Merge commit 'v3.3-rc1' into fbdev-next

1 files changed, 84 insertions, 27 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1c4f3e9b9bc5..4032ec1cf836 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -220,7 +220,7 @@ extern char ___assert_task_state[1 - 2*!!(
 			((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
 #define task_contributes_to_load(task)	\
 				((task->state & TASK_UNINTERRUPTIBLE) != 0 && \
-				 (task->flags & PF_FREEZING) == 0)
+				 (task->flags & PF_FROZEN) == 0)
 
 #define __set_task_state(tsk, state_value)		\
 	do { (tsk)->state = (state_value); } while (0)
@@ -273,9 +273,11 @@ extern int runqueue_is_locked(int cpu);
 
 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ)
 extern void select_nohz_load_balancer(int stop_tick);
+extern void set_cpu_sd_state_idle(void);
 extern int get_nohz_timer_target(void);
 #else
 static inline void select_nohz_load_balancer(int stop_tick) { }
+static inline void set_cpu_sd_state_idle(void) { }
 #endif
 
 /*
@@ -483,8 +485,8 @@ struct task_cputime {
 
 #define INIT_CPUTIME	\
 	(struct task_cputime) {					\
-		.utime = cputime_zero,				\
-		.stime = cputime_zero,				\
+		.utime = 0,					\
+		.stime = 0,					\
 		.sum_exec_runtime = 0,				\
 	}
 
@@ -635,13 +637,15 @@ struct signal_struct {
 #endif
 #ifdef CONFIG_CGROUPS
 	/*
-	 * The threadgroup_fork_lock prevents threads from forking with
-	 * CLONE_THREAD while held for writing. Use this for fork-sensitive
-	 * threadgroup-wide operations. It's taken for reading in fork.c in
-	 * copy_process().
-	 * Currently only needed write-side by cgroups.
+	 * group_rwsem prevents new tasks from entering the threadgroup and
+	 * member tasks from exiting,a more specifically, setting of
+	 * PF_EXITING.  fork and exit paths are protected with this rwsem
+	 * using threadgroup_change_begin/end().  Users which require
+	 * threadgroup to remain stable should use threadgroup_[un]lock()
+	 * which also takes care of exec path.  Currently, cgroup is the
+	 * only user.
 	 */
-	struct rw_semaphore threadgroup_fork_lock;
+	struct rw_semaphore group_rwsem;
 #endif
 
 	int oom_adj;		/* OOM kill score adjustment (bit shift) */
@@ -901,6 +905,10 @@ struct sched_group_power {
 	 * single CPU.
 	 */
 	unsigned int power, power_orig;
+	/*
+	 * Number of busy cpus in this group.
+	 */
+	atomic_t nr_busy_cpus;
 };
 
 struct sched_group {
@@ -925,6 +933,15 @@ static inline struct cpumask *sched_group_cpus(struct sched_group *sg)
 	return to_cpumask(sg->cpumask);
 }
 
+/**
+ * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
+ * @group: The group whose first cpu is to be returned.
+ */
+static inline unsigned int group_first_cpu(struct sched_group *group)
+{
+	return cpumask_first(sched_group_cpus(group));
+}
+
 struct sched_domain_attr {
 	int relax_domain_level;
 };
@@ -1315,8 +1332,8 @@ struct task_struct {
 	 * older sibling, respectively.  (p->father can be replaced with 
 	 * p->real_parent->pid)
 	 */
-	struct task_struct *real_parent; /* real parent process */
-	struct task_struct *parent; /* recipient of SIGCHLD, wait4() reports */
+	struct task_struct __rcu *real_parent; /* real parent process */
+	struct task_struct __rcu *parent; /* recipient of SIGCHLD, wait4() reports */
 	/*
 	 * children/sibling forms the list of my natural children
 	 */
@@ -1527,6 +1544,7 @@ struct task_struct {
 	 */
 	int nr_dirtied;
 	int nr_dirtied_pause;
+	unsigned long dirty_paused_when; /* start of a write-and-pause period */
 
 #ifdef CONFIG_LATENCYTOP
 	int latency_record_count;
@@ -1772,7 +1790,6 @@ extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *
 #define PF_MEMALLOC	0x00000800	/* Allocating memory */
 #define PF_NPROC_EXCEEDED 0x00001000	/* set_user noticed that RLIMIT_NPROC was exceeded */
 #define PF_USED_MATH	0x00002000	/* if unset the fpu must be initialized before use */
-#define PF_FREEZING	0x00004000	/* freeze in progress. do not account to load */
 #define PF_NOFREEZE	0x00008000	/* this thread should not be frozen */
 #define PF_FROZEN	0x00010000	/* frozen for system suspend */
 #define PF_FSTRANS	0x00020000	/* inside a filesystem transaction */
@@ -1788,7 +1805,6 @@ extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *
 #define PF_MEMPOLICY	0x10000000	/* Non-default NUMA mempolicy */
 #define PF_MUTEX_TESTER	0x20000000	/* Thread belongs to the rt mutex tester */
 #define PF_FREEZER_SKIP	0x40000000	/* Freezer should not count it as freezable */
-#define PF_FREEZER_NOSIG 0x80000000	/* Freezer won't send signals to it */
 
