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Message-Id: <1199112209.31975.11.camel@lappy>
Date: Mon, 31 Dec 2007 15:43:29 +0100
From: Peter Zijlstra <a.p.zijlstra@...llo.nl>
To: balbir@...ux.vnet.ibm.com
Cc: LKML <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...e.hu>,
dmitry.adamushko@...il.com,
Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>,
Steven Rostedt <rostedt@...dmis.org>,
Gregory Haskins <ghaskins@...ell.com>
Subject: Re: [RFC/PATCH 0/3] sched: hrtick and rt group scheduling
On Mon, 2007-12-31 at 19:21 +0530, Balbir Singh wrote:
> Peter Zijlstra wrote:
> > I spend xmas implementing group scheduling for the realtime scheduling classes.
> > Its a tad raw, but seems to work for the trivial test cases I threw at it.
> >
>
> Excellent, will test & review and get back.
replacement patch for 3/3
fixes one crash bug in smp load balancing
simplifies the throttling
ensures \Sum tg.rt_ratio <= syctl_sched_rt_ratio
Index: linux-2.6/include/linux/sched.h
===================================================================
--- linux-2.6.orig/include/linux/sched.h
+++ linux-2.6/include/linux/sched.h
@@ -963,6 +963,15 @@ struct sched_rt_entity {
struct list_head run_list;
unsigned int time_slice;
unsigned long timeout;
+ int nr_cpus_allowed;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ struct sched_rt_entity *parent;
+ /* rq on which this entity is (to be) queued: */
+ struct rt_rq *rt_rq;
+ /* rq "owned" by this entity/group: */
+ struct rt_rq *my_q;
+#endif
};
struct task_struct {
@@ -1007,7 +1016,6 @@ struct task_struct {
unsigned int policy;
cpumask_t cpus_allowed;
- int nr_cpus_allowed;
#ifdef CONFIG_PREEMPT_RCU
int rcu_read_lock_nesting;
Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -161,6 +161,8 @@ struct rt_prio_array {
struct cfs_rq;
+static LIST_HEAD(task_groups);
+
/* task group related information */
struct task_group {
#ifdef CONFIG_FAIR_CGROUP_SCHED
@@ -171,6 +173,11 @@ struct task_group {
/* runqueue "owned" by this group on each cpu */
struct cfs_rq **cfs_rq;
+ struct sched_rt_entity **rt_se;
+ struct rt_rq **rt_rq;
+
+ unsigned int rt_ratio;
+
/*
* shares assigned to a task group governs how much of cpu bandwidth
* is allocated to the group. The more shares a group has, the more is
@@ -208,6 +215,7 @@ struct task_group {
unsigned long shares;
struct rcu_head rcu;
+ struct list_head list;
};
/* Default task group's sched entity on each cpu */
@@ -215,9 +223,15 @@ static DEFINE_PER_CPU(struct sched_entit
/* Default task group's cfs_rq on each cpu */
static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
+static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
+static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
+
static struct sched_entity *init_sched_entity_p[NR_CPUS];
static struct cfs_rq *init_cfs_rq_p[NR_CPUS];
+static struct sched_rt_entity *init_sched_rt_entity_p[NR_CPUS];
+static struct rt_rq *init_rt_rq_p[NR_CPUS];
+
/* task_group_mutex serializes add/remove of task groups and also changes to
* a task group's cpu shares.
*/
@@ -240,6 +254,9 @@ static void set_se_shares(struct sched_e
struct task_group init_task_group = {
.se = init_sched_entity_p,
.cfs_rq = init_cfs_rq_p,
+
+ .rt_se = init_sched_rt_entity_p,
+ .rt_rq = init_rt_rq_p,
};
#ifdef CONFIG_FAIR_USER_SCHED
@@ -269,10 +286,13 @@ static inline struct task_group *task_gr
}
/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
-static inline void set_task_cfs_rq(struct task_struct *p, unsigned int cpu)
+static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
{
p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
p->se.parent = task_group(p)->se[cpu];
+
+ p->rt.rt_rq = task_group(p)->rt_rq[cpu];
+ p->rt.parent = task_group(p)->rt_se[cpu];
}
static inline void lock_task_group_list(void)
@@ -297,7 +317,7 @@ static inline void unlock_doms_cur(void)
#else
-static inline void set_task_cfs_rq(struct task_struct *p, unsigned int cpu) { }
+static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
static inline void lock_task_group_list(void) { }
static inline void unlock_task_group_list(void) { }
static inline void lock_doms_cur(void) { }
@@ -343,13 +363,22 @@ struct cfs_rq {
struct rt_rq {
struct rt_prio_array active;
unsigned long rt_nr_running;
+#if defined CONFIG_SMP || defined CONFIG_FAIR_GROUP_SCHED
+ int highest_prio; /* highest queued rt task prio */
+#endif
#ifdef CONFIG_SMP
unsigned long rt_nr_migratory;
- int highest_prio; /* highest queued rt task prio */
int overloaded;
#endif
+ int rt_throttled;
u64 rt_time;
- u64 rt_throttled;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ struct rq *rq;
+ struct list_head leaf_rt_rq_list;
+ struct task_group *tg;
+ struct sched_rt_entity *rt_se;
+#endif
};
#ifdef CONFIG_SMP
@@ -411,12 +440,14 @@ struct rq {
u64 nr_switches;
struct cfs_rq cfs;
+ struct rt_rq rt;
+ u64 rt_period_expire;
+
#ifdef CONFIG_FAIR_GROUP_SCHED
/* list of leaf cfs_rq on this cpu: */
struct list_head leaf_cfs_rq_list;
+ struct list_head leaf_rt_rq_list;
#endif
- struct rt_rq rt;
- u64 rt_period_expire;
/*
* This is part of a global counter where only the total sum
@@ -613,9 +644,9 @@ const_debug unsigned int sysctl_sched_rt
/*
* ratio of time -rt tasks may consume.
