/*
* linux/kernel/timer.c
*
- * Kernel internal timers, kernel timekeeping, basic process system calls
+ * Kernel internal timers, basic process system calls
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/swap.h>
+#include <linux/pid_namespace.h>
#include <linux/notifier.h>
#include <linux/thread_info.h>
#include <linux/time.h>
#include <linux/cpu.h>
#include <linux/syscalls.h>
#include <linux/delay.h>
+#include <linux/tick.h>
+#include <linux/kallsyms.h>
+#include <linux/perf_event.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/timex.h>
#include <asm/io.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/timer.h>
+
u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
EXPORT_SYMBOL(jiffies_64);
#define TVN_MASK (TVN_SIZE - 1)
#define TVR_MASK (TVR_SIZE - 1)
-typedef struct tvec_s {
+struct tvec {
struct list_head vec[TVN_SIZE];
-} tvec_t;
+};
-typedef struct tvec_root_s {
+struct tvec_root {
struct list_head vec[TVR_SIZE];
-} tvec_root_t;
+};
-struct tvec_t_base_s {
+struct tvec_base {
spinlock_t lock;
struct timer_list *running_timer;
unsigned long timer_jiffies;
- tvec_root_t tv1;
- tvec_t tv2;
- tvec_t tv3;
- tvec_t tv4;
- tvec_t tv5;
-} ____cacheline_aligned_in_smp;
-
-typedef struct tvec_t_base_s tvec_base_t;
-
-tvec_base_t boot_tvec_bases;
+ unsigned long next_timer;
+ struct tvec_root tv1;
+ struct tvec tv2;
+ struct tvec tv3;
+ struct tvec tv4;
+ struct tvec tv5;
+} ____cacheline_aligned;
+
+struct tvec_base boot_tvec_bases;
EXPORT_SYMBOL(boot_tvec_bases);
-static DEFINE_PER_CPU(tvec_base_t *, tvec_bases) = &boot_tvec_bases;
+static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
-/**
- * __round_jiffies - function to round jiffies to a full second
- * @j: the time in (absolute) jiffies that should be rounded
- * @cpu: the processor number on which the timeout will happen
- *
- * __round_jiffies() rounds an absolute time in the future (in jiffies)
- * up or down to (approximately) full seconds. This is useful for timers
- * for which the exact time they fire does not matter too much, as long as
- * they fire approximately every X seconds.
- *
- * By rounding these timers to whole seconds, all such timers will fire
- * at the same time, rather than at various times spread out. The goal
- * of this is to have the CPU wake up less, which saves power.
- *
- * The exact rounding is skewed for each processor to avoid all
- * processors firing at the exact same time, which could lead
- * to lock contention or spurious cache line bouncing.
- *
- * The return value is the rounded version of the @j parameter.
+/*
+ * 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 for
+ * the new flag to indicate whether the timer is deferrable
*/
-unsigned long __round_jiffies(unsigned long j, int cpu)
+#define TBASE_DEFERRABLE_FLAG (0x1)
+
+/* 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);
+}
+
+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 = ((struct tvec_base *)((unsigned long)(timer->base) |
+ TBASE_DEFERRABLE_FLAG));
+}
+
+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));
+}
+
+static unsigned long round_jiffies_common(unsigned long j, int cpu,
+ bool force_up)
{
int rem;
unsigned long original = j;
* due to delays of the timer irq, long irq off times etc etc) then
* we should round down to the whole second, not up. Use 1/4th second
* as cutoff for this rounding as an extreme upper bound for this.
+ * But never round down if @force_up is set.
*/
- if (rem < HZ/4) /* round down */
+ if (rem < HZ/4 && !force_up) /* round down */
j = j - rem;
else /* round up */
j = j - rem + HZ;
return original;
return j;
}
+
+/**
+ * __round_jiffies - function to round jiffies to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * __round_jiffies() rounds an absolute time in the future (in jiffies)
+ * up or down to (approximately) full seconds. This is useful for timers
+ * for which the exact time they fire does not matter too much, as long as
+ * they fire approximately every X seconds.
+ *
+ * By rounding these timers to whole seconds, all such timers will fire
+ * at the same time, rather than at various times spread out. The goal
+ * of this is to have the CPU wake up less, which saves power.
+ *
+ * The exact rounding is skewed for each processor to avoid all
+ * processors firing at the exact same time, which could lead
+ * to lock contention or spurious cache line bouncing.
+ *
+ * The return value is the rounded version of the @j parameter.
+ */
+unsigned long __round_jiffies(unsigned long j, int cpu)
+{
+ return round_jiffies_common(j, cpu, false);
+}
EXPORT_SYMBOL_GPL(__round_jiffies);
/**
*/
unsigned long __round_jiffies_relative(unsigned long j, int cpu)
{
- /*
- * In theory the following code can skip a jiffy in case jiffies
- * increments right between the addition and the later subtraction.
- * However since the entire point of this function is to use approximate
- * timeouts, it's entirely ok to not handle that.
- */
- return __round_jiffies(j + jiffies, cpu) - jiffies;
+ unsigned long j0 = jiffies;
+
+ /* Use j0 because jiffies might change while we run */
+ return round_jiffies_common(j + j0, cpu, false) - j0;
}
EXPORT_SYMBOL_GPL(__round_jiffies_relative);
*/
unsigned long round_jiffies(unsigned long j)
{
- return __round_jiffies(j, raw_smp_processor_id());
+ return round_jiffies_common(j, raw_smp_processor_id(), false);
}
EXPORT_SYMBOL_GPL(round_jiffies);
}
EXPORT_SYMBOL_GPL(round_jiffies_relative);
+/**
+ * __round_jiffies_up - function to round jiffies up to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * This is the same as __round_jiffies() except that it will never
+ * round down. This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long __round_jiffies_up(unsigned long j, int cpu)
+{
+ return round_jiffies_common(j, cpu, true);
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_up);
+
+/**
+ * __round_jiffies_up_relative - function to round jiffies up to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * This is the same as __round_jiffies_relative() except that it will never
+ * round down. This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long __round_jiffies_up_relative(unsigned long j, int cpu)
+{
+ unsigned long j0 = jiffies;
+
+ /* Use j0 because jiffies might change while we run */
+ return round_jiffies_common(j + j0, cpu, true) - j0;
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_up_relative);
+
+/**
+ * round_jiffies_up - function to round jiffies up to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ *
+ * This is the same as round_jiffies() except that it will never
+ * round down. This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long round_jiffies_up(unsigned long j)
+{
+ return round_jiffies_common(j, raw_smp_processor_id(), true);
+}
+EXPORT_SYMBOL_GPL(round_jiffies_up);
+
+/**
+ * round_jiffies_up_relative - function to round jiffies up to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ *
+ * This is the same as round_jiffies_relative() except that it will never
+ * round down. This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long round_jiffies_up_relative(unsigned long j)
+{
+ return __round_jiffies_up_relative(j, raw_smp_processor_id());
+}
+EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
+
+/**
+ * set_timer_slack - set the allowed slack for a timer
+ * @slack_hz: the amount of time (in jiffies) allowed for rounding
+ *
+ * Set the amount of time, in jiffies, that a certain timer has
+ * in terms of slack. By setting this value, the timer subsystem
+ * will schedule the actual timer somewhere between
+ * the time mod_timer() asks for, and that time plus the slack.
+ *
+ * By setting the slack to -1, a percentage of the delay is used
+ * instead.
