17 files changed, 339 insertions, 115 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index a512a75a5560..8fe8c0cb137b 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2500,7 +2500,6 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
         list_del(&cgrp->sibling);
         spin_lock(&cgrp->dentry->d_lock);
         d = dget(cgrp->dentry);
-        cgrp->dentry = NULL;
         spin_unlock(&d->d_lock);
 
         cgroup_d_remove_dir(d);
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index 7fa476f01d05..fb249e2bcada 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -184,9 +184,20 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
 {
         struct freezer *freezer;
 
-        task_lock(task);
+        /*
+         * No lock is needed, since the task isn't on tasklist yet,
+         * so it can't be moved to another cgroup, which means the
+         * freezer won't be removed and will be valid during this
+         * function call.
+         */
         freezer = task_freezer(task);
-        task_unlock(task);
+
+        /*
+         * The root cgroup is non-freezable, so we can skip the
+         * following check.
+         */
+        if (!freezer->css.cgroup->parent)
+                return;
 
         spin_lock_irq(&freezer->lock);
         BUG_ON(freezer->state == CGROUP_FROZEN);
@@ -331,7 +342,7 @@ static int freezer_write(struct cgroup *cgroup,
         else if (strcmp(buffer, freezer_state_strs[CGROUP_FROZEN]) == 0)
                 goal_state = CGROUP_FROZEN;
         else
-                return -EIO;
+                return -EINVAL;
 
         if (!cgroup_lock_live_group(cgroup))
                 return -ENODEV;
@@ -350,6 +361,8 @@ static struct cftype files[] = {
 
 static int freezer_populate(struct cgroup_subsys *ss, struct cgroup *cgroup)
 {
+        if (!cgroup->parent)
+                return 0;
         return cgroup_add_files(cgroup, ss, files, ARRAY_SIZE(files));
 }
 
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 86d49045daed..5a732c5ef08b 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -499,3 +499,6 @@ const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
 #endif
 };
 EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
+
+const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
+EXPORT_SYMBOL(cpu_all_bits);
diff --git a/kernel/exit.c b/kernel/exit.c
index c0711da15486..16eda9b39f8d 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -143,6 +143,11 @@ static void __exit_signal(struct task_struct *tsk)
         if (sig) {
                 flush_sigqueue(&sig->shared_pending);
                 taskstats_tgid_free(sig);
+                /*
+                 * Make sure ->signal can't go away under rq->lock,
+                 * see account_group_exec_runtime().
+                 */
+                task_rq_unlock_wait(tsk);
                 __cleanup_signal(sig);
         }
 }
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 2b465dfde426..47e63349d1b2 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -664,14 +664,6 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
 
                 /* Timer is expired, act upon the callback mode */
                 switch(timer->cb_mode) {
-                case HRTIMER_CB_IRQSAFE_NO_RESTART:
-                        debug_hrtimer_deactivate(timer);
-                        /*
-                         * We can call the callback from here. No restart
-                         * happens, so no danger of recursion
-                         */
-                        BUG_ON(timer->function(timer) != HRTIMER_NORESTART);
-                        return 1;
                 case HRTIMER_CB_IRQSAFE_PERCPU:
                 case HRTIMER_CB_IRQSAFE_UNLOCKED:
                         /*
@@ -683,7 +675,6 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
                          */
                         debug_hrtimer_deactivate(timer);
                         return 1;
-                case HRTIMER_CB_IRQSAFE:
                 case HRTIMER_CB_SOFTIRQ:
                         /*
                          * Move everything else into the softirq pending list !
@@ -1209,6 +1200,7 @@ static void run_hrtimer_pending(struct hrtimer_cpu_base *cpu_base)
                 enum hrtimer_restart (*fn)(struct hrtimer *);
                 struct hrtimer *timer;
                 int restart;
+                int emulate_hardirq_ctx = 0;
 
                 timer = list_entry(cpu_base->cb_pending.next,
                                    struct hrtimer, cb_entry);
@@ -1217,10 +1209,24 @@ static void run_hrtimer_pending(struct hrtimer_cpu_base *cpu_base)
                 timer_stats_account_hrtimer(timer);
 
                 fn = timer->function;
+                /*
+                 * A timer might have been added to the cb_pending list
+                 * when it was migrated during a cpu-offline operation.
+                 * Emulate hardirq context for such timers.
+                 */
+                if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU ||
+                    timer->cb_mode == HRTIMER_CB_IRQSAFE_UNLOCKED)
+                        emulate_hardirq_ctx = 1;
+
                 __remove_hrtimer(timer, timer->base, HRTIMER_STATE_CALLBACK, 0);
                 spin_unlock_irq(&cpu_base->lock);
 
