Hi Odin, On Thu, 27 May 2021 at 14:29, Vincent Guittot <vincent.guittot@xxxxxxxxxx> wrote: > > Odin reported some fairness problem between cgroup because of stalled > value in cfs_rq->tg_load_avg_contrib: > > https://lkml.org/lkml/2021/5/18/566 > > > 2 problems generated this situation: > -1st: After propagating load in the hierarchy, load_sum can be null > whereas load_avg isn't so the cfs_rq is removed whereas it still > contribute to th tg's load > -2nd: cfs_rq->tg_load_avg_contrib was not always updated after > significant changes like becoming null because cfs_rq had already > been updated when propagating a child load. > This series fixes the problem triggered by your 1st script on my test machine. But could you confirm that this patchset also fixes the problem on yours Regards, Vincent > > Vincent Guittot (2): > sched/fair: keep load_avg and load_sum synced > sched/fair: make sure to update tg contrib for blocked load > > kernel/sched/fair.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > -- > 2.17.1 >
