On 6/12/19 9:32 PM, Rik van Riel wrote: > Flatten the hierarchical runqueues into just the per CPU rq.cfs runqueue. > > Iteration of the sched_entity hierarchy is rate limited to once per jiffy > per sched_entity, which is a smaller change than it seems, because load > average adjustments were already rate limited to once per jiffy before this > patch series. > > This patch breaks CONFIG_CFS_BANDWIDTH. The plan for that is to park tasks > from throttled cgroups onto their cgroup runqueues, and slowly (using the > GENTLE_FAIR_SLEEPERS) wake them back up, in vruntime order, once the cgroup > gets unthrottled, to prevent thundering herd issues. > > Signed-off-by: Rik van Riel <[email protected]> > --- > include/linux/sched.h | 2 + > kernel/sched/fair.c | 478 +++++++++++++++++------------------------- > kernel/sched/pelt.c | 6 +- > kernel/sched/pelt.h | 2 +- > kernel/sched/sched.h | 2 +- > 5 files changed, 194 insertions(+), 296 deletions(-) >
[...] > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c [...] > @@ -3491,7 +3544,7 @@ static inline bool update_load_avg(struct cfs_rq > *cfs_rq, struct sched_entity *s > * track group sched_entity load average for task_h_load calc in > migration > */ > if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD)) > - updated = __update_load_avg_se(now, cfs_rq, se); > + updated = __update_load_avg_se(now, cfs_rq, se, curr, curr); I wonder if task migration is still working correctly. migrate_task_rq_fair(p, ...) -> remove_entity_load_avg(&p->se) would use cfs_rq = se->cfs_rq (i.e. root cfs_rq). So load (and util) will not propagate through the taskgroup hierarchy. [...]