-                restart = fn(timer);
+                if (unlikely(emulate_hardirq_ctx)) {
+                        local_irq_disable();
+                        restart = fn(timer);
+                        local_irq_enable();
+                } else
+                        restart = fn(timer);
 
                 spin_lock_irq(&cpu_base->lock);
 
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 8b57a2597f21..9f8a3f25259a 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -72,7 +72,7 @@ static bool kprobe_enabled;
 DEFINE_MUTEX(kprobe_mutex);             /* Protects kprobe_table */
 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
 static struct {
-        spinlock_t lock ____cacheline_aligned;
+        spinlock_t lock ____cacheline_aligned_in_smp;
 } kretprobe_table_locks[KPROBE_TABLE_SIZE];
 
 static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
@@ -613,30 +613,37 @@ static int __kprobes __register_kprobe(struct kprobe *p,
                 return -EINVAL;
         p->addr = addr;
 
-        if (!kernel_text_address((unsigned long) p->addr) ||
-            in_kprobes_functions((unsigned long) p->addr))
+        preempt_disable();
+        if (!__kernel_text_address((unsigned long) p->addr) ||
+            in_kprobes_functions((unsigned long) p->addr)) {
+                preempt_enable();
                 return -EINVAL;
+        }
 
         p->mod_refcounted = 0;
 
         /*
          * Check if are we probing a module.
          */
-        probed_mod = module_text_address((unsigned long) p->addr);
+        probed_mod = __module_text_address((unsigned long) p->addr);
         if (probed_mod) {
-                struct module *calling_mod = module_text_address(called_from);
+                struct module *calling_mod;
+                calling_mod = __module_text_address(called_from);
                 /*
                  * We must allow modules to probe themself and in this case
                  * avoid incrementing the module refcount, so as to allow
                  * unloading of self probing modules.
                  */
                 if (calling_mod && calling_mod != probed_mod) {
-                        if (unlikely(!try_module_get(probed_mod)))
+                        if (unlikely(!try_module_get(probed_mod))) {
+                                preempt_enable();
                                 return -EINVAL;
+                        }
                         p->mod_refcounted = 1;
                 } else
                         probed_mod = NULL;
         }
+        preempt_enable();
 
         p->nmissed = 0;
         INIT_LIST_HEAD(&p->list);
@@ -718,6 +725,10 @@ static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
         struct kprobe *old_p;
 
         if (p->mod_refcounted) {
+                /*
+                 * Since we've already incremented refcount,
+                 * we don't need to disable preemption.
+                 */
                 mod = module_text_address((unsigned long)p->addr);
                 if (mod)
                         module_put(mod);
diff --git a/kernel/sched.c b/kernel/sched.c
index 92992e287b10..204d0662b438 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -399,9 +399,9 @@ struct cfs_rq {
          * 'curr' points to currently running entity on this cfs_rq.
          * It is set to NULL otherwise (i.e when none are currently running).
          */
-        struct sched_entity *curr, *next;
+        struct sched_entity *curr, *next, *last;
 
-        unsigned long nr_spread_over;
+        unsigned int nr_spread_over;
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
         struct rq *rq;  /* cpu runqueue to which this cfs_rq is attached */
@@ -971,6 +971,14 @@ static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
         }
 }
 
