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| author | Peter Zijlstra <peterz@infradead.org> | 2020-10-14 21:06:49 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-10-29 11:00:30 +0100 |
| commit | 934fc3314b39e16a89fc4d5d0d5cbfe71dcbe7b1 (patch) | |
| tree | cde90f2929580bce91b9dcdda8651265e5a38606 /kernel/sched | |
| parent | 1b08782ce31f612d98e11ccccf3e3df9a147a67d (diff) | |
| download | lwn-934fc3314b39e16a89fc4d5d0d5cbfe71dcbe7b1.tar.gz lwn-934fc3314b39e16a89fc4d5d0d5cbfe71dcbe7b1.zip | |
sched/cpupri: Remap CPUPRI_NORMAL to MAX_RT_PRIO-1
This makes the mapping continuous and frees up 100 for other usage.
Prev mapping:
p->rt_priority p->prio newpri cpupri
-1 -1 (CPUPRI_INVALID)
100 0 (CPUPRI_NORMAL)
1 98 98 1
...
49 50 50 49
50 49 49 50
...
99 0 0 99
New mapping:
p->rt_priority p->prio newpri cpupri
-1 -1 (CPUPRI_INVALID)
99 0 (CPUPRI_NORMAL)
1 98 98 1
...
49 50 50 49
50 49 49 50
...
99 0 0 99
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/cpupri.c | 34 | ||||
| -rw-r--r-- | kernel/sched/rt.c | 16 |
2 files changed, 36 insertions, 14 deletions
diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c index 8d9952a51664..e43491039226 100644 --- a/kernel/sched/cpupri.c +++ b/kernel/sched/cpupri.c @@ -24,17 +24,37 @@ */ #include "sched.h" -/* Convert between a 140 based task->prio, and our 100 based cpupri */ +/* + * p->rt_priority p->prio newpri cpupri + * + * -1 -1 (CPUPRI_INVALID) + * + * 99 0 (CPUPRI_NORMAL) + * + * 1 98 98 1 + * ... + * 49 50 50 49 + * 50 49 49 50 + * ... + * 99 0 0 99 + */ static int convert_prio(int prio) { int cpupri; - if (prio == CPUPRI_INVALID) - cpupri = CPUPRI_INVALID; - else if (prio >= MAX_RT_PRIO) - cpupri = CPUPRI_NORMAL; - else - cpupri = MAX_RT_PRIO - prio - 1; + switch (prio) { + case CPUPRI_INVALID: + cpupri = CPUPRI_INVALID; /* -1 */ + break; + + case 0 ... 98: + cpupri = MAX_RT_PRIO-1 - prio; /* 1 ... 99 */ + break; + + case MAX_RT_PRIO-1: + cpupri = CPUPRI_NORMAL; /* 0 */ + break; + } return cpupri; } diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 49ec096a8aa1..8a3b1ba09253 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -89,8 +89,8 @@ void init_rt_rq(struct rt_rq *rt_rq) __set_bit(MAX_RT_PRIO, array->bitmap); #if defined CONFIG_SMP - rt_rq->highest_prio.curr = MAX_RT_PRIO; - rt_rq->highest_prio.next = MAX_RT_PRIO; + rt_rq->highest_prio.curr = MAX_RT_PRIO-1; + rt_rq->highest_prio.next = MAX_RT_PRIO-1; rt_rq->rt_nr_migratory = 0; rt_rq->overloaded = 0; plist_head_init(&rt_rq->pushable_tasks); @@ -161,7 +161,7 @@ void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq, { struct rq *rq = cpu_rq(cpu); - rt_rq->highest_prio.curr = MAX_RT_PRIO; + rt_rq->highest_prio.curr = MAX_RT_PRIO-1; rt_rq->rt_nr_boosted = 0; rt_rq->rq = rq; rt_rq->tg = tg; @@ -393,8 +393,9 @@ static void dequeue_pushable_task(struct rq *rq, struct task_struct *p) p = plist_first_entry(&rq->rt.pushable_tasks, struct task_struct, pushable_tasks); rq->rt.highest_prio.next = p->prio; - } else - rq->rt.highest_prio.next = MAX_RT_PRIO; + } else { + rq->rt.highest_prio.next = MAX_RT_PRIO-1; + } } #else @@ -1147,8 +1148,9 @@ dec_rt_prio(struct rt_rq *rt_rq, int prio) sched_find_first_bit(array->bitmap); } - } else - rt_rq->highest_prio.curr = MAX_RT_PRIO; + } else { + rt_rq->highest_prio.curr = MAX_RT_PRIO-1; + } dec_rt_prio_smp(rt_rq, prio, prev_prio); } |