- * default: 100%
+ * default: 95%
*/
-const_debug unsigned int sysctl_sched_rt_ratio = SCHED_RT_FRAC;
+const_debug unsigned int sysctl_sched_rt_ratio = 62259;
/*
* For kernel-internal use: high-speed (but slightly incorrect) per-cpu
@@ -1337,7 +1368,7 @@ unsigned long weighted_cpuload(const int
static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
{
- set_task_cfs_rq(p, cpu);
+ set_task_rq(p, cpu);
#ifdef CONFIG_SMP
/*
* After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
@@ -5272,7 +5303,7 @@ int set_cpus_allowed(struct task_struct
p->sched_class->set_cpus_allowed(p, &new_mask);
else {
p->cpus_allowed = new_mask;
- p->nr_cpus_allowed = cpus_weight(new_mask);
+ p->rt.nr_cpus_allowed = cpus_weight(new_mask);
}
/* Can the task run on the task's current CPU? If so, we're done */
@@ -7067,8 +7098,50 @@ static void init_rt_rq(struct rt_rq *rt_
rt_rq->rt_time = 0;
rt_rq->rt_throttled = 0;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ rt_rq->rq = rq;
+#endif
}
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void init_tg_cfs_entry(struct rq *rq, struct task_group *tg,
+ struct cfs_rq *cfs_rq, struct sched_entity *se,
+ int cpu, int add)
+{
+ tg->cfs_rq[cpu] = cfs_rq;
+ init_cfs_rq(cfs_rq, rq);
+ cfs_rq->tg = tg;
+ if (add)
+ list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+
+ tg->se[cpu] = se;
+ se->cfs_rq = &rq->cfs;
+ se->my_q = cfs_rq;
+ se->load.weight = tg->shares;
+ se->load.inv_weight = div64_64(1ULL<<32, se->load.weight);
+ se->parent = NULL;
+}
+
+static void init_tg_rt_entry(struct rq *rq, struct task_group *tg,
+ struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
+ int cpu, int add)
+{
+ tg->rt_rq[cpu] = rt_rq;
+ init_rt_rq(rt_rq, rq);
+ rt_rq->tg = tg;
+ rt_rq->rt_se = rt_se;
+ if (add)
+ list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
+
+ tg->rt_se[cpu] = rt_se;
+ rt_se->rt_rq = &rq->rt;
+ rt_se->my_q = rt_rq;
+ rt_se->parent = NULL;
+ INIT_LIST_HEAD(&rt_se->run_list);
+}
+#endif
+
void __init sched_init(void)
{
int highest_cpu = 0;
@@ -7087,30 +7160,22 @@ void __init sched_init(void)
rq->nr_running = 0;
rq->clock = 1;
init_cfs_rq(&rq->cfs, rq);
+ init_rt_rq(&rq->rt, rq);
#ifdef CONFIG_FAIR_GROUP_SCHED
- INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
- {
- struct cfs_rq *cfs_rq = &per_cpu(init_cfs_rq, i);
- struct sched_entity *se =
- &per_cpu(init_sched_entity, i);
-
- init_cfs_rq_p[i] = cfs_rq;
- init_cfs_rq(cfs_rq, rq);
- cfs_rq->tg = &init_task_group;
- list_add(&cfs_rq->leaf_cfs_rq_list,
- &rq->leaf_cfs_rq_list);
-
- init_sched_entity_p[i] = se;
- se->cfs_rq = &rq->cfs;
- se->my_q = cfs_rq;
- se->load.weight = init_task_group_load;
- se->load.inv_weight =
- div64_64(1ULL<<32, init_task_group_load);
- se->parent = NULL;
- }
init_task_group.shares = init_task_group_load;
+ INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
+ init_tg_cfs_entry(rq, &init_task_group,
+ &per_cpu(init_cfs_rq, i),
+ &per_cpu(init_sched_entity, i), i, 1);
+
+ init_task_group.rt_ratio = sysctl_sched_rt_ratio; /* XXX */
+ INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
+ init_tg_rt_entry(rq, &init_task_group,
+ &per_cpu(init_rt_rq, i),
+ &per_cpu(init_sched_rt_entity, i), i, 1);
+
+ list_add(&init_task_group.list, &task_groups);
#endif
- init_rt_rq(&rq->rt, rq);
rq->rt_period_expire = 0;
for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
@@ -7448,12 +7513,36 @@ static int load_balance_monitor(void *un
}
#endif /* CONFIG_SMP */
+static void free_sched_group(struct task_group *tg)
+{
+ int i;
+
+ for_each_possible_cpu(i) {
+ if (tg->cfs_rq)
+ kfree(tg->cfs_rq[i]);
+ if (tg->se)
+ kfree(tg->se[i]);
+ if (tg->rt_rq)
+ kfree(tg->rt_rq[i]);
+ if (tg->rt_se)
+ kfree(tg->rt_se[i]);