+void task_rq_unlock_wait(struct task_struct *p)
+{
+        struct rq *rq = task_rq(p);
+
+        smp_mb(); /* spin-unlock-wait is not a full memory barrier */
+        spin_unlock_wait(&rq->lock);
+}
+
 static void __task_rq_unlock(struct rq *rq)
         __releases(rq->lock)
 {
@@ -1450,6 +1458,8 @@ static unsigned long cpu_avg_load_per_task(int cpu)
 
         if (rq->nr_running)
                 rq->avg_load_per_task = rq->load.weight / rq->nr_running;
+        else
+                rq->avg_load_per_task = 0;
 
         return rq->avg_load_per_task;
 }
@@ -1807,7 +1817,9 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
         /*
          * Buddy candidates are cache hot:
          */
-        if (sched_feat(CACHE_HOT_BUDDY) && (&p->se == cfs_rq_of(&p->se)->next))
+        if (sched_feat(CACHE_HOT_BUDDY) &&
+                        (&p->se == cfs_rq_of(&p->se)->next ||
+                         &p->se == cfs_rq_of(&p->se)->last))
                 return 1;
 
         if (p->sched_class != &fair_sched_class)
@@ -5874,6 +5886,8 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
         struct rq *rq = cpu_rq(cpu);
         unsigned long flags;
 
+        spin_lock_irqsave(&rq->lock, flags);
+
         __sched_fork(idle);
         idle->se.exec_start = sched_clock();
 
@@ -5881,7 +5895,6 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
         idle->cpus_allowed = cpumask_of_cpu(cpu);
         __set_task_cpu(idle, cpu);
 
-        spin_lock_irqsave(&rq->lock, flags);
         rq->curr = rq->idle = idle;
 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
         idle->oncpu = 1;
@@ -6891,15 +6904,17 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
         struct sched_domain *tmp;
 
         /* Remove the sched domains which do not contribute to scheduling. */
-        for (tmp = sd; tmp; tmp = tmp->parent) {
+        for (tmp = sd; tmp; ) {
                 struct sched_domain *parent = tmp->parent;
                 if (!parent)
                         break;
+
                 if (sd_parent_degenerate(tmp, parent)) {
                         tmp->parent = parent->parent;
                         if (parent->parent)
                                 parent->parent->child = tmp;
-                }
+                } else
+                        tmp = tmp->parent;
         }
 
         if (sd && sd_degenerate(sd)) {
@@ -7688,6 +7703,7 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
 error:
         free_sched_groups(cpu_map, tmpmask);
         SCHED_CPUMASK_FREE((void *)allmasks);
+        kfree(rd);
         return -ENOMEM;
 #endif
 }
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 5ae17762ec32..48ecc51e7701 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -144,7 +144,7 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
         last = __pick_last_entity(cfs_rq);
         if (last)
                 max_vruntime = last->vruntime;
-        min_vruntime = rq->cfs.min_vruntime;
+        min_vruntime = cfs_rq->min_vruntime;
         rq0_min_vruntime = per_cpu(runqueues, 0).cfs.min_vruntime;
         spin_unlock_irqrestore(&rq->lock, flags);
         SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "MIN_vruntime",
@@ -161,26 +161,8 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
                         SPLIT_NS(spread0));
         SEQ_printf(m, "  .%-30s: %ld\n", "nr_running", cfs_rq->nr_running);
         SEQ_printf(m, "  .%-30s: %ld\n", "load", cfs_rq->load.weight);
-#ifdef CONFIG_SCHEDSTATS
-#define P(n) SEQ_printf(m, "  .%-30s: %d\n", #n, rq->n);
-
-        P(yld_exp_empty);
-        P(yld_act_empty);
-        P(yld_both_empty);
-        P(yld_count);
 
-        P(sched_switch);
-        P(sched_count);
-        P(sched_goidle);
-
-        P(ttwu_count);
-        P(ttwu_local);
-
-        P(bkl_count);
-
-#undef P
-#endif
-        SEQ_printf(m, "  .%-30s: %ld\n", "nr_spread_over",
+        SEQ_printf(m, "  .%-30s: %d\n", "nr_spread_over",
                         cfs_rq->nr_spread_over);
 #ifdef CONFIG_FAIR_GROUP_SCHED
 #ifdef CONFIG_SMP
@@ -260,6 +242,25 @@ static void print_cpu(struct seq_file *m, int cpu)
 #undef P
 #undef PN
 
+#ifdef CONFIG_SCHEDSTATS
+#define P(n) SEQ_printf(m, "  .%-30s: %d\n", #n, rq->n);
+
+        P(yld_exp_empty);
+        P(yld_act_empty);
+        P(yld_both_empty);
+        P(yld_count);
+
+        P(sched_switch);
+        P(sched_count);
+        P(sched_goidle);
+
+        P(ttwu_count);
+        P(ttwu_local);
+
+        P(bkl_count);
+
+#undef P
+#endif
         print_cfs_stats(m, cpu);
         print_rt_stats(m, cpu);
 
