Messages in this thread | | | From | Vincent Guittot <> | Date | Tue, 3 Sep 2019 17:38:43 +0200 | Subject | Re: [PATCH 09/15] sched,fair: refactor enqueue/dequeue_entity |
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Hi Rik,
On Thu, 22 Aug 2019 at 04:18, Rik van Riel <riel@surriel.com> wrote: > > Refactor enqueue_entity, dequeue_entity, and update_load_avg, in order > to split out the things we still want to happen at every level in the > cgroup hierarchy with a flat runqueue from the things we only need to > happen once. > > No functional changes. > > Signed-off-by: Rik van Riel <riel@surriel.com> > --- > kernel/sched/fair.c | 64 +++++++++++++++++++++++++++++---------------- > 1 file changed, 42 insertions(+), 22 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 74ee22c59d13..7b0d95f2e3a8 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -3502,7 +3502,7 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s > #define DO_ATTACH 0x4 > > /* Update task and its cfs_rq load average */ > -static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > +static inline bool update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > { > u64 now = cfs_rq_clock_pelt(cfs_rq); > int decayed; > @@ -3531,6 +3531,8 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s > > } else if (decayed && (flags & UPDATE_TG)) > update_tg_load_avg(cfs_rq, 0); > + > + return decayed;
This is a functional change, isn't it ? update_cfs_group is now called only if decayed but we can we attach a task during the enqueue and there is no decay
> > } > > #ifndef CONFIG_64BIT > @@ -3747,9 +3749,10 @@ static inline void update_misfit_status(struct task_struct *p, struct rq *rq) > #define SKIP_AGE_LOAD 0x0 > #define DO_ATTACH 0x0 > > -static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1) > +static inline bool update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1) > { > cfs_rq_util_change(cfs_rq, 0); > + return false; > } > > static inline void remove_entity_load_avg(struct sched_entity *se) {} > @@ -3872,6 +3875,24 @@ static inline void check_schedstat_required(void) > * CPU and an up-to-date min_vruntime on the destination CPU. > */ > > +static bool > +enqueue_entity_groups(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > +{ > + /* > + * When enqueuing a sched_entity, we must: > + * - Update loads to have both entity and cfs_rq synced with now. > + * - Add its load to cfs_rq->runnable_avg > + * - For group_entity, update its weight to reflect the new share of > + * its group cfs_rq > + * - Add its new weight to cfs_rq->load.weight > + */ > + if (!update_load_avg(cfs_rq, se, UPDATE_TG | DO_ATTACH)) > + return false; > > + > + update_cfs_group(se); > + return true; > +} > + > static void > enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > { > @@ -3896,16 +3917,6 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > if (renorm && !curr) > se->vruntime += cfs_rq->min_vruntime; > > - /* > - * When enqueuing a sched_entity, we must: > - * - Update loads to have both entity and cfs_rq synced with now. > - * - Add its load to cfs_rq->runnable_avg > - * - For group_entity, update its weight to reflect the new share of > - * its group cfs_rq > - * - Add its new weight to cfs_rq->load.weight > - */ > - update_load_avg(cfs_rq, se, UPDATE_TG | DO_ATTACH); > - update_cfs_group(se); > enqueue_runnable_load_avg(cfs_rq, se); > account_entity_enqueue(cfs_rq, se); > > @@ -3972,14 +3983,9 @@ static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) > > static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq); > > -static void > -dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > +static bool > +dequeue_entity_groups(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > { > - /* > - * Update run-time statistics of the 'current'. > - */ > - update_curr(cfs_rq); > - > /* > * When dequeuing a sched_entity, we must: > * - Update loads to have both entity and cfs_rq synced with now. > @@ -3988,7 +3994,21 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > * - For group entity, update its weight to reflect the new share > * of its group cfs_rq. > */ > - update_load_avg(cfs_rq, se, UPDATE_TG); > + if (!update_load_avg(cfs_rq, se, UPDATE_TG)) > + return false; > + update_cfs_group(se); > + > + return true; > +} > + > +static void > +dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > +{ > + /* > + * Update run-time statistics of the 'current'. > + */ > + update_curr(cfs_rq); > + > dequeue_runnable_load_avg(cfs_rq, se); > > update_stats_dequeue(cfs_rq, se, flags); > @@ -4012,8 +4032,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > /* return excess runtime on last dequeue */ > return_cfs_rq_runtime(cfs_rq); > > - update_cfs_group(se); > - > /* > * Now advance min_vruntime if @se was the entity holding it back, > * except when: DEQUEUE_SAVE && !DEQUEUE_MOVE, in this case we'll be > @@ -5178,6 +5196,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) > if (se->on_rq) > break; > cfs_rq = cfs_rq_of(se); > + enqueue_entity_groups(cfs_rq, se, flags); > enqueue_entity(cfs_rq, se, flags); > > /* > @@ -5260,6 +5279,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) > > for_each_sched_entity(se) { > cfs_rq = cfs_rq_of(se); > + dequeue_entity_groups(cfs_rq, se, flags); > dequeue_entity(cfs_rq, se, flags); > > /* > -- > 2.20.1 >
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