kernel/sched/fair.c | 92 ++++++++++++++------------------------------- 1 file changed, 28 insertions(+), 64 deletions(-)
We notice the rq leaf_cfs_rq_list has two problems when do bugfix
backports and some test profiling.
1. cfs_rqs under throttled subtree could be added to the list, and
make their fully decayed ancestors on the list, even though not needed.
2. #1 also make the leaf_cfs_rq_list management complex and error prone,
this is the list of related bugfix so far:
commit 31bc6aeaab1d ("sched/fair: Optimize update_blocked_averages()")
commit fe61468b2cbc ("sched/fair: Fix enqueue_task_fair warning")
commit b34cb07dde7c ("sched/fair: Fix enqueue_task_fair() warning some more")
commit 39f23ce07b93 ("sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list")
commit 0258bdfaff5b ("sched/fair: Fix unfairness caused by missing load decay")
commit a7b359fc6a37 ("sched/fair: Correctly insert cfs_rq's to list on unthrottle")
commit fdaba61ef8a2 ("sched/fair: Ensure that the CFS parent is added after unthrottling")
commit 2630cde26711 ("sched/fair: Add ancestors of unthrottled undecayed cfs_rq")
commit 31bc6aeaab1d ("sched/fair: Optimize update_blocked_averages()")
delete every cfs_rq under throttled subtree from rq->leaf_cfs_rq_list,
and delete the throttled_hierarchy() test in update_blocked_averages(),
which optimized update_blocked_averages().
But those later bugfix add cfs_rqs under throttled subtree back to
rq->leaf_cfs_rq_list again, with their fully decayed ancestors, for
the integrity of rq->leaf_cfs_rq_list.
This patch takes another method, skip all cfs_rqs under throttled
hierarchy when list_add_leaf_cfs_rq(), to completely make cfs_rqs
under throttled subtree off the leaf_cfs_rq_list.
So we don't need to consider throttled related things in
enqueue_entity(), unthrottle_cfs_rq() and enqueue_task_fair(),
which simplify the code a lot. Also optimize update_blocked_averages()
since cfs_rqs under throttled hierarchy and their ancestors
won't be on the leaf_cfs_rq_list.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
v4:
- make sure the attach/detach is propagated down up to
the throttled cfs_rq. Thanks Vincent.
v3:
- fix !CONFIG_FAIR_GROUP_SCHED build error, reported by
kernel test robot <lkp@intel.com>
v2:
- move throttled_hierarchy() outside list_add_leaf_cfs_rq(),
suggested by Vincent.
---
kernel/sched/fair.c | 92 ++++++++++++++-------------------------------
1 file changed, 28 insertions(+), 64 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 77b2048a9326..b3371fa40548 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3144,6 +3144,8 @@ void reweight_task(struct task_struct *p, int prio)
load->inv_weight = sched_prio_to_wmult[prio];
}
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
+
#ifdef CONFIG_FAIR_GROUP_SCHED
#ifdef CONFIG_SMP
/*
@@ -3254,8 +3256,6 @@ static long calc_group_shares(struct cfs_rq *cfs_rq)
}
#endif /* CONFIG_SMP */
-static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
-
/*
* Recomputes the group entity based on the current state of its group
* runqueue.
@@ -4368,16 +4368,11 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
__enqueue_entity(cfs_rq, se);
se->on_rq = 1;
- /*
- * When bandwidth control is enabled, cfs might have been removed
- * because of a parent been throttled but cfs->nr_running > 1. Try to
- * add it unconditionally.