+ */
+void set_timer_slack(struct timer_list *timer, int slack_hz)
+{
+ timer->slack = slack_hz;
+}
+EXPORT_SYMBOL_GPL(set_timer_slack);
+
-static inline void set_running_timer(tvec_base_t *base,
+static inline void set_running_timer(struct tvec_base *base,
struct timer_list *timer)
{
#ifdef CONFIG_SMP
#endif
}
-static void internal_add_timer(tvec_base_t *base, struct timer_list *timer)
+static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)
{
unsigned long expires = timer->expires;
unsigned long idx = expires - base->timer_jiffies;
list_add_tail(&timer->entry, vec);
}
+#ifdef CONFIG_TIMER_STATS
+void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr)
+{
+ if (timer->start_site)
+ return;
+
+ timer->start_site = addr;
+ memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
+ timer->start_pid = current->pid;
+}
+
+static void timer_stats_account_timer(struct timer_list *timer)
+{
+ unsigned int flag = 0;
+
+ if (likely(!timer->start_site))
+ return;
+ if (unlikely(tbase_get_deferrable(timer->base)))
+ flag |= TIMER_STATS_FLAG_DEFERRABLE;
+
+ timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
+ timer->function, timer->start_comm, flag);
+}
+
+#else
+static void timer_stats_account_timer(struct timer_list *timer) {}
+#endif
+
+#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
+
+static struct debug_obj_descr timer_debug_descr;
+
+/*
+ * fixup_init is called when:
+ * - an active object is initialized
+ */
+static int timer_fixup_init(void *addr, enum debug_obj_state state)
+{
+ struct timer_list *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ del_timer_sync(timer);
+ debug_object_init(timer, &timer_debug_descr);
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+/*
+ * fixup_activate is called when:
+ * - an active object is activated
+ * - an unknown object is activated (might be a statically initialized object)
+ */
+static int timer_fixup_activate(void *addr, enum debug_obj_state state)
+{
+ struct timer_list *timer = addr;
+
+ switch (state) {
+
+ case ODEBUG_STATE_NOTAVAILABLE:
+ /*
+ * This is not really a fixup. The timer was
+ * statically initialized. We just make sure that it
+ * is tracked in the object tracker.
+ */
+ if (timer->entry.next == NULL &&
+ timer->entry.prev == TIMER_ENTRY_STATIC) {
+ debug_object_init(timer, &timer_debug_descr);
+ debug_object_activate(timer, &timer_debug_descr);
+ return 0;
+ } else {
+ WARN_ON_ONCE(1);
+ }
+ return 0;
+
+ case ODEBUG_STATE_ACTIVE:
+ WARN_ON(1);
+
+ default:
+ return 0;
+ }
+}
+
+/*
+ * fixup_free is called when:
+ * - an active object is freed
+ */
+static int timer_fixup_free(void *addr, enum debug_obj_state state)
+{
+ struct timer_list *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ del_timer_sync(timer);
+ debug_object_free(timer, &timer_debug_descr);
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+static struct debug_obj_descr timer_debug_descr = {
+ .name = "timer_list",
+ .fixup_init = timer_fixup_init,
+ .fixup_activate = timer_fixup_activate,
+ .fixup_free = timer_fixup_free,
+};
+
+static inline void debug_timer_init(struct timer_list *timer)
+{
+ debug_object_init(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_activate(struct timer_list *timer)
+{
+ debug_object_activate(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_deactivate(struct timer_list *timer)
+{
+ debug_object_deactivate(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_free(struct timer_list *timer)
+{
+ debug_object_free(timer, &timer_debug_descr);
+}
+
+static void __init_timer(struct timer_list *timer,
+ 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)
+{
+ debug_object_init_on_stack(timer, &timer_debug_descr);
+ __init_timer(timer, name, key);
+}
+EXPORT_SYMBOL_GPL(init_timer_on_stack_key);
+
+void destroy_timer_on_stack(struct timer_list *timer)
+{
+ debug_object_free(timer, &timer_debug_descr);
+}
+EXPORT_SYMBOL_GPL(destroy_timer_on_stack);
+
+#else
+static inline void debug_timer_init(struct timer_list *timer) { }
+static inline void debug_timer_activate(struct timer_list *timer) { }
+static inline void debug_timer_deactivate(struct timer_list *timer) { }
+#endif
+
+static inline void debug_init(struct timer_list *timer)
+{
+ debug_timer_init(timer);
+ trace_timer_init(timer);
+}
+
+static inline void
+debug_activate(struct timer_list *timer, unsigned long expires)
+{
+ debug_timer_activate(timer);
+ trace_timer_start(timer, expires);
+}
+
+static inline void debug_deactivate(struct timer_list *timer)
+{
+ debug_timer_deactivate(timer);
+ trace_timer_cancel(timer);
+}
+
+static void __init_timer(struct timer_list *timer,
+ const char *name,
+ struct lock_class_key *key)
+{
+ timer->entry.next = NULL;
+ timer->base = __raw_get_cpu_var(tvec_bases);
+ timer->slack = -1;
+#ifdef CONFIG_TIMER_STATS
+ timer->start_site = NULL;
+ timer->start_pid = -1;
+ memset(timer->start_comm, 0, TASK_COMM_LEN);
+#endif
+ lockdep_init_map(&timer->lockdep_map, name, key, 0);
+}
+
/**
- * init_timer - initialize a timer.
+ * init_timer_key - initialize a timer
* @timer: the timer to be initialized
+ * @name: name of the timer
+ * @key: lockdep class key of the fake lock used for tracking timer
+ * sync lock dependencies
*
- * init_timer() must be done to a timer prior calling *any* of the
+ * init_timer_key() must be done to a timer prior calling *any* of the
* other timer functions.
*/
-void fastcall init_timer(struct timer_list *timer)
+void init_timer_key(struct timer_list *timer,
+ const char *name,
+ struct lock_class_key *key)
{
- timer->entry.next = NULL;
- timer->base = __raw_get_cpu_var(tvec_bases);
+ debug_init(timer);
+ __init_timer(timer, 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);
+EXPORT_SYMBOL(init_timer_deferrable_key);
static inline void detach_timer(struct timer_list *timer,
- int clear_pending)
+ int clear_pending)
{
struct list_head *entry = &timer->entry;
+ debug_deactivate(timer);
+
__list_del(entry->prev, entry->next);
if (clear_pending)
entry->next = NULL;
* possible to set timer->base = NULL and drop the lock: the timer remains
* locked.
*/
-static tvec_base_t *lock_timer_base(struct timer_list *timer,
+static struct tvec_base *lock_timer_base(struct timer_list *timer,
unsigned long *flags)
__acquires(timer->base->lock)
{
- tvec_base_t *base;
+ struct tvec_base *base;
for (;;) {
- base = timer->base;
+ struct tvec_base *prelock_base = timer->base;
+ base = tbase_get_base(prelock_base);
if (likely(base != NULL)) {
spin_lock_irqsave(&base->lock, *flags);
- if (likely(base == timer->base))
+ if (likely(prelock_base == timer->base))
return base;
/* The timer has migrated to another CPU */
spin_unlock_irqrestore(&base->lock, *flags);
}
}
-int __mod_timer(struct timer_list *timer, unsigned long expires)
+static inline int
+__mod_timer(struct timer_list *timer, unsigned long expires,
+ bool pending_only, int pinned)
{
- tvec_base_t *base, *new_base;
+ struct tvec_base *base, *new_base;
unsigned long flags;
- int ret = 0;
+ int ret = 0 , cpu;
+ timer_stats_timer_set_start_info(timer);
BUG_ON(!timer->function);
base = lock_timer_base(timer, &flags);
if (timer_pending(timer)) {
detach_timer(timer, 0);
+ if (timer->expires == base->next_timer &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = base->timer_jiffies;
ret = 1;
+ } else {
+ if (pending_only)
+ goto out_unlock;
}
- new_base = __get_cpu_var(tvec_bases);
+ debug_activate(timer, expires);
+
+ cpu = smp_processor_id();
+
+#if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP)
+ if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu)) {
+ int preferred_cpu = get_nohz_load_balancer();
+
+ if (preferred_cpu >= 0)
+ cpu = preferred_cpu;
+ }
+#endif
+ new_base = per_cpu(tvec_bases, cpu);
if (base != new_base) {
/*
*/
if (likely(base->running_timer != timer)) {
/* See the comment in lock_timer_base() */
- timer->base = NULL;
+ timer_set_base(timer, NULL);
spin_unlock(&base->lock);
base = new_base;
spin_lock(&base->lock);
- timer->base = base;
+ timer_set_base(timer, base);
}
}
timer->expires = expires;
+ if (time_before(timer->expires, base->next_timer) &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = timer->expires;
internal_add_timer(base, timer);
+
+out_unlock:
spin_unlock_irqrestore(&base->lock, flags);
return ret;
}
-EXPORT_SYMBOL(__mod_timer);
-
/**
- * add_timer_on - start a timer on a particular CPU
- * @timer: the timer to be added
- * @cpu: the CPU to start it on
+ * mod_timer_pending - modify a pending timer's timeout
+ * @timer: the pending timer to be modified
+ * @expires: new timeout in jiffies
*
- * This is not very scalable on SMP. Double adds are not possible.
