]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - kernel/sched.c
[PATCH] sched: force /sbin/init off isolated cpus
[linux-2.6-omap-h63xx.git] / kernel / sched.c
index b44b9a43b0fcadbe0745aafd876e2a17a7daa9d5..ddf418810c3930eb7c15c617e0127c7014555154 100644 (file)
@@ -49,7 +49,7 @@
 #include <linux/seq_file.h>
 #include <linux/syscalls.h>
 #include <linux/times.h>
-#include <linux/acct.h>
+#include <linux/tsacct_kern.h>
 #include <linux/kprobes.h>
 #include <linux/delayacct.h>
 #include <asm/tlb.h>
@@ -238,6 +238,7 @@ struct rq {
        /* For active balancing */
        int active_balance;
        int push_cpu;
+       int cpu;                /* cpu of this runqueue */
 
        struct task_struct *migration_thread;
        struct list_head migration_queue;
@@ -267,6 +268,15 @@ struct rq {
 
 static DEFINE_PER_CPU(struct rq, runqueues);
 
+static inline int cpu_of(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+       return rq->cpu;
+#else
+       return 0;
+#endif
+}
+
 /*
  * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
  * See detach_destroy_domains: synchronize_sched for details.
@@ -1745,27 +1755,27 @@ static inline void finish_task_switch(struct rq *rq, struct task_struct *prev)
        __releases(rq->lock)
 {
        struct mm_struct *mm = rq->prev_mm;
-       unsigned long prev_task_flags;
+       long prev_state;
 
        rq->prev_mm = NULL;
 
        /*
         * A task struct has one reference for the use as "current".
-        * If a task dies, then it sets EXIT_ZOMBIE in tsk->exit_state and
-        * calls schedule one last time. The schedule call will never return,
-        * and the scheduled task must drop that reference.
-        * The test for EXIT_ZOMBIE must occur while the runqueue locks are
+        * If a task dies, then it sets TASK_DEAD in tsk->state and calls
+        * schedule one last time. The schedule call will never return, and
+        * the scheduled task must drop that reference.
+        * The test for TASK_DEAD must occur while the runqueue locks are
         * still held, otherwise prev could be scheduled on another cpu, die
         * there before we look at prev->state, and then the reference would
         * be dropped twice.
         *              Manfred Spraul <manfred@colorfullife.com>
         */
-       prev_task_flags = prev->flags;
+       prev_state = prev->state;
        finish_arch_switch(prev);
        finish_lock_switch(rq, prev);
        if (mm)
                mmdrop(mm);
-       if (unlikely(prev_task_flags & PF_DEAD)) {
+       if (unlikely(prev_state == TASK_DEAD)) {
                /*
                 * Remove function-return probe instances associated with this
                 * task and put them back on the free list.
@@ -2211,7 +2221,8 @@ out:
  */
 static struct sched_group *
 find_busiest_group(struct sched_domain *sd, int this_cpu,
-                  unsigned long *imbalance, enum idle_type idle, int *sd_idle)
+                  unsigned long *imbalance, enum idle_type idle, int *sd_idle,
+                  cpumask_t *cpus)
 {
        struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
        unsigned long max_load, avg_load, total_load, this_load, total_pwr;
@@ -2248,7 +2259,12 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
                sum_weighted_load = sum_nr_running = avg_load = 0;
 
                for_each_cpu_mask(i, group->cpumask) {
-                       struct rq *rq = cpu_rq(i);
+                       struct rq *rq;
+
+                       if (!cpu_isset(i, *cpus))
+                               continue;
+
+                       rq = cpu_rq(i);
 