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index ce514afd78ff..98345e45b059 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -341,23 +341,20 @@ static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
                 cfs_rq->rb_leftmost = next_node;
         }
 
-        if (cfs_rq->next == se)
-                cfs_rq->next = NULL;
-
         rb_erase(&se->run_node, &cfs_rq->tasks_timeline);
 }
 
-static inline struct rb_node *first_fair(struct cfs_rq *cfs_rq)
-{
-        return cfs_rq->rb_leftmost;
-}
-
 static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq)
 {
-        return rb_entry(first_fair(cfs_rq), struct sched_entity, run_node);
+        struct rb_node *left = cfs_rq->rb_leftmost;
+
+        if (!left)
+                return NULL;
+
+        return rb_entry(left, struct sched_entity, run_node);
 }
 
-static inline struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
+static struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
 {
         struct rb_node *last = rb_last(&cfs_rq->tasks_timeline);
 
@@ -719,6 +716,15 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)
                 __enqueue_entity(cfs_rq, se);
 }
 
+static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+        if (cfs_rq->last == se)
+                cfs_rq->last = NULL;
+
+        if (cfs_rq->next == se)
+                cfs_rq->next = NULL;
+}
+
 static void
 dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
 {
@@ -741,6 +747,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
 #endif
         }
 
+        clear_buddies(cfs_rq, se);
+
         if (se != cfs_rq->curr)
                 __dequeue_entity(cfs_rq, se);
         account_entity_dequeue(cfs_rq, se);
@@ -794,24 +802,15 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
 static int
 wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se);
 
-static struct sched_entity *
-pick_next(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-        if (!cfs_rq->next || wakeup_preempt_entity(cfs_rq->next, se) == 1)
-                return se;
-
-        return cfs_rq->next;
-}
-
 static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq)
 {
-        struct sched_entity *se = NULL;
+        struct sched_entity *se = __pick_next_entity(cfs_rq);
 
-        if (first_fair(cfs_rq)) {
-                se = __pick_next_entity(cfs_rq);
-                se = pick_next(cfs_rq, se);
-                set_next_entity(cfs_rq, se);
-        }
+        if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, se) < 1)
+                return cfs_rq->next;
+
+        if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, se) < 1)
+                return cfs_rq->last;
 
         return se;
 }
@@ -983,6 +982,8 @@ static void yield_task_fair(struct rq *rq)
         if (unlikely(cfs_rq->nr_running == 1))
                 return;
 
+        clear_buddies(cfs_rq, se);
+
         if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) {
                 update_rq_clock(rq);
                 /*
@@ -1325,26 +1326,53 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
         return 0;
 }
 
+static void set_last_buddy(struct sched_entity *se)
+{
+        for_each_sched_entity(se)
+                cfs_rq_of(se)->last = se;
+}
+
+static void set_next_buddy(struct sched_entity *se)
+{
+        for_each_sched_entity(se)
+                cfs_rq_of(se)->next = se;
+}
+
 /*
  * Preempt the current task with a newly woken task if needed:
  */
 static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
 {
         struct task_struct *curr = rq->curr;
-        struct cfs_rq *cfs_rq = task_cfs_rq(curr);
         struct sched_entity *se = &curr->se, *pse = &p->se;
 
         if (unlikely(rt_prio(p->prio))) {
+                struct cfs_rq *cfs_rq = task_cfs_rq(curr);
+
                 update_rq_clock(rq);
                 update_curr(cfs_rq);
                 resched_task(curr);
                 return;
         }
 
+        if (unlikely(p->sched_class != &fair_sched_class))
+                return;
+
         if (unlikely(se == pse))
                 return;
 
-        cfs_rq_of(pse)->next = pse;
+        /*
+         * Only set the backward buddy when the current task is still on the
+         * rq. This can happen when a wakeup gets interleaved with schedule on
+         * the ->pre_schedule() or idle_balance() point, either of which can
+         * drop the rq lock.
+         *
+         * Also, during early boot the idle thread is in the fair class, for
+         * obvious reasons its a bad idea to schedule back to the idle thread.
+         */
+        if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle))
+                set_last_buddy(se);
+        set_next_buddy(pse);
 