+ * mod_timer_pending() is the same for pending timers as mod_timer(),
+ * but will not re-activate and modify already deleted timers.
+ *
+ * It is useful for unserialized use of timers.
*/
-void add_timer_on(struct timer_list *timer, int cpu)
+int mod_timer_pending(struct timer_list *timer, unsigned long expires)
{
- tvec_base_t *base = per_cpu(tvec_bases, cpu);
- unsigned long flags;
-
- BUG_ON(timer_pending(timer) || !timer->function);
- spin_lock_irqsave(&base->lock, flags);
- timer->base = base;
- internal_add_timer(base, timer);
- spin_unlock_irqrestore(&base->lock, flags);
+ return __mod_timer(timer, expires, true, TIMER_NOT_PINNED);
}
+EXPORT_SYMBOL(mod_timer_pending);
+
+/*
+ * Decide where to put the timer while taking the slack into account
+ *
+ * Algorithm:
+ * 1) calculate the maximum (absolute) time
+ * 2) calculate the highest bit where the expires and new max are different
+ * 3) use this bit to make a mask
+ * 4) use the bitmask to round down the maximum time, so that all last
+ * bits are zeros
+ */
+static inline
+unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
+{
+ unsigned long expires_limit, mask;
+ int bit;
+
+ expires_limit = expires + timer->slack;
+
+ if (timer->slack < 0) /* auto slack: use 0.4% */
+ expires_limit = expires + (expires - jiffies)/256;
+
+ mask = expires ^ expires_limit;
+
+ if (mask == 0)
+ return expires;
+
+ bit = find_last_bit(&mask, BITS_PER_LONG);
+
+ mask = (1 << bit) - 1;
+
+ expires_limit = expires_limit & ~(mask);
+ return expires_limit;
+}
/**
* mod_timer - modify a timer's timeout
*/
int mod_timer(struct timer_list *timer, unsigned long expires)
{
- BUG_ON(!timer->function);
-
/*
* This is a common optimization triggered by the
* networking code - if the timer is re-modified
* to be the same thing then just return:
*/
- if (timer->expires == expires && timer_pending(timer))
+ if (timer_pending(timer) && timer->expires == expires)
return 1;
- return __mod_timer(timer, expires);
-}
+ expires = apply_slack(timer, expires);
+ return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
+}
EXPORT_SYMBOL(mod_timer);
/**
- * del_timer - deactive a timer.
- * @timer: the timer to be deactivated
+ * mod_timer_pinned - modify a timer's timeout
+ * @timer: the timer to be modified
+ * @expires: new timeout in jiffies
*
- * del_timer() deactivates a timer - this works on both active and inactive
- * timers.
+ * mod_timer_pinned() is a way to update the expire field of an
+ * active timer (if the timer is inactive it will be activated)
+ * and not allow the timer to be migrated to a different CPU.
*
- * The function returns whether it has deactivated a pending timer or not.
- * (ie. del_timer() of an inactive timer returns 0, del_timer() of an
- * active timer returns 1.)
+ * mod_timer_pinned(timer, expires) is equivalent to:
+ *
+ * del_timer(timer); timer->expires = expires; add_timer(timer);
*/
-int del_timer(struct timer_list *timer)
+int mod_timer_pinned(struct timer_list *timer, unsigned long expires)
{
- tvec_base_t *base;
- unsigned long flags;
+ if (timer->expires == expires && timer_pending(timer))
+ return 1;
+
+ return __mod_timer(timer, expires, false, TIMER_PINNED);
+}
+EXPORT_SYMBOL(mod_timer_pinned);
+
+/**
+ * add_timer - start a timer
+ * @timer: the timer to be added
+ *
+ * The kernel will do a ->function(->data) callback from the
+ * timer interrupt at the ->expires point in the future. The
+ * current time is 'jiffies'.
+ *
+ * The timer's ->expires, ->function (and if the handler uses it, ->data)
+ * fields must be set prior calling this function.
+ *
+ * Timers with an ->expires field in the past will be executed in the next
+ * timer tick.
+ */
+void add_timer(struct timer_list *timer)
+{
+ BUG_ON(timer_pending(timer));
+ mod_timer(timer, timer->expires);
+}
+EXPORT_SYMBOL(add_timer);
+
+/**
+ * add_timer_on - start a timer on a particular CPU
+ * @timer: the timer to be added
+ * @cpu: the CPU to start it on
+ *
+ * This is not very scalable on SMP. Double adds are not possible.
+ */
+void add_timer_on(struct timer_list *timer, int cpu)
+{
+ struct tvec_base *base = per_cpu(tvec_bases, cpu);
+ unsigned long flags;
+
+ timer_stats_timer_set_start_info(timer);
+ BUG_ON(timer_pending(timer) || !timer->function);
+ spin_lock_irqsave(&base->lock, flags);
+ timer_set_base(timer, base);
+ debug_activate(timer, timer->expires);
+ if (time_before(timer->expires, base->next_timer) &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = timer->expires;
+ internal_add_timer(base, timer);
+ /*
+ * Check whether the other CPU is idle and needs to be
+ * triggered to reevaluate the timer wheel when nohz is
+ * active. We are protected against the other CPU fiddling
+ * with the timer by holding the timer base lock. This also
+ * makes sure that a CPU on the way to idle can not evaluate
+ * the timer wheel.
+ */
+ wake_up_idle_cpu(cpu);
+ spin_unlock_irqrestore(&base->lock, flags);
+}
+EXPORT_SYMBOL_GPL(add_timer_on);
+
+/**
+ * del_timer - deactive a timer.
+ * @timer: the timer to be deactivated
+ *
+ * del_timer() deactivates a timer - this works on both active and inactive
+ * timers.
+ *
+ * The function returns whether it has deactivated a pending timer or not.
+ * (ie. del_timer() of an inactive timer returns 0, del_timer() of an
+ * active timer returns 1.)
+ */
+int del_timer(struct timer_list *timer)
+{
+ struct tvec_base *base;
+ unsigned long flags;
int ret = 0;
+ timer_stats_timer_clear_start_info(timer);
if (timer_pending(timer)) {
base = lock_timer_base(timer, &flags);
if (timer_pending(timer)) {
detach_timer(timer, 1);
+ if (timer->expires == base->next_timer &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = base->timer_jiffies;
ret = 1;
}
spin_unlock_irqrestore(&base->lock, flags);
return ret;
}
-
EXPORT_SYMBOL(del_timer);
#ifdef CONFIG_SMP
*/
int try_to_del_timer_sync(struct timer_list *timer)
{
- tvec_base_t *base;
+ struct tvec_base *base;
unsigned long flags;
int ret = -1;
if (base->running_timer == timer)
goto out;
+ timer_stats_timer_clear_start_info(timer);
ret = 0;
if (timer_pending(timer)) {
detach_timer(timer, 1);
+ if (timer->expires == base->next_timer &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = base->timer_jiffies;
ret = 1;
}
out:
return ret;
}
+EXPORT_SYMBOL(try_to_del_timer_sync);
/**
* del_timer_sync - deactivate a timer and wait for the handler to finish.
*/
int del_timer_sync(struct timer_list *timer)
{
+#ifdef CONFIG_LOCKDEP
+ unsigned long flags;
+
+ local_irq_save(flags);
+ lock_map_acquire(&timer->lockdep_map);
+ lock_map_release(&timer->lockdep_map);
+ local_irq_restore(flags);
+#endif
+
for (;;) {
int ret = try_to_del_timer_sync(timer);
if (ret >= 0)
cpu_relax();
}
}
-
EXPORT_SYMBOL(del_timer_sync);
#endif
-static int cascade(tvec_base_t *base, tvec_t *tv, int index)
+static int cascade(struct tvec_base *base, struct tvec *tv, int index)
{
/* cascade all the timers from tv up one level */
struct timer_list *timer, *tmp;
* don't have to detach them individually.
*/
list_for_each_entry_safe(timer, tmp, &tv_list, entry) {
- BUG_ON(timer->base != base);
+ BUG_ON(tbase_get_base(timer->base) != base);
internal_add_timer(base, timer);
}
return index;
}
+static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
+ unsigned long data)
+{
+ int preempt_count = preempt_count();
+
+#ifdef CONFIG_LOCKDEP
+ /*
+ * It is permissible to free the timer from inside the
+ * function that is called from it, this we need to take into
+ * account for lockdep too. To avoid bogus "held lock freed"
+ * warnings as well as problems when looking into
+ * timer->lockdep_map, make a copy and use that here.
