Hi, On Mon, Aug 17, 2015 at 04:45:50PM +0900, byungchul.p...@lge.com wrote: > From: Byungchul Park <byungchul.p...@lge.com> > > current code is wrong with cfs_rq's avg loads when changing a task's > cfs_rq to another. i tested with "echo pid > cgroup" and found that > e.g. cfs_rq->avg.load_avg became larger and larger whenever i changed > a cgroup to another again and again. we have to sync se's avg loads > with both *prev* cfs_rq and next cfs_rq when changing its group. >
my simple think about above, may be nothing or wrong, just ignore it. if a load balance migration happened just before cgroup change, prev cfs_rq and next cfs_rq will be on different cpu. migrate_task_rq_fair() and update_cfs_rq_load_avg() will sync and remove se's load avg from prev cfs_rq. whether or not queued, well done. dequeue_task() decay se and pre_cfs before calling task_move_group_fair(). after set cfs_rq in task_move_group_fair(), if queued, se's load avg do not add to next cfs_rq(try set last_update_time to 0 like migration to add), if !queued, also need to add se's load avg to next cfs_rq. if no load balance migration happened when change cgroup. prev cfs_rq and next cfs_rq may be on same cpu(not sure), this time, need to remove se's load avg by ourself, also need to add se's load avg on next cfs_rq. thinks, -- Tao -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