         /*
          * We can come here with TIF_NEED_RESCHED already set from new task
@@ -1396,6 +1424,7 @@ static struct task_struct *pick_next_task_fair(struct rq *rq)
 
         do {
                 se = pick_next_entity(cfs_rq);
+                set_next_entity(cfs_rq, se);
                 cfs_rq = group_cfs_rq(se);
         } while (cfs_rq);
 
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index fda016218296..da5d93b5d2c6 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -12,3 +12,4 @@ SCHED_FEAT(LB_BIAS, 1)
 SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
 SCHED_FEAT(ASYM_EFF_LOAD, 1)
 SCHED_FEAT(WAKEUP_OVERLAP, 0)
+SCHED_FEAT(LAST_BUDDY, 1)
diff --git a/kernel/smp.c b/kernel/smp.c
index f362a8553777..75c8dde58c55 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -51,10 +51,6 @@ static void csd_flag_wait(struct call_single_data *data)
 {
         /* Wait for response */
         do {
-                /*
-                 * We need to see the flags store in the IPI handler
-                 */
-                smp_mb();
                 if (!(data->flags & CSD_FLAG_WAIT))
                         break;
                 cpu_relax();
@@ -76,6 +72,11 @@ static void generic_exec_single(int cpu, struct call_single_data *data)
         list_add_tail(&data->list, &dst->list);
         spin_unlock_irqrestore(&dst->lock, flags);
 
+        /*
+         * Make the list addition visible before sending the ipi.
+         */
+        smp_mb();
+
         if (ipi)
                 arch_send_call_function_single_ipi(cpu);
 
@@ -157,7 +158,7 @@ void generic_smp_call_function_single_interrupt(void)
          * Need to see other stores to list head for checking whether
          * list is empty without holding q->lock
          */
-        smp_mb();
+        smp_read_barrier_depends();
         while (!list_empty(&q->list)) {
                 unsigned int data_flags;
 
@@ -191,7 +192,7 @@ void generic_smp_call_function_single_interrupt(void)
                 /*
                  * See comment on outer loop
                  */
-                smp_mb();
+                smp_read_barrier_depends();
         }
 }
 
@@ -370,6 +371,11 @@ int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info,
         list_add_tail_rcu(&data->csd.list, &call_function_queue);
         spin_unlock_irqrestore(&call_function_lock, flags);
 
+        /*
+         * Make the list addition visible before sending the ipi.
+         */
+        smp_mb();
+
         /* Send a message to all CPUs in the map */
         arch_send_call_function_ipi(mask);
 
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 7110daeb9a90..e7c69a720d69 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -269,10 +269,11 @@ void irq_enter(void)
 {
         int cpu = smp_processor_id();
 
-        if (idle_cpu(cpu) && !in_interrupt())
+        if (idle_cpu(cpu) && !in_interrupt()) {
+                __irq_enter();
                 tick_check_idle(cpu);
-
-        __irq_enter();
+        } else
+                __irq_enter();
 }
 
 #ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 5bbb1044f847..342fc9ccab46 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -568,6 +568,9 @@ static void tick_nohz_switch_to_nohz(void)
  */
 static void tick_nohz_kick_tick(int cpu)
 {
+#if 0
+        /* Switch back to 2.6.27 behaviour */
+
         struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
         ktime_t delta, now;
 
@@ -584,6 +587,7 @@ static void tick_nohz_kick_tick(int cpu)
                 return;
 
         tick_nohz_restart(ts, now);
+#endif
 }
 
 #else
diff --git a/kernel/timer.c b/kernel/timer.c
index b54e4646cee7..566257d1dc10 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -112,27 +112,8 @@ timer_set_base(struct timer_list *timer, struct tvec_base *new_base)
                                       tbase_get_deferrable(timer->base));
 }
 
