Merge commit 'v2.6.27-rc8' into core/rcu

kernel/cgroup.c

@@ -2738,14 +2738,15 @@ void cgroup_fork_callbacks(struct task_struct *child)
  */
 void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new)
 {
-	struct cgroup *oldcgrp, *newcgrp;
+	struct cgroup *oldcgrp, *newcgrp = NULL;
 
 	if (need_mm_owner_callback) {
 		int i;
 		for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
 			struct cgroup_subsys *ss = subsys[i];
 			oldcgrp = task_cgroup(old, ss->subsys_id);
-			newcgrp = task_cgroup(new, ss->subsys_id);
+			if (new)
+				newcgrp = task_cgroup(new, ss->subsys_id);
 			if (oldcgrp == newcgrp)
 				continue;
 			if (ss->mm_owner_changed)

kernel/cpuset.c

@@ -843,37 +843,25 @@ static void cpuset_change_cpumask(struct task_struct *tsk,
 /**
  * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
  * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
+ * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
  *
  * Called with cgroup_mutex held
  *
  * The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
  * calling callback functions for each.
  *
- * Return 0 if successful, -errno if not.
+ * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0
+ * if @heap != NULL.
  */
-static int update_tasks_cpumask(struct cpuset *cs)
+static void update_tasks_cpumask(struct cpuset *cs, struct ptr_heap *heap)
 {
 	struct cgroup_scanner scan;
-	struct ptr_heap heap;
-	int retval;
-
-	/*
-	 * cgroup_scan_tasks() will initialize heap->gt for us.
-	 * heap_init() is still needed here for we should not change
-	 * cs->cpus_allowed when heap_init() fails.
-	 */
-	retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
-	if (retval)
-		return retval;
 
 	scan.cg = cs->css.cgroup;
 	scan.test_task = cpuset_test_cpumask;
 	scan.process_task = cpuset_change_cpumask;
-	scan.heap = &heap;
-	retval = cgroup_scan_tasks(&scan);
-
-	heap_free(&heap);
-	return retval;
+	scan.heap = heap;
+	cgroup_scan_tasks(&scan);
 }
 
 /**
@@ -883,6 +871,7 @@ static int update_tasks_cpumask(struct cpuset *cs)
  */
 static int update_cpumask(struct cpuset *cs, const char *buf)
 {
+	struct ptr_heap heap;
 	struct cpuset trialcs;
 	int retval;
 	int is_load_balanced;
@@ -917,6 +906,10 @@ static int update_cpumask(struct cpuset *cs, const char *buf)
 	if (cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed))
 		return 0;
 
+	retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
+	if (retval)
+		return retval;
+
 	is_load_balanced = is_sched_load_balance(&trialcs);
 
 	mutex_lock(&callback_mutex);
@@ -927,9 +920,9 @@ static int update_cpumask(struct cpuset *cs, const char *buf)
 	 * Scan tasks in the cpuset, and update the cpumasks of any
 	 * that need an update.
 	 */
-	retval = update_tasks_cpumask(cs);
-	if (retval < 0)
-		return retval;
+	update_tasks_cpumask(cs, &heap);
+
+	heap_free(&heap);
 
 	if (is_load_balanced)
 		async_rebuild_sched_domains();
@@ -1965,7 +1958,7 @@ static void scan_for_empty_cpusets(const struct cpuset *root)
 		     nodes_empty(cp->mems_allowed))
 			remove_tasks_in_empty_cpuset(cp);
 		else {
-			update_tasks_cpumask(cp);
+			update_tasks_cpumask(cp, NULL);
 			update_tasks_nodemask(cp, &oldmems);
 		}
 	}

kernel/exit.c

@@ -583,8 +583,6 @@ mm_need_new_owner(struct mm_struct *mm, struct task_struct *p)
 	 * If there are other users of the mm and the owner (us) is exiting
 	 * we need to find a new owner to take on the responsibility.
 	 */
-	if (!mm)
-		return 0;
 	if (atomic_read(&mm->mm_users) <= 1)
 		return 0;
 	if (mm->owner != p)
@@ -627,6 +625,16 @@ retry:
 	} while_each_thread(g, c);
 
 	read_unlock(&tasklist_lock);
+	/*
+	 * We found no owner yet mm_users > 1: this implies that we are
+	 * most likely racing with swapoff (try_to_unuse()) or /proc or
+	 * ptrace or page migration (get_task_mm()).  Mark owner as NULL,
+	 * so that subsystems can understand the callback and take action.
+	 */
+	down_write(&mm->mmap_sem);
+	cgroup_mm_owner_callbacks(mm->owner, NULL);
+	mm->owner = NULL;
+	up_write(&mm->mmap_sem);
 	return;
 
 assign_new_owner:

kernel/kexec.c

@@ -753,8 +753,14 @@ static struct page *kimage_alloc_page(struct kimage *image,
 			*old = addr | (*old & ~PAGE_MASK);
 
