Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched

* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched:
  sched: mark CONFIG_FAIR_GROUP_SCHED as !EXPERIMENTAL
  sched: isolate SMP balancing code a bit more
  sched: reduce balance-tasks overhead
  sched: make cpu_shares_{show,store}() static
  sched: clean up some control group code
  sched: constify sched.h
  sched: document profile=sleep requiring CONFIG_SCHEDSTATS
  sched: use show_regs() to improve __schedule_bug() output
  sched: clean up sched_domain_debug()
  sched: fix fastcall mismatch in completion APIs
  sched: fix sched_domain sysctl registration again

Documentation/kernel-parameters.txt

@@ -1444,7 +1444,8 @@ and is between 256 and 4096 characters. It is defined in the file
 			Param: "schedule" - profile schedule points.
 			Param: <number> - step/bucket size as a power of 2 for
 				statistical time based profiling.
-			Param: "sleep" - profile D-state sleeping (millisecs)
+			Param: "sleep" - profile D-state sleeping (millisecs).
+				Requires CONFIG_SCHEDSTATS
 			Param: "kvm" - profile VM exits.
 
 	processor.max_cstate=	[HW,ACPI]

include/linux/completion.h

@@ -42,15 +42,15 @@ static inline void init_completion(struct completion *x)
 	init_waitqueue_head(&x->wait);
 }
 
-extern void FASTCALL(wait_for_completion(struct completion *));
-extern int FASTCALL(wait_for_completion_interruptible(struct completion *x));
-extern unsigned long FASTCALL(wait_for_completion_timeout(struct completion *x,
-						   unsigned long timeout));
-extern unsigned long FASTCALL(wait_for_completion_interruptible_timeout(
-			struct completion *x, unsigned long timeout));
-
-extern void FASTCALL(complete(struct completion *));
-extern void FASTCALL(complete_all(struct completion *));
+extern void wait_for_completion(struct completion *);
+extern int wait_for_completion_interruptible(struct completion *x);
+extern unsigned long wait_for_completion_timeout(struct completion *x,
+						   unsigned long timeout);
+extern unsigned long wait_for_completion_interruptible_timeout(
+			struct completion *x, unsigned long timeout);
+
+extern void complete(struct completion *);
+extern void complete_all(struct completion *);
 
 #define INIT_COMPLETION(x)	((x).done = 0)
 

include/linux/sched.h

@@ -828,12 +828,17 @@ struct sched_class {
 	struct task_struct * (*pick_next_task) (struct rq *rq);
 	void (*put_prev_task) (struct rq *rq, struct task_struct *p);
 
+#ifdef CONFIG_SMP
 	unsigned long (*load_balance) (struct rq *this_rq, int this_cpu,
-			struct rq *busiest,
-			unsigned long max_nr_move, unsigned long max_load_move,
+			struct rq *busiest, unsigned long max_load_move,
 			struct sched_domain *sd, enum cpu_idle_type idle,
 			int *all_pinned, int *this_best_prio);
 
+	int (*move_one_task) (struct rq *this_rq, int this_cpu,
+			      struct rq *busiest, struct sched_domain *sd,
+			      enum cpu_idle_type idle);
+#endif
+
 	void (*set_curr_task) (struct rq *rq);
 	void (*task_tick) (struct rq *rq, struct task_struct *p);
 	void (*task_new) (struct rq *rq, struct task_struct *p);
@@ -1196,7 +1201,7 @@ static inline int rt_prio(int prio)
 	return 0;
 }
 
-static inline int rt_task(struct task_struct *p)
+static inline int rt_task(const struct task_struct *p)
 {
 	return rt_prio(p->prio);
 }
@@ -1211,22 +1216,22 @@ static inline void set_task_pgrp(struct task_struct *tsk, pid_t pgrp)
 	tsk->signal->__pgrp = pgrp;
 }
 
-static inline struct pid *task_pid(struct task_struct *task)
+static inline struct pid *task_pid(const struct task_struct *task)
 {
 	return task->pids[PIDTYPE_PID].pid;
 }
 
-static inline struct pid *task_tgid(struct task_struct *task)
+static inline struct pid *task_tgid(const struct task_struct *task)
 {
 	return task->group_leader->pids[PIDTYPE_PID].pid;
 }
 