+ */
+ struct lockdep_map lockdep_map = timer->lockdep_map;
+#endif
+ /*
+ * Couple the lock chain with the lock chain at
+ * del_timer_sync() by acquiring the lock_map around the fn()
+ * call here and in del_timer_sync().
+ */
+ lock_map_acquire(&lockdep_map);
+
+ trace_timer_expire_entry(timer);
+ fn(data);
+ trace_timer_expire_exit(timer);
+
+ lock_map_release(&lockdep_map);
+
+ if (preempt_count != preempt_count()) {
+ WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n",
+ fn, preempt_count, preempt_count());
+ /*
+ * Restore the preempt count. That gives us a decent
+ * chance to survive and extract information. If the
+ * callback kept a lock held, bad luck, but not worse
+ * than the BUG() we had.
+ */
+ preempt_count() = preempt_count;
+ }
+}
+
#define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
/**
* This function cascades all vectors and executes all expired timer
* vectors.
*/
-static inline void __run_timers(tvec_base_t *base)
+static inline void __run_timers(struct tvec_base *base)
{
struct timer_list *timer;
while (time_after_eq(jiffies, base->timer_jiffies)) {
struct list_head work_list;
struct list_head *head = &work_list;
- int index = base->timer_jiffies & TVR_MASK;
-
- /*
- * Cascade timers:
- */
- if (!index &&
- (!cascade(base, &base->tv2, INDEX(0))) &&
- (!cascade(base, &base->tv3, INDEX(1))) &&
- !cascade(base, &base->tv4, INDEX(2)))
- cascade(base, &base->tv5, INDEX(3));
- ++base->timer_jiffies;
- list_replace_init(base->tv1.vec + index, &work_list);
- while (!list_empty(head)) {
- void (*fn)(unsigned long);
- unsigned long data;
-
- timer = list_entry(head->next,struct timer_list,entry);
- fn = timer->function;
- data = timer->data;
-
- set_running_timer(base, timer);
- detach_timer(timer, 1);
- spin_unlock_irq(&base->lock);
- {
- int preempt_count = preempt_count();
- fn(data);
- if (preempt_count != preempt_count()) {
- printk(KERN_WARNING "huh, entered %p "
- "with preempt_count %08x, exited"
- " with %08x?\n",
- fn, preempt_count,
- preempt_count());
- BUG();
- }
- }
- spin_lock_irq(&base->lock);
- }
- }
- set_running_timer(base, NULL);
- spin_unlock_irq(&base->lock);
-}
-
-#if defined(CONFIG_NO_IDLE_HZ) || defined(CONFIG_NO_HZ)
-/*
- * Find out when the next timer event is due to happen. This
- * is used on S/390 to stop all activity when a cpus is idle.
- * This functions needs to be called disabled.
- */
-static unsigned long __next_timer_interrupt(tvec_base_t *base)
-{
- unsigned long timer_jiffies = base->timer_jiffies;
- unsigned long expires = timer_jiffies + (LONG_MAX >> 1);
- int index, slot, array, found = 0;
- struct timer_list *nte;
- tvec_t *varray[4];
-
- /* Look for timer events in tv1. */
- index = slot = timer_jiffies & TVR_MASK;
- do {
- list_for_each_entry(nte, base->tv1.vec + slot, entry) {
- found = 1;
- expires = nte->expires;
- /* Look at the cascade bucket(s)? */
- if (!index || slot < index)
- goto cascade;
- return expires;
- }
- slot = (slot + 1) & TVR_MASK;
- } while (slot != index);
-
-cascade:
- /* Calculate the next cascade event */
- if (index)
- timer_jiffies += TVR_SIZE - index;
- timer_jiffies >>= TVR_BITS;
-
- /* Check tv2-tv5. */
- varray[0] = &base->tv2;
- varray[1] = &base->tv3;
- varray[2] = &base->tv4;
- varray[3] = &base->tv5;
-
- for (array = 0; array < 4; array++) {
- tvec_t *varp = varray[array];
-
- index = slot = timer_jiffies & TVN_MASK;
- do {
- list_for_each_entry(nte, varp->vec + slot, entry) {
- found = 1;
- if (time_before(nte->expires, expires))
- expires = nte->expires;
- }
- /*
- * Do we still search for the first timer or are
- * we looking up the cascade buckets ?
- */
- if (found) {
- /* Look at the cascade bucket(s)? */
- if (!index || slot < index)
- break;
- return expires;
- }
- slot = (slot + 1) & TVN_MASK;
- } while (slot != index);
-
- if (index)
- timer_jiffies += TVN_SIZE - index;
- timer_jiffies >>= TVN_BITS;
- }
- return expires;
-}
-
-/*
- * Check, if the next hrtimer event is before the next timer wheel
- * event:
- */
-static unsigned long cmp_next_hrtimer_event(unsigned long now,
- unsigned long expires)
-{
- ktime_t hr_delta = hrtimer_get_next_event();
- struct timespec tsdelta;
-
- if (hr_delta.tv64 == KTIME_MAX)
- return expires;
-
- if (hr_delta.tv64 <= TICK_NSEC)
- return now;
-
- tsdelta = ktime_to_timespec(hr_delta);
- now += timespec_to_jiffies(&tsdelta);
- if (time_before(now, expires))
- return now;
- return expires;
-}
-
-/**
- * next_timer_interrupt - return the jiffy of the next pending timer
- */
-unsigned long get_next_timer_interrupt(unsigned long now)
-{
- tvec_base_t *base = __get_cpu_var(tvec_bases);
- unsigned long expires;
-
- spin_lock(&base->lock);
- expires = __next_timer_interrupt(base);
- spin_unlock(&base->lock);
-
- if (time_before_eq(expires, now))
- return now;
-
- return cmp_next_hrtimer_event(now, expires);
-}
-
-#ifdef CONFIG_NO_IDLE_HZ
-unsigned long next_timer_interrupt(void)
-{
- return get_next_timer_interrupt(jiffies);
-}
-#endif
-
-#endif
-
-/******************************************************************/
-
-/*
- * The current time
- * wall_to_monotonic is what we need to add to xtime (or xtime corrected
- * for sub jiffie times) to get to monotonic time. Monotonic is pegged
- * at zero at system boot time, so wall_to_monotonic will be negative,
- * however, we will ALWAYS keep the tv_nsec part positive so we can use
- * the usual normalization.
- */
-struct timespec xtime __attribute__ ((aligned (16)));
-struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
-
-EXPORT_SYMBOL(xtime);
-
-
-/* XXX - all of this timekeeping code should be later moved to time.c */
-#include <linux/clocksource.h>
-static struct clocksource *clock; /* pointer to current clocksource */
-
-#ifdef CONFIG_GENERIC_TIME
-/**
- * __get_nsec_offset - Returns nanoseconds since last call to periodic_hook
- *
- * private function, must hold xtime_lock lock when being
- * called. Returns the number of nanoseconds since the
- * last call to update_wall_time() (adjusted by NTP scaling)
- */
-static inline s64 __get_nsec_offset(void)
-{
- cycle_t cycle_now, cycle_delta;
- s64 ns_offset;
-
- /* read clocksource: */
- cycle_now = clocksource_read(clock);
-
- /* calculate the delta since the last update_wall_time: */
- cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
-
- /* convert to nanoseconds: */
- ns_offset = cyc2ns(clock, cycle_delta);
-
- return ns_offset;
-}
-
-/**
- * __get_realtime_clock_ts - Returns the time of day in a timespec
- * @ts: pointer to the timespec to be set
- *
- * Returns the time of day in a timespec. Used by
- * do_gettimeofday() and get_realtime_clock_ts().
- */
-static inline void __get_realtime_clock_ts(struct timespec *ts)
-{
- unsigned long seq;
- s64 nsecs;
-
- do {
- seq = read_seqbegin(&xtime_lock);
-
- *ts = xtime;
- nsecs = __get_nsec_offset();
-
- } while (read_seqretry(&xtime_lock, seq));
-
- timespec_add_ns(ts, nsecs);
-}
-
-/**
- * getnstimeofday - Returns the time of day in a timespec
- * @ts: pointer to the timespec to be set
- *
- * Returns the time of day in a timespec.