 /*
  * Only the _current_ task can read/write to tsk->flags, but other
@@ -2070,6 +2086,14 @@ extern int sched_setscheduler(struct task_struct *, int,
 extern int sched_setscheduler_nocheck(struct task_struct *, int,
 				      const struct sched_param *);
 extern struct task_struct *idle_task(int cpu);
+/**
+ * is_idle_task - is the specified task an idle task?
+ * @tsk: the task in question.
+ */
+static inline bool is_idle_task(struct task_struct *p)
+{
+	return p->pid == 0;
+}
 extern struct task_struct *curr_task(int cpu);
 extern void set_curr_task(int cpu, struct task_struct *p);
 
@@ -2251,7 +2275,7 @@ extern void __cleanup_sighand(struct sighand_struct *);
 extern void exit_itimers(struct signal_struct *);
 extern void flush_itimer_signals(void);
 
-extern NORET_TYPE void do_group_exit(int);
+extern void do_group_exit(int);
 
 extern void daemonize(const char *, ...);
 extern int allow_signal(int);
@@ -2373,29 +2397,62 @@ static inline void unlock_task_sighand(struct task_struct *tsk,
 	spin_unlock_irqrestore(&tsk->sighand->siglock, *flags);
 }
 
-/* See the declaration of threadgroup_fork_lock in signal_struct. */
 #ifdef CONFIG_CGROUPS
-static inline void threadgroup_fork_read_lock(struct task_struct *tsk)
+static inline void threadgroup_change_begin(struct task_struct *tsk)
 {
-	down_read(&tsk->signal->threadgroup_fork_lock);
+	down_read(&tsk->signal->group_rwsem);
 }
-static inline void threadgroup_fork_read_unlock(struct task_struct *tsk)
+static inline void threadgroup_change_end(struct task_struct *tsk)
 {
-	up_read(&tsk->signal->threadgroup_fork_lock);
+	up_read(&tsk->signal->group_rwsem);
 }
-static inline void threadgroup_fork_write_lock(struct task_struct *tsk)
+
+/**
+ * threadgroup_lock - lock threadgroup
+ * @tsk: member task of the threadgroup to lock
+ *
+ * Lock the threadgroup @tsk belongs to.  No new task is allowed to enter
+ * and member tasks aren't allowed to exit (as indicated by PF_EXITING) or
+ * perform exec.  This is useful for cases where the threadgroup needs to
+ * stay stable across blockable operations.
+ *
+ * fork and exit paths explicitly call threadgroup_change_{begin|end}() for
+ * synchronization.  While held, no new task will be added to threadgroup
+ * and no existing live task will have its PF_EXITING set.
+ *
+ * During exec, a task goes and puts its thread group through unusual
+ * changes.  After de-threading, exclusive access is assumed to resources
+ * which are usually shared by tasks in the same group - e.g. sighand may
+ * be replaced with a new one.  Also, the exec'ing task takes over group
+ * leader role including its pid.  Exclude these changes while locked by
+ * grabbing cred_guard_mutex which is used to synchronize exec path.
+ */
+static inline void threadgroup_lock(struct task_struct *tsk)
 {
-	down_write(&tsk->signal->threadgroup_fork_lock);
+	/*
+	 * exec uses exit for de-threading nesting group_rwsem inside
+	 * cred_guard_mutex. Grab cred_guard_mutex first.
+	 */
+	mutex_lock(&tsk->signal->cred_guard_mutex);
+	down_write(&tsk->signal->group_rwsem);
 }
-static inline void threadgroup_fork_write_unlock(struct task_struct *tsk)
+
+/**
+ * threadgroup_unlock - unlock threadgroup
+ * @tsk: member task of the threadgroup to unlock
+ *
+ * Reverse threadgroup_lock().
+ */
+static inline void threadgroup_unlock(struct task_struct *tsk)
 {
-	up_write(&tsk->signal->threadgroup_fork_lock);
+	up_write(&tsk->signal->group_rwsem);
+	mutex_unlock(&tsk->signal->cred_guard_mutex);
 }
 #else
-static inline void threadgroup_fork_read_lock(struct task_struct *tsk) {}
-static inline void threadgroup_fork_read_unlock(struct task_struct *tsk) {}
-static inline void threadgroup_fork_write_lock(struct task_struct *tsk) {}
-static inline void threadgroup_fork_write_unlock(struct task_struct *tsk) {}
+static inline void threadgroup_change_begin(struct task_struct *tsk) {}
+static inline void threadgroup_change_end(struct task_struct *tsk) {}
+static inline void threadgroup_lock(struct task_struct *tsk) {}
+static inline void threadgroup_unlock(struct task_struct *tsk) {}
 #endif
 
 #ifndef __HAVE_THREAD_FUNCTIONS