Commit e98abd22 authored by Tejun Heo's avatar Tejun Heo
Browse files

sched_ext: Account for idle policy when setting p->scx.weight in scx_ops_enable_task() 



When initializing p->scx.weight, scx_ops_enable_task() wasn't considering
whether the task is SCHED_IDLE. Update it to use WEIGHT_IDLEPRIO as the
source weight for SCHED_IDLE tasks. This leaves reweight_task_scx() the sole
user of set_task_scx_weight(). Open code it. @weight is going to be provided
by sched core in the future anyway.

v2: Use the newly available @lw->weight to set @p->scx.weight in
    reweight_task_scx().

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: David Vernet <void@manifault.com>
Cc: Peter Zijlstra <peterz@infradead.org>
parent 60564acb

kernel/sched/ext.c

+10 −9
Original line number Diff line number Diff line
@@ -3237,22 +3237,23 @@ static int scx_ops_init_task(struct task_struct *p, struct task_group *tg, bool 
	return 0;

}



static void set_task_scx_weight(struct task_struct *p)

{

	u32 weight = sched_prio_to_weight[p->static_prio - MAX_RT_PRIO];



	p->scx.weight = sched_weight_to_cgroup(weight);

}



static void scx_ops_enable_task(struct task_struct *p)

{

	u32 weight;



	lockdep_assert_rq_held(task_rq(p));



	/*

	 * Set the weight before calling ops.enable() so that the scheduler

	 * doesn't see a stale value if they inspect the task struct.

	 */

	set_task_scx_weight(p);

	if (task_has_idle_policy(p))

		weight = WEIGHT_IDLEPRIO;

	else

		weight = sched_prio_to_weight[p->static_prio - MAX_RT_PRIO];



	p->scx.weight = sched_weight_to_cgroup(weight);



	if (SCX_HAS_OP(enable))

		SCX_CALL_OP_TASK(SCX_KF_REST, enable, p);

	scx_set_task_state(p, SCX_TASK_ENABLED);
@@ -3408,7 +3409,7 @@ static void reweight_task_scx(struct rq *rq, struct task_struct *p, 
{

	lockdep_assert_rq_held(task_rq(p));



	set_task_scx_weight(p);

	p->scx.weight = sched_weight_to_cgroup(scale_load_down(lw->weight));

	if (SCX_HAS_OP(set_weight))

		SCX_CALL_OP_TASK(SCX_KF_REST, set_weight, p, p->scx.weight);

}