Merge 'Linux v3.0' into Litmus

Some notes:
* Litmus^RT scheduling class is the topmost scheduling class
  (above stop_sched_class).
* scheduler_ipi() function (e.g., in smp_reschedule_interrupt())
  may increase IPI latencies.
* Added path into schedule() to quickly re-evaluate scheduling
  decision without becoming preemptive again. This used to be
  a standard path before the removal of BKL.

Conflicts:
	Makefile
	arch/arm/kernel/calls.S
	arch/arm/kernel/smp.c
	arch/x86/include/asm/unistd_32.h
	arch/x86/kernel/smp.c
	arch/x86/kernel/syscall_table_32.S
	include/linux/hrtimer.h
	kernel/printk.c
	kernel/sched.c
	kernel/sched_fair.c

1 files changed, 49 insertions, 41 deletions

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 76da541c1f6..d91bba539ca 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -22,7 +22,7 @@
 #include <linux/wait.h>
 #include <linux/percpu.h>
 #include <linux/timer.h>
-
+#include <linux/timerqueue.h>
 
 struct hrtimer_clock_base;
 struct hrtimer_cpu_base;
@@ -54,11 +54,13 @@ enum hrtimer_restart {
  * 0x00         inactive
  * 0x01         enqueued into rbtree
  * 0x02         callback function running
+ * 0x04         timer is migrated to another cpu
  *
  * Special cases:
  * 0x03         callback function running and enqueued
  *              (was requeued on another CPU)
- * 0x09         timer was migrated on CPU hotunplug
+ * 0x05         timer was migrated on CPU hotunplug
+ *
  * The "callback function running and enqueued" status is only possible on
  * SMP. It happens for example when a posix timer expired and the callback
  * queued a signal. Between dropping the lock which protects the posix timer
@@ -67,8 +69,11 @@ enum hrtimer_restart {
  * as otherwise the timer could be removed before the softirq code finishes the
  * the handling of the timer.
  *
- * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state to
- * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario.
+ * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state
+ * to preserve the HRTIMER_STATE_CALLBACK in the above scenario. This
+ * also affects HRTIMER_STATE_MIGRATE where the preservation is not
+ * necessary. HRTIMER_STATE_MIGRATE is cleared after the timer is
+ * enqueued on the new cpu.
  *
  * All state transitions are protected by cpu_base->lock.
  */
@@ -79,8 +84,8 @@ enum hrtimer_restart {
 
 /**
  * struct hrtimer - the basic hrtimer structure
- * @node:       red black tree node for time ordered insertion
- * @_expires:   the absolute expiry time in the hrtimers internal
+ * @node:       timerqueue node, which also manages node.expires,
+ *              the absolute expiry time in the hrtimers internal
  *              representation. The time is related to the clock on
  *              which the timer is based. Is setup by adding
  *              slack to the _softexpires value. For non range timers
@@ -101,8 +106,7 @@ enum hrtimer_restart {
  * The hrtimer structure must be initialized by hrtimer_init()
  */
 struct hrtimer {
-        struct rb_node                  node;
-        ktime_t                         _expires;
+        struct timerqueue_node          node;
         ktime_t                         _softexpires;
         enum hrtimer_restart            (*function)(struct hrtimer *);
         struct hrtimer_clock_base       *base;
@@ -131,8 +135,8 @@ struct hrtimer_sleeper {
  * @cpu_base:           per cpu clock base
  * @index:              clock type index for per_cpu support when moving a
  *                      timer to a base on another cpu.
+ * @clockid:            clock id for per_cpu support
  * @active:             red black tree root node for the active timers
- * @first:              pointer to the timer node which expires first
  * @resolution:         the resolution of the clock, in nanoseconds
  * @get_time:           function to retrieve the current time of the clock
  * @softirq_time:       the time when running the hrtimer queue in the softirq
@@ -140,25 +144,27 @@ struct hrtimer_sleeper {
  */
 struct hrtimer_clock_base {
         struct hrtimer_cpu_base *cpu_base;
-        clockid_t               index;
-        struct rb_root          active;
-        struct rb_node          *first;
+        int                     index;
+        clockid_t               clockid;
+        struct timerqueue_head  active;
         ktime_t                 resolution;
         ktime_t                 (*get_time)(void);
         ktime_t                 softirq_time;
-#ifdef CONFIG_HIGH_RES_TIMERS
         ktime_t                 offset;
-#endif
 };
 
-#define HRTIMER_MAX_CLOCK_BASES 2
+enum  hrtimer_base_type {
+        HRTIMER_BASE_MONOTONIC,
+        HRTIMER_BASE_REALTIME,
+        HRTIMER_BASE_BOOTTIME,
+        HRTIMER_MAX_CLOCK_BASES,
+};
 
 /*
  * struct hrtimer_cpu_base - the per cpu clock bases
  * @lock:               lock protecting the base and associated clock bases
  *                      and timers
- * @clock_base:         array of clock bases for this cpu
- * @curr_timer:         the timer which is executing a callback right now
+ * @active_bases:       Bitfield to mark bases with active timers
  * @expires_next:       absolute time of the next event which was scheduled
  *                      via clock_set_next_event()
  * @hres_active:        State of high resolution mode
@@ -167,11 +173,12 @@ struct hrtimer_clock_base {
  * @nr_retries:         Total number of hrtimer interrupt retries
  * @nr_hangs:           Total number of hrtimer interrupt hangs
  * @max_hang_time:      Maximum time spent in hrtimer_interrupt
+ * @clock_base:         array of clock bases for this cpu
  * @to_pull:            LITMUS^RT list of timers to be pulled on this cpu
  */
 struct hrtimer_cpu_base {
         raw_spinlock_t                  lock;
-        struct hrtimer_clock_base       clock_base[HRTIMER_MAX_CLOCK_BASES];
+        unsigned long                   active_bases;
 #ifdef CONFIG_HIGH_RES_TIMERS
         ktime_t                         expires_next;
         int                             hres_active;
@@ -181,6 +188,7 @@ struct hrtimer_cpu_base {
         unsigned long                   nr_hangs;
         ktime_t                         max_hang_time;
 #endif
+        struct hrtimer_clock_base       clock_base[HRTIMER_MAX_CLOCK_BASES];
         struct list_head                to_pull;
 };
 
@@ -209,43 +217,43 @@ struct hrtimer_start_on_info {
 
 static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
 {
-        timer->_expires = time;
+        timer->node.expires = time;
         timer->_softexpires = time;
 }
 
 static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
 {
         timer->_softexpires = time;
-        timer->_expires = ktime_add_safe(time, delta);
+        timer->node.expires = ktime_add_safe(time, delta);
 }
 
 static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta)
 {
         timer->_softexpires = time;
-        timer->_expires = ktime_add_safe(time, ns_to_ktime(delta));
+        timer->node.expires = ktime_add_safe(time, ns_to_ktime(delta));
 }
 
 static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
 {
-        timer->_expires.tv64 = tv64;
+        timer->node.expires.tv64 = tv64;
         timer->_softexpires.tv64 = tv64;
 }
 
 static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
 {
-        timer->_expires = ktime_add_safe(timer->_expires, time);
+        timer->node.expires = ktime_add_safe(timer->node.expires, time);
         timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
 }
 
 static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)
 {
-        timer->_expires = ktime_add_ns(timer->_expires, ns);
+        timer->node.expires = ktime_add_ns(timer->node.expires, ns);
         timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
 }
 
 static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
 {
-        return timer->_expires;
+        return timer->node.expires;
 }
 
 static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
@@ -255,7 +263,7 @@ static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
 
 static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
 {
-        return timer->_expires.tv64;
+        return timer->node.expires.tv64;
 }
 static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
 {
@@ -264,19 +272,17 @@ static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
 
 static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
 {
-        return ktime_to_ns(timer->_expires);
+        return ktime_to_ns(timer->node.expires);
 }
 
 static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
 {
-    return ktime_sub(timer->_expires, timer->base->get_time());
+        return ktime_sub(timer->node.expires, timer->base->get_time());
 }
 
 #ifdef CONFIG_HIGH_RES_TIMERS
 struct clock_event_device;
 
-extern void clock_was_set(void);
-extern void hres_timers_resume(void);
 extern void hrtimer_interrupt(struct clock_event_device *dev);
 
 /*
@@ -310,16 +316,8 @@ extern void hrtimer_peek_ahead_timers(void);
 # define MONOTONIC_RES_NSEC     LOW_RES_NSEC
 # define KTIME_MONOTONIC_RES    KTIME_LOW_RES
 
-/*
- * clock_was_set() is a NOP for non- high-resolution systems. The
- * time-sorted order guarantees that a timer does not expire early and
- * is expired in the next softirq when the clock was advanced.
- */
-static inline void clock_was_set(void) { }
 static inline void hrtimer_peek_ahead_timers(void) { }
 
-static inline void hres_timers_resume(void) { }
-
 /*
  * In non high resolution mode the time reference is taken from
  * the base softirq time variable.
@@ -335,9 +333,18 @@ static inline int hrtimer_is_hres_active(struct hrtimer *timer)
 }
 #endif
 
+extern void clock_was_set(void);
+#ifdef CONFIG_TIMERFD
+extern void timerfd_clock_was_set(void);
+#else
+static inline void timerfd_clock_was_set(void) { }
+#endif
+extern void hrtimers_resume(void);
+
 extern ktime_t ktime_get(void);
 extern ktime_t ktime_get_real(void);
-
+extern ktime_t ktime_get_boottime(void);
+extern ktime_t ktime_get_monotonic_offset(void);
 
 DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
 
@@ -406,8 +413,9 @@ extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
 extern ktime_t hrtimer_get_next_event(void);
 
 /*
- * A timer is active, when it is enqueued into the rbtree or the callback
- * function is running.
+ * A timer is active, when it is enqueued into the rbtree or the
+ * callback function is running or it's in the state of being migrated
+ * to another cpu.
  */
 static inline int hrtimer_active(const struct hrtimer *timer)
 {