+ }
+
+ kfree(tg->cfs_rq);
+ kfree(tg->se);
+ kfree(tg->rt_rq);
+ kfree(tg->rt_se);
+ kfree(tg);
+}
+
/* allocate runqueue etc for a new task group */
struct task_group *sched_create_group(void)
{
struct task_group *tg;
struct cfs_rq *cfs_rq;
struct sched_entity *se;
+ struct rt_rq *rt_rq;
+ struct sched_rt_entity *rt_se;
struct rq *rq;
int i;
@@ -7467,100 +7556,89 @@ struct task_group *sched_create_group(vo
tg->se = kzalloc(sizeof(se) * NR_CPUS, GFP_KERNEL);
if (!tg->se)
goto err;
+ tg->rt_rq = kzalloc(sizeof(rt_rq) * NR_CPUS, GFP_KERNEL);
+ if (!tg->rt_rq)
+ goto err;
+ tg->rt_se = kzalloc(sizeof(rt_se) * NR_CPUS, GFP_KERNEL);
+ if (!tg->rt_se)
+ goto err;
+
+ tg->shares = NICE_0_LOAD;
+ tg->rt_ratio = 0; /* XXX */
for_each_possible_cpu(i) {
rq = cpu_rq(i);
- cfs_rq = kmalloc_node(sizeof(struct cfs_rq), GFP_KERNEL,
- cpu_to_node(i));
+ cfs_rq = kmalloc_node(sizeof(struct cfs_rq),
+ GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
if (!cfs_rq)
goto err;
- se = kmalloc_node(sizeof(struct sched_entity), GFP_KERNEL,
- cpu_to_node(i));
+ se = kmalloc_node(sizeof(struct sched_entity),
+ GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
if (!se)
goto err;
- memset(cfs_rq, 0, sizeof(struct cfs_rq));
- memset(se, 0, sizeof(struct sched_entity));
+ rt_rq = kmalloc_node(sizeof(struct rt_rq),
+ GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
+ if (!rt_rq)
+ goto err;
- tg->cfs_rq[i] = cfs_rq;
- init_cfs_rq(cfs_rq, rq);
- cfs_rq->tg = tg;
-
- tg->se[i] = se;
- se->cfs_rq = &rq->cfs;
- se->my_q = cfs_rq;
- se->load.weight = NICE_0_LOAD;
- se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD);
- se->parent = NULL;
- }
+ rt_se = kmalloc_node(sizeof(struct sched_rt_entity),
+ GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
+ if (!rt_se)
+ goto err;
- tg->shares = NICE_0_LOAD;
+ init_tg_cfs_entry(rq, tg, cfs_rq, se, i, 0);
+ init_tg_rt_entry(rq, tg, rt_rq, rt_se, i, 0);
+ }
lock_task_group_list();
for_each_possible_cpu(i) {
rq = cpu_rq(i);
cfs_rq = tg->cfs_rq[i];
list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+ rt_rq = tg->rt_rq[i];
+ list_add_rcu(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
}
+ list_add_rcu(&tg->list, &task_groups);
unlock_task_group_list();
return tg;
err:
- for_each_possible_cpu(i) {
- if (tg->cfs_rq)
- kfree(tg->cfs_rq[i]);
- if (tg->se)
- kfree(tg->se[i]);
- }
- kfree(tg->cfs_rq);
- kfree(tg->se);
- kfree(tg);
-
+ free_sched_group(tg);
return ERR_PTR(-ENOMEM);
}
/* rcu callback to free various structures associated with a task group */
-static void free_sched_group(struct rcu_head *rhp)
+static void free_sched_group_rcu(struct rcu_head *rhp)
{
- struct task_group *tg = container_of(rhp, struct task_group, rcu);
- struct cfs_rq *cfs_rq;
- struct sched_entity *se;
- int i;
-
/* now it should be safe to free those cfs_rqs */
- for_each_possible_cpu(i) {
- cfs_rq = tg->cfs_rq[i];
- kfree(cfs_rq);
-
- se = tg->se[i];
- kfree(se);
- }
-
- kfree(tg->cfs_rq);
- kfree(tg->se);
- kfree(tg);
+ free_sched_group(container_of(rhp, struct task_group, rcu));
}
/* Destroy runqueue etc associated with a task group */
void sched_destroy_group(struct task_group *tg)
{
struct cfs_rq *cfs_rq = NULL;
+ struct rt_rq *rt_rq = NULL;
int i;
lock_task_group_list();
for_each_possible_cpu(i) {
cfs_rq = tg->cfs_rq[i];
list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
+ rt_rq = tg->rt_rq[i];
+ list_del_rcu(&rt_rq->leaf_rt_rq_list);
}
+ list_del_rcu(&tg->list);
unlock_task_group_list();
BUG_ON(!cfs_rq);
/* wait for possible concurrent references to cfs_rqs complete */
- call_rcu(&tg->rcu, free_sched_group);
+ call_rcu(&tg->rcu, free_sched_group_rcu);
}
/* change task's runqueue when it moves between groups.
