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Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Browse source 
Pull timer changes from Ingo Molnar:
 "Timer enhancements, generalizations and cleanups from Tejun Heo, in
  preparation for workqueue facility enhancements."

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timer: Implement TIMER_IRQSAFE
  timer: Clean up timer initializers
  timer: Relocate declarations of init_timer_on_stack_key()
  timer: Generalize timer->base flags handling
This commit is contained in:
Linus Torvalds 2012-10-01 10:45:16 -07:00
commit 2fff56641b
2 changed files with 120 additions and 165 deletions
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173
include/linux/timer.h
View file

@ -49,147 +49,112 @@ extern struct tvec_base boot_tvec_bases;
#endif
/*
* Note that all tvec_bases are 2 byte aligned and lower bit of
* base in timer_list is guaranteed to be zero. Use the LSB to
* indicate whether the timer is deferrable.
* Note that all tvec_bases are at least 4 byte aligned and lower two bits
* of base in timer_list is guaranteed to be zero. Use them for flags.
*
* A deferrable timer will work normally when the system is busy, but
* will not cause a CPU to come out of idle just to service it; instead,
* the timer will be serviced when the CPU eventually wakes up with a
* subsequent non-deferrable timer.
*
* An irqsafe timer is executed with IRQ disabled and it's safe to wait for
* the completion of the running instance from IRQ handlers, for example,
* by calling del_timer_sync().
*
* Note: The irq disabled callback execution is a special case for
* workqueue locking issues. It's not meant for executing random crap
* with interrupts disabled. Abuse is monitored!
*/
#define TBASE_DEFERRABLE_FLAG (0x1)
#define TIMER_DEFERRABLE 0x1LU
#define TIMER_IRQSAFE 0x2LU
#define TIMER_INITIALIZER(_function, _expires, _data) { \
#define TIMER_FLAG_MASK 0x3LU
#define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \
.entry = { .prev = TIMER_ENTRY_STATIC }, \
.function = (_function), \
.expires = (_expires), \
.data = (_data), \
.base = &boot_tvec_bases, \
.base = (void *)((unsigned long)&boot_tvec_bases + (_flags)), \
.slack = -1, \
__TIMER_LOCKDEP_MAP_INITIALIZER( \
__FILE__ ":" __stringify(__LINE__)) \
}
#define TBASE_MAKE_DEFERRED(ptr) ((struct tvec_base *) \
((unsigned char *)(ptr) + TBASE_DEFERRABLE_FLAG))
#define TIMER_INITIALIZER(_function, _expires, _data) \
__TIMER_INITIALIZER((_function), (_expires), (_data), 0)
#define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data) {\
.entry = { .prev = TIMER_ENTRY_STATIC }, \
.function = (_function), \
.expires = (_expires), \
.data = (_data), \
.base = TBASE_MAKE_DEFERRED(&boot_tvec_bases), \
__TIMER_LOCKDEP_MAP_INITIALIZER( \
__FILE__ ":" __stringify(__LINE__)) \
}
#define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data) \
__TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE)
#define DEFINE_TIMER(_name, _function, _expires, _data) \
struct timer_list _name = \
TIMER_INITIALIZER(_function, _expires, _data)
void init_timer_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key);
void init_timer_deferrable_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key);
#ifdef CONFIG_LOCKDEP
#define init_timer(timer) \
do { \
static struct lock_class_key __key; \
init_timer_key((timer), #timer, &__key); \
} while (0)
#define init_timer_deferrable(timer) \
do { \
static struct lock_class_key __key; \
init_timer_deferrable_key((timer), #timer, &__key); \
} while (0)
#define init_timer_on_stack(timer) \
do { \
static struct lock_class_key __key; \
init_timer_on_stack_key((timer), #timer, &__key); \
} while (0)
#define setup_timer(timer, fn, data) \
do { \
static struct lock_class_key __key; \
