10 files changed, 361 insertions, 168 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index d5ab79cf516d..f227bc172690 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -14,6 +14,8 @@
  *  2003-10-22 Updates by Stephen Hemminger.
  *  2004 May-July Rework by Paul Jackson.
  *  2006 Rework by Paul Menage to use generic cgroups
+ *  2008 Rework of the scheduler domains and CPU hotplug handling
+ *       by Max Krasnyansky
  *
  *  This file is subject to the terms and conditions of the GNU General Public
  *  License.  See the file COPYING in the main directory of the Linux
@@ -236,9 +238,11 @@ static struct cpuset top_cpuset = {
 
 static DEFINE_MUTEX(callback_mutex);
 
-/* This is ugly, but preserves the userspace API for existing cpuset
+/*
+ * This is ugly, but preserves the userspace API for existing cpuset
  * users. If someone tries to mount the "cpuset" filesystem, we
- * silently switch it to mount "cgroup" instead */
+ * silently switch it to mount "cgroup" instead
+ */
 static int cpuset_get_sb(struct file_system_type *fs_type,
                          int flags, const char *unused_dev_name,
                          void *data, struct vfsmount *mnt)
@@ -473,10 +477,9 @@ static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
 }
 
 /*
- * Helper routine for rebuild_sched_domains().
+ * Helper routine for generate_sched_domains().
  * Do cpusets a, b have overlapping cpus_allowed masks?
  */
-
 static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
 {
         return cpus_intersects(a->cpus_allowed, b->cpus_allowed);
@@ -518,26 +521,15 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)
 }
 
 /*
- * rebuild_sched_domains()
- *
- * This routine will be called to rebuild the scheduler's dynamic
- * sched domains:
- * - if the flag 'sched_load_balance' of any cpuset with non-empty
- *   'cpus' changes,
- * - or if the 'cpus' allowed changes in any cpuset which has that
- *   flag enabled,
- * - or if the 'sched_relax_domain_level' of any cpuset which has
- *   that flag enabled and with non-empty 'cpus' changes,
- * - or if any cpuset with non-empty 'cpus' is removed,
- * - or if a cpu gets offlined.
- *
- * This routine builds a partial partition of the systems CPUs
- * (the set of non-overlappping cpumask_t's in the array 'part'
- * below), and passes that partial partition to the kernel/sched.c
- * partition_sched_domains() routine, which will rebuild the
- * schedulers load balancing domains (sched domains) as specified
- * by that partial partition.  A 'partial partition' is a set of
- * non-overlapping subsets whose union is a subset of that set.
+ * generate_sched_domains()
+ *
+ * This function builds a partial partition of the systems CPUs
+ * A 'partial partition' is a set of non-overlapping subsets whose
+ * union is a subset of that set.
+ * The output of this function needs to be passed to kernel/sched.c
+ * partition_sched_domains() routine, which will rebuild the scheduler's
+ * load balancing domains (sched domains) as specified by that partial
+ * partition.
  *
  * See "What is sched_load_balance" in Documentation/cpusets.txt
  * for a background explanation of this.
@@ -547,13 +539,7 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)
  * domains when operating in the severe memory shortage situations
  * that could cause allocation failures below.
  *
- * Call with cgroup_mutex held.  May take callback_mutex during
- * call due to the kfifo_alloc() and kmalloc() calls.  May nest
- * a call to the get_online_cpus()/put_online_cpus() pair.
- * Must not be called holding callback_mutex, because we must not
- * call get_online_cpus() while holding callback_mutex.  Elsewhere
- * the kernel nests callback_mutex inside get_online_cpus() calls.
- * So the reverse nesting would risk an ABBA deadlock.
+ * Must be called with cgroup_lock held.
  *
  * The three key local variables below are:
  *    q  - a linked-list queue of cpuset pointers, used to implement a
@@ -588,10 +574,10 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)
  *      element of the partition (one sched domain) to be passed to
  *      partition_sched_domains().
  */
-
-void rebuild_sched_domains(void)
+static int generate_sched_domains(cpumask_t **domains,
+                        struct sched_domain_attr **attributes)
 {
-        LIST_HEAD(q);           /* queue of cpusets to be scanned*/
+        LIST_HEAD(q);           /* queue of cpusets to be scanned */
         struct cpuset *cp;      /* scans q */
         struct cpuset **csa;    /* array of all cpuset ptrs */
         int csn;                /* how many cpuset ptrs in csa so far */
@@ -601,23 +587,26 @@ void rebuild_sched_domains(void)
         int ndoms;              /* number of sched domains in result */
         int nslot;              /* next empty doms[] cpumask_t slot */
 