 			/* The old page I have found cannot be a
-			 * destination page, so return it.
+			 * destination page, so return it if it's
+			 * gfp_flags honor the ones passed in.
 			 */
+			if (!(gfp_mask & __GFP_HIGHMEM) &&
+			    PageHighMem(old_page)) {
+				kimage_free_pages(old_page);
+				continue;
+			}
 			addr = old_addr;
 			page = old_page;
 			break;

kernel/kgdb.c

@@ -488,7 +488,7 @@ static int write_mem_msg(int binary)
 		if (err)
 			return err;
 		if (CACHE_FLUSH_IS_SAFE)
-			flush_icache_range(addr, addr + length + 1);
+			flush_icache_range(addr, addr + length);
 		return 0;
 	}
 
@@ -1462,7 +1462,7 @@ acquirelock:
 	 * Get the passive CPU lock which will hold all the non-primary
 	 * CPU in a spin state while the debugger is active
 	 */
-	if (!kgdb_single_step || !kgdb_contthread) {
+	if (!kgdb_single_step) {
 		for (i = 0; i < NR_CPUS; i++)
 			atomic_set(&passive_cpu_wait[i], 1);
 	}
@@ -1475,7 +1475,7 @@ acquirelock:
 
 #ifdef CONFIG_SMP
 	/* Signal the other CPUs to enter kgdb_wait() */
-	if ((!kgdb_single_step || !kgdb_contthread) && kgdb_do_roundup)
+	if ((!kgdb_single_step) && kgdb_do_roundup)
 		kgdb_roundup_cpus(flags);
 #endif
 
@@ -1494,7 +1494,7 @@ acquirelock:
 	kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
 	kgdb_deactivate_sw_breakpoints();
 	kgdb_single_step = 0;
-	kgdb_contthread = NULL;
+	kgdb_contthread = current;
 	exception_level = 0;
 
 	/* Talk to debugger with gdbserial protocol */
@@ -1508,7 +1508,7 @@ acquirelock:
 	kgdb_info[ks->cpu].task = NULL;
 	atomic_set(&cpu_in_kgdb[ks->cpu], 0);
 
-	if (!kgdb_single_step || !kgdb_contthread) {
+	if (!kgdb_single_step) {
 		for (i = NR_CPUS-1; i >= 0; i--)
 			atomic_set(&passive_cpu_wait[i], 0);
 		/*

kernel/sched.c

@@ -1087,7 +1087,7 @@ hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
 	return NOTIFY_DONE;
 }
 
-static void init_hrtick(void)
+static __init void init_hrtick(void)
 {
 	hotcpu_notifier(hotplug_hrtick, 0);
 }
@@ -8909,6 +8909,9 @@ static int sched_rt_global_constraints(void)
 	u64 rt_runtime, rt_period;
 	int ret = 0;
 
+	if (sysctl_sched_rt_period <= 0)
+		return -EINVAL;
+
 	rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
 	rt_runtime = tg->rt_bandwidth.rt_runtime;
 
@@ -8925,6 +8928,9 @@ static int sched_rt_global_constraints(void)
 	unsigned long flags;
 	int i;
 
+	if (sysctl_sched_rt_period <= 0)
+		return -EINVAL;
+
 	spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
 	for_each_possible_cpu(i) {
 		struct rt_rq *rt_rq = &cpu_rq(i)->rt;

kernel/sched_rt.c

@@ -350,6 +350,7 @@ static void __enable_runtime(struct rq *rq)
 		spin_lock(&rt_rq->rt_runtime_lock);
 		rt_rq->rt_runtime = rt_b->rt_runtime;
 		rt_rq->rt_time = 0;
+		rt_rq->rt_throttled = 0;
 		spin_unlock(&rt_rq->rt_runtime_lock);
 		spin_unlock(&rt_b->rt_runtime_lock);
 	}

kernel/time/clockevents.c

@@ -71,6 +71,16 @@ void clockevents_set_mode(struct clock_event_device *dev,
 	}
 }
 