@@ -7576,11 +7654,6 @@ void sched_move_task(struct task_struct
rq = task_rq_lock(tsk, &flags);
- if (tsk->sched_class != &fair_sched_class) {
- set_task_cfs_rq(tsk, task_cpu(tsk));
- goto done;
- }
-
update_rq_clock(rq);
running = task_current(rq, tsk);
@@ -7592,7 +7665,7 @@ void sched_move_task(struct task_struct
tsk->sched_class->put_prev_task(rq, tsk);
}
- set_task_cfs_rq(tsk, task_cpu(tsk));
+ set_task_rq(tsk, task_cpu(tsk));
if (on_rq) {
if (unlikely(running))
@@ -7600,7 +7673,6 @@ void sched_move_task(struct task_struct
enqueue_task(rq, tsk, 0);
}
-done:
task_rq_unlock(rq, &flags);
}
@@ -7685,6 +7757,31 @@ unsigned long sched_group_shares(struct
return tg->shares;
}
+/*
+ * Ensure the total rt_ratio <= sysctl_sched_rt_ratio
+ */
+int sched_group_set_rt_ratio(struct task_group *tg, unsigned long rt_ratio)
+{
+ struct task_group *tgi;
+ unsigned long total = 0;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(tgi, &task_groups, list)
+ total += tgi->rt_ratio;
+ rcu_read_unlock();
+
+ if (total + rt_ratio - tg->rt_ratio > sysctl_sched_rt_ratio)
+ return -EINVAL;
+
+ tg->rt_ratio = rt_ratio;
+ return 0;
+}
+
+unsigned long sched_group_rt_ratio(struct task_group *tg)
+{
+ return tg->rt_ratio;
+}
+
#endif /* CONFIG_FAIR_GROUP_SCHED */
#ifdef CONFIG_FAIR_CGROUP_SCHED
@@ -7760,12 +7857,30 @@ static u64 cpu_shares_read_uint(struct c
return (u64) tg->shares;
}
+static int cpu_rt_ratio_write_uint(struct cgroup *cgrp, struct cftype *cftype,
+ u64 rt_ratio_val)
+{
+ return sched_group_set_rt_ratio(cgroup_tg(cgrp), rt_ratio_val);
+}
+
+static u64 cpu_rt_ratio_read_uint(struct cgroup *cgrp, struct cftype *cft)
+{
+ struct task_group *tg = cgroup_tg(cgrp);
+
+ return (u64) tg->rt_ratio;
+}
+
static struct cftype cpu_files[] = {
{
.name = "shares",
.read_uint = cpu_shares_read_uint,
.write_uint = cpu_shares_write_uint,
},
+ {
+ .name = "rt_ratio",
+ .read_uint = cpu_rt_ratio_read_uint,
+ .write_uint = cpu_rt_ratio_write_uint,
+ },
};
static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
Index: linux-2.6/kernel/sched_rt.c
===================================================================
--- linux-2.6.orig/kernel/sched_rt.c
+++ linux-2.6/kernel/sched_rt.c
@@ -45,47 +45,167 @@ static void update_rt_migration(struct r
}
#endif /* CONFIG_SMP */
-static int sched_rt_ratio_exceeded(struct rq *rq, struct rt_rq *rt_rq)
+static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
{
+ return container_of(rt_se, struct task_struct, rt);
+}
+
+static inline int on_rt_rq(struct sched_rt_entity *rt_se)
+{
+ return !list_empty(&rt_se->run_list);
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+static inline unsigned int sched_rt_ratio(struct rt_rq *rt_rq)
+{
+ if (!rt_rq->tg)
+ return SCHED_RT_FRAC;
+
+ return rt_rq->tg->rt_ratio;
+}
+
+#define for_each_leaf_rt_rq(rt_rq, rq) \
+ list_for_each_entry(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
+
+static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+{
+ return rt_rq->rq;
+}
+
+static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+{
+ return rt_se->rt_rq;
+}
+
+#define for_each_sched_rt_entity(rt_se) \