-static inline struct pid *task_pgrp(struct task_struct *task)
+static inline struct pid *task_pgrp(const struct task_struct *task)
 {
 	return task->group_leader->pids[PIDTYPE_PGID].pid;
 }
 
-static inline struct pid *task_session(struct task_struct *task)
+static inline struct pid *task_session(const struct task_struct *task)
 {
 	return task->group_leader->pids[PIDTYPE_SID].pid;
 }
@@ -1255,7 +1260,7 @@ struct pid_namespace;
  * see also pid_nr() etc in include/linux/pid.h
  */
 
-static inline pid_t task_pid_nr(struct task_struct *tsk)
+static inline pid_t task_pid_nr(const struct task_struct *tsk)
 {
 	return tsk->pid;
 }
@@ -1268,7 +1273,7 @@ static inline pid_t task_pid_vnr(struct task_struct *tsk)
 }
 
 
-static inline pid_t task_tgid_nr(struct task_struct *tsk)
+static inline pid_t task_tgid_nr(const struct task_struct *tsk)
 {
 	return tsk->tgid;
 }
@@ -1281,7 +1286,7 @@ static inline pid_t task_tgid_vnr(struct task_struct *tsk)
 }
 
 
-static inline pid_t task_pgrp_nr(struct task_struct *tsk)
+static inline pid_t task_pgrp_nr(const struct task_struct *tsk)
 {
 	return tsk->signal->__pgrp;
 }
@@ -1294,7 +1299,7 @@ static inline pid_t task_pgrp_vnr(struct task_struct *tsk)
 }
 
 
-static inline pid_t task_session_nr(struct task_struct *tsk)
+static inline pid_t task_session_nr(const struct task_struct *tsk)
 {
 	return tsk->signal->__session;
 }
@@ -1321,7 +1326,7 @@ static inline pid_t task_ppid_nr_ns(struct task_struct *tsk,
  * If pid_alive fails, then pointers within the task structure
  * can be stale and must not be dereferenced.
  */
-static inline int pid_alive(struct task_struct *p)
+static inline int pid_alive(const struct task_struct *p)
 {
 	return p->pids[PIDTYPE_PID].pid != NULL;
 }
@@ -1332,7 +1337,7 @@ static inline int pid_alive(struct task_struct *p)
  *
  * Check if a task structure is the first user space task the kernel created.
  */
-static inline int is_global_init(struct task_struct *tsk)
+static inline int is_global_init(const struct task_struct *tsk)
 {
 	return tsk->pid == 1;
 }
@@ -1469,7 +1474,7 @@ extern int rt_mutex_getprio(struct task_struct *p);
 extern void rt_mutex_setprio(struct task_struct *p, int prio);
 extern void rt_mutex_adjust_pi(struct task_struct *p);
 #else
-static inline int rt_mutex_getprio(struct task_struct *p)
+static inline int rt_mutex_getprio(const struct task_struct *p)
 {
 	return p->normal_prio;
 }
@@ -1721,7 +1726,7 @@ extern void wait_task_inactive(struct task_struct * p);
  * all we care about is that we have a task with the appropriate
  * pid, we don't actually care if we have the right task.
  */
-static inline int has_group_leader_pid(struct task_struct *p)
+static inline int has_group_leader_pid(const struct task_struct *p)
 {
 	return p->pid == p->tgid;
 }
@@ -1738,7 +1743,7 @@ static inline struct task_struct *next_thread(const struct task_struct *p)
 			  struct task_struct, thread_group);
 }
 
-static inline int thread_group_empty(struct task_struct *p)
+static inline int thread_group_empty(const struct task_struct *p)
 {
 	return list_empty(&p->thread_group);
 }

init/Kconfig

@@ -322,7 +322,6 @@ config CPUSETS
 config FAIR_GROUP_SCHED
 	bool "Fair group CPU scheduler"
 	default y
-	depends on EXPERIMENTAL
 	help
 	  This feature lets CPU scheduler recognize task groups and control CPU
 	  bandwidth allocation to such task groups.

