From 5aaa0b7a2ed5b12692c9ffb5222182bd558d3146 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 17 May 2012 17:15:29 +0200 Subject: sched/nohz: Fix rq->cpu_load calculations some more Follow up on commit 556061b00 ("sched/nohz: Fix rq->cpu_load[] calculations") since while that fixed the busy case it regressed the mostly idle case. Add a callback from the nohz exit to also age the rq->cpu_load[] array. This closes the hole where either there was no nohz load balance pass during the nohz, or there was a 'significant' amount of idle time between the last nohz balance and the nohz exit. So we'll update unconditionally from the tick to not insert any accidental 0 load periods while busy, and we try and catch up from nohz idle balance and nohz exit. Both these are still prone to missing a jiffy, but that has always been the case. Signed-off-by: Peter Zijlstra Cc: pjt@google.com Cc: Venkatesh Pallipadi Link: http://lkml.kernel.org/n/tip-kt0trz0apodbf84ucjfdbr1a@git.kernel.org Signed-off-by: Ingo Molnar --- include/linux/sched.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/sched.h b/include/linux/sched.h index f45c0b280b5d..d61e5977e517 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -145,6 +145,7 @@ extern unsigned long this_cpu_load(void); extern void calc_global_load(unsigned long ticks); +extern void update_cpu_load_nohz(void); extern unsigned long get_parent_ip(unsigned long addr); -- cgit v1.2.3 From 29baa7478ba47d746e3625c91d3b2afbf46b4312 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 23 Apr 2012 12:11:21 +0200 Subject: sched: Move nr_cpus_allowed out of 'struct sched_rt_entity' Since nr_cpus_allowed is used outside of sched/rt.c and wants to be used outside of there more, move it to a more natural site. Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-kr61f02y9brwzkh6x53pdptm@git.kernel.org Signed-off-by: Ingo Molnar --- arch/blackfin/kernel/process.c | 2 +- include/linux/init_task.h | 2 +- include/linux/sched.h | 2 +- kernel/sched/core.c | 2 +- kernel/sched/fair.c | 2 +- kernel/sched/rt.c | 36 +++++++++++++++++++++--------------- 6 files changed, 26 insertions(+), 20 deletions(-) (limited to 'include') diff --git a/arch/blackfin/kernel/process.c b/arch/blackfin/kernel/process.c index 2e3994b20169..62bcea7dcc6d 100644 --- a/arch/blackfin/kernel/process.c +++ b/arch/blackfin/kernel/process.c @@ -173,7 +173,7 @@ asmlinkage int bfin_clone(struct pt_regs *regs) unsigned long newsp; #ifdef __ARCH_SYNC_CORE_DCACHE - if (current->rt.nr_cpus_allowed == num_possible_cpus()) + if (current->nr_cpus_allowed == num_possible_cpus()) set_cpus_allowed_ptr(current, cpumask_of(smp_processor_id())); #endif diff --git a/include/linux/init_task.h b/include/linux/init_task.h index e4baff5f7ff4..9e65eff6af3b 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -149,6 +149,7 @@ extern struct cred init_cred; .normal_prio = MAX_PRIO-20, \ .policy = SCHED_NORMAL, \ .cpus_allowed = CPU_MASK_ALL, \ + .nr_cpus_allowed= NR_CPUS, \ .mm = NULL, \ .active_mm = &init_mm, \ .se = { \ @@ -157,7 +158,6 @@ extern struct cred init_cred; .rt = { \ .run_list = LIST_HEAD_INIT(tsk.rt.run_list), \ .time_slice = RR_TIMESLICE, \ - .nr_cpus_allowed = NR_CPUS, \ }, \ .tasks = LIST_HEAD_INIT(tsk.tasks), \ INIT_PUSHABLE_TASKS(tsk) \ diff --git a/include/linux/sched.h b/include/linux/sched.h index d61e5977e517..0f50e78f7f44 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1188,7 +1188,6 @@ struct sched_rt_entity { struct list_head run_list; unsigned long timeout; unsigned int time_slice; - int nr_cpus_allowed; struct sched_rt_entity *back; #ifdef CONFIG_RT_GROUP_SCHED @@ -1253,6 +1252,7 @@ struct task_struct { #endif unsigned int policy; + int nr_cpus_allowed; cpumask_t cpus_allowed; #ifdef CONFIG_PREEMPT_RCU diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3a69374fb427..70cc36a6073f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5015,7 +5015,7 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) p->sched_class->set_cpus_allowed(p, new_mask); cpumask_copy(&p->cpus_allowed, new_mask); - p->rt.nr_cpus_allowed = cpumask_weight(new_mask); + p->nr_cpus_allowed = cpumask_weight(new_mask); } /* diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 