setup_timer_key((timer), #timer, &__key, (fn), (data));\
} while (0)
#define setup_timer_on_stack(timer, fn, data) \
do { \
static struct lock_class_key __key; \
setup_timer_on_stack_key((timer), #timer, &__key, \
(fn), (data)); \
} while (0)
#define setup_deferrable_timer_on_stack(timer, fn, data) \
do { \
static struct lock_class_key __key; \
setup_deferrable_timer_on_stack_key((timer), #timer, \
&__key, (fn), \
(data)); \
} while (0)
#else
#define init_timer(timer)\
init_timer_key((timer), NULL, NULL)
#define init_timer_deferrable(timer)\
init_timer_deferrable_key((timer), NULL, NULL)
#define init_timer_on_stack(timer)\
init_timer_on_stack_key((timer), NULL, NULL)
#define setup_timer(timer, fn, data)\
setup_timer_key((timer), NULL, NULL, (fn), (data))
#define setup_timer_on_stack(timer, fn, data)\
setup_timer_on_stack_key((timer), NULL, NULL, (fn), (data))
#define setup_deferrable_timer_on_stack(timer, fn, data)\
setup_deferrable_timer_on_stack_key((timer), NULL, NULL, (fn), (data))
#endif
void init_timer_key(struct timer_list *timer, unsigned int flags,
const char *name, struct lock_class_key *key);
#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
extern void init_timer_on_stack_key(struct timer_list *timer,
const char *name,
unsigned int flags, const char *name,
struct lock_class_key *key);
extern void destroy_timer_on_stack(struct timer_list *timer);
#else
static inline void destroy_timer_on_stack(struct timer_list *timer) { }
static inline void init_timer_on_stack_key(struct timer_list *timer,
const char *name,
unsigned int flags, const char *name,
struct lock_class_key *key)
{
init_timer_key(timer, name, key);
init_timer_key(timer, flags, name, key);
}
#endif
static inline void setup_timer_key(struct timer_list * timer,
const char *name,
struct lock_class_key *key,
void (*function)(unsigned long),
unsigned long data)
{
timer->function = function;
timer->data = data;
init_timer_key(timer, name, key);
}
#ifdef CONFIG_LOCKDEP
#define __init_timer(_timer, _flags) \
do { \
static struct lock_class_key __key; \
init_timer_key((_timer), (_flags), #_timer, &__key); \
} while (0)
static inline void setup_timer_on_stack_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key,
void (*function)(unsigned long),
unsigned long data)
{
timer->function = function;
timer->data = data;
init_timer_on_stack_key(timer, name, key);
}
#define __init_timer_on_stack(_timer, _flags) \
do { \
static struct lock_class_key __key; \
init_timer_on_stack_key((_timer), (_flags), #_timer, &__key); \
} while (0)
#else
#define __init_timer(_timer, _flags) \
init_timer_key((_timer), (_flags), NULL, NULL)
#define __init_timer_on_stack(_timer, _flags) \
init_timer_on_stack_key((_timer), (_flags), NULL, NULL)
#endif
extern void setup_deferrable_timer_on_stack_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key,
void (*function)(unsigned long),
unsigned long data);
#define init_timer(timer) \
__init_timer((timer), 0)
#define init_timer_deferrable(timer) \
__init_timer((timer), TIMER_DEFERRABLE)
#define init_timer_on_stack(timer) \
__init_timer_on_stack((timer), 0)
#define __setup_timer(_timer, _fn, _data, _flags) \
do { \
__init_timer((_timer), (_flags)); \
(_timer)->function = (_fn); \
(_timer)->data = (_data); \
} while (0)
#define __setup_timer_on_stack(_timer, _fn, _data, _flags) \
do { \
__init_timer_on_stack((_timer), (_flags)); \
(_timer)->function = (_fn); \
(_timer)->data = (_data); \
} while (0)
#define setup_timer(timer, fn, data) \
__setup_timer((timer), (fn), (data), 0)
#define setup_timer_on_stack(timer, fn, data) \
__setup_timer_on_stack((timer), (fn), (data), 0)
#define setup_deferrable_timer_on_stack(timer, fn, data) \
__setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE)
/**
* timer_pending - is a timer pending?

