From e83edbf88f18087b5b349c7ff701b030dd53dff3 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 18 Jun 2024 10:09:16 -1000 Subject: [PATCH] sched: Add sched_class->reweight_task() Currently, during a task weight change, sched core directly calls reweight_task() defined in fair.c if @p is on CFS. Let's make it a proper sched_class operation instead. CFS's reweight_task() is renamed to reweight_task_fair() and now called through sched_class. While it turns a direct call into an indirect one, set_load_weight() isn't called from a hot path and this change shouldn't cause any noticeable difference. This will be used to implement reweight_task for a new BPF extensible sched_class so that it can keep its cached task weight up-to-date. Signed-off-by: Tejun Heo Reviewed-by: David Vernet Acked-by: Josh Don Acked-by: Hao Luo Acked-by: Barret Rhoden --- kernel/sched/core.c | 4 ++-- kernel/sched/fair.c | 3 ++- kernel/sched/sched.h | 4 ++-- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 095604490c26..48f9d00d0666 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1343,8 +1343,8 @@ void set_load_weight(struct task_struct *p, bool update_load) * SCHED_OTHER tasks have to update their load when changing their * weight */ - if (update_load && p->sched_class == &fair_sched_class) { - reweight_task(p, prio); + if (update_load && p->sched_class->reweight_task) { + p->sched_class->reweight_task(task_rq(p), p, prio); } else { load->weight = scale_load(sched_prio_to_weight[prio]); load->inv_weight = sched_prio_to_wmult[prio]; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 41b58387023d..18ecd4f908e4 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3835,7 +3835,7 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, } } -void reweight_task(struct task_struct *p, int prio) +static void reweight_task_fair(struct rq *rq, struct task_struct *p, int prio) { struct sched_entity *se = &p->se; struct cfs_rq *cfs_rq = cfs_rq_of(se); @@ -13221,6 +13221,7 @@ DEFINE_SCHED_CLASS(fair) = { .task_tick = task_tick_fair, .task_fork = task_fork_fair, + .reweight_task = reweight_task_fair, .prio_changed = prio_changed_fair, .switched_from = switched_from_fair, .switched_to = switched_to_fair, diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 62fd8bc6fd08..a2399ccf259a 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2324,6 +2324,8 @@ struct sched_class { */ void (*switched_from)(struct rq *this_rq, struct task_struct *task); void (*switched_to) (struct rq *this_rq, struct task_struct *task); + void (*reweight_task)(struct rq *this_rq, struct task_struct *task, + int newprio); void (*prio_changed) (struct rq *this_rq, struct task_struct *task, int oldprio); @@ -2509,8 +2511,6 @@ extern void init_sched_dl_class(void); extern void init_sched_rt_class(void); extern void init_sched_fair_class(void); -extern void reweight_task(struct task_struct *p, int prio); - extern void resched_curr(struct rq *rq); extern void resched_cpu(int cpu);