                        if (*sd_idle && !idle_cpu(i))
                                *sd_idle = 0;
@@ -2466,13 +2482,17 @@ ret:
  */
 static struct rq *
 find_busiest_queue(struct sched_group *group, enum idle_type idle,
-                  unsigned long imbalance)
+                  unsigned long imbalance, cpumask_t *cpus)
 {
        struct rq *busiest = NULL, *rq;
        unsigned long max_load = 0;
        int i;
 
        for_each_cpu_mask(i, group->cpumask) {
+
+               if (!cpu_isset(i, *cpus))
+                       continue;
+
                rq = cpu_rq(i);
 
                if (rq->nr_running == 1 && rq->raw_weighted_load > imbalance)
@@ -2511,6 +2531,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
        struct sched_group *group;
        unsigned long imbalance;
        struct rq *busiest;
+       cpumask_t cpus = CPU_MASK_ALL;
 
        if (idle != NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
            !sched_smt_power_savings)
@@ -2518,13 +2539,15 @@ static int load_balance(int this_cpu, struct rq *this_rq,
 
        schedstat_inc(sd, lb_cnt[idle]);
 
-       group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle);
+redo:
+       group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
+                                                       &cpus);
        if (!group) {
                schedstat_inc(sd, lb_nobusyg[idle]);
                goto out_balanced;
        }
 
-       busiest = find_busiest_queue(group, idle, imbalance);
+       busiest = find_busiest_queue(group, idle, imbalance, &cpus);
        if (!busiest) {
                schedstat_inc(sd, lb_nobusyq[idle]);
                goto out_balanced;
@@ -2549,8 +2572,12 @@ static int load_balance(int this_cpu, struct rq *this_rq,
                double_rq_unlock(this_rq, busiest);
 
                /* All tasks on this runqueue were pinned by CPU affinity */
-               if (unlikely(all_pinned))
+               if (unlikely(all_pinned)) {
+                       cpu_clear(cpu_of(busiest), cpus);
+                       if (!cpus_empty(cpus))
+                               goto redo;
                        goto out_balanced;
+               }
        }
 
        if (!nr_moved) {
@@ -2639,18 +2666,22 @@ load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd)
        unsigned long imbalance;
        int nr_moved = 0;
        int sd_idle = 0;
+       cpumask_t cpus = CPU_MASK_ALL;
 
        if (sd->flags & SD_SHARE_CPUPOWER && !sched_smt_power_savings)
                sd_idle = 1;
 
        schedstat_inc(sd, lb_cnt[NEWLY_IDLE]);
-       group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE, &sd_idle);
+redo:
+       group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE,
+                               &sd_idle, &cpus);
        if (!group) {
                schedstat_inc(sd, lb_nobusyg[NEWLY_IDLE]);
                goto out_balanced;
        }
 
-       busiest = find_busiest_queue(group, NEWLY_IDLE, imbalance);
+       busiest = find_busiest_queue(group, NEWLY_IDLE, imbalance,
+                               &cpus);
        if (!busiest) {
                schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]);
                goto out_balanced;
@@ -2668,6 +2699,12 @@ load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd)
                                        minus_1_or_zero(busiest->nr_running),
                                        imbalance, sd, NEWLY_IDLE, NULL);
                spin_unlock(&busiest->lock);
+
+               if (!nr_moved) {
+                       cpu_clear(cpu_of(busiest), cpus);
+                       if (!cpus_empty(cpus))
+                               goto redo;
+               }
        }
 
        if (!nr_moved) {
@@ -3311,9 +3348,6 @@ need_resched_nonpreemptible:
 
        spin_lock_irq(&rq->lock);
 
-       if (unlikely(prev->flags & PF_DEAD))
-               prev->state = EXIT_DEAD;
-
        switch_count = &prev->nivcsw;
        if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
                switch_count = &prev->nvcsw;
@@ -4043,6 +4077,8 @@ static void __setscheduler(struct task_struct *p, int policy, int prio)
  * @p: the task in question.
  * @policy: new policy.
  * @param: structure containing the new RT priority.
+ *
+ * NOTE: the task may be already dead
  */
 int sched_setscheduler(struct task_struct *p, int policy,
                       struct sched_param *param)
@@ -4070,28 +4106,32 @@ recheck:
            (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
            (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
                return -EINVAL;
-       if ((policy == SCHED_NORMAL || policy == SCHED_BATCH)
-                                       != (param->sched_priority == 0))
+       if (is_rt_policy(policy) != (param->sched_priority != 0))
                return -EINVAL;
 