106
kernel/timer.c
View file

@ -92,24 +92,25 @@ static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
/* Functions below help us manage 'deferrable' flag */
static inline unsigned int tbase_get_deferrable(struct tvec_base *base)
{
return ((unsigned int)(unsigned long)base & TBASE_DEFERRABLE_FLAG);
return ((unsigned int)(unsigned long)base & TIMER_DEFERRABLE);
}
static inline unsigned int tbase_get_irqsafe(struct tvec_base *base)
{
return ((unsigned int)(unsigned long)base & TIMER_IRQSAFE);
}
static inline struct tvec_base *tbase_get_base(struct tvec_base *base)
{
return ((struct tvec_base *)((unsigned long)base & ~TBASE_DEFERRABLE_FLAG));
}
static inline void timer_set_deferrable(struct timer_list *timer)
{
timer->base = TBASE_MAKE_DEFERRED(timer->base);
return ((struct tvec_base *)((unsigned long)base & ~TIMER_FLAG_MASK));
}
static inline void
timer_set_base(struct timer_list *timer, struct tvec_base *new_base)
{
timer->base = (struct tvec_base *)((unsigned long)(new_base) |
tbase_get_deferrable(timer->base));
unsigned long flags = (unsigned long)timer->base & TIMER_FLAG_MASK;
timer->base = (struct tvec_base *)((unsigned long)(new_base) | flags);
}
static unsigned long round_jiffies_common(unsigned long j, int cpu,
@ -563,16 +564,14 @@ static inline void debug_timer_assert_init(struct timer_list *timer)
debug_object_assert_init(timer, &timer_debug_descr);
}
static void __init_timer(struct timer_list *timer,
const char *name,
struct lock_class_key *key);
static void do_init_timer(struct timer_list *timer, unsigned int flags,
const char *name, struct lock_class_key *key);
void init_timer_on_stack_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
void init_timer_on_stack_key(struct timer_list *timer, unsigned int flags,
const char *name, struct lock_class_key *key)
{
debug_object_init_on_stack(timer, &timer_debug_descr);
__init_timer(timer, name, key);
do_init_timer(timer, flags, name, key);
}
EXPORT_SYMBOL_GPL(init_timer_on_stack_key);
@ -613,12 +612,13 @@ static inline void debug_assert_init(struct timer_list *timer)
debug_timer_assert_init(timer);
}
static void __init_timer(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
static void do_init_timer(struct timer_list *timer, unsigned int flags,
const char *name, struct lock_class_key *key)
{
struct tvec_base *base = __raw_get_cpu_var(tvec_bases);
timer->entry.next = NULL;
timer->base = __raw_get_cpu_var(tvec_bases);
timer->base = (void *)((unsigned long)base | flags);
timer->slack = -1;
#ifdef CONFIG_TIMER_STATS
timer->start_site = NULL;
@ -628,22 +628,10 @@ static void __init_timer(struct timer_list *timer,
lockdep_init_map(&timer->lockdep_map, name, key, 0);
}
void setup_deferrable_timer_on_stack_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key,
void (*function)(unsigned long),
unsigned long data)
{
timer->function = function;
timer->data = data;
init_timer_on_stack_key(timer, name, key);
timer_set_deferrable(timer);
}
EXPORT_SYMBOL_GPL(setup_deferrable_timer_on_stack_key);
/**
* init_timer_key - initialize a timer
* @timer: the timer to be initialized
* @flags: timer flags
* @name: name of the timer
* @key: lockdep class key of the fake lock used for tracking timer
* sync lock dependencies
@ -651,24 +639,14 @@ EXPORT_SYMBOL_GPL(setup_deferrable_timer_on_stack_key);
* init_timer_key() must be done to a timer prior calling *any* of the
* other timer functions.