- */
- if (cfs_rq->nr_running == 1 || cfs_bandwidth_used())
- list_add_leaf_cfs_rq(cfs_rq);
-
- if (cfs_rq->nr_running == 1)
+ if (cfs_rq->nr_running == 1) {
check_enqueue_throttle(cfs_rq);
+ if (!throttled_hierarchy(cfs_rq))
+ list_add_leaf_cfs_rq(cfs_rq);
+ }
}
static void __clear_buddies_last(struct sched_entity *se)
@@ -4992,11 +4987,18 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
/* update hierarchical throttle state */
walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq);
- /* Nothing to run but something to decay (on_list)? Complete the branch */
if (!cfs_rq->load.weight) {
- if (cfs_rq->on_list)
- goto unthrottle_throttle;
- return;
+ if (!cfs_rq->on_list)
+ return;
+ /*
+ * Nothing to run but something to decay (on_list)?
+ * Complete the branch.
+ */
+ for_each_sched_entity(se) {
+ if (list_add_leaf_cfs_rq(cfs_rq_of(se)))
+ break;
+ }
+ goto unthrottle_throttle;
}
task_delta = cfs_rq->h_nr_running;
@@ -5034,31 +5036,12 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
/* end evaluation on encountering a throttled cfs_rq */
if (cfs_rq_throttled(qcfs_rq))
goto unthrottle_throttle;
-
- /*
- * One parent has been throttled and cfs_rq removed from the
- * list. Add it back to not break the leaf list.
- */
- if (throttled_hierarchy(qcfs_rq))
- list_add_leaf_cfs_rq(qcfs_rq);
}
/* At this point se is NULL and we are at root level*/
add_nr_running(rq, task_delta);
unthrottle_throttle:
- /*
- * The cfs_rq_throttled() breaks in the above iteration can result in
- * incomplete leaf list maintenance, resulting in triggering the
- * assertion below.
- */
- for_each_sched_entity(se) {
- struct cfs_rq *qcfs_rq = cfs_rq_of(se);
-
- if (list_add_leaf_cfs_rq(qcfs_rq))
- break;
- }
-
assert_list_leaf_cfs_rq(rq);
/* Determine whether we need to wake up potentially idle CPU: */
@@ -5713,13 +5696,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
/* end evaluation on encountering a throttled cfs_rq */
if (cfs_rq_throttled(cfs_rq))
goto enqueue_throttle;
-
- /*
- * One parent has been throttled and cfs_rq removed from the
- * list. Add it back to not break the leaf list.
- */
- if (throttled_hierarchy(cfs_rq))
- list_add_leaf_cfs_rq(cfs_rq);
}
/* At this point se is NULL and we are at root level*/
@@ -5743,21 +5719,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
update_overutilized_status(rq);
enqueue_throttle:
- if (cfs_bandwidth_used()) {
- /*
- * When bandwidth control is enabled; the cfs_rq_throttled()
- * breaks in the above iteration can result in incomplete
- * leaf list maintenance, resulting in triggering the assertion
- * below.
- */
- for_each_sched_entity(se) {
- cfs_rq = cfs_rq_of(se);
-
- if (list_add_leaf_cfs_rq(cfs_rq))
- break;
- }
- }
-
assert_list_leaf_cfs_rq(rq);
hrtick_update(rq);
@@ -11287,9 +11248,13 @@ static inline bool vruntime_normalized(struct task_struct *p)
*/
static void propagate_entity_cfs_rq(struct sched_entity *se)
{
- struct cfs_rq *cfs_rq;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ if (cfs_rq_throttled(cfs_rq))
+ return;
- list_add_leaf_cfs_rq(cfs_rq_of(se));
+ if (!throttled_hierarchy(cfs_rq))
+ list_add_leaf_cfs_rq(cfs_rq);
/* Start to propagate at parent */
se = se->parent;
@@ -11297,14 +11262,13 @@ static void propagate_entity_cfs_rq(struct sched_entity *se)
for_each_sched_entity(se) {
cfs_rq = cfs_rq_of(se);
- if (!cfs_rq_throttled(cfs_rq)){
- update_load_avg(cfs_rq, se, UPDATE_TG);
- list_add_leaf_cfs_rq(cfs_rq);
- continue;
- }
+ update_load_avg(cfs_rq, se, UPDATE_TG);
- if (list_add_leaf_cfs_rq(cfs_rq))
+ if (cfs_rq_throttled(cfs_rq))
break;
+
+ if (!throttled_hierarchy(cfs_rq))
+ list_add_leaf_cfs_rq(cfs_rq);
}
}
#else
--
2.36.1On Wed, 1 Jun 2022 at 04:19, Chengming Zhou <zhouchengming@bytedance.com> wrote:
>
> We notice the rq leaf_cfs_rq_list has two problems when do bugfix
> backports and some test profiling.