        /*
         * Allow unprivileged RT tasks to decrease priority:
         */
        if (!capable(CAP_SYS_NICE)) {
-               /*
-                * can't change policy, except between SCHED_NORMAL
-                * and SCHED_BATCH:
-                */
-               if (((policy != SCHED_NORMAL && p->policy != SCHED_BATCH) &&
-                       (policy != SCHED_BATCH && p->policy != SCHED_NORMAL)) &&
-                               !p->signal->rlim[RLIMIT_RTPRIO].rlim_cur)
-                       return -EPERM;
-               /* can't increase priority */
-               if ((policy != SCHED_NORMAL && policy != SCHED_BATCH) &&
-                   param->sched_priority > p->rt_priority &&
-                   param->sched_priority >
-                               p->signal->rlim[RLIMIT_RTPRIO].rlim_cur)
-                       return -EPERM;
+               if (is_rt_policy(policy)) {
+                       unsigned long rlim_rtprio;
+                       unsigned long flags;
+
+                       if (!lock_task_sighand(p, &flags))
+                               return -ESRCH;
+                       rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
+                       unlock_task_sighand(p, &flags);
+
+                       /* can't set/change the rt policy */
+                       if (policy != p->policy && !rlim_rtprio)
+                               return -EPERM;
+
+                       /* can't increase priority */
+                       if (param->sched_priority > p->rt_priority &&
+                           param->sched_priority > rlim_rtprio)
+                               return -EPERM;
+               }
+
                /* can't change other user's priorities */
                if ((current->euid != p->euid) &&
                    (current->euid != p->uid))
@@ -4156,16 +4196,13 @@ do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
                return -EINVAL;
        if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
                return -EFAULT;
-       read_lock_irq(&tasklist_lock);
+
+       rcu_read_lock();
+       retval = -ESRCH;
        p = find_process_by_pid(pid);
-       if (!p) {
-               read_unlock_irq(&tasklist_lock);
-               return -ESRCH;
-       }
-       get_task_struct(p);
-       read_unlock_irq(&tasklist_lock);
-       retval = sched_setscheduler(p, policy, &lparam);
-       put_task_struct(p);
+       if (p != NULL)
+               retval = sched_setscheduler(p, policy, &lparam);
+       rcu_read_unlock();
 
        return retval;
 }
@@ -4347,7 +4384,10 @@ EXPORT_SYMBOL(cpu_present_map);
 
 #ifndef CONFIG_SMP
 cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL;
+EXPORT_SYMBOL(cpu_online_map);
+
 cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL;
+EXPORT_SYMBOL(cpu_possible_map);
 #endif
 
 long sched_getaffinity(pid_t pid, cpumask_t *mask)
@@ -4456,9 +4496,9 @@ asmlinkage long sys_sched_yield(void)
        return 0;
 }
 
-static inline int __resched_legal(void)
+static inline int __resched_legal(int expected_preempt_count)
 {
-       if (unlikely(preempt_count()))
+       if (unlikely(preempt_count() != expected_preempt_count))
                return 0;
        if (unlikely(system_state != SYSTEM_RUNNING))
                return 0;
@@ -4484,7 +4524,7 @@ static void __cond_resched(void)
 
 int __sched cond_resched(void)
 {
-       if (need_resched() && __resched_legal()) {
+       if (need_resched() && __resched_legal(0)) {
                __cond_resched();
                return 1;
        }
@@ -4510,7 +4550,7 @@ int cond_resched_lock(spinlock_t *lock)
                ret = 1;
                spin_lock(lock);
        }
-       if (need_resched() && __resched_legal()) {
+       if (need_resched() && __resched_legal(1)) {
                spin_release(&lock->dep_map, 1, _THIS_IP_);
                _raw_spin_unlock(lock);
                preempt_enable_no_resched();
@@ -4526,7 +4566,7 @@ int __sched cond_resched_softirq(void)
 {
        BUG_ON(!in_softirq());
 
