Messages in this thread Patch in this message | | | From | Chengming Zhou <> | Subject | [PATCH v5 2/9] sched/fair: remove redundant cpu_cgrp_subsys->fork() | Date | Thu, 18 Aug 2022 11:43:36 +0800 |
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We use cpu_cgrp_subsys->fork() to set task group for the new fair task in cgroup_post_fork().
Since commit b1e8206582f9 ("sched: Fix yet more sched_fork() races") has already set_task_rq() for the new fair task in sched_cgroup_fork(), so cpu_cgrp_subsys->fork() can be removed.
cgroup_can_fork() --> pin parent's sched_task_group sched_cgroup_fork() __set_task_cpu() set_task_rq() cgroup_post_fork() ss->fork() := cpu_cgroup_fork() sched_change_group(..., TASK_SET_GROUP) task_set_group_fair() set_task_rq() --> can be removed
After this patch's change, task_change_group_fair() only need to care about task cgroup migration, make the code much simplier.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> --- kernel/sched/core.c | 27 ++++----------------------- kernel/sched/fair.c | 23 +---------------------- kernel/sched/sched.h | 5 +---- 3 files changed, 6 insertions(+), 49 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 863b5203e357..8e3f1c3f0b2c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -481,8 +481,7 @@ sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags) { } * p->se.load, p->rt_priority, * p->dl.dl_{runtime, deadline, period, flags, bw, density} * - sched_setnuma(): p->numa_preferred_nid - * - sched_move_task()/ - * cpu_cgroup_fork(): p->sched_task_group + * - sched_move_task(): p->sched_task_group * - uclamp_update_active() p->uclamp* * * p->state <- TASK_*: @@ -10166,7 +10165,7 @@ void sched_release_group(struct task_group *tg) spin_unlock_irqrestore(&task_group_lock, flags); } -static void sched_change_group(struct task_struct *tsk, int type) +static void sched_change_group(struct task_struct *tsk) { struct task_group *tg; @@ -10182,7 +10181,7 @@ static void sched_change_group(struct task_struct *tsk, int type) #ifdef CONFIG_FAIR_GROUP_SCHED if (tsk->sched_class->task_change_group) - tsk->sched_class->task_change_group(tsk, type); + tsk->sched_class->task_change_group(tsk); else #endif set_task_rq(tsk, task_cpu(tsk)); @@ -10213,7 +10212,7 @@ void sched_move_task(struct task_struct *tsk) if (running) put_prev_task(rq, tsk); - sched_change_group(tsk, TASK_MOVE_GROUP); + sched_change_group(tsk); if (queued) enqueue_task(rq, tsk, queue_flags); @@ -10291,23 +10290,6 @@ static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) sched_unregister_group(tg); } -/* - * This is called before wake_up_new_task(), therefore we really only - * have to set its group bits, all the other stuff does not apply. - */ -static void cpu_cgroup_fork(struct task_struct *task) -{ - struct rq_flags rf; - struct rq *rq; - - rq = task_rq_lock(task, &rf); - - update_rq_clock(rq); - sched_change_group(task, TASK_SET_GROUP); - - task_rq_unlock(rq, task, &rf); -} - static int cpu_cgroup_can_attach(struct cgroup_taskset *tset) { struct task_struct *task; @@ -11173,7 +11155,6 @@ struct cgroup_subsys cpu_cgrp_subsys = { .css_released = cpu_cgroup_css_released, .css_free = cpu_cgroup_css_free, .css_extra_stat_show = cpu_extra_stat_show, - .fork = cpu_cgroup_fork, .can_attach = cpu_cgroup_can_attach, .attach = cpu_cgroup_attach, .legacy_cftypes = cpu_legacy_files, diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c5ee08b187ec..4b95599aa951 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -11821,15 +11821,7 @@ void init_cfs_rq(struct cfs_rq *cfs_rq) } #ifdef CONFIG_FAIR_GROUP_SCHED -static void task_set_group_fair(struct task_struct *p) -{ - struct sched_entity *se = &p->se; - - set_task_rq(p, task_cpu(p)); - se->depth = se->parent ? se->parent->depth + 1 : 0; -} - -static void task_move_group_fair(struct task_struct *p) +static void task_change_group_fair(struct task_struct *p) { detach_task_cfs_rq(p); set_task_rq(p, task_cpu(p)); @@ -11841,19 +11833,6 @@ static void task_move_group_fair(struct task_struct *p) attach_task_cfs_rq(p); } -static void task_change_group_fair(struct task_struct *p, int type) -{ - switch (type) { - case TASK_SET_GROUP: - task_set_group_fair(p); - break; - - case TASK_MOVE_GROUP: - task_move_group_fair(p); - break; - } -} - void free_fair_sched_group(struct task_group *tg) { int i; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 628ffa974123..2db7b0494c19 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2195,11 +2195,8 @@ struct sched_class { void (*update_curr)(struct rq *rq); -#define TASK_SET_GROUP 0 -#define TASK_MOVE_GROUP 1 - #ifdef CONFIG_FAIR_GROUP_SCHED - void (*task_change_group)(struct task_struct *p, int type); + void (*task_change_group)(struct task_struct *p); #endif }; -- 2.37.2
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