>
> 1. cfs_rqs under throttled subtree could be added to the list, and
> make their fully decayed ancestors on the list, even though not needed.
>
> 2. #1 also make the leaf_cfs_rq_list management complex and error prone,
> this is the list of related bugfix so far:
>
> commit 31bc6aeaab1d ("sched/fair: Optimize update_blocked_averages()")
> commit fe61468b2cbc ("sched/fair: Fix enqueue_task_fair warning")
> commit b34cb07dde7c ("sched/fair: Fix enqueue_task_fair() warning some more")
> commit 39f23ce07b93 ("sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list")
> commit 0258bdfaff5b ("sched/fair: Fix unfairness caused by missing load decay")
> commit a7b359fc6a37 ("sched/fair: Correctly insert cfs_rq's to list on unthrottle")
> commit fdaba61ef8a2 ("sched/fair: Ensure that the CFS parent is added after unthrottling")
> commit 2630cde26711 ("sched/fair: Add ancestors of unthrottled undecayed cfs_rq")
>
> commit 31bc6aeaab1d ("sched/fair: Optimize update_blocked_averages()")
> delete every cfs_rq under throttled subtree from rq->leaf_cfs_rq_list,
> and delete the throttled_hierarchy() test in update_blocked_averages(),
> which optimized update_blocked_averages().
>
> But those later bugfix add cfs_rqs under throttled subtree back to
> rq->leaf_cfs_rq_list again, with their fully decayed ancestors, for
> the integrity of rq->leaf_cfs_rq_list.
>
> This patch takes another method, skip all cfs_rqs under throttled
> hierarchy when list_add_leaf_cfs_rq(), to completely make cfs_rqs
> under throttled subtree off the leaf_cfs_rq_list.
>
> So we don't need to consider throttled related things in
> enqueue_entity(), unthrottle_cfs_rq() and enqueue_task_fair(),
> which simplify the code a lot. Also optimize update_blocked_averages()
> since cfs_rqs under throttled hierarchy and their ancestors
> won't be on the leaf_cfs_rq_list.
>
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
> v4:
> - make sure the attach/detach is propagated down up to
> the throttled cfs_rq. Thanks Vincent.
>
> v3:
> - fix !CONFIG_FAIR_GROUP_SCHED build error, reported by
> kernel test robot <lkp@intel.com>
>
> v2:
> - move throttled_hierarchy() outside list_add_leaf_cfs_rq(),
> suggested by Vincent.
> ---
> kernel/sched/fair.c | 92 ++++++++++++++-------------------------------
> 1 file changed, 28 insertions(+), 64 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 77b2048a9326..b3371fa40548 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3144,6 +3144,8 @@ void reweight_task(struct task_struct *p, int prio)
> load->inv_weight = sched_prio_to_wmult[prio];
> }
>
> +static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
> +
> #ifdef CONFIG_FAIR_GROUP_SCHED
> #ifdef CONFIG_SMP
> /*
> @@ -3254,8 +3256,6 @@ static long calc_group_shares(struct cfs_rq *cfs_rq)
> }
> #endif /* CONFIG_SMP */
>
> -static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
> -
> /*
> * Recomputes the group entity based on the current state of its group
> * runqueue.
> @@ -4368,16 +4368,11 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
> __enqueue_entity(cfs_rq, se);
> se->on_rq = 1;
>
> - /*
> - * When bandwidth control is enabled, cfs might have been removed
> - * because of a parent been throttled but cfs->nr_running > 1. Try to
> - * add it unconditionally.