kernel/profile.c

@@ -60,6 +60,7 @@ static int __init profile_setup(char * str)
 	int par;
 
 	if (!strncmp(str, sleepstr, strlen(sleepstr))) {
+#ifdef CONFIG_SCHEDSTATS
 		prof_on = SLEEP_PROFILING;
 		if (str[strlen(sleepstr)] == ',')
 			str += strlen(sleepstr) + 1;
@@ -68,6 +69,10 @@ static int __init profile_setup(char * str)
 		printk(KERN_INFO
 			"kernel sleep profiling enabled (shift: %ld)\n",
 			prof_shift);
+#else
+		printk(KERN_WARNING
+			"kernel sleep profiling requires CONFIG_SCHEDSTATS\n");
+#endif /* CONFIG_SCHEDSTATS */
 	} else if (!strncmp(str, schedstr, strlen(schedstr))) {
 		prof_on = SCHED_PROFILING;
 		if (str[strlen(schedstr)] == ',')

kernel/sched.c

@@ -66,6 +66,7 @@
 #include <linux/pagemap.h>
 
 #include <asm/tlb.h>
+#include <asm/irq_regs.h>
 
 /*
  * Scheduler clock - returns current time in nanosec units.
@@ -837,12 +838,19 @@ struct rq_iterator {
 	struct task_struct *(*next)(void *);
 };
 
-static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
-		      unsigned long max_nr_move, unsigned long max_load_move,
-		      struct sched_domain *sd, enum cpu_idle_type idle,
-		      int *all_pinned, unsigned long *load_moved,
+#ifdef CONFIG_SMP
+static unsigned long
+balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
+	      unsigned long max_load_move, struct sched_domain *sd,
+	      enum cpu_idle_type idle, int *all_pinned,
 	      int *this_best_prio, struct rq_iterator *iterator);
 
+static int
+iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
+		   struct sched_domain *sd, enum cpu_idle_type idle,
+		   struct rq_iterator *iterator);
+#endif
+
 #include "sched_stats.h"
 #include "sched_idletask.c"
 #include "sched_fair.c"
@@ -2223,17 +2231,17 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
 	return 1;
 }
 
-static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
-		      unsigned long max_nr_move, unsigned long max_load_move,
-		      struct sched_domain *sd, enum cpu_idle_type idle,
-		      int *all_pinned, unsigned long *load_moved,
+static unsigned long
+balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
+	      unsigned long max_load_move, struct sched_domain *sd,
+	      enum cpu_idle_type idle, int *all_pinned,
 	      int *this_best_prio, struct rq_iterator *iterator)
 {
 	int pulled = 0, pinned = 0, skip_for_load;
 	struct task_struct *p;
 	long rem_load_move = max_load_move;
 
-	if (max_nr_move == 0 || max_load_move == 0)
+	if (max_load_move == 0)
 		goto out;
 
 	pinned = 1;
@@ -2266,7 +2274,7 @@ static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
 	 * We only want to steal up to the prescribed number of tasks
 	 * and the prescribed amount of weighted load.
 	 */
-	if (pulled < max_nr_move && rem_load_move > 0) {
+	if (rem_load_move > 0) {
 		if (p->prio < *this_best_prio)
 			*this_best_prio = p->prio;
 		p = iterator->next(iterator->arg);
@@ -2274,7 +2282,7 @@ static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
 	}
 out:
 	/*
-	 * Right now, this is the only place pull_task() is called,
+	 * Right now, this is one of only two places pull_task() is called,
 	 * so we can safely collect pull_task() stats here rather than
 	 * inside pull_task().
 	 */
@@ -2282,8 +2290,8 @@ static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
 
 	if (all_pinned)
 		*all_pinned = pinned;
-	*load_moved = max_load_move - rem_load_move;
-	return pulled;
+
+	return max_load_move - rem_load_move;
 }
 
 /*
@@ -2305,7 +2313,7 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
 	do {
 		total_load_moved +=
 			class->load_balance(this_rq, this_cpu, busiest,
-				ULONG_MAX, max_load_move - total_load_moved,
+				max_load_move - total_load_moved,
 				sd, idle, all_pinned, &this_best_prio);
 		class = class->next;
 	} while (class && max_load_move > total_load_moved);
@@ -2313,6 +2321,32 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
 	return total_load_moved > 0;
 }
 
