[PATCH] kill __init_timer_base in favor of boot_tvec_bases

Commit a4a6198b80cf82eb8160603c98da218d1bd5e104:
	[PATCH] tvec_bases too large for per-cpu data

introduced "struct tvec_t_base_s boot_tvec_bases" which is visible at
compile time.  This means we can kill __init_timer_base and move
timer_base_s's content into tvec_t_base_s.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 39 insertions, 53 deletions

diff --git a/include/linux/timer.h b/include/linux/timer.h
index b5caabca553c..0a485beba9f5 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -6,7 +6,7 @@
 #include <linux/spinlock.h>
 #include <linux/stddef.h>
 
-struct timer_base_s;
+struct tvec_t_base_s;
 
 struct timer_list {
         struct list_head entry;
@@ -15,16 +15,16 @@ struct timer_list {
         void (*function)(unsigned long);
         unsigned long data;
 
-        struct timer_base_s *base;
+        struct tvec_t_base_s *base;
 };
 
-extern struct timer_base_s __init_timer_base;
+extern struct tvec_t_base_s boot_tvec_bases;
 
 #define TIMER_INITIALIZER(_function, _expires, _data) {         \
                 .function = (_function),                        \
                 .expires = (_expires),                          \
                 .data = (_data),                                \
-                .base = &__init_timer_base,                     \
+                .base = &boot_tvec_bases,                       \
         }
 
 #define DEFINE_TIMER(_name, _function, _expires, _data)         \
diff --git a/kernel/timer.c b/kernel/timer.c
index ab189dd187cb..b04dc03b5934 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -54,7 +54,6 @@ EXPORT_SYMBOL(jiffies_64);
 /*
  * per-CPU timer vector definitions:
  */
-
 #define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
 #define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
 #define TVN_SIZE (1 << TVN_BITS)
@@ -62,11 +61,6 @@ EXPORT_SYMBOL(jiffies_64);
 #define TVN_MASK (TVN_SIZE - 1)
 #define TVR_MASK (TVR_SIZE - 1)
 
-struct timer_base_s {
-        spinlock_t lock;
-        struct timer_list *running_timer;
-};
-
 typedef struct tvec_s {
         struct list_head vec[TVN_SIZE];
 } tvec_t;
@@ -76,7 +70,8 @@ typedef struct tvec_root_s {
 } tvec_root_t;
 
 struct tvec_t_base_s {
-        struct timer_base_s t_base;
+        spinlock_t lock;
+        struct timer_list *running_timer;
         unsigned long timer_jiffies;
         tvec_root_t tv1;
         tvec_t tv2;
@@ -87,13 +82,14 @@ struct tvec_t_base_s {
 
 typedef struct tvec_t_base_s tvec_base_t;
 static DEFINE_PER_CPU(tvec_base_t *, tvec_bases);
-static tvec_base_t boot_tvec_bases;
+tvec_base_t boot_tvec_bases;
+EXPORT_SYMBOL(boot_tvec_bases);
 
 static inline void set_running_timer(tvec_base_t *base,
                                         struct timer_list *timer)
 {
 #ifdef CONFIG_SMP
-        base->t_base.running_timer = timer;
+        base->running_timer = timer;
 #endif
 }
 
@@ -139,15 +135,6 @@ static void internal_add_timer(tvec_base_t *base, struct timer_list *timer)
         list_add_tail(&timer->entry, vec);
 }
 
-typedef struct timer_base_s timer_base_t;
-/*
- * Used by TIMER_INITIALIZER, we can't use per_cpu(tvec_bases)
- * at compile time, and we need timer->base to lock the timer.
- */
-timer_base_t __init_timer_base
-        ____cacheline_aligned_in_smp = { .lock = SPIN_LOCK_UNLOCKED };
-EXPORT_SYMBOL(__init_timer_base);
-
 /***
  * init_timer - initialize a timer.
  * @timer: the timer to be initialized
@@ -158,7 +145,7 @@ EXPORT_SYMBOL(__init_timer_base);
 void fastcall init_timer(struct timer_list *timer)
 {
         timer->entry.next = NULL;
-        timer->base = &per_cpu(tvec_bases, raw_smp_processor_id())->t_base;
+        timer->base = per_cpu(tvec_bases, raw_smp_processor_id());
 }
 EXPORT_SYMBOL(init_timer);
 