> - */
> - if (cfs_rq->nr_running == 1 || cfs_bandwidth_used())
> - list_add_leaf_cfs_rq(cfs_rq);
> -
> - if (cfs_rq->nr_running == 1)
> + if (cfs_rq->nr_running == 1) {
> check_enqueue_throttle(cfs_rq);
> + if (!throttled_hierarchy(cfs_rq))
> + list_add_leaf_cfs_rq(cfs_rq);
> + }
> }
>
> static void __clear_buddies_last(struct sched_entity *se)
> @@ -4992,11 +4987,18 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
> /* update hierarchical throttle state */
> walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq);
>
> - /* Nothing to run but something to decay (on_list)? Complete the branch */
> if (!cfs_rq->load.weight) {
> - if (cfs_rq->on_list)
> - goto unthrottle_throttle;
> - return;
> + if (!cfs_rq->on_list)
> + return;
> + /*
> + * Nothing to run but something to decay (on_list)?
> + * Complete the branch.
> + */
> + for_each_sched_entity(se) {
> + if (list_add_leaf_cfs_rq(cfs_rq_of(se)))
> + break;
> + }
> + goto unthrottle_throttle;
> }
>
> task_delta = cfs_rq->h_nr_running;
> @@ -5034,31 +5036,12 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
> /* end evaluation on encountering a throttled cfs_rq */
> if (cfs_rq_throttled(qcfs_rq))
> goto unthrottle_throttle;
> -
> - /*
> - * One parent has been throttled and cfs_rq removed from the
> - * list. Add it back to not break the leaf list.
> - */
> - if (throttled_hierarchy(qcfs_rq))
> - list_add_leaf_cfs_rq(qcfs_rq);
> }
>
> /* At this point se is NULL and we are at root level*/
> add_nr_running(rq, task_delta);
>
> unthrottle_throttle:
> - /*
> - * The cfs_rq_throttled() breaks in the above iteration can result in
> - * incomplete leaf list maintenance, resulting in triggering the
> - * assertion below.
> - */
> - for_each_sched_entity(se) {
> - struct cfs_rq *qcfs_rq = cfs_rq_of(se);
> -
> - if (list_add_leaf_cfs_rq(qcfs_rq))
> - break;
> - }
> -
> assert_list_leaf_cfs_rq(rq);
>
> /* Determine whether we need to wake up potentially idle CPU: */
> @@ -5713,13 +5696,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
> /* end evaluation on encountering a throttled cfs_rq */
> if (cfs_rq_throttled(cfs_rq))
> goto enqueue_throttle;
> -
> - /*
> - * One parent has been throttled and cfs_rq removed from the
> - * list. Add it back to not break the leaf list.
> - */
> - if (throttled_hierarchy(cfs_rq))
> - list_add_leaf_cfs_rq(cfs_rq);
> }
>
> /* At this point se is NULL and we are at root level*/
> @@ -5743,21 +5719,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
> update_overutilized_status(rq);
>
> enqueue_throttle:
> - if (cfs_bandwidth_used()) {
> - /*
> - * When bandwidth control is enabled; the cfs_rq_throttled()
> - * breaks in the above iteration can result in incomplete
> - * leaf list maintenance, resulting in triggering the assertion
> - * below.