+static int
+iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
+		   struct sched_domain *sd, enum cpu_idle_type idle,
+		   struct rq_iterator *iterator)
+{
+	struct task_struct *p = iterator->start(iterator->arg);
+	int pinned = 0;
+
+	while (p) {
+		if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
+			pull_task(busiest, p, this_rq, this_cpu);
+			/*
+			 * Right now, this is only the second place pull_task()
+			 * is called, so we can safely collect pull_task()
+			 * stats here rather than inside pull_task().
+			 */
+			schedstat_inc(sd, lb_gained[idle]);
+
+			return 1;
+		}
+		p = iterator->next(iterator->arg);
+	}
+
+	return 0;
+}
+
 /*
  * move_one_task tries to move exactly one task from busiest to this_rq, as
  * part of active balancing operations within "domain".
@@ -2324,12 +2358,9 @@ static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
 			 struct sched_domain *sd, enum cpu_idle_type idle)
 {
 	const struct sched_class *class;
-	int this_best_prio = MAX_PRIO;
 
 	for (class = sched_class_highest; class; class = class->next)
-		if (class->load_balance(this_rq, this_cpu, busiest,
-					1, ULONG_MAX, sd, idle, NULL,
-					&this_best_prio))
+		if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
 			return 1;
 
 	return 0;
@@ -3266,18 +3297,6 @@ static inline void idle_balance(int cpu, struct rq *rq)
 {
 }
 
-/* Avoid "used but not defined" warning on UP */
-static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
-		      unsigned long max_nr_move, unsigned long max_load_move,
-		      struct sched_domain *sd, enum cpu_idle_type idle,
-		      int *all_pinned, unsigned long *load_moved,
-		      int *this_best_prio, struct rq_iterator *iterator)
-{
-	*load_moved = 0;
-
-	return 0;
-}
-
 #endif
 
 DEFINE_PER_CPU(struct kernel_stat, kstat);
@@ -3507,11 +3526,18 @@ EXPORT_SYMBOL(sub_preempt_count);
  */
 static noinline void __schedule_bug(struct task_struct *prev)
 {
-	printk(KERN_ERR "BUG: scheduling while atomic: %s/0x%08x/%d\n",
-		prev->comm, preempt_count(), task_pid_nr(prev));
+	struct pt_regs *regs = get_irq_regs();
+
+	printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
+		prev->comm, prev->pid, preempt_count());
+
 	debug_show_held_locks(prev);
 	if (irqs_disabled())
 		print_irqtrace_events(prev);
+
+	if (regs)
+		show_regs(regs);
+	else
 		dump_stack();
 }
 
@@ -3820,7 +3846,7 @@ __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
 }
 EXPORT_SYMBOL_GPL(__wake_up_sync);	/* For internal use only */
 
-void fastcall complete(struct completion *x)
+void complete(struct completion *x)
 {
 	unsigned long flags;
 
@@ -3832,7 +3858,7 @@ void fastcall complete(struct completion *x)
 }
 EXPORT_SYMBOL(complete);
 
-void fastcall complete_all(struct completion *x)
+void complete_all(struct completion *x)
 {
 	unsigned long flags;
 
@@ -3884,13 +3910,13 @@ wait_for_common(struct completion *x, long timeout, int state)
 	return timeout;
 }
 
-void fastcall __sched wait_for_completion(struct completion *x)
+void __sched wait_for_completion(struct completion *x)
 {
 	wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
 }
 EXPORT_SYMBOL(wait_for_completion);
 
-unsigned long fastcall __sched
+unsigned long __sched
 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
 {
 	return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
@@ -3906,7 +3932,7 @@ int __sched wait_for_completion_interruptible(struct completion *x)
 }
 EXPORT_SYMBOL(wait_for_completion_interruptible);
 
-unsigned long fastcall __sched
+unsigned long __sched
 wait_for_completion_interruptible_timeout(struct completion *x,
 					  unsigned long timeout)
 {
@@ -5461,11 +5487,12 @@ static void register_sched_domain_sysctl(void)
 	struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
 	char buf[32];
 
+	WARN_ON(sd_ctl_dir[0].child);
+	sd_ctl_dir[0].child = entry;
+
 	if (entry == NULL)
 		return;
 
-	sd_ctl_dir[0].child = entry;
-
 	for_each_online_cpu(i) {
 		snprintf(buf, 32, "cpu%d", i);
 		entry->procname = kstrdup(buf, GFP_KERNEL);
@@ -5473,13 +5500,18 @@ static void register_sched_domain_sysctl(void)
 		entry->child = sd_alloc_ctl_cpu_table(i);
 		entry++;
 	}
+
+	WARN_ON(sd_sysctl_header);
 	sd_sysctl_header = register_sysctl_table(sd_ctl_root);
 }
 