-        csa = NULL;
+        ndoms = 0;
         doms = NULL;
         dattr = NULL;
+        csa = NULL;
 
         /* Special case for the 99% of systems with one, full, sched domain */
         if (is_sched_load_balance(&top_cpuset)) {
-                ndoms = 1;
                 doms = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
                 if (!doms)
-                        goto rebuild;
+                        goto done;
+
                 dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
                 if (dattr) {
                         *dattr = SD_ATTR_INIT;
                         update_domain_attr_tree(dattr, &top_cpuset);
                 }
                 *doms = top_cpuset.cpus_allowed;
-                goto rebuild;
+
+                ndoms = 1;
+                goto done;
         }
 
         csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL);
@@ -680,61 +669,141 @@ restart:
                 }
         }
 
-        /* Convert <csn, csa> to <ndoms, doms> */
+        /*
+         * Now we know how many domains to create.
+         * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
+         */
         doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL);
-        if (!doms)
-                goto rebuild;
+        if (!doms) {
+                ndoms = 0;
+                goto done;
+        }
+
+        /*
+         * The rest of the code, including the scheduler, can deal with
+         * dattr==NULL case. No need to abort if alloc fails.
+         */
         dattr = kmalloc(ndoms * sizeof(struct sched_domain_attr), GFP_KERNEL);
 
         for (nslot = 0, i = 0; i < csn; i++) {
                 struct cpuset *a = csa[i];
+                cpumask_t *dp;
                 int apn = a->pn;
 
-                if (apn >= 0) {
-                        cpumask_t *dp = doms + nslot;
-
-                        if (nslot == ndoms) {
-                                static int warnings = 10;
-                                if (warnings) {
-                                        printk(KERN_WARNING
-                                         "rebuild_sched_domains confused:"
-                                          " nslot %d, ndoms %d, csn %d, i %d,"
-                                          " apn %d\n",
-                                          nslot, ndoms, csn, i, apn);
-                                        warnings--;
-                                }
-                                continue;
+                if (apn < 0) {
+                        /* Skip completed partitions */
+                        continue;
+                }
+
+                dp = doms + nslot;
+
+                if (nslot == ndoms) {
+                        static int warnings = 10;
+                        if (warnings) {
+                                printk(KERN_WARNING
+                                 "rebuild_sched_domains confused:"
+                                  " nslot %d, ndoms %d, csn %d, i %d,"
+                                  " apn %d\n",
+                                  nslot, ndoms, csn, i, apn);
+                                warnings--;
                         }
+                        continue;
+                }
 
-                        cpus_clear(*dp);
-                        if (dattr)
-                                *(dattr + nslot) = SD_ATTR_INIT;
-                        for (j = i; j < csn; j++) {
-                                struct cpuset *b = csa[j];
-
-                                if (apn == b->pn) {
-                                        cpus_or(*dp, *dp, b->cpus_allowed);
-                                        b->pn = -1;
-                                        if (dattr)
-                                                update_domain_attr_tree(dattr
-                                                                   + nslot, b);
-                                }
+                cpus_clear(*dp);
+                if (dattr)
+                        *(dattr + nslot) = SD_ATTR_INIT;
+                for (j = i; j < csn; j++) {
+                        struct cpuset *b = csa[j];
+
+                        if (apn == b->pn) {
+                                cpus_or(*dp, *dp, b->cpus_allowed);
+                                if (dattr)
+                                        update_domain_attr_tree(dattr + nslot, b);
+
+                                /* Done with this partition */
+                                b->pn = -1;
                         }
-                        nslot++;
                 }
+                nslot++;
         }
         BUG_ON(nslot != ndoms);
 