> - */
> - for_each_sched_entity(se) {
> - cfs_rq = cfs_rq_of(se);
> -
> - if (list_add_leaf_cfs_rq(cfs_rq))
> - break;
> - }
> - }
> -
> assert_list_leaf_cfs_rq(rq);
>
> hrtick_update(rq);
> @@ -11287,9 +11248,13 @@ static inline bool vruntime_normalized(struct task_struct *p)
> */
> static void propagate_entity_cfs_rq(struct sched_entity *se)
> {
> - struct cfs_rq *cfs_rq;
> + struct cfs_rq *cfs_rq = cfs_rq_of(se);
> +
> + if (cfs_rq_throttled(cfs_rq))
> + return;
>
> - list_add_leaf_cfs_rq(cfs_rq_of(se));
> + if (!throttled_hierarchy(cfs_rq))
> + list_add_leaf_cfs_rq(cfs_rq);
>
> /* Start to propagate at parent */
> se = se->parent;
> @@ -11297,14 +11262,13 @@ static void propagate_entity_cfs_rq(struct sched_entity *se)
> for_each_sched_entity(se) {
> cfs_rq = cfs_rq_of(se);
>
> - if (!cfs_rq_throttled(cfs_rq)){
> - update_load_avg(cfs_rq, se, UPDATE_TG);
> - list_add_leaf_cfs_rq(cfs_rq);
> - continue;
> - }
> + update_load_avg(cfs_rq, se, UPDATE_TG);
>
> - if (list_add_leaf_cfs_rq(cfs_rq))
> + if (cfs_rq_throttled(cfs_rq))
> break;
> +
> + if (!throttled_hierarchy(cfs_rq))
> + list_add_leaf_cfs_rq(cfs_rq);
> }
> }
> #else
> --
> 2.36.1
>
On Wed, Jun 01, 2022 at 03:22:12PM +0200, Vincent Guittot wrote:
> On Wed, 1 Jun 2022 at 04:19, Chengming Zhou <zhouchengming@bytedance.com> wrote:
> >
> > We notice the rq leaf_cfs_rq_list has two problems when do bugfix
> > backports and some test profiling.
> >
> > 1. cfs_rqs under throttled subtree could be added to the list, and
> > make their fully decayed ancestors on the list, even though not needed.
> >
> > 2. #1 also make the leaf_cfs_rq_list management complex and error prone,
> > this is the list of related bugfix so far:
> >
> > commit 31bc6aeaab1d ("sched/fair: Optimize update_blocked_averages()")
> > commit fe61468b2cbc ("sched/fair: Fix enqueue_task_fair warning")
> > commit b34cb07dde7c ("sched/fair: Fix enqueue_task_fair() warning some more")
> > commit 39f23ce07b93 ("sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list")
> > commit 0258bdfaff5b ("sched/fair: Fix unfairness caused by missing load decay")
> > commit a7b359fc6a37 ("sched/fair: Correctly insert cfs_rq's to list on unthrottle")
> > commit fdaba61ef8a2 ("sched/fair: Ensure that the CFS parent is added after unthrottling")
> > commit 2630cde26711 ("sched/fair: Add ancestors of unthrottled undecayed cfs_rq")
> >
> > commit 31bc6aeaab1d ("sched/fair: Optimize update_blocked_averages()")
> > delete every cfs_rq under throttled subtree from rq->leaf_cfs_rq_list,
> > and delete the throttled_hierarchy() test in update_blocked_averages(),
> > which optimized update_blocked_averages().
> >
> > But those later bugfix add cfs_rqs under throttled subtree back to
> > rq->leaf_cfs_rq_list again, with their fully decayed ancestors, for
> > the integrity of rq->leaf_cfs_rq_list.
> >
> > This patch takes another method, skip all cfs_rqs under throttled
> > hierarchy when list_add_leaf_cfs_rq(), to completely make cfs_rqs
> > under throttled subtree off the leaf_cfs_rq_list.
> >
> > So we don't need to consider throttled related things in
> > enqueue_entity(), unthrottle_cfs_rq() and enqueue_task_fair(),
> > which simplify the code a lot. Also optimize update_blocked_averages()
> > since cfs_rqs under throttled hierarchy and their ancestors
> > won't be on the leaf_cfs_rq_list.
> >
> > Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
>
> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Thanks!
The following commit has been merged into the sched/core branch of tip:
Commit-ID: 51bf903b64bdde4e4c9009a9e2b4a589845d9d81
Gitweb: https://git.kernel.org/tip/51bf903b64bdde4e4c9009a9e2b4a589845d9d81
Author: Chengming Zhou <zhouchengming@bytedance.com>
AuthorDate: Wed, 01 Jun 2022 10:18:48 +08:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 13 Jun 2022 10:30:00 +02:00
sched/fair: Optimize and simplify rq leaf_cfs_rq_list
We notice the rq leaf_cfs_rq_list has two problems when do bugfix
backports and some test profiling.
1. cfs_rqs under throttled subtree could be added to the list, and
make their fully decayed ancestors on the list, even though not needed.
2. #1 also make the leaf_cfs_rq_list management complex and error prone,
this is the list of related bugfix so far:
commit 31bc6aeaab1d ("sched/fair: Optimize update_blocked_averages()")
commit fe61468b2cbc ("sched/fair: Fix enqueue_task_fair warning")
commit b34cb07dde7c ("sched/fair: Fix enqueue_task_fair() warning some more")
commit 39f23ce07b93 ("sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list")
commit 0258bdfaff5b ("sched/fair: Fix unfairness caused by missing load decay")
commit a7b359fc6a37 ("sched/fair: Correctly insert cfs_rq's to list on unthrottle")
commit fdaba61ef8a2 ("sched/fair: Ensure that the CFS parent is added after unthrottling")
commit 2630cde26711 ("sched/fair: Add ancestors of unthrottled undecayed cfs_rq")
commit 31bc6aeaab1d ("sched/fair: Optimize update_blocked_averages()")
delete every cfs_rq under throttled subtree from rq->leaf_cfs_rq_list,
and delete the throttled_hierarchy() test in update_blocked_averages(),
which optimized update_blocked_averages().
But those later bugfix add cfs_rqs under throttled subtree back to
rq->leaf_cfs_rq_list again, with their fully decayed ancestors, for
the integrity of rq->leaf_cfs_rq_list.
This patch takes another method, skip all cfs_rqs under throttled
hierarchy when list_add_leaf_cfs_rq(), to completely make cfs_rqs
under throttled subtree off the leaf_cfs_rq_list.
So we don't need to consider throttled related things in
enqueue_entity(), unthrottle_cfs_rq() and enqueue_task_fair(),
which simplify the code a lot. Also optimize update_blocked_averages()
since cfs_rqs under throttled hierarchy and their ancestors
won't be on the leaf_cfs_rq_list.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20220601021848.76943-1-zhouchengming@bytedance.com
---
kernel/sched/fair.c | 92 +++++++++++++-------------------------------
1 file changed, 28 insertions(+), 64 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 1b2cac7..7d8ef01 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3179,6 +3179,8 @@ void reweight_task(struct task_struct *p, int prio)
load->inv_weight = sched_prio_to_wmult[prio];
}
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
+
#ifdef CONFIG_FAIR_GROUP_SCHED
#ifdef CONFIG_SMP
/*
@@ -3289,8 +3291,6 @@ static long calc_group_shares(struct cfs_rq *cfs_rq)
}
#endif /* CONFIG_SMP */
-static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
-
/*
* Recomputes the group entity based on the current state of its group
* runqueue.
@@ -4403,16 +4403,11 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
__enqueue_entity(cfs_rq, se);
se->on_rq = 1;
- /*
- * When bandwidth control is enabled, cfs might have been removed
- * because of a parent been throttled but cfs->nr_running > 1. Try to
- * add it unconditionally.
- */
- if (cfs_rq->nr_running == 1 || cfs_bandwidth_used())
- list_add_leaf_cfs_rq(cfs_rq);
-
- if (cfs_rq->nr_running == 1)
+ if (cfs_rq->nr_running == 1) {
check_enqueue_throttle(cfs_rq);
+ if (!throttled_hierarchy(cfs_rq))
+ list_add_leaf_cfs_rq(cfs_rq);
+ }
}
static void __clear_buddies_last(struct sched_entity *se)
@@ -5027,11 +5022,18 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
/* update hierarchical throttle state */
walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq);
- /* Nothing to run but something to decay (on_list)? Complete the branch */
if (!cfs_rq->load.weight) {
- if (cfs_rq->on_list)
- goto unthrottle_throttle;
- return;
+ if (!cfs_rq->on_list)
+ return;
+ /*
+ * Nothing to run but something to decay (on_list)?