+/* may be called multiple times per register */
 static void unregister_sched_domain_sysctl(void)
 {
+	if (sd_sysctl_header)
 		unregister_sysctl_table(sd_sysctl_header);
 	sd_sysctl_header = NULL;
+	if (sd_ctl_dir[0].child)
 		sd_free_ctl_entry(&sd_ctl_dir[0].child);
 }
 #else
@@ -5611,52 +5643,38 @@ int nr_cpu_ids __read_mostly = NR_CPUS;
 EXPORT_SYMBOL(nr_cpu_ids);
 
 #ifdef CONFIG_SCHED_DEBUG
-static void sched_domain_debug(struct sched_domain *sd, int cpu)
-{
-	int level = 0;
-
-	if (!sd) {
-		printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
-		return;
-	}
 
-	printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
-
-	do {
-		int i;
-		char str[NR_CPUS];
+static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level)
+{
 	struct sched_group *group = sd->groups;
 	cpumask_t groupmask;
+	char str[NR_CPUS];
 
 	cpumask_scnprintf(str, NR_CPUS, sd->span);
 	cpus_clear(groupmask);
 
-		printk(KERN_DEBUG);
-		for (i = 0; i < level + 1; i++)
-			printk(" ");
-		printk("domain %d: ", level);
+	printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
 
 	if (!(sd->flags & SD_LOAD_BALANCE)) {
 		printk("does not load-balance\n");
 		if (sd->parent)
 			printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
 					" has parent");
-			break;
+		return -1;
 	}
 
-		printk("span %s\n", str);
+	printk(KERN_CONT "span %s\n", str);
 
-		if (!cpu_isset(cpu, sd->span))
+	if (!cpu_isset(cpu, sd->span)) {
 		printk(KERN_ERR "ERROR: domain->span does not contain "
 				"CPU%d\n", cpu);
-		if (!cpu_isset(cpu, group->cpumask))
+	}
+	if (!cpu_isset(cpu, group->cpumask)) {
 		printk(KERN_ERR "ERROR: domain->groups does not contain"
 				" CPU%d\n", cpu);
+	}
 
-		printk(KERN_DEBUG);
-		for (i = 0; i < level + 2; i++)
-			printk(" ");
-		printk("groups:");
+	printk(KERN_DEBUG "%*s groups:", level + 1, "");
 	do {
 		if (!group) {
 			printk("\n");
@@ -5693,19 +5711,33 @@ static void sched_domain_debug(struct sched_domain *sd, int cpu)
 	printk(KERN_CONT "\n");
 
 	if (!cpus_equal(sd->span, groupmask))
-			printk(KERN_ERR "ERROR: groups don't span "
-					"domain->span\n");
+		printk(KERN_ERR "ERROR: groups don't span domain->span\n");
 
-		level++;
-		sd = sd->parent;
-		if (!sd)
-			continue;
-
-		if (!cpus_subset(groupmask, sd->span))
+	if (sd->parent && !cpus_subset(groupmask, sd->parent->span))
 		printk(KERN_ERR "ERROR: parent span is not a superset "
 			"of domain->span\n");
+	return 0;
+}
+
+static void sched_domain_debug(struct sched_domain *sd, int cpu)
+{
+	int level = 0;
+
+	if (!sd) {
+		printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
+		return;
+	}
+
+	printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
 
-	} while (sd);
+	for (;;) {
+		if (sched_domain_debug_one(sd, cpu, level))
+			break;
+		level++;
+		sd = sd->parent;
+		if (!sd)
+			break;
+	}
 }
 #else
 # define sched_domain_debug(sd, cpu) do { } while (0)
@@ -6424,13 +6456,17 @@ static cpumask_t fallback_doms;
  */
 static int arch_init_sched_domains(const cpumask_t *cpu_map)
 {
+	int err;
+
 	ndoms_cur = 1;
 	doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
 	if (!doms_cur)
 		doms_cur = &fallback_doms;
 	cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map);
+	err = build_sched_domains(doms_cur);
 	register_sched_domain_sysctl();
-	return build_sched_domains(doms_cur);
+
+	return err;
 }
 
 static void arch_destroy_sched_domains(const cpumask_t *cpu_map)
@@ -6479,6 +6515,9 @@ void partition_sched_domains(int ndoms_new, cpumask_t *doms_new)
 {
 	int i, j;
 
+	/* always unregister in case we don't destroy any domains */
+	unregister_sched_domain_sysctl();
+
 	if (doms_new == NULL) {
 		ndoms_new = 1;
 		doms_new = &fallback_doms;
@@ -6514,6 +6553,8 @@ void partition_sched_domains(int ndoms_new, cpumask_t *doms_new)
 		kfree(doms_cur);
 	doms_cur = doms_new;
 	ndoms_cur = ndoms_new;
+
+	register_sched_domain_sysctl();
 }
 
 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
@@ -7101,25 +7142,25 @@ unsigned long sched_group_shares(struct task_group *tg)
 #ifdef CONFIG_FAIR_CGROUP_SCHED
 
 /* return corresponding task_group object of a cgroup */
-static inline struct task_group *cgroup_tg(struct cgroup *cont)
+static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
 {
-	return container_of(cgroup_subsys_state(cont, cpu_cgroup_subsys_id),
+	return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
 			    struct task_group, css);
 }
 
 static struct cgroup_subsys_state *
-cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
+cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
 {
 	struct task_group *tg;
 
-	if (!cont->parent) {
+	if (!cgrp->parent) {
 		/* This is early initialization for the top cgroup */
-		init_task_group.css.cgroup = cont;
+		init_task_group.css.cgroup = cgrp;
 		return &init_task_group.css;
 	}
 
 	/* we support only 1-level deep hierarchical scheduler atm */
-	if (cont->parent->parent)
+	if (cgrp->parent->parent)
 		return ERR_PTR(-EINVAL);
 
 	tg = sched_create_group();
@@ -7127,21 +7168,21 @@ cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 		return ERR_PTR(-ENOMEM);
 
 	/* Bind the cgroup to task_group object we just created */
-	tg->css.cgroup = cont;
+	tg->css.cgroup = cgrp;
 
 	return &tg->css;
 }
 
 static void cpu_cgroup_destroy(struct cgroup_subsys *ss,
-					struct cgroup *cont)
+			       struct cgroup *cgrp)
 {
-	struct task_group *tg = cgroup_tg(cont);
+	struct task_group *tg = cgroup_tg(cgrp);
 
 	sched_destroy_group(tg);
 }
 
 static int cpu_cgroup_can_attach(struct cgroup_subsys *ss,
-			     struct cgroup *cont, struct task_struct *tsk)
+			     struct cgroup *cgrp, struct task_struct *tsk)
 {
 	/* We don't support RT-tasks being in separate groups */
 	if (tsk->sched_class != &fair_sched_class)
@@ -7151,38 +7192,21 @@ static int cpu_cgroup_can_attach(struct cgroup_subsys *ss,
 }
 
 static void
-cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cont,
+cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
 			struct cgroup *old_cont, struct task_struct *tsk)
 {
 	sched_move_task(tsk);
 }
 
-static ssize_t cpu_shares_write(struct cgroup *cont, struct cftype *cftype,
-				struct file *file, const char __user *userbuf,
-				size_t nbytes, loff_t *ppos)
+static int cpu_shares_write_uint(struct cgroup *cgrp, struct cftype *cftype,
+				u64 shareval)
 {
-	unsigned long shareval;
-	struct task_group *tg = cgroup_tg(cont);
-	char buffer[2*sizeof(unsigned long) + 1];
-	int rc;
-
-	if (nbytes > 2*sizeof(unsigned long))	/* safety check */
-		return -E2BIG;
-
-	if (copy_from_user(buffer, userbuf, nbytes))
-		return -EFAULT;
-
-	buffer[nbytes] = 0;	/* nul-terminate */
-	shareval = simple_strtoul(buffer, NULL, 10);
-
-	rc = sched_group_set_shares(tg, shareval);
-
-	return (rc < 0 ? rc : nbytes);
+	return sched_group_set_shares(cgroup_tg(cgrp), shareval);
 }
 