@@ -174,7 +161,7 @@ static inline void detach_timer(struct timer_list *timer,
 }
 
 /*
- * We are using hashed locking: holding per_cpu(tvec_bases).t_base.lock
+ * We are using hashed locking: holding per_cpu(tvec_bases).lock
  * means that all timers which are tied to this base via timer->base are
  * locked, and the base itself is locked too.
  *
@@ -185,10 +172,10 @@ static inline void detach_timer(struct timer_list *timer,
  * possible to set timer->base = NULL and drop the lock: the timer remains
  * locked.
  */
-static timer_base_t *lock_timer_base(struct timer_list *timer,
+static tvec_base_t *lock_timer_base(struct timer_list *timer,
                                         unsigned long *flags)
 {
-        timer_base_t *base;
+        tvec_base_t *base;
 
         for (;;) {
                 base = timer->base;
@@ -205,8 +192,7 @@ static timer_base_t *lock_timer_base(struct timer_list *timer,
 
 int __mod_timer(struct timer_list *timer, unsigned long expires)
 {
-        timer_base_t *base;
-        tvec_base_t *new_base;
+        tvec_base_t *base, *new_base;
         unsigned long flags;
         int ret = 0;
 
@@ -221,7 +207,7 @@ int __mod_timer(struct timer_list *timer, unsigned long expires)
 
         new_base = __get_cpu_var(tvec_bases);
 
-        if (base != &new_base->t_base) {
+        if (base != new_base) {
                 /*
                  * We are trying to schedule the timer on the local CPU.
                  * However we can't change timer's base while it is running,
@@ -231,19 +217,19 @@ int __mod_timer(struct timer_list *timer, unsigned long expires)
                  */
                 if (unlikely(base->running_timer == timer)) {
                         /* The timer remains on a former base */
-                        new_base = container_of(base, tvec_base_t, t_base);
+                        new_base = base;
                 } else {
                         /* See the comment in lock_timer_base() */
                         timer->base = NULL;
                         spin_unlock(&base->lock);
-                        spin_lock(&new_base->t_base.lock);
-                        timer->base = &new_base->t_base;
+                        spin_lock(&new_base->lock);
+                        timer->base = new_base;
                 }
         }
 
         timer->expires = expires;
         internal_add_timer(new_base, timer);
-        spin_unlock_irqrestore(&new_base->t_base.lock, flags);
+        spin_unlock_irqrestore(&new_base->lock, flags);
 
         return ret;
 }
@@ -263,10 +249,10 @@ void add_timer_on(struct timer_list *timer, int cpu)
         unsigned long flags;
 
         BUG_ON(timer_pending(timer) || !timer->function);
-        spin_lock_irqsave(&base->t_base.lock, flags);
-        timer->base = &base->t_base;
+        spin_lock_irqsave(&base->lock, flags);
+        timer->base = base;
         internal_add_timer(base, timer);
-        spin_unlock_irqrestore(&base->t_base.lock, flags);
+        spin_unlock_irqrestore(&base->lock, flags);
 }
 
 
@@ -319,7 +305,7 @@ EXPORT_SYMBOL(mod_timer);
  */
 int del_timer(struct timer_list *timer)
 {
-        timer_base_t *base;
+        tvec_base_t *base;
         unsigned long flags;
         int ret = 0;
 
@@ -346,7 +332,7 @@ EXPORT_SYMBOL(del_timer);
  */
 int try_to_del_timer_sync(struct timer_list *timer)
 {
-        timer_base_t *base;
+        tvec_base_t *base;
         unsigned long flags;
         int ret = -1;
 