-       if (need_resched() && __resched_legal()) {
+       if (need_resched() && __resched_legal(0)) {
                raw_local_irq_disable();
                _local_bh_enable();
                raw_local_irq_enable();
@@ -4777,7 +4817,7 @@ void show_state(void)
  * NOTE: this function does not set the idle thread's NEED_RESCHED
  * flag, to make booting more robust.
  */
-void __devinit init_idle(struct task_struct *idle, int cpu)
+void __cpuinit init_idle(struct task_struct *idle, int cpu)
 {
        struct rq *rq = cpu_rq(cpu);
        unsigned long flags;
@@ -5116,7 +5156,7 @@ static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
        BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD);
 
        /* Cannot have done final schedule yet: would have vanished. */
-       BUG_ON(p->flags & PF_DEAD);
+       BUG_ON(p->state == TASK_DEAD);
 
        get_task_struct(p);
 
@@ -5237,9 +5277,11 @@ static struct notifier_block __cpuinitdata migration_notifier = {
 int __init migration_init(void)
 {
        void *cpu = (void *)(long)smp_processor_id();
+       int err;
 
        /* Start one for the boot CPU: */
-       migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
+       err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
+       BUG_ON(err == NOTIFY_BAD);
        migration_call(&migration_notifier, CPU_ONLINE, cpu);
        register_cpu_notifier(&migration_notifier);
 
@@ -5419,7 +5461,7 @@ static void cpu_attach_domain(struct sched_domain *sd, int cpu)
 }
 
 /* cpus with isolated domains */
-static cpumask_t __devinitdata cpu_isolated_map = CPU_MASK_NONE;
+static cpumask_t __cpuinitdata cpu_isolated_map = CPU_MASK_NONE;
 
 /* Setup the mask of cpus configured for isolated domains */
 static int __init isolated_cpu_setup(char *str)
@@ -6494,7 +6536,12 @@ static int build_sched_domains(const cpumask_t *cpu_map)
        for (i = 0; i < MAX_NUMNODES; i++)
                init_numa_sched_groups_power(sched_group_nodes[i]);
 
-       init_numa_sched_groups_power(sched_group_allnodes);
+       if (sched_group_allnodes) {
+               int group = cpu_to_allnodes_group(first_cpu(*cpu_map));
+               struct sched_group *sg = &sched_group_allnodes[group];
+
+               init_numa_sched_groups_power(sg);
+       }
 #endif
 
        /* Attach the domains */
@@ -6700,11 +6747,20 @@ static int update_sched_domains(struct notifier_block *nfb,
 
 void __init sched_init_smp(void)
 {
+       cpumask_t non_isolated_cpus;
+
        lock_cpu_hotplug();
        arch_init_sched_domains(&cpu_online_map);
+       cpus_andnot(non_isolated_cpus, cpu_online_map, cpu_isolated_map);
+       if (cpus_empty(non_isolated_cpus))
+               cpu_set(smp_processor_id(), non_isolated_cpus);
        unlock_cpu_hotplug();
        /* XXX: Theoretical race here - CPU may be hotplugged now */
        hotcpu_notifier(update_sched_domains, 0);
+
+       /* Move init over to a non-isolated CPU */
+       if (set_cpus_allowed(current, non_isolated_cpus) < 0)
+               BUG();
 }
 #else
 void __init sched_init_smp(void)
@@ -6744,6 +6800,7 @@ void __init sched_init(void)
                        rq->cpu_load[j] = 0;
                rq->active_balance = 0;
                rq->push_cpu = 0;
+               rq->cpu = i;
                rq->migration_thread = NULL;
                INIT_LIST_HEAD(&rq->migration_queue);
 #endif
@@ -6761,6 +6818,11 @@ void __init sched_init(void)
        }
 
        set_load_weight(&init_task);
+
+#ifdef CONFIG_RT_MUTEXES
+       plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
+#endif
+
        /*
         * The boot idle thread does lazy MMU switching as well:
         */