On Mon, 15 Oct 2007, Paul Jackson wrote: > My solution may be worse than that. Because set_cpus_allowed() will > fail if asked to set a non-overlapping cpumask, my solution could never > terminate. If asked to set a cpusets cpus to something that went off > line right then, this I'd guess this code could keep looping forever, > looking for cpumasks that didn't match, and then not noticing that it > was failing to set them so as they would match. > Why can't you just add a helper function to sched.c: void set_hotcpus_allowed(struct task_struct *task, cpumask_t cpumask) { mutex_lock(&sched_hotcpu_mutex); set_cpus_allowed(task, cpumask); mutex_unlock(&sched_hotcpu_mutex); } And then change each task's cpus_allowed via that function instead of set_cpus_allowed() directly? You don't need to worry about making the task->cpuset->cpus_allowed assignment a critical section because common_cpu_mem_hotplug_unplug() will remove any hot-unplugged cpus from each cpuset's cpus_allowed in the hierarchy. Your loop will still need to be reworked so that cgroup_iter_{start,end}() are not reinvoked unnecessarily and you rely only on cgroup_iter_next() returning NULL to determine when you've gone through the entire list. There's no need to go back and check the cpus_allowed of tasks you've already called set_cpus_allowed() on either directly or indirectly via my helper function above. David _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers