* [PATCH v4] sched/fair: combine detach into dequeue when migrating task
@ 2022-06-20 13:36 Chengming Zhou
2022-06-28 12:32 ` Chengming Zhou
2022-06-28 15:26 ` Vincent Guittot
0 siblings, 2 replies; 4+ messages in thread
From: Chengming Zhou @ 2022-06-20 13:36 UTC (permalink / raw)
To: mingo, peterz, vincent.guittot, dietmar.eggemann, bsegall, vschneid
Cc: linux-kernel, Chengming Zhou
When we are migrating task out of the CPU, we can combine detach and
propagation into dequeue_entity() to save the detach_entity_cfs_rq()
-> propagate_entity_cfs_rq() call in detach_entity_cfs_rq() in
migrate_task_rq_fair().
This optimization is like combining DO_ATTACH in the enqueue_entity()
when migrating task to the CPU.
So we don't have to traverse the CFS tree extra time to do the
detach_entity_cfs_rq() -> propagate_entity_cfs_rq() call, which
wouldn't be called anymore with this patch's change.
Copied from Dietmar's much clearer comment:
detach_task()
deactivate_task()
dequeue_task_fair()
for_each_sched_entity(se)
dequeue_entity()
update_load_avg() /* (1) */
set_task_cpu()
migrate_task_rq_fair()
/* called detach_entity_cfs_rq() before the patch (2) */
This patch save the propagate_entity_cfs_rq(&p->se) call from (2)
by doing the detach_entity_load_avg(), update_tg_load_avg() for
a migrating task inside (1) (the task being the first se in the loop)
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
v4:
- change the commit message a little.
- remove the forward declaration of detach_entity_cfs_rq()
- remove verbose comments in code.
v3:
- change to use task_on_rq_migrating() and put Dietmar's much clearer
description in the commit message. Thanks!
v2:
- fix !CONFIG_SMP build error
---
kernel/sched/fair.c | 30 +++++++++++++++++-------------
1 file changed, 17 insertions(+), 13 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8bed75757e65..31d53c11e244 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3931,6 +3931,7 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
#define UPDATE_TG 0x1
#define SKIP_AGE_LOAD 0x2
#define DO_ATTACH 0x4
+#define DO_DETACH 0x8
/* 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)
@@ -3948,7 +3949,14 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
decayed = update_cfs_rq_load_avg(now, cfs_rq);
decayed |= propagate_entity_load_avg(se);
- if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
+ if (flags & DO_DETACH) {
+ /*
+ * DO_DETACH means we're here from dequeue_entity()
+ * and we are migrating task out of the CPU.
+ */
+ detach_entity_load_avg(cfs_rq, se);
+ update_tg_load_avg(cfs_rq);
+ } else if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
/*
* DO_ATTACH means we're here from enqueue_entity().
@@ -4241,6 +4249,7 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
#define UPDATE_TG 0x0
#define SKIP_AGE_LOAD 0x0
#define DO_ATTACH 0x0
+#define DO_DETACH 0x0
static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1)
{
@@ -4460,6 +4469,11 @@ 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)
{
+ int action = UPDATE_TG;
+
+ if (entity_is_task(se) && task_on_rq_migrating(task_of(se)))
+ action |= DO_DETACH;
+
/*
* Update run-time statistics of the 'current'.
*/
@@ -4473,7 +4487,7 @@ 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);
+ update_load_avg(cfs_rq, se, action);
se_update_runnable(se);
update_stats_dequeue_fair(cfs_rq, se, flags);
@@ -6938,8 +6952,6 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
return new_cpu;
}
-static void detach_entity_cfs_rq(struct sched_entity *se);
-
/*
* Called immediately before a task is migrated to a new CPU; task_cpu(p) and
* cfs_rq_of(p) references at time of call are still valid and identify the
@@ -6973,15 +6985,7 @@ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu)
se->vruntime -= min_vruntime;
}
- if (p->on_rq == TASK_ON_RQ_MIGRATING) {
- /*
- * In case of TASK_ON_RQ_MIGRATING we in fact hold the 'old'
- * rq->lock and can modify state directly.
- */
- lockdep_assert_rq_held(task_rq(p));
- detach_entity_cfs_rq(&p->se);
-
- } else {
+ if (!task_on_rq_migrating(p)) {
/*
* We are supposed to update the task to "current" time, then
* its up to date and ready to go to new CPU/cfs_rq. But we
--
2.36.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v4] sched/fair: combine detach into dequeue when migrating task
2022-06-20 13:36 [PATCH v4] sched/fair: combine detach into dequeue when migrating task Chengming Zhou
@ 2022-06-28 12:32 ` Chengming Zhou
2022-06-28 15:26 ` Vincent Guittot
1 sibling, 0 replies; 4+ messages in thread
From: Chengming Zhou @ 2022-06-28 12:32 UTC (permalink / raw)
To: mingo, peterz, vincent.guittot, dietmar.eggemann, bsegall, vschneid
Cc: linux-kernel
Hello, friendly ping...
Thanks.
On 2022/6/20 21:36, Chengming Zhou wrote:
> When we are migrating task out of the CPU, we can combine detach and
> propagation into dequeue_entity() to save the detach_entity_cfs_rq()
> -> propagate_entity_cfs_rq() call in detach_entity_cfs_rq() in
> migrate_task_rq_fair().
>
> This optimization is like combining DO_ATTACH in the enqueue_entity()
> when migrating task to the CPU.
>
> So we don't have to traverse the CFS tree extra time to do the
> detach_entity_cfs_rq() -> propagate_entity_cfs_rq() call, which
> wouldn't be called anymore with this patch's change.
>
> Copied from Dietmar's much clearer comment:
>
> detach_task()
> deactivate_task()
> dequeue_task_fair()
> for_each_sched_entity(se)
> dequeue_entity()
> update_load_avg() /* (1) */
>
> set_task_cpu()
> migrate_task_rq_fair()
> /* called detach_entity_cfs_rq() before the patch (2) */
>
> This patch save the propagate_entity_cfs_rq(&p->se) call from (2)
> by doing the detach_entity_load_avg(), update_tg_load_avg() for
> a migrating task inside (1) (the task being the first se in the loop)
>
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
> ---
> v4:
> - change the commit message a little.
> - remove the forward declaration of detach_entity_cfs_rq()
> - remove verbose comments in code.
>
> v3:
> - change to use task_on_rq_migrating() and put Dietmar's much clearer
> description in the commit message. Thanks!
>
> v2:
> - fix !CONFIG_SMP build error
> ---
> kernel/sched/fair.c | 30 +++++++++++++++++-------------
> 1 file changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 8bed75757e65..31d53c11e244 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3931,6 +3931,7 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
> #define UPDATE_TG 0x1
> #define SKIP_AGE_LOAD 0x2
> #define DO_ATTACH 0x4
> +#define DO_DETACH 0x8
>
> /* 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)
> @@ -3948,7 +3949,14 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
> decayed = update_cfs_rq_load_avg(now, cfs_rq);
> decayed |= propagate_entity_load_avg(se);
>
> - if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
> + if (flags & DO_DETACH) {
> + /*
> + * DO_DETACH means we're here from dequeue_entity()
> + * and we are migrating task out of the CPU.
> + */
> + detach_entity_load_avg(cfs_rq, se);
> + update_tg_load_avg(cfs_rq);
> + } else if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
>
> /*
> * DO_ATTACH means we're here from enqueue_entity().
> @@ -4241,6 +4249,7 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
> #define UPDATE_TG 0x0
> #define SKIP_AGE_LOAD 0x0
> #define DO_ATTACH 0x0
> +#define DO_DETACH 0x0
>
> static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1)
> {
> @@ -4460,6 +4469,11 @@ 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)
> {
> + int action = UPDATE_TG;
> +
> + if (entity_is_task(se) && task_on_rq_migrating(task_of(se)))
> + action |= DO_DETACH;
> +
> /*
> * Update run-time statistics of the 'current'.
> */
> @@ -4473,7 +4487,7 @@ 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);
> + update_load_avg(cfs_rq, se, action);
> se_update_runnable(se);
>
> update_stats_dequeue_fair(cfs_rq, se, flags);
> @@ -6938,8 +6952,6 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
> return new_cpu;
> }
>
> -static void detach_entity_cfs_rq(struct sched_entity *se);
> -
> /*
> * Called immediately before a task is migrated to a new CPU; task_cpu(p) and
> * cfs_rq_of(p) references at time of call are still valid and identify the
> @@ -6973,15 +6985,7 @@ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu)
> se->vruntime -= min_vruntime;
> }
>
> - if (p->on_rq == TASK_ON_RQ_MIGRATING) {
> - /*
> - * In case of TASK_ON_RQ_MIGRATING we in fact hold the 'old'
> - * rq->lock and can modify state directly.
> - */
> - lockdep_assert_rq_held(task_rq(p));
> - detach_entity_cfs_rq(&p->se);
> -
> - } else {
> + if (!task_on_rq_migrating(p)) {
> /*
> * We are supposed to update the task to "current" time, then
> * its up to date and ready to go to new CPU/cfs_rq. But we
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v4] sched/fair: combine detach into dequeue when migrating task
2022-06-20 13:36 [PATCH v4] sched/fair: combine detach into dequeue when migrating task Chengming Zhou
2022-06-28 12:32 ` Chengming Zhou
@ 2022-06-28 15:26 ` Vincent Guittot
2022-06-29 1:37 ` [External] " Chengming Zhou
1 sibling, 1 reply; 4+ messages in thread
From: Vincent Guittot @ 2022-06-28 15:26 UTC (permalink / raw)
To: Chengming Zhou
Cc: mingo, peterz, dietmar.eggemann, bsegall, vschneid, linux-kernel
On Mon, 20 Jun 2022 at 15:36, Chengming Zhou
<zhouchengming@bytedance.com> wrote:
>
> When we are migrating task out of the CPU, we can combine detach and
> propagation into dequeue_entity() to save the detach_entity_cfs_rq()
> -> propagate_entity_cfs_rq() call in detach_entity_cfs_rq() in
> migrate_task_rq_fair().
>
> This optimization is like combining DO_ATTACH in the enqueue_entity()
> when migrating task to the CPU.
> -> propagate_entity_cfs_rq() call in detach_entity_cfs_rq() in
> migrate_task_rq_fair().
>
>
> So we don't have to traverse the CFS tree extra time to do the
> detach_entity_cfs_rq() -> propagate_entity_cfs_rq() call, which
> wouldn't be called anymore with this patch's change.
>
> Copied from Dietmar's much clearer comment:
Although It's nice to keep the author of a comment, it should not be
part of the commit message.
> detach_task()
> deactivate_task()
> dequeue_task_fair()
> for_each_sched_entity(se)
> dequeue_entity()
> update_load_avg() /* (1) */
detach_entity_load_avg()
> set_task_cpu()
> migrate_task_rq_fair()
> detach_entity_cfs_rq() /* (2) */
update_load_avg();
detach_entity_load_avg();
propagate_entity_cfs_rq();
for_each_sched_entity()
update_load_avg()
Could you add the full call stack so we can see more easily the extra
loop that is saved
>
> This patch save the propagate_entity_cfs_rq(&p->se) call from (2)
> by doing the detach_entity_load_avg(), update_tg_load_avg() for
> a migrating task inside (1) (the task being the first se in the loop)
>
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Apart the small nit above:
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
> v4:
> - change the commit message a little.
> - remove the forward declaration of detach_entity_cfs_rq()
> - remove verbose comments in code.
>
> v3:
> - change to use task_on_rq_migrating() and put Dietmar's much clearer
> description in the commit message. Thanks!
>
> v2:
> - fix !CONFIG_SMP build error
> ---
> kernel/sched/fair.c | 30 +++++++++++++++++-------------
> 1 file changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 8bed75757e65..31d53c11e244 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3931,6 +3931,7 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
> #define UPDATE_TG 0x1
> #define SKIP_AGE_LOAD 0x2
> #define DO_ATTACH 0x4
> +#define DO_DETACH 0x8
>
> /* 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)
> @@ -3948,7 +3949,14 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
> decayed = update_cfs_rq_load_avg(now, cfs_rq);
> decayed |= propagate_entity_load_avg(se);
>
> - if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
> + if (flags & DO_DETACH) {
> + /*
> + * DO_DETACH means we're here from dequeue_entity()
> + * and we are migrating task out of the CPU.
> + */
> + detach_entity_load_avg(cfs_rq, se);
> + update_tg_load_avg(cfs_rq);
> + } else if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
>
> /*
> * DO_ATTACH means we're here from enqueue_entity().
> @@ -4241,6 +4249,7 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
> #define UPDATE_TG 0x0
> #define SKIP_AGE_LOAD 0x0
> #define DO_ATTACH 0x0
> +#define DO_DETACH 0x0
>
> static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1)
> {
> @@ -4460,6 +4469,11 @@ 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)
> {
> + int action = UPDATE_TG;
> +
> + if (entity_is_task(se) && task_on_rq_migrating(task_of(se)))
> + action |= DO_DETACH;
> +
> /*
> * Update run-time statistics of the 'current'.
> */
> @@ -4473,7 +4487,7 @@ 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);
> + update_load_avg(cfs_rq, se, action);
> se_update_runnable(se);
>
> update_stats_dequeue_fair(cfs_rq, se, flags);
> @@ -6938,8 +6952,6 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
> return new_cpu;
> }
>
> -static void detach_entity_cfs_rq(struct sched_entity *se);
> -
> /*
> * Called immediately before a task is migrated to a new CPU; task_cpu(p) and
> * cfs_rq_of(p) references at time of call are still valid and identify the
> @@ -6973,15 +6985,7 @@ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu)
> se->vruntime -= min_vruntime;
> }
>
> - if (p->on_rq == TASK_ON_RQ_MIGRATING) {
> - /*
> - * In case of TASK_ON_RQ_MIGRATING we in fact hold the 'old'
> - * rq->lock and can modify state directly.
> - */
> - lockdep_assert_rq_held(task_rq(p));
> - detach_entity_cfs_rq(&p->se);
> -
> - } else {
> + if (!task_on_rq_migrating(p)) {
> /*
> * We are supposed to update the task to "current" time, then
> * its up to date and ready to go to new CPU/cfs_rq. But we
> --
> 2.36.1
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [External] Re: [PATCH v4] sched/fair: combine detach into dequeue when migrating task
2022-06-28 15:26 ` Vincent Guittot
@ 2022-06-29 1:37 ` Chengming Zhou
0 siblings, 0 replies; 4+ messages in thread
From: Chengming Zhou @ 2022-06-29 1:37 UTC (permalink / raw)
To: Vincent Guittot
Cc: mingo, peterz, dietmar.eggemann, bsegall, vschneid, linux-kernel
Hi, thanks for your review.
On 2022/6/28 23:26, Vincent Guittot wrote:
> On Mon, 20 Jun 2022 at 15:36, Chengming Zhou
> <zhouchengming@bytedance.com> wrote:
>>
>> When we are migrating task out of the CPU, we can combine detach and
>> propagation into dequeue_entity() to save the detach_entity_cfs_rq()
>> -> propagate_entity_cfs_rq() call in detach_entity_cfs_rq() in
>> migrate_task_rq_fair().
>>
>> This optimization is like combining DO_ATTACH in the enqueue_entity()
>> when migrating task to the CPU.
>> -> propagate_entity_cfs_rq() call in detach_entity_cfs_rq() in
>> migrate_task_rq_fair().
>>
>>
>> So we don't have to traverse the CFS tree extra time to do the
>> detach_entity_cfs_rq() -> propagate_entity_cfs_rq() call, which
>> wouldn't be called anymore with this patch's change.
>>
>> Copied from Dietmar's much clearer comment:
>
> Although It's nice to keep the author of a comment, it should not be
> part of the commit message.
Ok, I will delete this.
>
>> detach_task()
>> deactivate_task()
>> dequeue_task_fair()
>> for_each_sched_entity(se)
>> dequeue_entity()
>> update_load_avg() /* (1) */
> detach_entity_load_avg()
>
>> set_task_cpu()
>> migrate_task_rq_fair()
>> detach_entity_cfs_rq() /* (2) */
> update_load_avg();
> detach_entity_load_avg();
> propagate_entity_cfs_rq();
> for_each_sched_entity()
> update_load_avg()
>
> Could you add the full call stack so we can see more easily the extra
> loop that is saved
Good advice, I will add it.