-rebuild:
-        /* Have scheduler rebuild sched domains */
+done:
+        kfree(csa);
+
+        *domains    = doms;
+        *attributes = dattr;
+        return ndoms;
+}
+
+/*
+ * Rebuild scheduler domains.
+ *
+ * Call with neither cgroup_mutex held nor within get_online_cpus().
+ * Takes both cgroup_mutex and get_online_cpus().
+ *
+ * Cannot be directly called from cpuset code handling changes
+ * to the cpuset pseudo-filesystem, because it cannot be called
+ * from code that already holds cgroup_mutex.
+ */
+static void do_rebuild_sched_domains(struct work_struct *unused)
+{
+        struct sched_domain_attr *attr;
+        cpumask_t *doms;
+        int ndoms;
+
         get_online_cpus();
-        partition_sched_domains(ndoms, doms, dattr);
+
+        /* Generate domain masks and attrs */
+        cgroup_lock();
+        ndoms = generate_sched_domains(&doms, &attr);
+        cgroup_unlock();
+
+        /* Have scheduler rebuild the domains */
+        partition_sched_domains(ndoms, doms, attr);
+
         put_online_cpus();
+}
 
-done:
-        kfree(csa);
-        /* Don't kfree(doms) -- partition_sched_domains() does that. */
-        /* Don't kfree(dattr) -- partition_sched_domains() does that. */
+static DECLARE_WORK(rebuild_sched_domains_work, do_rebuild_sched_domains);
+
+/*
+ * Rebuild scheduler domains, asynchronously via workqueue.
+ *
+ * If the flag 'sched_load_balance' of any cpuset with non-empty
+ * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
+ * which has that flag enabled, or if any cpuset with a non-empty
+ * 'cpus' is removed, then call this routine to rebuild the
+ * scheduler's dynamic sched domains.
+ *
+ * The rebuild_sched_domains() and partition_sched_domains()
+ * routines must nest cgroup_lock() inside get_online_cpus(),
+ * but such cpuset changes as these must nest that locking the
+ * other way, holding cgroup_lock() for much of the code.
+ *
+ * So in order to avoid an ABBA deadlock, the cpuset code handling
+ * these user changes delegates the actual sched domain rebuilding
+ * to a separate workqueue thread, which ends up processing the
+ * above do_rebuild_sched_domains() function.
+ */
+static void async_rebuild_sched_domains(void)
+{
+        schedule_work(&rebuild_sched_domains_work);
+}
+
+/*
+ * Accomplishes the same scheduler domain rebuild as the above
+ * async_rebuild_sched_domains(), however it directly calls the
+ * rebuild routine synchronously rather than calling it via an
+ * asynchronous work thread.
+ *
+ * This can only be called from code that is not holding
+ * cgroup_mutex (not nested in a cgroup_lock() call.)
+ */
+void rebuild_sched_domains(void)
+{
+        do_rebuild_sched_domains(NULL);
 }
 
 /**
@@ -863,7 +932,7 @@ static int update_cpumask(struct cpuset *cs, const char *buf)
                 return retval;
 
         if (is_load_balanced)
-                rebuild_sched_domains();
+                async_rebuild_sched_domains();
         return 0;
 }
 