-static u64 cpu_shares_read_uint(struct cgroup *cont, struct cftype *cft)
+static u64 cpu_shares_read_uint(struct cgroup *cgrp, struct cftype *cft)
 {
-	struct task_group *tg = cgroup_tg(cont);
+	struct task_group *tg = cgroup_tg(cgrp);
 
 	return (u64) tg->shares;
 }
@@ -7190,7 +7214,7 @@ static u64 cpu_shares_read_uint(struct cgroup *cont, struct cftype *cft)
 static struct cftype cpu_shares = {
 	.name = "shares",
 	.read_uint = cpu_shares_read_uint,
-	.write = cpu_shares_write,
+	.write_uint = cpu_shares_write_uint,
 };
 
 static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)

kernel/sched_fair.c

@@ -876,6 +876,7 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
 	}
 }
 
+#ifdef CONFIG_SMP
 /**************************************************
  * Fair scheduling class load-balancing methods:
  */
@@ -936,12 +937,11 @@ static int cfs_rq_best_prio(struct cfs_rq *cfs_rq)
 
 static unsigned long
 load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
-		  unsigned long max_nr_move, unsigned long max_load_move,
+		  unsigned long max_load_move,
 		  struct sched_domain *sd, enum cpu_idle_type idle,
 		  int *all_pinned, int *this_best_prio)
 {
 	struct cfs_rq *busy_cfs_rq;
-	unsigned long load_moved, total_nr_moved = 0, nr_moved;
 	long rem_load_move = max_load_move;
 	struct rq_iterator cfs_rq_iterator;
 
@@ -969,25 +969,48 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
 #else
 # define maxload rem_load_move
 #endif
-		/* pass busy_cfs_rq argument into
+		/*
+		 * pass busy_cfs_rq argument into
 		 * load_balance_[start|next]_fair iterators
 		 */
 		cfs_rq_iterator.arg = busy_cfs_rq;
-		nr_moved = balance_tasks(this_rq, this_cpu, busiest,
-				max_nr_move, maxload, sd, idle, all_pinned,
-				&load_moved, this_best_prio, &cfs_rq_iterator);
-
-		total_nr_moved += nr_moved;
-		max_nr_move -= nr_moved;
-		rem_load_move -= load_moved;
+		rem_load_move -= balance_tasks(this_rq, this_cpu, busiest,
+					       maxload, sd, idle, all_pinned,
+					       this_best_prio,
+					       &cfs_rq_iterator);
 
-		if (max_nr_move <= 0 || rem_load_move <= 0)
+		if (rem_load_move <= 0)
 			break;
 	}
 
 	return max_load_move - rem_load_move;
 }
 
+static int
+move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
+		   struct sched_domain *sd, enum cpu_idle_type idle)
+{
+	struct cfs_rq *busy_cfs_rq;
+	struct rq_iterator cfs_rq_iterator;
+
+	cfs_rq_iterator.start = load_balance_start_fair;
+	cfs_rq_iterator.next = load_balance_next_fair;
+
+	for_each_leaf_cfs_rq(busiest, busy_cfs_rq) {
+		/*
+		 * pass busy_cfs_rq argument into
+		 * load_balance_[start|next]_fair iterators
+		 */
+		cfs_rq_iterator.arg = busy_cfs_rq;
+		if (iter_move_one_task(this_rq, this_cpu, busiest, sd, idle,
+				       &cfs_rq_iterator))
+		    return 1;
+	}
+
+	return 0;
+}
+#endif
+
 /*
  * scheduler tick hitting a task of our scheduling class:
  */
@@ -1063,7 +1086,10 @@ static const struct sched_class fair_sched_class = {
 	.pick_next_task		= pick_next_task_fair,
 	.put_prev_task		= put_prev_task_fair,
 
+#ifdef CONFIG_SMP
 	.load_balance		= load_balance_fair,
+	.move_one_task		= move_one_task_fair,
+#endif
 
 	.set_curr_task          = set_curr_task_fair,
 	.task_tick		= task_tick_fair,

kernel/sched_idletask.c

@@ -37,15 +37,24 @@ static void put_prev_task_idle(struct rq *rq, struct task_struct *prev)
 {
 }
 
+#ifdef CONFIG_SMP
 static unsigned long
 load_balance_idle(struct rq *this_rq, int this_cpu, struct rq *busiest,
-			unsigned long max_nr_move, unsigned long max_load_move,
+		  unsigned long max_load_move,
 		  struct sched_domain *sd, enum cpu_idle_type idle,
 		  int *all_pinned, int *this_best_prio)
 {
 	return 0;
 }
 