- */
-void getnstimeofday(struct timespec *ts)
-{
- __get_realtime_clock_ts(ts);
-}
-
-EXPORT_SYMBOL(getnstimeofday);
-
-/**
- * do_gettimeofday - Returns the time of day in a timeval
- * @tv: pointer to the timeval to be set
- *
- * NOTE: Users should be converted to using get_realtime_clock_ts()
- */
-void do_gettimeofday(struct timeval *tv)
-{
- struct timespec now;
-
- __get_realtime_clock_ts(&now);
- tv->tv_sec = now.tv_sec;
- tv->tv_usec = now.tv_nsec/1000;
-}
-
-EXPORT_SYMBOL(do_gettimeofday);
-/**
- * do_settimeofday - Sets the time of day
- * @tv: pointer to the timespec variable containing the new time
- *
- * Sets the time of day to the new time and update NTP and notify hrtimers
- */
-int do_settimeofday(struct timespec *tv)
-{
- unsigned long flags;
- time_t wtm_sec, sec = tv->tv_sec;
- long wtm_nsec, nsec = tv->tv_nsec;
-
- if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
- return -EINVAL;
-
- write_seqlock_irqsave(&xtime_lock, flags);
-
- nsec -= __get_nsec_offset();
-
- wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
- wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
-
- set_normalized_timespec(&xtime, sec, nsec);
- set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
-
- clock->error = 0;
- ntp_clear();
-
- write_sequnlock_irqrestore(&xtime_lock, flags);
-
- /* signal hrtimers about time change */
- clock_was_set();
-
- return 0;
-}
-
-EXPORT_SYMBOL(do_settimeofday);
-
-/**
- * change_clocksource - Swaps clocksources if a new one is available
- *
- * Accumulates current time interval and initializes new clocksource
- */
-static void change_clocksource(void)
-{
- struct clocksource *new;
- cycle_t now;
- u64 nsec;
-
- new = clocksource_get_next();
-
- if (clock == new)
- return;
-
- now = clocksource_read(new);
- nsec = __get_nsec_offset();
- timespec_add_ns(&xtime, nsec);
-
- clock = new;
- clock->cycle_last = now;
-
- clock->error = 0;
- clock->xtime_nsec = 0;
- clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
-
- printk(KERN_INFO "Time: %s clocksource has been installed.\n",
- clock->name);
-}
-#else
-static inline void change_clocksource(void) { }
-#endif
-
-/**
- * timeofday_is_continuous - check to see if timekeeping is free running
- */
-int timekeeping_is_continuous(void)
-{
- unsigned long seq;
- int ret;
-
- do {
- seq = read_seqbegin(&xtime_lock);
-
- ret = clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
-
- } while (read_seqretry(&xtime_lock, seq));
-
- return ret;
-}
-
-/**
- * read_persistent_clock - Return time in seconds from the persistent clock.
- *
- * Weak dummy function for arches that do not yet support it.
- * Returns seconds from epoch using the battery backed persistent clock.
- * Returns zero if unsupported.
- *
- * XXX - Do be sure to remove it once all arches implement it.
- */
-unsigned long __attribute__((weak)) read_persistent_clock(void)
-{
- return 0;
-}
-
-/*
- * timekeeping_init - Initializes the clocksource and common timekeeping values
- */
-void __init timekeeping_init(void)
-{
- unsigned long flags;
- unsigned long sec = read_persistent_clock();
+ int index = base->timer_jiffies & TVR_MASK;
- write_seqlock_irqsave(&xtime_lock, flags);
+ /*
+ * Cascade timers:
+ */
+ if (!index &&
+ (!cascade(base, &base->tv2, INDEX(0))) &&
+ (!cascade(base, &base->tv3, INDEX(1))) &&
+ !cascade(base, &base->tv4, INDEX(2)))
+ cascade(base, &base->tv5, INDEX(3));
+ ++base->timer_jiffies;
+ list_replace_init(base->tv1.vec + index, &work_list);
+ while (!list_empty(head)) {
+ void (*fn)(unsigned long);
+ unsigned long data;
- ntp_clear();
+ timer = list_first_entry(head, struct timer_list,entry);
+ fn = timer->function;
+ data = timer->data;
- clock = clocksource_get_next();
- clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
- clock->cycle_last = clocksource_read(clock);
+ timer_stats_account_timer(timer);
- xtime.tv_sec = sec;
- xtime.tv_nsec = 0;
- set_normalized_timespec(&wall_to_monotonic,
- -xtime.tv_sec, -xtime.tv_nsec);
+ set_running_timer(base, timer);
+ detach_timer(timer, 1);
- write_sequnlock_irqrestore(&xtime_lock, flags);
+ spin_unlock_irq(&base->lock);
+ call_timer_fn(timer, fn, data);
+ spin_lock_irq(&base->lock);
+ }
+ }
+ set_running_timer(base, NULL);
+ spin_unlock_irq(&base->lock);
}
-
-/* flag for if timekeeping is suspended */
-static int timekeeping_suspended;
-/* time in seconds when suspend began */
-static unsigned long timekeeping_suspend_time;
-
-/**
- * timekeeping_resume - Resumes the generic timekeeping subsystem.
- * @dev: unused
- *
- * This is for the generic clocksource timekeeping.
- * xtime/wall_to_monotonic/jiffies/etc are
- * still managed by arch specific suspend/resume code.
+#ifdef CONFIG_NO_HZ
+/*
+ * Find out when the next timer event is due to happen. This
+ * is used on S/390 to stop all activity when a CPU is idle.
+ * This function needs to be called with interrupts disabled.
*/
-static int timekeeping_resume(struct sys_device *dev)
+static unsigned long __next_timer_interrupt(struct tvec_base *base)
{
- unsigned long flags;
- unsigned long now = read_persistent_clock();
-
- write_seqlock_irqsave(&xtime_lock, flags);
-
- if (now && (now > timekeeping_suspend_time)) {
- unsigned long sleep_length = now - timekeeping_suspend_time;
+ unsigned long timer_jiffies = base->timer_jiffies;
+ unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA;
+ int index, slot, array, found = 0;
+ struct timer_list *nte;
+ struct tvec *varray[4];
- xtime.tv_sec += sleep_length;
- wall_to_monotonic.tv_sec -= sleep_length;
- }
- /* re-base the last cycle value */
- clock->cycle_last = clocksource_read(clock);
- clock->error = 0;
- timekeeping_suspended = 0;
- write_sequnlock_irqrestore(&xtime_lock, flags);
+ /* Look for timer events in tv1. */
+ index = slot = timer_jiffies & TVR_MASK;
+ do {
+ list_for_each_entry(nte, base->tv1.vec + slot, entry) {
+ if (tbase_get_deferrable(nte->base))
+ continue;
- touch_softlockup_watchdog();
- hrtimer_notify_resume();
+ found = 1;
+ expires = nte->expires;
+ /* Look at the cascade bucket(s)? */
+ if (!index || slot < index)
+ goto cascade;
+ return expires;
+ }
+ slot = (slot + 1) & TVR_MASK;
+ } while (slot != index);
- return 0;
-}
+cascade:
+ /* Calculate the next cascade event */
+ if (index)
+ timer_jiffies += TVR_SIZE - index;
+ timer_jiffies >>= TVR_BITS;
-static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
-{
- unsigned long flags;
+ /* Check tv2-tv5. */
+ varray[0] = &base->tv2;
+ varray[1] = &base->tv3;
+ varray[2] = &base->tv4;
+ varray[3] = &base->tv5;
- write_seqlock_irqsave(&xtime_lock, flags);
- timekeeping_suspended = 1;
- timekeeping_suspend_time = read_persistent_clock();
- write_sequnlock_irqrestore(&xtime_lock, flags);
- return 0;
-}
+ for (array = 0; array < 4; array++) {
+ struct tvec *varp = varray[array];
-/* sysfs resume/suspend bits for timekeeping */
-static struct sysdev_class timekeeping_sysclass = {
- .resume = timekeeping_resume,
- .suspend = timekeeping_suspend,
- set_kset_name("timekeeping"),
-};
+ index = slot = timer_jiffies & TVN_MASK;
+ do {
+ list_for_each_entry(nte, varp->vec + slot, entry) {
+ if (tbase_get_deferrable(nte->base))
+ continue;
-static struct sys_device device_timer = {
- .id = 0,
- .cls = &timekeeping_sysclass,
-};
+ found = 1;
+ if (time_before(nte->expires, expires))
+ expires = nte->expires;
+ }
+ /*
+ * Do we still search for the first timer or are
+ * we looking up the cascade buckets ?