2b449a762074..b2a2d236f27b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2703,7 +2703,7 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) int want_sd = 1; int sync = wake_flags & WF_SYNC; - if (p->rt.nr_cpus_allowed == 1) + if (p->nr_cpus_allowed == 1) return prev_cpu; if (sd_flag & SD_BALANCE_WAKE) { diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index c5565c3c515f..295da737b6fe 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -274,13 +274,16 @@ static void update_rt_migration(struct rt_rq *rt_rq) static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) { + struct task_struct *p; + if (!rt_entity_is_task(rt_se)) return; + p = rt_task_of(rt_se); rt_rq = &rq_of_rt_rq(rt_rq)->rt; rt_rq->rt_nr_total++; - if (rt_se->nr_cpus_allowed > 1) + if (p->nr_cpus_allowed > 1) rt_rq->rt_nr_migratory++; update_rt_migration(rt_rq); @@ -288,13 +291,16 @@ static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) { + struct task_struct *p; + if (!rt_entity_is_task(rt_se)) return; + p = rt_task_of(rt_se); rt_rq = &rq_of_rt_rq(rt_rq)->rt; rt_rq->rt_nr_total--; - if (rt_se->nr_cpus_allowed > 1) + if (p->nr_cpus_allowed > 1) rt_rq->rt_nr_migratory--; update_rt_migration(rt_rq); @@ -1161,7 +1167,7 @@ enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags) enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD); - if (!task_current(rq, p) && p->rt.nr_cpus_allowed > 1) + if (!task_current(rq, p) && p->nr_cpus_allowed > 1) enqueue_pushable_task(rq, p); inc_nr_running(rq); @@ -1225,7 +1231,7 @@ select_task_rq_rt(struct task_struct *p, int sd_flag, int flags) cpu = task_cpu(p); - if (p->rt.nr_cpus_allowed == 1) + if (p->nr_cpus_allowed == 1) goto out; /* For anything but wake ups, just return the task_cpu */ @@ -1260,9 +1266,9 @@ select_task_rq_rt(struct task_struct *p, int sd_flag, int flags) * will have to sort it out. */ if (curr && unlikely(rt_task(curr)) && - (curr->rt.nr_cpus_allowed < 2 || + (curr->nr_cpus_allowed < 2 || curr->prio <= p->prio) && - (p->rt.nr_cpus_allowed > 1)) { + (p->nr_cpus_allowed > 1)) { int target = find_lowest_rq(p); if (target != -1) @@ -1276,10 +1282,10 @@ out: static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p) { - if (rq->curr->rt.nr_cpus_allowed == 1) + if (rq->curr->nr_cpus_allowed == 1) return; - if (p->rt.nr_cpus_allowed != 1 + if (p->nr_cpus_allowed != 1 && cpupri_find(&rq->rd->cpupri, p, NULL)) return; @@ -1395,7 +1401,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p) * The previous task needs to be made eligible for pushing * if it is still active */ - if (on_rt_rq(&p->rt) && p->rt.nr_cpus_allowed > 1) + if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1) enqueue_pushable_task(rq, p); } @@ -1408,7 +1414,7 @@ static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu) { if (!task_running(rq, p) && (cpu < 0 || cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) && - (p->rt.nr_cpus_allowed > 1)) + (p->nr_cpus_allowed > 1)) return 1; return 0; } @@ -1464,7 +1470,7 @@ static int find_lowest_rq(struct task_struct *task) if (unlikely(!lowest_mask)) return -1; - if (task->rt.nr_cpus_allowed == 1) + if (task->nr_cpus_allowed == 1) return -1; /* No other targets possible */ if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask)) @@ -1586,7 +1592,7 @@ static struct task_struct *pick_next_pushable_task(struct rq *rq) BUG_ON(rq->cpu != task_cpu(p)); BUG_ON(task_current(rq, p)); - BUG_ON(p->rt.nr_cpus_allowed <= 1); + BUG_ON(p->nr_cpus_allowed <= 1); BUG_ON(!p->on_rq); BUG_ON(!rt_task(p)); @@ -1793,9 +1799,9 @@ static void task_woken_rt(struct rq *rq, struct task_struct *p) if (!task_running(rq, p) && !test_tsk_need_resched(rq->curr) && has_pushable_tasks(rq) && - p->rt.nr_cpus_allowed > 1 && + p->nr_cpus_allowed > 1 && rt_task(rq->curr) && - (rq->curr->rt.nr_cpus_allowed < 2 || + (rq->curr->nr_cpus_allowed < 2 || rq->curr->prio <= p->prio)) push_rt_tasks(rq); } @@ -1817,7 +1823,7 @@ static void set_cpus_allowed_rt(struct task_struct *p, * Only update if the process changes its state from whether it * can migrate or not. */ - if ((p->rt.nr_cpus_allowed > 1) == (weight > 1)) + if ((p->nr_cpus_allowed > 1) == (weight > 1)) return; rq = task_rq(p); -- cgit v1.2.3