busy which reserves bandwidth for each tasks > in the destination cs. Will need to look into that. Do you know which > sort of operation would move multiple tasks at once?
Moving the process instead of the individual tasks makes cpuset_can_attach() have to deal with multiple tasks.
# ps2 | grep DLN 1614 1615 140 0 - DLN thread0-0 1614 1616 140 0 - DLN thread0-1 1614 1617 140 0 - DLN thread0-2
# echo 1614 > /sys/fs/cgroup/cpuset/cs2/cgroup.procs
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