+ */
+ if (found) {
+ /* Look at the cascade bucket(s)? */
+ if (!index || slot < index)
+ break;
+ return expires;
+ }
+ slot = (slot + 1) & TVN_MASK;
+ } while (slot != index);
-static int __init timekeeping_init_device(void)
-{
- int error = sysdev_class_register(&timekeeping_sysclass);
- if (!error)
- error = sysdev_register(&device_timer);
- return error;
+ if (index)
+ timer_jiffies += TVN_SIZE - index;
+ timer_jiffies >>= TVN_BITS;
+ }
+ return expires;
}
-device_initcall(timekeeping_init_device);
-
/*
- * If the error is already larger, we look ahead even further
- * to compensate for late or lost adjustments.
+ * Check, if the next hrtimer event is before the next timer wheel
+ * event:
*/
-static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
- s64 *offset)
+static unsigned long cmp_next_hrtimer_event(unsigned long now,
+ unsigned long expires)
{
- s64 tick_error, i;
- u32 look_ahead, adj;
- s32 error2, mult;
+ ktime_t hr_delta = hrtimer_get_next_event();
+ struct timespec tsdelta;
+ unsigned long delta;
- /*
- * Use the current error value to determine how much to look ahead.
- * The larger the error the slower we adjust for it to avoid problems
- * with losing too many ticks, otherwise we would overadjust and
- * produce an even larger error. The smaller the adjustment the
- * faster we try to adjust for it, as lost ticks can do less harm
- * here. This is tuned so that an error of about 1 msec is adusted
- * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
- */
- error2 = clock->error >> (TICK_LENGTH_SHIFT + 22 - 2 * SHIFT_HZ);
- error2 = abs(error2);
- for (look_ahead = 0; error2 > 0; look_ahead++)
- error2 >>= 2;
+ if (hr_delta.tv64 == KTIME_MAX)
+ return expires;
/*
- * Now calculate the error in (1 << look_ahead) ticks, but first
- * remove the single look ahead already included in the error.
+ * Expired timer available, let it expire in the next tick
*/
- tick_error = current_tick_length() >>
- (TICK_LENGTH_SHIFT - clock->shift + 1);
- tick_error -= clock->xtime_interval >> 1;
- error = ((error - tick_error) >> look_ahead) + tick_error;
-
- /* Finally calculate the adjustment shift value. */
- i = *interval;
- mult = 1;
- if (error < 0) {
- error = -error;
- *interval = -*interval;
- *offset = -*offset;
- mult = -1;
- }
- for (adj = 0; error > i; adj++)
- error >>= 1;
+ if (hr_delta.tv64 <= 0)
+ return now + 1;
- *interval <<= adj;
- *offset <<= adj;
- return mult << adj;
-}
+ tsdelta = ktime_to_timespec(hr_delta);
+ delta = timespec_to_jiffies(&tsdelta);
-/*
- * Adjust the multiplier to reduce the error value,
- * this is optimized for the most common adjustments of -1,0,1,
- * for other values we can do a bit more work.
- */
-static void clocksource_adjust(struct clocksource *clock, s64 offset)
-{
- s64 error, interval = clock->cycle_interval;
- int adj;
-
- error = clock->error >> (TICK_LENGTH_SHIFT - clock->shift - 1);
- if (error > interval) {
- error >>= 2;
- if (likely(error <= interval))
- adj = 1;
- else
- adj = clocksource_bigadjust(error, &interval, &offset);
- } else if (error < -interval) {
- error >>= 2;
- if (likely(error >= -interval)) {
- adj = -1;
- interval = -interval;
- offset = -offset;
- } else
- adj = clocksource_bigadjust(error, &interval, &offset);
- } else
- return;
+ /*
+ * Limit the delta to the max value, which is checked in
+ * tick_nohz_stop_sched_tick():
+ */
+ if (delta > NEXT_TIMER_MAX_DELTA)
+ delta = NEXT_TIMER_MAX_DELTA;
- clock->mult += adj;
- clock->xtime_interval += interval;
- clock->xtime_nsec -= offset;
- clock->error -= (interval - offset) <<
- (TICK_LENGTH_SHIFT - clock->shift);
+ /*
+ * Take rounding errors in to account and make sure, that it
+ * expires in the next tick. Otherwise we go into an endless
+ * ping pong due to tick_nohz_stop_sched_tick() retriggering
+ * the timer softirq
+ */
+ if (delta < 1)
+ delta = 1;
+ now += delta;
+ if (time_before(now, expires))
+ return now;
+ return expires;
}
/**
- * update_wall_time - Uses the current clocksource to increment the wall time
- *
- * Called from the timer interrupt, must hold a write on xtime_lock.
+ * get_next_timer_interrupt - return the jiffy of the next pending timer
+ * @now: current time (in jiffies)
*/
-static void update_wall_time(void)
+unsigned long get_next_timer_interrupt(unsigned long now)
{
- cycle_t offset;
-
- /* Make sure we're fully resumed: */
- if (unlikely(timekeeping_suspended))
- return;
-
-#ifdef CONFIG_GENERIC_TIME
- offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask;
-#else
- offset = clock->cycle_interval;
-#endif
- clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift;
-
- /* normally this loop will run just once, however in the
- * case of lost or late ticks, it will accumulate correctly.
- */
- while (offset >= clock->cycle_interval) {
- /* accumulate one interval */
- clock->xtime_nsec += clock->xtime_interval;
- clock->cycle_last += clock->cycle_interval;
- offset -= clock->cycle_interval;
-
- if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
- clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift;
- xtime.tv_sec++;
- second_overflow();
- }
-
- /* interpolator bits */
- time_interpolator_update(clock->xtime_interval
- >> clock->shift);
-
- /* accumulate error between NTP and clock interval */
- clock->error += current_tick_length();
- clock->error -= clock->xtime_interval << (TICK_LENGTH_SHIFT - clock->shift);
- }
+ struct tvec_base *base = __get_cpu_var(tvec_bases);
+ unsigned long expires;
- /* correct the clock when NTP error is too big */
- clocksource_adjust(clock, offset);
+ spin_lock(&base->lock);
+ if (time_before_eq(base->next_timer, base->timer_jiffies))
+ base->next_timer = __next_timer_interrupt(base);
+ expires = base->next_timer;
+ spin_unlock(&base->lock);
- /* store full nanoseconds into xtime */
- xtime.tv_nsec = (s64)clock->xtime_nsec >> clock->shift;
- clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
+ if (time_before_eq(expires, now))
+ return now;
- /* check to see if there is a new clocksource to use */
- change_clocksource();
+ return cmp_next_hrtimer_event(now, expires);
}
+#endif
/*
- * Called from the timer interrupt handler to charge one tick to the current
+ * Called from the timer interrupt handler to charge one tick to the current
* process. user_tick is 1 if the tick is user time, 0 for system.
*/
void update_process_times(int user_tick)
int cpu = smp_processor_id();
/* Note: this timer irq context must be accounted for as well. */
- if (user_tick)
- account_user_time(p, jiffies_to_cputime(1));
- else
- account_system_time(p, HARDIRQ_OFFSET, jiffies_to_cputime(1));
+ account_process_tick(p, user_tick);
run_local_timers();
- if (rcu_pending(cpu))
- rcu_check_callbacks(cpu, user_tick);
+ rcu_check_callbacks(cpu, user_tick);
+ printk_tick();
+ perf_event_do_pending();
scheduler_tick();
- run_posix_cpu_timers(p);
-}
-
-/*
- * Nr of active tasks - counted in fixed-point numbers
- */
-static unsigned long count_active_tasks(void)
-{
- return nr_active() * FIXED_1;
-}
-
-/*
- * Hmm.. Changed this, as the GNU make sources (load.c) seems to
- * imply that avenrun[] is the standard name for this kind of thing.
- * Nothing else seems to be standardized: the fractional size etc
- * all seem to differ on different machines.
- *
- * Requires xtime_lock to access.
- */
-unsigned long avenrun[3];
-
-EXPORT_SYMBOL(avenrun);
-
-/*
- * calc_load - given tick count, update the avenrun load estimates.
- * This is called while holding a write_lock on xtime_lock.