+ for (; rt_se; rt_se = rt_se->parent)
+
+static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
+{
+ return rt_se->my_q;
+}
+
+static void enqueue_rt_entity(struct sched_rt_entity *rt_se);
+static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
+
+static void sched_rt_ratio_enqueue(struct rt_rq *rt_rq)
+{
+ struct sched_rt_entity *rt_se = rt_rq->rt_se;
+
+ if (rt_se && !on_rt_rq(rt_se) && rt_rq->rt_nr_running) {
+ enqueue_rt_entity(rt_se);
+ resched_task(rq_of_rt_rq(rt_rq)->curr);
+ }
+}
+
+static void sched_rt_ratio_dequeue(struct rt_rq *rt_rq)
+{
+ struct sched_rt_entity *rt_se = rt_rq->rt_se;
+
+ if (rt_se && on_rt_rq(rt_se))
+ dequeue_rt_entity(rt_se);
+}
+
+#else
+
+static inline unsigned int sched_rt_ratio(struct rt_rq *rt_rq)
+{
+ return sysctl_sched_rt_ratio;
+}
+
+#define for_each_leaf_rt_rq(rt_rq, rq) \
+ for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
+
+static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+{
+ return container_of(rt_rq, struct rq, rt);
+}
+
+static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+{
+ struct task_struct *p = rt_task_of(rt_se);
+ struct rq *rq = task_rq(p);
+
+ return &rq->rt;
+}
+
+#define for_each_sched_rt_entity(rt_se) \
+ for (; rt_se; rt_se = NULL)
+
+static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
+{
+ return NULL;
+}
+
+static inline void sched_rt_ratio_enqueue(struct rt_rq *rt_rq)
+{
+}
+
+static inline void sched_rt_ratio_dequeue(struct rt_rq *rt_rq)
+{
+}
+
+#endif
+
+static inline int rt_se_prio(struct sched_rt_entity *rt_se)
+{
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ struct rt_rq *rt_rq = group_rt_rq(rt_se);
+
+ if (rt_rq)
+ return rt_rq->highest_prio;
+#endif
+
+ return rt_task_of(rt_se)->prio;
+}
+
+static int sched_rt_ratio_exceeded(struct rt_rq *rt_rq)
+{
+ unsigned int rt_ratio = sched_rt_ratio(rt_rq);
u64 period, ratio;
- if (sysctl_sched_rt_ratio == SCHED_RT_FRAC)
+ if (rt_ratio == SCHED_RT_FRAC)
return 0;
if (rt_rq->rt_throttled)
return 1;
period = (u64)sysctl_sched_rt_period * NSEC_PER_MSEC;
- ratio = (period * sysctl_sched_rt_ratio) >> SCHED_RT_FRAC_SHIFT;
+ ratio = (period * rt_ratio) >> SCHED_RT_FRAC_SHIFT;
if (rt_rq->rt_time > ratio) {
- rt_rq->rt_throttled = rq->clock + period - rt_rq->rt_time;
+ rt_rq->rt_throttled = 1;
+ sched_rt_ratio_dequeue(rt_rq);
return 1;
}
return 0;
}
+static void __update_sched_rt_period(struct rt_rq *rt_rq, u64 period)
+{
+ unsigned long rt_ratio = sched_rt_ratio(rt_rq);
+ u64 ratio = (period * rt_ratio) >> SCHED_RT_FRAC_SHIFT;
+
+ rt_rq->rt_time -= min(rt_rq->rt_time, ratio);
+ if (rt_rq->rt_throttled) {
+ rt_rq->rt_throttled = 0;
+ sched_rt_ratio_enqueue(rt_rq);
+ }
+}
+
static void update_sched_rt_period(struct rq *rq)
{
- while (rq->clock > rq->rt_period_expire) {
- u64 period, ratio;
+ struct rt_rq *rt_rq;
+ u64 period;
+ while (rq->clock > rq->rt_period_expire) {
period = (u64)sysctl_sched_rt_period * NSEC_PER_MSEC;
- ratio = (period * sysctl_sched_rt_ratio) >> SCHED_RT_FRAC_SHIFT;
-
- rq->rt.rt_time -= min(rq->rt.rt_time, ratio);
rq->rt_period_expire += period;
- }
- /*
- * When the rt throttle is expired, let them rip.