@@ -410,7 +396,7 @@ static int cascade(tvec_base_t *base, tvec_t *tv, int index)
                 struct timer_list *tmp;
 
                 tmp = list_entry(curr, struct timer_list, entry);
-                BUG_ON(tmp->base != &base->t_base);
+                BUG_ON(tmp->base != base);
                 curr = curr->next;
                 internal_add_timer(base, tmp);
         }
@@ -432,7 +418,7 @@ static inline void __run_timers(tvec_base_t *base)
 {
         struct timer_list *timer;
 
-        spin_lock_irq(&base->t_base.lock);
+        spin_lock_irq(&base->lock);
         while (time_after_eq(jiffies, base->timer_jiffies)) {
                 struct list_head work_list = LIST_HEAD_INIT(work_list);
                 struct list_head *head = &work_list;
@@ -458,7 +444,7 @@ static inline void __run_timers(tvec_base_t *base)
 
                         set_running_timer(base, timer);
                         detach_timer(timer, 1);
-                        spin_unlock_irq(&base->t_base.lock);
+                        spin_unlock_irq(&base->lock);
                         {
                                 int preempt_count = preempt_count();
                                 fn(data);
@@ -471,11 +457,11 @@ static inline void __run_timers(tvec_base_t *base)
                                         BUG();
                                 }
                         }
-                        spin_lock_irq(&base->t_base.lock);
+                        spin_lock_irq(&base->lock);
                 }
         }
         set_running_timer(base, NULL);
-        spin_unlock_irq(&base->t_base.lock);
+        spin_unlock_irq(&base->lock);
 }
 
 #ifdef CONFIG_NO_IDLE_HZ
@@ -506,7 +492,7 @@ unsigned long next_timer_interrupt(void)
         hr_expires += jiffies;
 
         base = __get_cpu_var(tvec_bases);
-        spin_lock(&base->t_base.lock);
+        spin_lock(&base->lock);
         expires = base->timer_jiffies + (LONG_MAX >> 1);
         list = NULL;
 
@@ -554,7 +540,7 @@ found:
                                 expires = nte->expires;
                 }
         }
-        spin_unlock(&base->t_base.lock);
+        spin_unlock(&base->lock);
 
         if (time_before(hr_expires, expires))
                 return hr_expires;
@@ -1262,7 +1248,7 @@ static int __devinit init_timers_cpu(int cpu)
                 }
                 per_cpu(tvec_bases, cpu) = base;
         }
-        spin_lock_init(&base->t_base.lock);
+        spin_lock_init(&base->lock);
         for (j = 0; j < TVN_SIZE; j++) {
                 INIT_LIST_HEAD(base->tv5.vec + j);
                 INIT_LIST_HEAD(base->tv4.vec + j);
@@ -1284,7 +1270,7 @@ static void migrate_timer_list(tvec_base_t *new_base, struct list_head *head)
         while (!list_empty(head)) {
                 timer = list_entry(head->next, struct timer_list, entry);
                 detach_timer(timer, 0);
-                timer->base = &new_base->t_base;
+                timer->base = new_base;
                 internal_add_timer(new_base, timer);
         }
 }
@@ -1300,11 +1286,11 @@ static void __devinit migrate_timers(int cpu)
         new_base = get_cpu_var(tvec_bases);
 
         local_irq_disable();
-        spin_lock(&new_base->t_base.lock);
-        spin_lock(&old_base->t_base.lock);
+        spin_lock(&new_base->lock);
+        spin_lock(&old_base->lock);
+
+        BUG_ON(old_base->running_timer);
 
-        if (old_base->t_base.running_timer)
-                BUG();
         for (i = 0; i < TVR_SIZE; i++)
                 migrate_timer_list(new_base, old_base->tv1.vec + i);
         for (i = 0; i < TVN_SIZE; i++) {
@@ -1314,8 +1300,8 @@ static void __devinit migrate_timers(int cpu)
                 migrate_timer_list(new_base, old_base->tv5.vec + i);
         }
 
-        spin_unlock(&old_base->t_base.lock);
-        spin_unlock(&new_base->t_base.lock);
+        spin_unlock(&old_base->lock);
+        spin_unlock(&new_base->lock);
         local_irq_enable();
         put_cpu_var(tvec_bases);
 }