- */
-static inline void calc_load(unsigned long ticks)
-{
- unsigned long active_tasks; /* fixed-point */
- static int count = LOAD_FREQ;
-
- count -= ticks;
- if (unlikely(count < 0)) {
- active_tasks = count_active_tasks();
- do {
- CALC_LOAD(avenrun[0], EXP_1, active_tasks);
- CALC_LOAD(avenrun[1], EXP_5, active_tasks);
- CALC_LOAD(avenrun[2], EXP_15, active_tasks);
- count += LOAD_FREQ;
- } while (count < 0);
- }
+ run_posix_cpu_timers(p);
}
/*
- * This read-write spinlock protects us from races in SMP while
- * playing with xtime and avenrun.
- */
-__attribute__((weak)) __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
-
-EXPORT_SYMBOL(xtime_lock);
-
-/*
* This function runs timers and the timer-tq in bottom half context.
*/
static void run_timer_softirq(struct softirq_action *h)
{
- tvec_base_t *base = __get_cpu_var(tvec_bases);
+ struct tvec_base *base = __get_cpu_var(tvec_bases);
+
+ hrtimer_run_pending();
- hrtimer_run_queues();
if (time_after_eq(jiffies, base->timer_jiffies))
__run_timers(base);
}
*/
void run_local_timers(void)
{
+ hrtimer_run_queues();
raise_softirq(TIMER_SOFTIRQ);
softlockup_tick();
}
/*
- * Called by the timer interrupt. xtime_lock must already be taken
- * by the timer IRQ!
- */
-static inline void update_times(unsigned long ticks)
-{
- update_wall_time();
- calc_load(ticks);
-}
-
-/*
* The 64-bit jiffies value is not atomic - you MUST NOT read it
* without sampling the sequence number in xtime_lock.
* jiffies is defined in the linker script...
void do_timer(unsigned long ticks)
{
jiffies_64 += ticks;
- update_times(ticks);
+ update_wall_time();
+ calc_global_load();
}
#ifdef __ARCH_WANT_SYS_ALARM
* For backwards compatibility? This can be done in libc so Alpha
* and all newer ports shouldn't need it.
*/
-asmlinkage unsigned long sys_alarm(unsigned int seconds)
+SYSCALL_DEFINE1(alarm, unsigned int, seconds)
{
return alarm_setitimer(seconds);
}
*
* This is SMP safe as current->tgid does not change.
*/
-asmlinkage long sys_getpid(void)
+SYSCALL_DEFINE0(getpid)
{
- return current->tgid;
+ return task_tgid_vnr(current);
}
/*
* value of ->real_parent under rcu_read_lock(), see
* release_task()->call_rcu(delayed_put_task_struct).
*/
-asmlinkage long sys_getppid(void)
+SYSCALL_DEFINE0(getppid)
{
int pid;
rcu_read_lock();
- pid = rcu_dereference(current->real_parent)->tgid;
+ pid = task_tgid_vnr(current->real_parent);
rcu_read_unlock();
return pid;
}
-asmlinkage long sys_getuid(void)
+SYSCALL_DEFINE0(getuid)
{
/* Only we change this so SMP safe */
- return current->uid;
+ return current_uid();
}
-asmlinkage long sys_geteuid(void)
+SYSCALL_DEFINE0(geteuid)
{
/* Only we change this so SMP safe */
- return current->euid;
+ return current_euid();
}
-asmlinkage long sys_getgid(void)
+SYSCALL_DEFINE0(getgid)
{
/* Only we change this so SMP safe */
- return current->gid;
+ return current_gid();
}
-asmlinkage long sys_getegid(void)
+SYSCALL_DEFINE0(getegid)
{
/* Only we change this so SMP safe */
- return current->egid;
+ return current_egid();
}
#endif
*
* In all cases the return value is guaranteed to be non-negative.
*/
-fastcall signed long __sched schedule_timeout(signed long timeout)
+signed long __sched schedule_timeout(signed long timeout)
{
struct timer_list timer;
unsigned long expire;
expire = timeout + jiffies;
- setup_timer(&timer, process_timeout, (unsigned long)current);
- __mod_timer(&timer, expire);
+ setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);
+ __mod_timer(&timer, expire, false, TIMER_NOT_PINNED);
schedule();
del_singleshot_timer_sync(&timer);
+ /* Remove the timer from the object tracker */
+ destroy_timer_on_stack(&timer);
+
timeout = expire - jiffies;
out:
}
EXPORT_SYMBOL(schedule_timeout_interruptible);
+signed long __sched schedule_timeout_killable(signed long timeout)
+{
+ __set_current_state(TASK_KILLABLE);
+ return schedule_timeout(timeout);
+}
+EXPORT_SYMBOL(schedule_timeout_killable);
+
signed long __sched schedule_timeout_uninterruptible(signed long timeout)
{
__set_current_state(TASK_UNINTERRUPTIBLE);
EXPORT_SYMBOL(schedule_timeout_uninterruptible);
/* Thread ID - the internal kernel "pid" */
-asmlinkage long sys_gettid(void)
+SYSCALL_DEFINE0(gettid)
{
- return current->pid;
+ return task_pid_vnr(current);
}
/**
* do_sysinfo - fill in sysinfo struct
* @info: pointer to buffer to fill
- */
+ */
int do_sysinfo(struct sysinfo *info)
{
unsigned long mem_total, sav_total;
unsigned int mem_unit, bitcount;
- unsigned long seq;
+ struct timespec tp;
memset(info, 0, sizeof(struct sysinfo));
- do {
- struct timespec tp;
- seq = read_seqbegin(&xtime_lock);
-
- /*
- * This is annoying. The below is the same thing
- * posix_get_clock_monotonic() does, but it wants to
- * take the lock which we want to cover the loads stuff
- * too.
- */
-
- getnstimeofday(&tp);
- tp.tv_sec += wall_to_monotonic.tv_sec;
- tp.tv_nsec += wall_to_monotonic.tv_nsec;
- if (tp.tv_nsec - NSEC_PER_SEC >= 0) {
- tp.tv_nsec = tp.tv_nsec - NSEC_PER_SEC;
- tp.tv_sec++;
- }
- info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
+ ktime_get_ts(&tp);
+ monotonic_to_bootbased(&tp);
+ info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
- info->loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT);
- info->loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT);
- info->loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT);
+ get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
- info->procs = nr_threads;
- } while (read_seqretry(&xtime_lock, seq));
+ info->procs = nr_threads;
si_meminfo(info);
si_swapinfo(info);
return 0;
}
-asmlinkage long sys_sysinfo(struct sysinfo __user *info)
+SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
{
struct sysinfo val;
return 0;
}
-/*
- * lockdep: we want to track each per-CPU base as a separate lock-class,
- * but timer-bases are kmalloc()-ed, so we need to attach separate
- * keys to them:
- */
-static struct lock_class_key base_lock_keys[NR_CPUS];
-
-static int __devinit init_timers_cpu(int cpu)
+static int __cpuinit init_timers_cpu(int cpu)
{
int j;
- tvec_base_t *base;
- static char __devinitdata tvec_base_done[NR_CPUS];
+ struct tvec_base *base;
+ static char __cpuinitdata tvec_base_done[NR_CPUS];
if (!tvec_base_done[cpu]) {
static char boot_done;
/*
* The APs use this path later in boot
*/
- base = kmalloc_node(sizeof(*base), GFP_KERNEL,
+ base = kmalloc_node(sizeof(*base),
+ GFP_KERNEL | __GFP_ZERO,
cpu_to_node(cpu));
if (!base)
return -ENOMEM;
- memset(base, 0, sizeof(*base));
+
+ /* Make sure that tvec_base is 2 byte aligned */
+ if (tbase_get_deferrable(base)) {
+ WARN_ON(1);
+ kfree(base);
+ return -ENOMEM;
+ }
per_cpu(tvec_bases, cpu) = base;
} else {
/*
}
spin_lock_init(&base->lock);
- lockdep_set_class(&base->lock, base_lock_keys + cpu);
for (j = 0; j < TVN_SIZE; j++) {
INIT_LIST_HEAD(base->tv5.vec + j);
INIT_LIST_HEAD(base->tv1.vec + j);
base->timer_jiffies = jiffies;
+ base->next_timer = base->timer_jiffies;
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
-static void migrate_timer_list(tvec_base_t *new_base, struct list_head *head)
+static void migrate_timer_list(struct tvec_base *new_base, struct list_head *head)
{
struct timer_list *timer;
while (!list_empty(head)) {
- timer = list_entry(head->next, struct timer_list, entry);
+ timer = list_first_entry(head, struct timer_list, entry);
detach_timer(timer, 0);
- timer->base = new_base;
+ timer_set_base(timer, new_base);
+ if (time_before(timer->expires, new_base->next_timer) &&
+ !tbase_get_deferrable(timer->base))
+ new_base->next_timer = timer->expires;
internal_add_timer(new_base, timer);
}
}
-static void __devinit migrate_timers(int cpu)
+static void __cpuinit migrate_timers(int cpu)
{
- tvec_base_t *old_base;
- tvec_base_t *new_base;
+ struct tvec_base *old_base;
+ struct tvec_base *new_base;
int i;
BUG_ON(cpu_online(cpu));
old_base = per_cpu(tvec_bases, cpu);
new_base = get_cpu_var(tvec_bases);
-
- local_irq_disable();
- spin_lock(&new_base->lock);
- spin_lock(&old_base->lock);
+ /*
+ * The caller is globally serialized and nobody else
+ * takes two locks at once, deadlock is not possible.