*/
void init_timer_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
void init_timer_key(struct timer_list *timer, unsigned int flags,
const char *name, struct lock_class_key *key)
{
debug_init(timer);
__init_timer(timer, name, key);
do_init_timer(timer, flags, name, key);
}
EXPORT_SYMBOL(init_timer_key);
void init_timer_deferrable_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
{
init_timer_key(timer, name, key);
timer_set_deferrable(timer);
}
EXPORT_SYMBOL(init_timer_deferrable_key);
static inline void detach_timer(struct timer_list *timer, bool clear_pending)
{
struct list_head *entry = &timer->entry;
@ -686,7 +664,7 @@ detach_expired_timer(struct timer_list *timer, struct tvec_base *base)
{
detach_timer(timer, true);
if (!tbase_get_deferrable(timer->base))
timer->base->active_timers--;
base->active_timers--;
}
static int detach_if_pending(struct timer_list *timer, struct tvec_base *base,
@ -697,7 +675,7 @@ static int detach_if_pending(struct timer_list *timer, struct tvec_base *base,
detach_timer(timer, clear_pending);
if (!tbase_get_deferrable(timer->base)) {
timer->base->active_timers--;
base->active_timers--;
if (timer->expires == base->next_timer)
base->next_timer = base->timer_jiffies;
}
@ -1029,14 +1007,14 @@ EXPORT_SYMBOL(try_to_del_timer_sync);
*
* Synchronization rules: Callers must prevent restarting of the timer,
* otherwise this function is meaningless. It must not be called from
* interrupt contexts. The caller must not hold locks which would prevent
* completion of the timer's handler. The timer's handler must not call
* add_timer_on(). Upon exit the timer is not queued and the handler is
* not running on any CPU.
* interrupt contexts unless the timer is an irqsafe one. The caller must
* not hold locks which would prevent completion of the timer's
* handler. The timer's handler must not call add_timer_on(). Upon exit the
* timer is not queued and the handler is not running on any CPU.
*
* Note: You must not hold locks that are held in interrupt context
* while calling this function. Even if the lock has nothing to do
* with the timer in question. Here's why:
* Note: For !irqsafe timers, you must not hold locks that are held in
* interrupt context while calling this function. Even if the lock has
* nothing to do with the timer in question. Here's why:
*
* CPU0 CPU1
* ---- ----
@ -1073,7 +1051,7 @@ int del_timer_sync(struct timer_list *timer)
* don't use it in hardirq context, because it
* could lead to deadlock.
*/
WARN_ON(in_irq());
WARN_ON(in_irq() && !tbase_get_irqsafe(timer->base));
for (;;) {
int ret = try_to_del_timer_sync(timer);
if (ret >= 0)
@ -1180,21 +1158,29 @@ static inline void __run_timers(struct tvec_base *base)
while (!list_empty(head)) {
void (*fn)(unsigned long);
unsigned long data;
bool irqsafe;
timer = list_first_entry(head, struct timer_list,entry);
fn = timer->function;
data = timer->data;
irqsafe = tbase_get_irqsafe(timer->base);
timer_stats_account_timer(timer);
base->running_timer = timer;
detach_expired_timer(timer, base);
if (irqsafe) {
spin_unlock(&base->lock);
call_timer_fn(timer, fn, data);
spin_lock(&base->lock);
} else {
spin_unlock_irq(&base->lock);
call_timer_fn(timer, fn, data);
spin_lock_irq(&base->lock);
}
}
}
base->running_timer = NULL;
spin_unlock_irq(&base->lock);
}
@ -1791,9 +1777,13 @@ static struct notifier_block __cpuinitdata timers_nb = {
void __init init_timers(void)
{
int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
(void *)(long)smp_processor_id());
int err;
/* ensure there are enough low bits for flags in timer->base pointer */
BUILD_BUG_ON(__alignof__(struct tvec_base) & TIMER_FLAG_MASK);
err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
(void *)(long)smp_processor_id());
init_timer_stats();
BUG_ON(err != NOTIFY_OK);