On Fri, Jun 17, 2016 at 03:58:37PM +0200, Vincent Guittot wrote: > On 17 June 2016 at 14:01, Peter Zijlstra <[email protected]> wrote: > > From: Vincent Guittot <[email protected]> > > > > A new fair task is detached and attached from/to task_group with: > > > > cgroup_post_fork() > > ss->fork(child) := cpu_cgroup_fork() > > sched_move_task() > > task_move_group_fair() > > > > Which is wrong, because at this point in fork() the task isn't fully > > initialized and it cannot 'move' to another group, because its not > > attached to any group as yet. > > > > In fact, cpu_cgroup_fork needs a small part of sched_move_task so we > > can just call this small part directly instead sched_move_task. And > > the task doesn't really migrate because it is not yet attached so we > > need the sequence: > > > > do_fork() > > sched_fork() > > __set_task_cpu() > > > > cgroup_post_fork() > > set_task_rq() # set task group and runqueue > > > > wake_up_new_task() > > select_task_rq() can select a new cpu > > __set_task_cpu > > post_init_entity_util_avg > > attach_task_cfs_rq() > > activate_task > > enqueue_task > > > > This patch makes that happen. > > > > With this patch and patch 1, the fork sequence looks correct in my test > > > Maybe-Signed-off-by: Vincent Guittot <[email protected]> > > You can remove the Maybe if you want
Thanks!