- * (XXX: use hrtick when available)
- */
- if (rq->rt.rt_throttled && rq->clock > rq->rt.rt_throttled) {
- rq->rt.rt_throttled = 0;
- if (!sched_rt_ratio_exceeded(rq, &rq->rt))
- resched_task(rq->curr);
+ for_each_leaf_rt_rq(rt_rq, rq)
+ __update_sched_rt_period(rt_rq, period);
}
}
@@ -96,10 +216,11 @@ static void update_sched_rt_period(struc
static void update_curr_rt(struct rq *rq)
{
struct task_struct *curr = rq->curr;
+ struct sched_rt_entity *rt_se = &curr->rt;
+ struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
u64 delta_exec;
- if (!task_has_rt_policy(curr))
- return;
+ BUG_ON(!task_has_rt_policy(curr));
delta_exec = rq->clock - curr->se.exec_start;
if (unlikely((s64)delta_exec < 0))
@@ -111,95 +232,184 @@ static void update_curr_rt(struct rq *rq
curr->se.exec_start = rq->clock;
cpuacct_charge(curr, delta_exec);
- rq->rt.rt_time += delta_exec;
- update_sched_rt_period(rq);
- if (sched_rt_ratio_exceeded(rq, &rq->rt))
+ rt_rq->rt_time += delta_exec;
+ /*
+ * might make it a tad more accurate:
+ *
+ * update_sched_rt_period(rq);
+ */
+ if (sched_rt_ratio_exceeded(rt_rq))
resched_task(curr);
}
-static inline void inc_rt_tasks(struct task_struct *p, struct rq *rq)
+static inline
+void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
- WARN_ON(!rt_task(p));
- rq->rt.rt_nr_running++;
+ WARN_ON(!rt_prio(rt_se_prio(rt_se)));
+ rt_rq->rt_nr_running++;
+#if defined CONFIG_SMP || defined CONFIG_FAIR_GROUP_SCHED
+ if (rt_se_prio(rt_se) < rt_rq->highest_prio)
+ rt_rq->highest_prio = rt_se_prio(rt_se);
+#endif
#ifdef CONFIG_SMP
- if (p->prio < rq->rt.highest_prio)
- rq->rt.highest_prio = p->prio;
- if (p->nr_cpus_allowed > 1)
+ if (rt_se->nr_cpus_allowed > 1) {
+ struct rq *rq = rq_of_rt_rq(rt_rq);
rq->rt.rt_nr_migratory++;
+ }
- update_rt_migration(rq);
-#endif /* CONFIG_SMP */
+ update_rt_migration(rq_of_rt_rq(rt_rq));
+#endif
}
-static inline void dec_rt_tasks(struct task_struct *p, struct rq *rq)
+static inline
+void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
- WARN_ON(!rt_task(p));
- WARN_ON(!rq->rt.rt_nr_running);
- rq->rt.rt_nr_running--;
-#ifdef CONFIG_SMP
- if (rq->rt.rt_nr_running) {
+ WARN_ON(!rt_prio(rt_se_prio(rt_se)));
+ WARN_ON(!rt_rq->rt_nr_running);
+ rt_rq->rt_nr_running--;
+#if defined CONFIG_SMP || defined CONFIG_FAIR_GROUP_SCHED
+ if (rt_rq->rt_nr_running) {
struct rt_prio_array *array;
- WARN_ON(p->prio < rq->rt.highest_prio);
- if (p->prio == rq->rt.highest_prio) {
+ WARN_ON(rt_se_prio(rt_se) < rt_rq->highest_prio);
+ if (rt_se_prio(rt_se) == rt_rq->highest_prio) {
/* recalculate */
- array = &rq->rt.active;
- rq->rt.highest_prio =
+ array = &rt_rq->active;
+ rt_rq->highest_prio =
sched_find_first_bit(array->bitmap);
} /* otherwise leave rq->highest prio alone */
} else
- rq->rt.highest_prio = MAX_RT_PRIO;
- if (p->nr_cpus_allowed > 1)
+ rt_rq->highest_prio = MAX_RT_PRIO;
+#endif
+#ifdef CONFIG_SMP
+ if (rt_se->nr_cpus_allowed > 1) {
+ struct rq *rq = rq_of_rt_rq(rt_rq);
rq->rt.rt_nr_migratory--;
+ }
- update_rt_migration(rq);
+ update_rt_migration(rq_of_rt_rq(rt_rq));
#endif /* CONFIG_SMP */
}
-static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
+static void enqueue_rt_entity(struct sched_rt_entity *rt_se)
{
- struct rt_prio_array *array = &rq->rt.active;
+ struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
+ struct rt_prio_array *array = &rt_rq->active;
+ struct rt_rq *group_rq = group_rt_rq(rt_se);
- list_add_tail(&p->rt.run_list, array->queue + p->prio);
- __set_bit(p->prio, array->bitmap);
- inc_cpu_load(rq, p->se.load.weight);
+ if (group_rq && group_rq->rt_throttled)
+ return;
- inc_rt_tasks(p, rq);
+ list_add_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se));
+ __set_bit(rt_se_prio(rt_se), array->bitmap);
- if (wakeup)
- p->rt.timeout = 0;
+ inc_rt_tasks(rt_se, rt_rq);
+}
+
+static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
+{
+ struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
+ struct rt_prio_array *array = &rt_rq->active;
+
+ list_del_init(&rt_se->run_list);
+ if (list_empty(array->queue + rt_se_prio(rt_se)))
+ __clear_bit(rt_se_prio(rt_se), array->bitmap);
+
+ dec_rt_tasks(rt_se, rt_rq);
+}
+
+/*
+ * Because the prio of an upper entry depends on the lower
+ * entries, we must remove entries top - down.
+ *
+ * XXX: O(1/2 h^2) because we can only walk up, not down the chain.
+ * doesn't matter much for now, as h=2 for GROUP_SCHED.
+ */
+static void dequeue_rt_stack(struct task_struct *p)
+{
+ struct sched_rt_entity *rt_se, *top_se;
+
+ /*
+ * dequeue all, top - down.
+ */
+ do {
+ rt_se = &p->rt;
+ top_se = NULL;
+ for_each_sched_rt_entity(rt_se) {
+ if (on_rt_rq(rt_se))
+ top_se = rt_se;
+ }
+ if (top_se)
+ dequeue_rt_entity(top_se);
+ } while (top_se);
}
/*
* Adding/removing a task to/from a priority array:
*/
+static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
+{
+ struct sched_rt_entity *rt_se = &p->rt;
+
+ if (wakeup)
+ rt_se->timeout = 0;
+
+ dequeue_rt_stack(p);
+
+ /*
+ * enqueue everybody, bottom - up.
+ */
+ for_each_sched_rt_entity(rt_se)
+ enqueue_rt_entity(rt_se);
+
+ inc_cpu_load(rq, p->se.load.weight);
+}
+
static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
{
- struct rt_prio_array *array = &rq->rt.active;
+ struct sched_rt_entity *rt_se = &p->rt;
+ struct rt_rq *rt_rq;
update_curr_rt(rq);
- list_del(&p->rt.run_list);
- if (list_empty(array->queue + p->prio))
- __clear_bit(p->prio, array->bitmap);
- dec_cpu_load(rq, p->se.load.weight);
+ dequeue_rt_stack(p);
+
+ /*
+ * re-enqueue all non-empty rt_rq entities.
+ */
+ for_each_sched_rt_entity(rt_se) {
+ rt_rq = group_rt_rq(rt_se);
+ if (rt_rq && rt_rq->rt_nr_running)
+ enqueue_rt_entity(rt_se);
+ }
- dec_rt_tasks(p, rq);
+ dec_cpu_load(rq, p->se.load.weight);
}
/*
* Put task to the end of the run list without the overhead of dequeue
* followed by enqueue.
*/
+static
+void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+{
+ struct rt_prio_array *array = &rt_rq->active;
+
+ list_move_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se));
+}
+
static void requeue_task_rt(struct rq *rq, struct task_struct *p)
{
- struct rt_prio_array *array = &rq->rt.active;
+ struct sched_rt_entity *rt_se = &p->rt;
+ struct rt_rq *rt_rq;
- list_move_tail(&p->rt.run_list, array->queue + p->prio);
+ for_each_sched_rt_entity(rt_se) {
+ rt_rq = rt_rq_of_se(rt_se);
+ requeue_rt_entity(rt_rq, rt_se);
+ }
}
-static void
-yield_task_rt(struct rq *rq)
+static void yield_task_rt(struct rq *rq)
{
requeue_task_rt(rq, rq->curr);
}
@@ -229,7 +439,7 @@ static int select_task_rq_rt(struct task
* cold cache anyway.
*/
if (unlikely(rt_task(rq->curr)) &&
- (p->nr_cpus_allowed > 1)) {
+ (p->rt.nr_cpus_allowed > 1)) {
int cpu = find_lowest_rq(p);
return (cpu == -1) ? task_cpu(p) : cpu;
@@ -252,27 +462,51 @@ static void check_preempt_curr_rt(struct
resched_task(rq->curr);
}
-static struct task_struct *pick_next_task_rt(struct rq *rq)
+static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
+ struct rt_rq *rt_rq)
{
- struct rt_prio_array *array = &rq->rt.active;
- struct task_struct *next;
+ struct rt_prio_array *array = &rt_rq->active;
+ struct sched_rt_entity *next = NULL;
struct list_head *queue;
- struct rt_rq *rt_rq = &rq->rt;
int idx;
- if (sched_rt_ratio_exceeded(rq, rt_rq))
- return NULL;
+ if (sched_rt_ratio_exceeded(rt_rq))
+ goto out;
idx = sched_find_first_bit(array->bitmap);
- if (idx >= MAX_RT_PRIO)
- return NULL;
+ BUG_ON(idx >= MAX_RT_PRIO);
queue = array->queue + idx;
- next = list_entry(queue->next, struct task_struct, rt.run_list);
+ next = list_entry(queue->next, struct sched_rt_entity, run_list);
+ out:
+ return next;
+}
- next->se.exec_start = rq->clock;
+static struct task_struct *pick_next_task_rt(struct rq *rq)
+{
+ struct sched_rt_entity *rt_se;
+ struct task_struct *p;
+ struct rt_rq *rt_rq;
- return next;
+ retry:
+ rt_rq = &rq->rt;
+
+ if (unlikely(!rt_rq->rt_nr_running))
+ return NULL;
+
+ if (sched_rt_ratio_exceeded(rt_rq))
+ return NULL;
+
+ do {
+ rt_se = pick_next_rt_entity(rq, rt_rq);
+ if (unlikely(!rt_se))
+ goto retry;
+ rt_rq = group_rt_rq(rt_se);
+ } while (rt_rq);
+
+ p = rt_task_of(rt_se);
+ p->se.exec_start = rq->clock;
+ return p;
}
static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
@@ -282,6 +516,7 @@ static void put_prev_task_rt(struct rq *
}
#ifdef CONFIG_SMP
+
/* Only try algorithms three times */
#define RT_MAX_TRIES 3
@@ -292,7 +527,7 @@ static int pick_rt_task(struct rq *rq, s
{
if (!task_running(rq, p) &&
(cpu < 0 || cpu_isset(cpu, p->cpus_allowed)) &&
- (p->nr_cpus_allowed > 1))
+ (p->rt.nr_cpus_allowed > 1))
return 1;
return 0;
}
@@ -300,52 +535,33 @@ static int pick_rt_task(struct rq *rq, s
/* Return the second highest RT task, NULL otherwise */
static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
{
- struct rt_prio_array *array = &rq->rt.active;
- struct task_struct *next;
- struct list_head *queue;
+ struct task_struct *next = NULL;
+ struct sched_rt_entity *rt_se;
+ struct rt_prio_array *array;
+ struct rt_rq *rt_rq;
int idx;
- if (likely(rq->rt.rt_nr_running < 2))
- return NULL;
-
- idx = sched_find_first_bit(array->bitmap);
- if (unlikely(idx >= MAX_RT_PRIO)) {
- WARN_ON(1); /* rt_nr_running is bad */
- return NULL;
- }
-
- queue = array->queue + idx;
- BUG_ON(list_empty(queue));
-
- next = list_entry(queue->next, struct task_struct, rt.run_list);
- if (unlikely(pick_rt_task(rq, next, cpu)))
- goto out;
-
- if (queue->next->next != queue) {
- /* same prio task */
- next = list_entry(queue->next->next, struct task_struct,
- rt.run_list);
- if (pick_rt_task(rq, next, cpu))
- goto out;
- }
-
- retry:
- /* slower, but more flexible */
- idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1);
- if (unlikely(idx >= MAX_RT_PRIO))
- return NULL;
-
- queue = array->queue + idx;
- BUG_ON(list_empty(queue));
-
- list_for_each_entry(next, queue, rt.run_list) {
- if (pick_rt_task(rq, next, cpu))
- goto out;
+ for_each_leaf_rt_rq(rt_rq, rq) {
+ array = &rt_rq->active;
+ idx = sched_find_first_bit(array->bitmap);
+ next_idx:
+ if (idx >= MAX_RT_PRIO)
+ continue;
+ if (next && next->prio < idx)
+ continue;
+ list_for_each_entry(rt_se, array->queue + idx, run_list) {
+ struct task_struct *p = rt_task_of(rt_se);
+ if (pick_rt_task(rq, p, cpu)) {
+ next = p;
+ break;
+ }
+ }
+ if (!next) {
+ idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1);
+ goto next_idx;
+ }
}
- goto retry;
-
- out:
return next;
}
@@ -774,12 +990,12 @@ static void set_cpus_allowed_rt(struct t
* Update the migration status of the RQ if we have an RT task
* which is running AND changing its weight value.
*/
- if (p->se.on_rq && (weight != p->nr_cpus_allowed)) {
+ if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) {
struct rq *rq = task_rq(p);
- if ((p->nr_cpus_allowed <= 1) && (weight > 1)) {
+ if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) {
rq->rt.rt_nr_migratory++;
- } else if ((p->nr_cpus_allowed > 1) && (weight <= 1)) {
+ } else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) {
BUG_ON(!rq->rt.rt_nr_migratory);
rq->rt.rt_nr_migratory--;
}
@@ -788,7 +1004,7 @@ static void set_cpus_allowed_rt(struct t
}
p->cpus_allowed = *new_mask;
- p->nr_cpus_allowed = weight;
+ p->rt.nr_cpus_allowed = weight;
}
/* Assumes rq->lock is held */
Index: linux-2.6/include/linux/init_task.h
===================================================================
--- linux-2.6.orig/include/linux/init_task.h
+++ linux-2.6/include/linux/init_task.h
@@ -141,12 +141,13 @@ extern struct group_info init_groups;
.normal_prio = MAX_PRIO-20, \
.policy = SCHED_NORMAL, \
.cpus_allowed = CPU_MASK_ALL, \
- .nr_cpus_allowed = NR_CPUS, \
.mm = NULL, \
.active_mm = &init_mm, \
.rt = { \
.run_list = LIST_HEAD_INIT(tsk.rt.run_list), \
- .time_slice = HZ, }, \
+ .time_slice = HZ, \
+ .nr_cpus_allowed = NR_CPUS, \
+ }, \
.ioprio = 0, \
.tasks = LIST_HEAD_INIT(tsk.tasks), \
.ptrace_children= LIST_HEAD_INIT(tsk.ptrace_children), \
Index: linux-2.6/kernel/fork.c
===================================================================
--- linux-2.6.orig/kernel/fork.c
+++ linux-2.6/kernel/fork.c
@@ -1252,7 +1252,7 @@ static struct task_struct *copy_process(
* parent's CPU). This avoids alot of nasty races.
*/
p->cpus_allowed = current->cpus_allowed;
- p->nr_cpus_allowed = current->nr_cpus_allowed;
+ p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed;
if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) ||
!cpu_online(task_cpu(p))))
set_task_cpu(p, smp_processor_id());
--
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