+static int
+move_one_task_idle(struct rq *this_rq, int this_cpu, struct rq *busiest,
+		   struct sched_domain *sd, enum cpu_idle_type idle)
+{
+	return 0;
+}
+#endif
+
 static void task_tick_idle(struct rq *rq, struct task_struct *curr)
 {
 }
@@ -69,7 +78,10 @@ const struct sched_class idle_sched_class = {
 	.pick_next_task		= pick_next_task_idle,
 	.put_prev_task		= put_prev_task_idle,
 
+#ifdef CONFIG_SMP
 	.load_balance		= load_balance_idle,
+	.move_one_task		= move_one_task_idle,
+#endif
 
 	.set_curr_task          = set_curr_task_idle,
 	.task_tick		= task_tick_idle,

kernel/sched_rt.c

@@ -98,6 +98,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
 	p->se.exec_start = 0;
 }
 
+#ifdef CONFIG_SMP
 /*
  * Load-balancing iterator. Note: while the runqueue stays locked
  * during the whole iteration, the current task might be
@@ -172,13 +173,11 @@ static struct task_struct *load_balance_next_rt(void *arg)
 
 static unsigned long
 load_balance_rt(struct rq *this_rq, int this_cpu, struct rq *busiest,
-			unsigned long max_nr_move, unsigned long max_load_move,
+		unsigned long max_load_move,
 		struct sched_domain *sd, enum cpu_idle_type idle,
 		int *all_pinned, int *this_best_prio)
 {
-	int nr_moved;
 	struct rq_iterator rt_rq_iterator;
-	unsigned long load_moved;
 
 	rt_rq_iterator.start = load_balance_start_rt;
 	rt_rq_iterator.next = load_balance_next_rt;
@@ -187,12 +186,24 @@ load_balance_rt(struct rq *this_rq, int this_cpu, struct rq *busiest,
 	 */
 	rt_rq_iterator.arg = busiest;
 
-	nr_moved = balance_tasks(this_rq, this_cpu, busiest, max_nr_move,
-			max_load_move, sd, idle, all_pinned, &load_moved,
-			this_best_prio, &rt_rq_iterator);
+	return balance_tasks(this_rq, this_cpu, busiest, max_load_move, sd,
+			     idle, all_pinned, this_best_prio, &rt_rq_iterator);
+}
+
+static int
+move_one_task_rt(struct rq *this_rq, int this_cpu, struct rq *busiest,
+		 struct sched_domain *sd, enum cpu_idle_type idle)
+{
+	struct rq_iterator rt_rq_iterator;
+
+	rt_rq_iterator.start = load_balance_start_rt;
+	rt_rq_iterator.next = load_balance_next_rt;
+	rt_rq_iterator.arg = busiest;
 
-	return load_moved;
+	return iter_move_one_task(this_rq, this_cpu, busiest, sd, idle,
+				  &rt_rq_iterator);
 }
+#endif
 
 static void task_tick_rt(struct rq *rq, struct task_struct *p)
 {
@@ -236,7 +247,10 @@ const struct sched_class rt_sched_class = {
 	.pick_next_task		= pick_next_task_rt,
 	.put_prev_task		= put_prev_task_rt,
 
+#ifdef CONFIG_SMP
 	.load_balance		= load_balance_rt,
+	.move_one_task		= move_one_task_rt,
+#endif
 
 	.set_curr_task          = set_curr_task_rt,
 	.task_tick		= task_tick_rt,

kernel/user.c

@@ -129,7 +129,7 @@ static inline void uids_mutex_unlock(void)
 }
 
 /* return cpu shares held by the user */
-ssize_t cpu_shares_show(struct kset *kset, char *buffer)
+static ssize_t cpu_shares_show(struct kset *kset, char *buffer)
 {
 	struct user_struct *up = container_of(kset, struct user_struct, kset);
 
@@ -137,7 +137,8 @@ ssize_t cpu_shares_show(struct kset *kset, char *buffer)
 }
 
 /* modify cpu shares held by the user */
-ssize_t cpu_shares_store(struct kset *kset, const char *buffer, size_t size)
+static ssize_t cpu_shares_store(struct kset *kset, const char *buffer,
+				size_t size)
 {
 	struct user_struct *up = container_of(kset, struct user_struct, kset);
 	unsigned long shares;