Thanks.
>>
>> This patch save the propagate_entity_cfs_rq(&p->se) call from (2)
>> by doing the detach_entity_load_avg(), update_tg_load_avg() for
>> a migrating task inside (1) (the task being the first se in the loop)
>>
>> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
>
> Apart the small nit above:
>
> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
>
>> ---
>> v4:
>> - change the commit message a little.
>> - remove the forward declaration of detach_entity_cfs_rq()
>> - remove verbose comments in code.
>>
>> v3:
>> - change to use task_on_rq_migrating() and put Dietmar's much clearer
>> description in the commit message. Thanks!
>>
>> v2:
>> - fix !CONFIG_SMP build error
>> ---
>> kernel/sched/fair.c | 30 +++++++++++++++++-------------
>> 1 file changed, 17 insertions(+), 13 deletions(-)
>>
>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> index 8bed75757e65..31d53c11e244 100644
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -3931,6 +3931,7 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
>> #define UPDATE_TG 0x1
>> #define SKIP_AGE_LOAD 0x2
>> #define DO_ATTACH 0x4
>> +#define DO_DETACH 0x8
>>
>> /* 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)
>> @@ -3948,7 +3949,14 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
>> decayed = update_cfs_rq_load_avg(now, cfs_rq);
>> decayed |= propagate_entity_load_avg(se);
>>
>> - if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
>> + if (flags & DO_DETACH) {
>> + /*
>> + * DO_DETACH means we're here from dequeue_entity()
>> + * and we are migrating task out of the CPU.
>> + */
>> + detach_entity_load_avg(cfs_rq, se);
>> + update_tg_load_avg(cfs_rq);
>> + } else if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
>>
>> /*
>> * DO_ATTACH means we're here from enqueue_entity().
>> @@ -4241,6 +4249,7 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
>> #define UPDATE_TG 0x0
>> #define SKIP_AGE_LOAD 0x0
>> #define DO_ATTACH 0x0
>> +#define DO_DETACH 0x0
>>
>> static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1)
>> {
>> @@ -4460,6 +4469,11 @@ 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)
>> {
>> + int action = UPDATE_TG;
>> +
>> + if (entity_is_task(se) && task_on_rq_migrating(task_of(se)))
>> + action |= DO_DETACH;
>> +
>> /*
>> * Update run-time statistics of the 'current'.
>> */
>> @@ -4473,7 +4487,7 @@ 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);
>> + update_load_avg(cfs_rq, se, action);
>> se_update_runnable(se);
>>
>> update_stats_dequeue_fair(cfs_rq, se, flags);
>> @@ -6938,8 +6952,6 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
>> return new_cpu;
>> }
>>
>> -static void detach_entity_cfs_rq(struct sched_entity *se);
>> -
>> /*
>> * Called immediately before a task is migrated to a new CPU; task_cpu(p) and
>> * cfs_rq_of(p) references at time of call are still valid and identify the
>> @@ -6973,15 +6985,7 @@ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu)
>> se->vruntime -= min_vruntime;
>> }
>>
>> - if (p->on_rq == TASK_ON_RQ_MIGRATING) {
>> - /*
>> - * In case of TASK_ON_RQ_MIGRATING we in fact hold the 'old'
>> - * rq->lock and can modify state directly.
>> - */
>> - lockdep_assert_rq_held(task_rq(p));
>> - detach_entity_cfs_rq(&p->se);
>> -
>> - } else {
>> + if (!task_on_rq_migrating(p)) {
>> /*
>> * We are supposed to update the task to "current" time, then
>> * its up to date and ready to go to new CPU/cfs_rq. But we
>> --
>> 2.36.1
>>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-06-29 1:38 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-06-20 13:36 [PATCH v4] sched/fair: combine detach into dequeue when migrating task Chengming Zhou
2022-06-28 12:32 ` Chengming Zhou
2022-06-28 15:26 ` Vincent Guittot
2022-06-29 1:37 ` [External] " Chengming Zhou
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