On Mon, Aug 10, 2015 at 03:08:59PM +0900, byungchul.p...@lge.com wrote: > From: Byungchul Park <byungchul.p...@lge.com> > > current code seems to be wrong with cfs_rq->blocked_load_avg when changing > a task's cgroup(=cfs_rq) to another. i tested with "echo pid > cgroup" and > found that cfs_rq->blocked_load_avg became larger and larger whenever i > changed a cgroup to another again and again. > > it is possible to move between groups within a cpu, and each cfs_rq is > tracking its own blocked load. so we have to sync se's average load with > both *prev* cfs_rq and next cfs_rq when changing its group. > > in addition, "#ifdef CONFIG_SMP" is removed becasuse we need to sync a > se's load with its cfs_rq even in the case of !SMP. remember it is possible > to move between groups in *a* cpu. > > i also removed some comments mentioning migration_task_rq_fair(). > migration_task_rq_fair() can be called in three cases. and in each case, > both decay counter and blocked load are already considered. so we > don't need to consider these in task_move_group_fair() at all. > > 1. the wake-up migration case > enqueue_entity_load_avg() makes se->avg.decay_count zero after applying it. > and it will be woken up soon so we don't need to add its load to > cfs_rq->blocked_load_avg. > > 2. the fork balancing case > se->avg.decay_count is initialized in __sched_fork() to zero. and > wake_up_new_task() calls activate_task() with flag = 0 so that > enqueue_entity_load_avg() can omit adding its load to > cfs_rq->blocked_load_avg, and it will be woken up soon. > > 3. the rq migration case (not wake up case) > the target task is already on rq, so we don't need to consider both its > decay counter and blocked load in this case. > > Signed-off-by: Byungchul Park <byungchul.p...@lge.com>
What code is this against? Please look at current code and try again. -- 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/