@@ -1090,7 +1159,7 @@ static int update_relax_domain_level(struct cpuset *cs, s64 val)
         if (val != cs->relax_domain_level) {
                 cs->relax_domain_level = val;
                 if (!cpus_empty(cs->cpus_allowed) && is_sched_load_balance(cs))
-                        rebuild_sched_domains();
+                        async_rebuild_sched_domains();
         }
 
         return 0;
@@ -1131,7 +1200,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
         mutex_unlock(&callback_mutex);
 
         if (cpus_nonempty && balance_flag_changed)
-                rebuild_sched_domains();
+                async_rebuild_sched_domains();
 
         return 0;
 }
@@ -1492,6 +1561,9 @@ static u64 cpuset_read_u64(struct cgroup *cont, struct cftype *cft)
         default:
                 BUG();
         }
+
+        /* Unreachable but makes gcc happy */
+        return 0;
 }
 
 static s64 cpuset_read_s64(struct cgroup *cont, struct cftype *cft)
@@ -1504,6 +1576,9 @@ static s64 cpuset_read_s64(struct cgroup *cont, struct cftype *cft)
         default:
                 BUG();
         }
+
+        /* Unrechable but makes gcc happy */
+        return 0;
 }
 
 
@@ -1692,15 +1767,9 @@ static struct cgroup_subsys_state *cpuset_create(
 }
 
 /*
- * Locking note on the strange update_flag() call below:
- *
  * If the cpuset being removed has its flag 'sched_load_balance'
  * enabled, then simulate turning sched_load_balance off, which
- * will call rebuild_sched_domains().  The get_online_cpus()
- * call in rebuild_sched_domains() must not be made while holding
- * callback_mutex.  Elsewhere the kernel nests callback_mutex inside
- * get_online_cpus() calls.  So the reverse nesting would risk an
- * ABBA deadlock.
+ * will call async_rebuild_sched_domains().
  */
 
 static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
@@ -1719,7 +1788,7 @@ static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
 struct cgroup_subsys cpuset_subsys = {
         .name = "cpuset",
         .create = cpuset_create,
-        .destroy  = cpuset_destroy,
+        .destroy = cpuset_destroy,
         .can_attach = cpuset_can_attach,
         .attach = cpuset_attach,
         .populate = cpuset_populate,
@@ -1811,7 +1880,7 @@ static void move_member_tasks_to_cpuset(struct cpuset *from, struct cpuset *to)
 }
 
 /*
- * If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs
+ * If CPU and/or memory hotplug handlers, below, unplug any CPUs
  * or memory nodes, we need to walk over the cpuset hierarchy,
  * removing that CPU or node from all cpusets.  If this removes the
  * last CPU or node from a cpuset, then move the tasks in the empty
@@ -1903,35 +1972,6 @@ static void scan_for_empty_cpusets(const struct cpuset *root)
 }
 
 /*
- * The cpus_allowed and mems_allowed nodemasks in the top_cpuset track
- * cpu_online_map and node_states[N_HIGH_MEMORY].  Force the top cpuset to
- * track what's online after any CPU or memory node hotplug or unplug event.
- *
- * Since there are two callers of this routine, one for CPU hotplug
- * events and one for memory node hotplug events, we could have coded
- * two separate routines here.  We code it as a single common routine
- * in order to minimize text size.
- */
-
-static void common_cpu_mem_hotplug_unplug(int rebuild_sd)
-{
-        cgroup_lock();
-
-        top_cpuset.cpus_allowed = cpu_online_map;
-        top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
-        scan_for_empty_cpusets(&top_cpuset);
-
-        /*
-         * Scheduler destroys domains on hotplug events.
-         * Rebuild them based on the current settings.
-         */
-        if (rebuild_sd)
-                rebuild_sched_domains();
-
-        cgroup_unlock();
-}
-
-/*
  * The top_cpuset tracks what CPUs and Memory Nodes are online,
  * period.  This is necessary in order to make cpusets transparent
  * (of no affect) on systems that are actively using CPU hotplug
@@ -1939,40 +1979,52 @@ static void common_cpu_mem_hotplug_unplug(int rebuild_sd)
  *
  * This routine ensures that top_cpuset.cpus_allowed tracks
  * cpu_online_map on each CPU hotplug (cpuhp) event.
+ *
+ * Called within get_online_cpus().  Needs to call cgroup_lock()
+ * before calling generate_sched_domains().
  */
-
-static int cpuset_handle_cpuhp(struct notifier_block *unused_nb,
+static int cpuset_track_online_cpus(struct notifier_block *unused_nb,
                                 unsigned long phase, void *unused_cpu)
 {
+        struct sched_domain_attr *attr;
+        cpumask_t *doms;
+        int ndoms;
+
         switch (phase) {
-        case CPU_UP_CANCELED:
-        case CPU_UP_CANCELED_FROZEN:
-        case CPU_DOWN_FAILED:
-        case CPU_DOWN_FAILED_FROZEN:
         case CPU_ONLINE:
         case CPU_ONLINE_FROZEN:
         case CPU_DEAD:
         case CPU_DEAD_FROZEN:
-                common_cpu_mem_hotplug_unplug(1);
                 break;
+
         default:
                 return NOTIFY_DONE;
         }
 
+        cgroup_lock();
+        top_cpuset.cpus_allowed = cpu_online_map;
+        scan_for_empty_cpusets(&top_cpuset);
+        ndoms = generate_sched_domains(&doms, &attr);
+        cgroup_unlock();
+
+        /* Have scheduler rebuild the domains */
+        partition_sched_domains(ndoms, doms, attr);
+
         return NOTIFY_OK;
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
 /*
  * Keep top_cpuset.mems_allowed tracking node_states[N_HIGH_MEMORY].
- * Call this routine anytime after you change
- * node_states[N_HIGH_MEMORY].
- * See also the previous routine cpuset_handle_cpuhp().
+ * Call this routine anytime after node_states[N_HIGH_MEMORY] changes.
+ * See also the previous routine cpuset_track_online_cpus().
  */
-
 void cpuset_track_online_nodes(void)
 {
-        common_cpu_mem_hotplug_unplug(0);
+        cgroup_lock();
+        top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
+        scan_for_empty_cpusets(&top_cpuset);
+        cgroup_unlock();
 }
 #endif
 
@@ -1987,7 +2039,7 @@ void __init cpuset_init_smp(void)
         top_cpuset.cpus_allowed = cpu_online_map;
         top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
 
-        hotcpu_notifier(cpuset_handle_cpuhp, 0);
+        hotcpu_notifier(cpuset_track_online_cpus, 0);
 }
 
 /**
diff --git a/kernel/exit.c b/kernel/exit.c
index 25ed2ad986df..16395644a98f 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -112,9 +112,9 @@ static void __exit_signal(struct task_struct *tsk)
                  * We won't ever get here for the group leader, since it
                  * will have been the last reference on the signal_struct.
                  */
-                sig->utime = cputime_add(sig->utime, tsk->utime);
-                sig->stime = cputime_add(sig->stime, tsk->stime);
-                sig->gtime = cputime_add(sig->gtime, tsk->gtime);
+                sig->utime = cputime_add(sig->utime, task_utime(tsk));
+                sig->stime = cputime_add(sig->stime, task_stime(tsk));
+                sig->gtime = cputime_add(sig->gtime, task_gtime(tsk));
                 sig->min_flt += tsk->min_flt;
                 sig->maj_flt += tsk->maj_flt;
                 sig->nvcsw += tsk->nvcsw;
diff --git a/kernel/sched.c b/kernel/sched.c
index 9a1ddb84e26d..cc1f81b50b82 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4179,6 +4179,65 @@ void account_steal_time(struct task_struct *p, cputime_t steal)
 }
 
 /*
+ * Use precise platform statistics if available:
+ */
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+cputime_t task_utime(struct task_struct *p)
+{
+        return p->utime;
+}
+
+cputime_t task_stime(struct task_struct *p)
+{
+        return p->stime;
+}
+#else
+cputime_t task_utime(struct task_struct *p)
+{
+        clock_t utime = cputime_to_clock_t(p->utime),
+                total = utime + cputime_to_clock_t(p->stime);
+        u64 temp;
+
+        /*
+         * Use CFS's precise accounting:
+         */
+        temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
+
+        if (total) {
+                temp *= utime;
+                do_div(temp, total);
+        }
+        utime = (clock_t)temp;
+
+        p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime));
+        return p->prev_utime;
+}
+
+cputime_t task_stime(struct task_struct *p)
+{
+        clock_t stime;
+
+        /*
+         * Use CFS's precise accounting. (we subtract utime from
+         * the total, to make sure the total observed by userspace
+         * grows monotonically - apps rely on that):
+         */
+        stime = nsec_to_clock_t(p->se.sum_exec_runtime) -
+                        cputime_to_clock_t(task_utime(p));
+
+        if (stime >= 0)
+                p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime));
+
+        return p->prev_stime;
+}
+#endif
+
+inline cputime_t task_gtime(struct task_struct *p)
+{
+        return p->gtime;
+}
+
+/*
  * This function gets called by the timer code, with HZ frequency.
  * We call it with interrupts disabled.
  *
@@ -7637,24 +7696,27 @@ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
  * and partition_sched_domains() will fallback to the single partition
  * 'fallback_doms', it also forces the domains to be rebuilt.
  *
+ * If doms_new==NULL it will be replaced with cpu_online_map.
+ * ndoms_new==0 is a special case for destroying existing domains.
+ * It will not create the default domain.
+ *
  * Call with hotplug lock held
  */
 void partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
                              struct sched_domain_attr *dattr_new)
 {
-        int i, j;
+        int i, j, n;
 
         mutex_lock(&sched_domains_mutex);
 
         /* always unregister in case we don't destroy any domains */
         unregister_sched_domain_sysctl();
 
-        if (doms_new == NULL)
-                ndoms_new = 0;
+        n = doms_new ? ndoms_new : 0;
 
         /* Destroy deleted domains */
         for (i = 0; i < ndoms_cur; i++) {
-                for (j = 0; j < ndoms_new; j++) {
+                for (j = 0; j < n; j++) {
                         if (cpus_equal(doms_cur[i], doms_new[j])
                             && dattrs_equal(dattr_cur, i, dattr_new, j))
                                 goto match1;
@@ -7667,7 +7729,6 @@ match1:
 
         if (doms_new == NULL) {
                 ndoms_cur = 0;
-                ndoms_new = 1;
                 doms_new = &fallback_doms;
                 cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
                 dattr_new = NULL;
@@ -7704,8 +7765,13 @@ match2:
 int arch_reinit_sched_domains(void)
 {
         get_online_cpus();
+
+        /* Destroy domains first to force the rebuild */
+        partition_sched_domains(0, NULL, NULL);
+
         rebuild_sched_domains();
         put_online_cpus();
+
         return 0;
 }
 
@@ -7789,7 +7855,7 @@ static int update_sched_domains(struct notifier_block *nfb,
         case CPU_ONLINE_FROZEN:
         case CPU_DEAD:
         case CPU_DEAD_FROZEN:
-                partition_sched_domains(0, NULL, NULL);
+                partition_sched_domains(1, NULL, NULL);
                 return NOTIFY_OK;
 
         default:
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 3d1e3e1a1971..1876b526c778 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -177,7 +177,7 @@ void clockevents_register_device(struct clock_event_device *dev)
 /*
  * Noop handler when we shut down an event device
  */
-static void clockevents_handle_noop(struct clock_event_device *dev)
+void clockevents_handle_noop(struct clock_event_device *dev)
 {
 }
 
@@ -199,7 +199,6 @@ void clockevents_exchange_device(struct clock_event_device *old,
          * released list and do a notify add later.
          */
         if (old) {
-                old->event_handler = clockevents_handle_noop;
                 clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
                 list_del(&old->list);
                 list_add(&old->list, &clockevents_released);
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 5125ddd8196b..1ad46f3df6e7 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -245,7 +245,7 @@ static void sync_cmos_clock(unsigned long dummy)
         if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
                 fail = update_persistent_clock(now);
 
-        next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec;
+        next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);
         if (next.tv_nsec <= 0)
                 next.tv_nsec += NSEC_PER_SEC;
 