-/**
- * __round_jiffies - function to round jiffies to a full second
- * @j: the time in (absolute) jiffies that should be rounded
- * @cpu: the processor number on which the timeout will happen
- *
- * __round_jiffies() rounds an absolute time in the future (in jiffies)
- * up or down to (approximately) full seconds. This is useful for timers
- * for which the exact time they fire does not matter too much, as long as
- * they fire approximately every X seconds.
- *
- * By rounding these timers to whole seconds, all such timers will fire
- * at the same time, rather than at various times spread out. The goal
- * of this is to have the CPU wake up less, which saves power.
- *
- * The exact rounding is skewed for each processor to avoid all
- * processors firing at the exact same time, which could lead
- * to lock contention or spurious cache line bouncing.
- *
- * The return value is the rounded version of the @j parameter.
- */
-unsigned long __round_jiffies(unsigned long j, int cpu)
+static unsigned long round_jiffies_common(unsigned long j, int cpu,
+                bool force_up)
 {
         int rem;
         unsigned long original = j;
@@ -154,8 +135,9 @@ unsigned long __round_jiffies(unsigned long j, int cpu)
          * due to delays of the timer irq, long irq off times etc etc) then
          * we should round down to the whole second, not up. Use 1/4th second
          * as cutoff for this rounding as an extreme upper bound for this.
+         * But never round down if @force_up is set.
          */
-        if (rem < HZ/4) /* round down */
+        if (rem < HZ/4 && !force_up) /* round down */
                 j = j - rem;
         else /* round up */
                 j = j - rem + HZ;
@@ -167,6 +149,31 @@ unsigned long __round_jiffies(unsigned long j, int cpu)
                 return original;
         return j;
 }
+
+/**
+ * __round_jiffies - function to round jiffies to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * __round_jiffies() rounds an absolute time in the future (in jiffies)
+ * up or down to (approximately) full seconds. This is useful for timers
+ * for which the exact time they fire does not matter too much, as long as
+ * they fire approximately every X seconds.
+ *
+ * By rounding these timers to whole seconds, all such timers will fire
+ * at the same time, rather than at various times spread out. The goal
+ * of this is to have the CPU wake up less, which saves power.
+ *
+ * The exact rounding is skewed for each processor to avoid all
+ * processors firing at the exact same time, which could lead
+ * to lock contention or spurious cache line bouncing.
+ *
+ * The return value is the rounded version of the @j parameter.
+ */
+unsigned long __round_jiffies(unsigned long j, int cpu)
+{
+        return round_jiffies_common(j, cpu, false);
+}
 EXPORT_SYMBOL_GPL(__round_jiffies);
 
 /**
@@ -191,13 +198,10 @@ EXPORT_SYMBOL_GPL(__round_jiffies);
  */
 unsigned long __round_jiffies_relative(unsigned long j, int cpu)
 {
-        /*
-         * In theory the following code can skip a jiffy in case jiffies
-         * increments right between the addition and the later subtraction.
-         * However since the entire point of this function is to use approximate
-         * timeouts, it's entirely ok to not handle that.
-         */
-        return  __round_jiffies(j + jiffies, cpu) - jiffies;
+        unsigned long j0 = jiffies;
+
+        /* Use j0 because jiffies might change while we run */
+        return round_jiffies_common(j + j0, cpu, false) - j0;
 }
 EXPORT_SYMBOL_GPL(__round_jiffies_relative);
 
@@ -218,7 +222,7 @@ EXPORT_SYMBOL_GPL(__round_jiffies_relative);
  */
 unsigned long round_jiffies(unsigned long j)
 {
-        return __round_jiffies(j, raw_smp_processor_id());
+        return round_jiffies_common(j, raw_smp_processor_id(), false);
 }
 EXPORT_SYMBOL_GPL(round_jiffies);
 
@@ -243,6 +247,71 @@ unsigned long round_jiffies_relative(unsigned long j)
 }
 EXPORT_SYMBOL_GPL(round_jiffies_relative);
 
+/**
+ * __round_jiffies_up - function to round jiffies up to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * This is the same as __round_jiffies() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long __round_jiffies_up(unsigned long j, int cpu)
+{
+        return round_jiffies_common(j, cpu, true);
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_up);
+
+/**
+ * __round_jiffies_up_relative - function to round jiffies up to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * This is the same as __round_jiffies_relative() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long __round_jiffies_up_relative(unsigned long j, int cpu)
+{
+        unsigned long j0 = jiffies;
+
+        /* Use j0 because jiffies might change while we run */
+        return round_jiffies_common(j + j0, cpu, true) - j0;
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_up_relative);
+
+/**
+ * round_jiffies_up - function to round jiffies up to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ *
+ * This is the same as round_jiffies() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long round_jiffies_up(unsigned long j)
+{
+        return round_jiffies_common(j, raw_smp_processor_id(), true);
+}
+EXPORT_SYMBOL_GPL(round_jiffies_up);
+
+/**
+ * round_jiffies_up_relative - function to round jiffies up to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ *
+ * This is the same as round_jiffies_relative() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long round_jiffies_up_relative(unsigned long j)
+{
+        return __round_jiffies_up_relative(j, raw_smp_processor_id());
+}
+EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
+
 
 static inline void set_running_timer(struct tvec_base *base,
                                         struct timer_list *timer)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 3f3380638646..2f76193c3489 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1060,7 +1060,7 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
 
                 /* Did the write stamp get updated already? */
                 if (unlikely(ts < cpu_buffer->write_stamp))
-                        goto again;
+                        delta = 0;
 
                 if (test_time_stamp(delta)) {
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 5c97c5b4ea8f..ffe7c96fa09b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1755,7 +1755,7 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
                 return TRACE_TYPE_HANDLED;
 
         SEQ_PUT_FIELD_RET(s, entry->pid);
-        SEQ_PUT_FIELD_RET(s, iter->cpu);
+        SEQ_PUT_FIELD_RET(s, entry->cpu);
         SEQ_PUT_FIELD_RET(s, iter->ts);
 
         switch (entry->type) {
@@ -2676,7 +2676,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
 {
         unsigned long val;
         char buf[64];
-        int ret;
+        int ret, cpu;
         struct trace_array *tr = filp->private_data;
 
         if (cnt >= sizeof(buf))
@@ -2704,6 +2704,14 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
                 goto out;
         }
 
+        /* disable all cpu buffers */
+        for_each_tracing_cpu(cpu) {
+                if (global_trace.data[cpu])
+                        atomic_inc(&global_trace.data[cpu]->disabled);
+                if (max_tr.data[cpu])
+                        atomic_inc(&max_tr.data[cpu]->disabled);
+        }
+
         if (val != global_trace.entries) {
                 ret = ring_buffer_resize(global_trace.buffer, val);
                 if (ret < 0) {
@@ -2735,6 +2743,13 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
         if (tracing_disabled)
                 cnt = -ENOMEM;
  out:
+        for_each_tracing_cpu(cpu) {
+                if (global_trace.data[cpu])
+                        atomic_dec(&global_trace.data[cpu]->disabled);
+                if (max_tr.data[cpu])
+                        atomic_dec(&max_tr.data[cpu]->disabled);
+        }
+
         max_tr.entries = global_trace.entries;
         mutex_unlock(&trace_types_lock);
 
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index f12ab5c4dec4..4952322cba45 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -970,6 +970,51 @@ undo:
         return ret;
 }
 
+#ifdef CONFIG_SMP
+struct work_for_cpu {
+        struct work_struct work;
+        long (*fn)(void *);
+        void *arg;
+        long ret;
+};
+
+static void do_work_for_cpu(struct work_struct *w)
+{
+        struct work_for_cpu *wfc = container_of(w, struct work_for_cpu, work);
+
+        wfc->ret = wfc->fn(wfc->arg);
+}
+
+/**
+ * work_on_cpu - run a function in user context on a particular cpu
+ * @cpu: the cpu to run on
+ * @fn: the function to run
+ * @arg: the function arg
+ *
+ * This will return -EINVAL in the cpu is not online, or the return value
+ * of @fn otherwise.
+ */
+long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
+{
+        struct work_for_cpu wfc;
+
+        INIT_WORK(&wfc.work, do_work_for_cpu);
+        wfc.fn = fn;
+        wfc.arg = arg;
+        get_online_cpus();
+        if (unlikely(!cpu_online(cpu)))
+                wfc.ret = -EINVAL;
+        else {
+                schedule_work_on(cpu, &wfc.work);
+                flush_work(&wfc.work);
+        }
+        put_online_cpus();
+
+        return wfc.ret;
+}
+EXPORT_SYMBOL_GPL(work_on_cpu);
+#endif /* CONFIG_SMP */
+
 void __init init_workqueues(void)
 {
         cpu_populated_map = cpu_online_map;