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sched/fair: Add newidle balance to pick_task_fair()

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With commit 50653216e4 ("sched: Add support to pick functions to
take rf") removing the balance callback, the pick_task() callback is
in charge of newidle balancing.

This means pick_task_fair() should do so too. This hasn't been a
problem in practise because pick_next_task_fair() is used. However,
since we'll be removing that one shortly, make sure pick_next_task()
is up to scratch.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://patch.msgid.link/20260511120627.944705718@infradead.org
This commit is contained in:
Peter Zijlstra 2026-05-11 13:31:12 +02:00
parent e05777c44e
commit b3a2dfa8b4
1 changed files with 15 additions and 23 deletions
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38
kernel/sched/fair.c
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@ -9863,16 +9863,18 @@ static void wakeup_preempt_fair(struct rq *rq, struct task_struct *p, int wake_f
}
static struct task_struct *pick_task_fair(struct rq *rq, struct rq_flags *rf)
__must_hold(__rq_lockp(rq))
{
struct sched_entity *se;
struct cfs_rq *cfs_rq;
struct task_struct *p;
bool throttled;
int new_tasks;
again:
cfs_rq = &rq->cfs;
if (!cfs_rq->nr_queued)
return NULL;
goto idle;
throttled = false;
@ -9893,6 +9895,14 @@ static struct task_struct *pick_task_fair(struct rq *rq, struct rq_flags *rf)
if (unlikely(throttled))
task_throttle_setup_work(p);
return p;
idle:
new_tasks = sched_balance_newidle(rq, rf);
if (new_tasks < 0)
return RETRY_TASK;
if (new_tasks > 0)
goto again;
return NULL;
}
static void __set_next_task_fair(struct rq *rq, struct task_struct *p, bool first);
@ -9904,12 +9914,12 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf
{
struct sched_entity *se;
struct task_struct *p;
int new_tasks;
again:
p = pick_task_fair(rq, rf);
if (unlikely(p == RETRY_TASK))
return p;
if (!p)
goto idle;
return p;
se = &p->se;
#ifdef CONFIG_FAIR_GROUP_SCHED
@ -9959,29 +9969,11 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf
#endif /* CONFIG_FAIR_GROUP_SCHED */
put_prev_set_next_task(rq, prev, p);
return p;
idle:
if (rf) {
new_tasks = sched_balance_newidle(rq, rf);
/*
* Because sched_balance_newidle() releases (and re-acquires)
* rq->lock, it is possible for any higher priority task to
* appear. In that case we must re-start the pick_next_entity()
* loop.
*/
if (new_tasks < 0)
return RETRY_TASK;
if (new_tasks > 0)
goto again;
}
return NULL;
}
static struct task_struct *
fair_server_pick_task(struct sched_dl_entity *dl_se, struct rq_flags *rf)
__must_hold(__rq_lockp(dl_se->rq))
{
return pick_task_fair(dl_se->rq, rf);
}