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 31463d370b94..2f5a38294bf9 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -175,6 +175,8 @@ static void tick_do_periodic_broadcast(void)
  */
 static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
 {
+        ktime_t next;
+
         tick_do_periodic_broadcast();
 
         /*
@@ -185,10 +187,13 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
 
         /*
          * Setup the next period for devices, which do not have
-         * periodic mode:
+         * periodic mode. We read dev->next_event first and add to it
+         * when the event alrady expired. clockevents_program_event()
+         * sets dev->next_event only when the event is really
+         * programmed to the device.
          */
-        for (;;) {
-                ktime_t next = ktime_add(dev->next_event, tick_period);
+        for (next = dev->next_event; ;) {
+                next = ktime_add(next, tick_period);
 
                 if (!clockevents_program_event(dev, next, ktime_get()))
                         return;
@@ -205,7 +210,7 @@ static void tick_do_broadcast_on_off(void *why)
         struct clock_event_device *bc, *dev;
         struct tick_device *td;
         unsigned long flags, *reason = why;
-        int cpu;
+        int cpu, bc_stopped;
 
         spin_lock_irqsave(&tick_broadcast_lock, flags);
 
@@ -223,6 +228,8 @@ static void tick_do_broadcast_on_off(void *why)
         if (!tick_device_is_functional(dev))
                 goto out;
 
+        bc_stopped = cpus_empty(tick_broadcast_mask);
+
         switch (*reason) {
         case CLOCK_EVT_NOTIFY_BROADCAST_ON:
         case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
@@ -245,9 +252,10 @@ static void tick_do_broadcast_on_off(void *why)
                 break;
         }
 
-        if (cpus_empty(tick_broadcast_mask))
-                clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
-        else {
+        if (cpus_empty(tick_broadcast_mask)) {
+                if (!bc_stopped)
+                        clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+        } else if (bc_stopped) {
                 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
                         tick_broadcast_start_periodic(bc);
                 else
@@ -364,16 +372,8 @@ cpumask_t *tick_get_broadcast_oneshot_mask(void)
 static int tick_broadcast_set_event(ktime_t expires, int force)
 {
         struct clock_event_device *bc = tick_broadcast_device.evtdev;
-        ktime_t now = ktime_get();
-        int res;
-
-        for(;;) {
-                res = clockevents_program_event(bc, expires, now);
-                if (!res || !force)
-                        return res;
-                now = ktime_get();
-                expires = ktime_add(now, ktime_set(0, bc->min_delta_ns));
-        }
+
+        return tick_dev_program_event(bc, expires, force);
 }
 
 int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
@@ -491,14 +491,52 @@ static void tick_broadcast_clear_oneshot(int cpu)
         cpu_clear(cpu, tick_broadcast_oneshot_mask);
 }
 
+static void tick_broadcast_init_next_event(cpumask_t *mask, ktime_t expires)
+{
+        struct tick_device *td;
+        int cpu;
+
+        for_each_cpu_mask_nr(cpu, *mask) {
+                td = &per_cpu(tick_cpu_device, cpu);
+                if (td->evtdev)
+                        td->evtdev->next_event = expires;
+        }
+}
+
 /**
  * tick_broadcast_setup_oneshot - setup the broadcast device
  */
 void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 {
-        bc->event_handler = tick_handle_oneshot_broadcast;
-        clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
-        bc->next_event.tv64 = KTIME_MAX;
+        /* Set it up only once ! */
+        if (bc->event_handler != tick_handle_oneshot_broadcast) {
+                int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
+                int cpu = smp_processor_id();
+                cpumask_t mask;
+
+                bc->event_handler = tick_handle_oneshot_broadcast;
+                clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
+
+                /* Take the do_timer update */
+                tick_do_timer_cpu = cpu;
+
+                /*
+                 * We must be careful here. There might be other CPUs
+                 * waiting for periodic broadcast. We need to set the
+                 * oneshot_mask bits for those and program the
+                 * broadcast device to fire.
+                 */
+                mask = tick_broadcast_mask;
+                cpu_clear(cpu, mask);
+                cpus_or(tick_broadcast_oneshot_mask,
+                        tick_broadcast_oneshot_mask, mask);
+
+                if (was_periodic && !cpus_empty(mask)) {
+                        tick_broadcast_init_next_event(&mask, tick_next_period);
+                        tick_broadcast_set_event(tick_next_period, 1);
+                } else
+                        bc->next_event.tv64 = KTIME_MAX;
+        }
 }
 