+/**
+ * clockevents_shutdown - shutdown the device and clear next_event
+ * @dev:	device to shutdown
+ */
+void clockevents_shutdown(struct clock_event_device *dev)
+{
+	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
+	dev->next_event.tv64 = KTIME_MAX;
+}
+
 /**
  * clockevents_program_event - Reprogram the clock event device.
  * @expires:	absolute expiry time (monotonic clock)
@@ -206,7 +216,7 @@ void clockevents_exchange_device(struct clock_event_device *old,
 
 	if (new) {
 		BUG_ON(new->mode != CLOCK_EVT_MODE_UNUSED);
-		clockevents_set_mode(new, CLOCK_EVT_MODE_SHUTDOWN);
+		clockevents_shutdown(new);
 	}
 	local_irq_restore(flags);
 }

kernel/time/tick-broadcast.c

@@ -235,9 +235,8 @@ static void tick_do_broadcast_on_off(void *why)
 	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
 		if (!cpu_isset(cpu, tick_broadcast_mask)) {
 			cpu_set(cpu, tick_broadcast_mask);
-			if (td->mode == TICKDEV_MODE_PERIODIC)
-				clockevents_set_mode(dev,
-						     CLOCK_EVT_MODE_SHUTDOWN);
+			if (bc->mode == TICKDEV_MODE_PERIODIC)
+				clockevents_shutdown(dev);
 		}
 		if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
 			tick_broadcast_force = 1;
@@ -246,7 +245,7 @@ static void tick_do_broadcast_on_off(void *why)
 		if (!tick_broadcast_force &&
 		    cpu_isset(cpu, tick_broadcast_mask)) {
 			cpu_clear(cpu, tick_broadcast_mask);
-			if (td->mode == TICKDEV_MODE_PERIODIC)
+			if (bc->mode == TICKDEV_MODE_PERIODIC)
 				tick_setup_periodic(dev, 0);
 		}
 		break;
@@ -254,7 +253,7 @@ static void tick_do_broadcast_on_off(void *why)
 
 	if (cpus_empty(tick_broadcast_mask)) {
 		if (!bc_stopped)
-			clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+			clockevents_shutdown(bc);
 	} else if (bc_stopped) {
 		if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
 			tick_broadcast_start_periodic(bc);
@@ -306,7 +305,7 @@ void tick_shutdown_broadcast(unsigned int *cpup)
 
 	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
 		if (bc && cpus_empty(tick_broadcast_mask))
-			clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+			clockevents_shutdown(bc);
 	}
 
 	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
@@ -321,7 +320,7 @@ void tick_suspend_broadcast(void)
 
 	bc = tick_broadcast_device.evtdev;
 	if (bc)
-		clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+		clockevents_shutdown(bc);
 
 	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
 }
@@ -576,4 +575,12 @@ void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
 	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
 }
 
+/*
+ * Check, whether the broadcast device is in one shot mode
+ */
+int tick_broadcast_oneshot_active(void)
+{
+	return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT;
+}
+
 #endif

kernel/time/tick-common.c

@@ -33,7 +33,7 @@ DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
  */
 ktime_t tick_next_period;
 ktime_t tick_period;
-int tick_do_timer_cpu __read_mostly = -1;
+int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT;
 DEFINE_SPINLOCK(tick_device_lock);
 
 /*
@@ -109,7 +109,8 @@ void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
 	if (!tick_device_is_functional(dev))
 		return;
 
-	if (dev->features & CLOCK_EVT_FEAT_PERIODIC) {
+	if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
+	    !tick_broadcast_oneshot_active()) {
 		clockevents_set_mode(dev, CLOCK_EVT_MODE_PERIODIC);
 	} else {
 		unsigned long seq;
@@ -148,7 +149,7 @@ static void tick_setup_device(struct tick_device *td,
 		 * If no cpu took the do_timer update, assign it to
 		 * this cpu:
 		 */
-		if (tick_do_timer_cpu == -1) {
+		if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
 			tick_do_timer_cpu = cpu;
 			tick_next_period = ktime_get();
 			tick_period = ktime_set(0, NSEC_PER_SEC / HZ);
@@ -249,7 +250,7 @@ static int tick_check_new_device(struct clock_event_device *newdev)
 	 * not give it back to the clockevents layer !
 	 */
 	if (tick_is_broadcast_device(curdev)) {
-		clockevents_set_mode(curdev, CLOCK_EVT_MODE_SHUTDOWN);
+		clockevents_shutdown(curdev);
 		curdev = NULL;
 	}
 	clockevents_exchange_device(curdev, newdev);
@@ -300,7 +301,8 @@ static void tick_shutdown(unsigned int *cpup)
 	if (*cpup == tick_do_timer_cpu) {
 		int cpu = first_cpu(cpu_online_map);
 
-		tick_do_timer_cpu = (cpu != NR_CPUS) ? cpu : -1;
+		tick_do_timer_cpu = (cpu != NR_CPUS) ? cpu :
+			TICK_DO_TIMER_NONE;
 	}
 	spin_unlock_irqrestore(&tick_device_lock, flags);
 }
@@ -311,7 +313,7 @@ static void tick_suspend(void)
 	unsigned long flags;
 
 	spin_lock_irqsave(&tick_device_lock, flags);
-	clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_SHUTDOWN);
+	clockevents_shutdown(td->evtdev);
 	spin_unlock_irqrestore(&tick_device_lock, flags);
 }
 

kernel/time/tick-internal.h

@@ -1,6 +1,10 @@
 /*
  * tick internal variable and functions used by low/high res code
  */
+
+#define TICK_DO_TIMER_NONE	-1
+#define TICK_DO_TIMER_BOOT	-2
+
 DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
 extern spinlock_t tick_device_lock;
 extern ktime_t tick_next_period;
@@ -10,6 +14,8 @@ extern int tick_do_timer_cpu __read_mostly;
 extern void tick_setup_periodic(struct clock_event_device *dev, int broadcast);
 extern void tick_handle_periodic(struct clock_event_device *dev);
 
+extern void clockevents_shutdown(struct clock_event_device *dev);
+
 /*
  * NO_HZ / high resolution timer shared code
  */
@@ -29,6 +35,7 @@ extern void tick_broadcast_oneshot_control(unsigned long reason);
 extern void tick_broadcast_switch_to_oneshot(void);
 extern void tick_shutdown_broadcast_oneshot(unsigned int *cpup);
 extern int tick_resume_broadcast_oneshot(struct clock_event_device *bc);
+extern int tick_broadcast_oneshot_active(void);
 # else /* BROADCAST */
 static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 {
@@ -37,6 +44,7 @@ static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 static inline void tick_broadcast_oneshot_control(unsigned long reason) { }
 static inline void tick_broadcast_switch_to_oneshot(void) { }
 static inline void tick_shutdown_broadcast_oneshot(unsigned int *cpup) { }
+static inline int tick_broadcast_oneshot_active(void) { return 0; }
 # endif /* !BROADCAST */
 
 #else /* !ONESHOT */
@@ -66,6 +74,7 @@ static inline int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
 {
 	return 0;
 }
+static inline int tick_broadcast_oneshot_active(void) { return 0; }
 #endif /* !TICK_ONESHOT */
 
 /*

kernel/time/tick-sched.c

@@ -75,6 +75,9 @@ static void tick_do_update_jiffies64(ktime_t now)
 							   incr * ticks);
 		}
 		do_timer(++ticks);
+
+		/* Keep the tick_next_period variable up to date */
+		tick_next_period = ktime_add(last_jiffies_update, tick_period);
 	}
 	write_sequnlock(&xtime_lock);
 }
@@ -221,7 +224,7 @@ void tick_nohz_stop_sched_tick(int inidle)
 	 */
 	if (unlikely(!cpu_online(cpu))) {
 		if (cpu == tick_do_timer_cpu)
-			tick_do_timer_cpu = -1;
+			tick_do_timer_cpu = TICK_DO_TIMER_NONE;
 	}
 
 	if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
@@ -303,7 +306,7 @@ void tick_nohz_stop_sched_tick(int inidle)
 		 * invoked.
 		 */
 		if (cpu == tick_do_timer_cpu)
-			tick_do_timer_cpu = -1;
+			tick_do_timer_cpu = TICK_DO_TIMER_NONE;
 
 		ts->idle_sleeps++;
 
@@ -468,7 +471,7 @@ static void tick_nohz_handler(struct clock_event_device *dev)
 	 * this duty, then the jiffies update is still serialized by
 	 * xtime_lock.
 	 */
-	if (unlikely(tick_do_timer_cpu == -1))
+	if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
 		tick_do_timer_cpu = cpu;
 
 	/* Check, if the jiffies need an update */
@@ -570,7 +573,7 @@ static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
 	 * this duty, then the jiffies update is still serialized by
 	 * xtime_lock.
 	 */
-	if (unlikely(tick_do_timer_cpu == -1))
+	if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
 		tick_do_timer_cpu = cpu;
 #endif