+ * Complete the branch.
+ */
+ for_each_sched_entity(se) {
+ if (list_add_leaf_cfs_rq(cfs_rq_of(se)))
+ break;
+ }
+ goto unthrottle_throttle;
}
task_delta = cfs_rq->h_nr_running;
@@ -5069,31 +5071,12 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
/* end evaluation on encountering a throttled cfs_rq */
if (cfs_rq_throttled(qcfs_rq))
goto unthrottle_throttle;
-
- /*
- * One parent has been throttled and cfs_rq removed from the
- * list. Add it back to not break the leaf list.
- */
- if (throttled_hierarchy(qcfs_rq))
- list_add_leaf_cfs_rq(qcfs_rq);
}
/* At this point se is NULL and we are at root level*/
add_nr_running(rq, task_delta);
unthrottle_throttle:
- /*
- * The cfs_rq_throttled() breaks in the above iteration can result in
- * incomplete leaf list maintenance, resulting in triggering the
- * assertion below.
- */
- for_each_sched_entity(se) {
- struct cfs_rq *qcfs_rq = cfs_rq_of(se);
-
- if (list_add_leaf_cfs_rq(qcfs_rq))
- break;
- }
-
assert_list_leaf_cfs_rq(rq);
/* Determine whether we need to wake up potentially idle CPU: */
@@ -5748,13 +5731,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
/* end evaluation on encountering a throttled cfs_rq */
if (cfs_rq_throttled(cfs_rq))
goto enqueue_throttle;
-
- /*
- * One parent has been throttled and cfs_rq removed from the
- * list. Add it back to not break the leaf list.
- */
- if (throttled_hierarchy(cfs_rq))
- list_add_leaf_cfs_rq(cfs_rq);
}
/* At this point se is NULL and we are at root level*/
@@ -5778,21 +5754,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
update_overutilized_status(rq);
enqueue_throttle:
- if (cfs_bandwidth_used()) {
- /*
- * When bandwidth control is enabled; the cfs_rq_throttled()
- * breaks in the above iteration can result in incomplete
- * leaf list maintenance, resulting in triggering the assertion
- * below.
- */
- for_each_sched_entity(se) {
- cfs_rq = cfs_rq_of(se);
-
- if (list_add_leaf_cfs_rq(cfs_rq))
- break;
- }
- }
-
assert_list_leaf_cfs_rq(rq);
hrtick_update(rq);
@@ -11316,9 +11277,13 @@ static inline bool vruntime_normalized(struct task_struct *p)
*/
static void propagate_entity_cfs_rq(struct sched_entity *se)
{
- struct cfs_rq *cfs_rq;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ if (cfs_rq_throttled(cfs_rq))
+ return;
- list_add_leaf_cfs_rq(cfs_rq_of(se));
+ if (!throttled_hierarchy(cfs_rq))
+ list_add_leaf_cfs_rq(cfs_rq);
/* Start to propagate at parent */
se = se->parent;
@@ -11326,14 +11291,13 @@ static void propagate_entity_cfs_rq(struct sched_entity *se)
for_each_sched_entity(se) {
cfs_rq = cfs_rq_of(se);
- if (!cfs_rq_throttled(cfs_rq)){
- update_load_avg(cfs_rq, se, UPDATE_TG);
- list_add_leaf_cfs_rq(cfs_rq);
- continue;
- }
+ update_load_avg(cfs_rq, se, UPDATE_TG);
- if (list_add_leaf_cfs_rq(cfs_rq))
+ if (cfs_rq_throttled(cfs_rq))
break;
+
+ if (!throttled_hierarchy(cfs_rq))
+ list_add_leaf_cfs_rq(cfs_rq);
}
}
#else© 2016 - 2026 Red Hat, Inc.