 /*
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 80c4336f4188..c4777193d567 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -161,6 +161,7 @@ static void tick_setup_device(struct tick_device *td,
         } else {
                 handler = td->evtdev->event_handler;
                 next_event = td->evtdev->next_event;
+                td->evtdev->event_handler = clockevents_handle_noop;
         }
 
         td->evtdev = newdev;
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index f13f2b7f4fd4..0ffc2918ea6f 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -17,6 +17,8 @@ extern void tick_handle_periodic(struct clock_event_device *dev);
 extern void tick_setup_oneshot(struct clock_event_device *newdev,
                                void (*handler)(struct clock_event_device *),
                                ktime_t nextevt);
+extern int tick_dev_program_event(struct clock_event_device *dev,
+                                  ktime_t expires, int force);
 extern int tick_program_event(ktime_t expires, int force);
 extern void tick_oneshot_notify(void);
 extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *));
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index 450c04935b66..2e8de678e767 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -23,24 +23,56 @@
 #include "tick-internal.h"
 
 /**
- * tick_program_event
+ * tick_program_event internal worker function
  */
-int tick_program_event(ktime_t expires, int force)
+int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires,
+                           int force)
 {
-        struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
         ktime_t now = ktime_get();
+        int i;
 
-        while (1) {
+        for (i = 0;;) {
                 int ret = clockevents_program_event(dev, expires, now);
 
                 if (!ret || !force)
                         return ret;
+
+                /*
+                 * We tried 2 times to program the device with the given
+                 * min_delta_ns. If that's not working then we double it
+                 * and emit a warning.
+                 */
+                if (++i > 2) {
+                        /* Increase the min. delta and try again */
+                        if (!dev->min_delta_ns)
+                                dev->min_delta_ns = 5000;
+                        else
+                                dev->min_delta_ns += dev->min_delta_ns >> 1;
+
+                        printk(KERN_WARNING
+                               "CE: %s increasing min_delta_ns to %lu nsec\n",
+                               dev->name ? dev->name : "?",
+                               dev->min_delta_ns << 1);
+
+                        i = 0;
+                }
+
                 now = ktime_get();
-                expires = ktime_add(now, ktime_set(0, dev->min_delta_ns));
+                expires = ktime_add_ns(now, dev->min_delta_ns);
         }
 }
 
 /**
+ * tick_program_event
+ */
+int tick_program_event(ktime_t expires, int force)
+{
+        struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
+
+        return tick_dev_program_event(dev, expires, force);
+}
+
+/**
  * tick_resume_onshot - resume oneshot mode
  */
 void tick_resume_oneshot(void)
@@ -61,7 +93,7 @@ void tick_setup_oneshot(struct clock_event_device *newdev,
 {
         newdev->event_handler = handler;
         clockevents_set_mode(newdev, CLOCK_EVT_MODE_ONESHOT);
-        clockevents_program_event(newdev, next_event, ktime_get());
+        tick_dev_program_event(newdev, next_event, 1);
 }
 
 /**
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 7a46bde78c66..a87b0468568b 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -162,6 +162,8 @@ void tick_nohz_stop_idle(int cpu)
                 ts->idle_lastupdate = now;
                 ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
                 ts->idle_active = 0;
+
+                sched_clock_idle_wakeup_event(0);
         }
 }
 
@@ -177,6 +179,7 @@ static ktime_t tick_nohz_start_idle(struct tick_sched *ts)
         }
         ts->idle_entrytime = now;
         ts->idle_active = 1;
+        sched_clock_idle_sleep_event();
         return now;
 }