The following commit has been merged into the sched/core branch of tip: Commit-ID: 934fc3314b39e16a89fc4d5d0d5cbfe71dcbe7b1 Gitweb: https://git.kernel.org/tip/934fc3314b39e16a89fc4d5d0d5cbfe71dcbe7b1 Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> AuthorDate: Wed, 14 Oct 2020 21:06:49 +02:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Thu, 29 Oct 2020 11:00:30 +01:00 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@xxxxxxxxxxxxx> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx> --- kernel/sched/cpupri.c | 34 +++++++++++++++++++++++++++------- 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 8d9952a..e434910 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 49ec096..8a3b1ba 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); }
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