+ */
+ spin_lock_irq(&new_base->lock);
+ spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
BUG_ON(old_base->running_timer);
}
spin_unlock(&old_base->lock);
- spin_unlock(&new_base->lock);
- local_irq_enable();
+ spin_unlock_irq(&new_base->lock);
put_cpu_var(tvec_bases);
}
#endif /* CONFIG_HOTPLUG_CPU */
long cpu = (long)hcpu;
switch(action) {
case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
if (init_timers_cpu(cpu) < 0)
return NOTIFY_BAD;
break;
#ifdef CONFIG_HOTPLUG_CPU
case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
migrate_timers(cpu);
break;
#endif
int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
(void *)(long)smp_processor_id());
+ init_timer_stats();
+
BUG_ON(err == NOTIFY_BAD);
register_cpu_notifier(&timers_nb);
- open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
-}
-
-#ifdef CONFIG_TIME_INTERPOLATION
-
-struct time_interpolator *time_interpolator __read_mostly;
-static struct time_interpolator *time_interpolator_list __read_mostly;
-static DEFINE_SPINLOCK(time_interpolator_lock);
-
-static inline cycles_t time_interpolator_get_cycles(unsigned int src)
-{
- unsigned long (*x)(void);
-
- switch (src)
- {
- case TIME_SOURCE_FUNCTION:
- x = time_interpolator->addr;
- return x();
-
- case TIME_SOURCE_MMIO64 :
- return readq_relaxed((void __iomem *)time_interpolator->addr);
-
- case TIME_SOURCE_MMIO32 :
- return readl_relaxed((void __iomem *)time_interpolator->addr);
-
- default: return get_cycles();
- }
-}
-
-static inline u64 time_interpolator_get_counter(int writelock)
-{
- unsigned int src = time_interpolator->source;
-
- if (time_interpolator->jitter)
- {
- cycles_t lcycle;
- cycles_t now;
-
- do {
- lcycle = time_interpolator->last_cycle;
- now = time_interpolator_get_cycles(src);
- if (lcycle && time_after(lcycle, now))
- return lcycle;
-
- /* When holding the xtime write lock, there's no need
- * to add the overhead of the cmpxchg. Readers are
- * force to retry until the write lock is released.
- */
- if (writelock) {
- time_interpolator->last_cycle = now;
- return now;
- }
- /* Keep track of the last timer value returned. The use of cmpxchg here
- * will cause contention in an SMP environment.
- */
- } while (unlikely(cmpxchg(&time_interpolator->last_cycle, lcycle, now) != lcycle));
- return now;
- }
- else
- return time_interpolator_get_cycles(src);
-}
-
-void time_interpolator_reset(void)
-{
- time_interpolator->offset = 0;
- time_interpolator->last_counter = time_interpolator_get_counter(1);
-}
-
-#define GET_TI_NSECS(count,i) (((((count) - i->last_counter) & (i)->mask) * (i)->nsec_per_cyc) >> (i)->shift)
-
-unsigned long time_interpolator_get_offset(void)
-{
- /* If we do not have a time interpolator set up then just return zero */
- if (!time_interpolator)
- return 0;
-
- return time_interpolator->offset +
- GET_TI_NSECS(time_interpolator_get_counter(0), time_interpolator);
-}
-
-#define INTERPOLATOR_ADJUST 65536
-#define INTERPOLATOR_MAX_SKIP 10*INTERPOLATOR_ADJUST
-
-void time_interpolator_update(long delta_nsec)
-{
- u64 counter;
- unsigned long offset;
-
- /* If there is no time interpolator set up then do nothing */
- if (!time_interpolator)
- return;
-
- /*
- * The interpolator compensates for late ticks by accumulating the late
- * time in time_interpolator->offset. A tick earlier than expected will
- * lead to a reset of the offset and a corresponding jump of the clock
- * forward. Again this only works if the interpolator clock is running
- * slightly slower than the regular clock and the tuning logic insures
- * that.
- */
-
- counter = time_interpolator_get_counter(1);
- offset = time_interpolator->offset +
- GET_TI_NSECS(counter, time_interpolator);
-
- if (delta_nsec < 0 || (unsigned long) delta_nsec < offset)
- time_interpolator->offset = offset - delta_nsec;
- else {
- time_interpolator->skips++;
- time_interpolator->ns_skipped += delta_nsec - offset;
- time_interpolator->offset = 0;
- }
- time_interpolator->last_counter = counter;
-
- /* Tuning logic for time interpolator invoked every minute or so.
- * Decrease interpolator clock speed if no skips occurred and an offset is carried.
- * Increase interpolator clock speed if we skip too much time.
- */
- if (jiffies % INTERPOLATOR_ADJUST == 0)
- {
- if (time_interpolator->skips == 0 && time_interpolator->offset > tick_nsec)
- time_interpolator->nsec_per_cyc--;
- if (time_interpolator->ns_skipped > INTERPOLATOR_MAX_SKIP && time_interpolator->offset == 0)
- time_interpolator->nsec_per_cyc++;
- time_interpolator->skips = 0;
- time_interpolator->ns_skipped = 0;
- }
-}
-
-static inline int
-is_better_time_interpolator(struct time_interpolator *new)
-{
- if (!time_interpolator)
- return 1;
- return new->frequency > 2*time_interpolator->frequency ||
- (unsigned long)new->drift < (unsigned long)time_interpolator->drift;
-}
-
-void
-register_time_interpolator(struct time_interpolator *ti)
-{
- unsigned long flags;
-
- /* Sanity check */
- BUG_ON(ti->frequency == 0 || ti->mask == 0);
-
- ti->nsec_per_cyc = ((u64)NSEC_PER_SEC << ti->shift) / ti->frequency;
- spin_lock(&time_interpolator_lock);
- write_seqlock_irqsave(&xtime_lock, flags);
- if (is_better_time_interpolator(ti)) {
- time_interpolator = ti;
- time_interpolator_reset();
- }
- write_sequnlock_irqrestore(&xtime_lock, flags);
-
- ti->next = time_interpolator_list;
- time_interpolator_list = ti;
- spin_unlock(&time_interpolator_lock);
-}
-
-void
-unregister_time_interpolator(struct time_interpolator *ti)
-{
- struct time_interpolator *curr, **prev;
- unsigned long flags;
-
- spin_lock(&time_interpolator_lock);
- prev = &time_interpolator_list;
- for (curr = *prev; curr; curr = curr->next) {
- if (curr == ti) {
- *prev = curr->next;
- break;
- }
- prev = &curr->next;
- }
-
- write_seqlock_irqsave(&xtime_lock, flags);
- if (ti == time_interpolator) {
- /* we lost the best time-interpolator: */
- time_interpolator = NULL;
- /* find the next-best interpolator */
- for (curr = time_interpolator_list; curr; curr = curr->next)
- if (is_better_time_interpolator(curr))
- time_interpolator = curr;
- time_interpolator_reset();
- }
- write_sequnlock_irqrestore(&xtime_lock, flags);
- spin_unlock(&time_interpolator_lock);
+ open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
}
-#endif /* CONFIG_TIME_INTERPOLATION */
/**
* msleep - sleep safely even with waitqueue interruptions
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff