I would try the cgroups mailing list: http://vger.kernel.org/vger-lists.html#cgroups Juan. On Tue, Sep 20, 2016 at 2:39 PM, Rahul Bhattacharya <rahulimpdocs@xxxxxxxxx> wrote: > Any idea or feedback for the person to contact? > Thanks > > br > rb > > On Wed, Sep 14, 2016 at 5:21 PM, Rahul Bhattacharya <rahulimpdocs@xxxxxxxxx> > wrote: >> >> When I try to move a RT task to a different cgroup(shown below) I get a >> EINVAL error. >> >> However I can change the cgroup first and then change the sched policy. >> >> After looking into kernel source code(I dont use CONFIG_RT_GROUP_SCHED >> config) I was able to extract this piece of logic >> >> >> >> chrt -p 777 >> pid 777's current scheduling policy: SCHED_OTHER >> pid 777's current scheduling priority: 0 >> >> cat /proc/777/cgroup >> 2:cpu,cpuacct:/system.slice >> 1:name=systemd:/system.slice/d.service >> >> chrt -f -p 50 777 >> >> root@mgu-high:~# chrt -p 777 >> pid 777's current scheduling policy: SCHED_FIFO >> pid 777's current scheduling priority: 50 >> >> /bin/echo 777>/sys/fs/cgroup/cpu,cpuacct/interaction.slice/tasks >> echo: write error: Invalid argument >> >> >> >> After browsing kernel sources I was able to find out the reason of >> failure. >> >> >> static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, >> struct cgroup_taskset *tset) >> { >> struct task_struct *task; >> >> >> cgroup_taskset_for_each(task, tset) { >> #ifdef CONFIG_RT_GROUP_SCHED >> if (!sched_rt_can_attach(css_tg(css), task)) >> return -EINVAL; >> #else >> /* We don't support RT-tasks being in separate groups */ >> if (task->sched_class != &fair_sched_class) >> { >> return -EINVAL; >> } >> #endif >> } >> return 0; >> } >> >> My question is why is this check required? Also, changing cgroups first >> and then the policy of FIFO works without issue(?) for the task. >> >> Thanks >> >> >> br >> >> rb > > > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > -- Juan-Luis de Sousa-Valadas Castaño Iberia Infrastructure Consultant - Red Hat _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
