From 7bb67439bf6bd3782f07f1d7be1e63406453d5de Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Sun, 31 Aug 2008 08:05:58 -0700 Subject: select: Introduce a hrtimeout function This patch adds a schedule_hrtimeout() function, to be used by select() and poll() in a later patch. This function works similar to schedule_timeout() in most ways, but takes a timespec rather than jiffies. With a lot of contributions/fixes from Thomas Signed-off-by: Arjan van de Ven Signed-off-by: Thomas Gleixner --- include/linux/hrtimer.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 6d93dce61cbb..becd17db1a1a 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -346,6 +346,8 @@ extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *tsk); +extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode); + /* Soft interrupt function to run the hrtimer queues: */ extern void hrtimer_run_queues(void); extern void hrtimer_run_pending(void); -- cgit v1.2.3 From 63ca243b271f5b44e0b1057003cf498b6d0fadf7 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Mon, 1 Sep 2008 14:35:02 -0700 Subject: hrtimer: add abstraction functions for accessing the "expires" member In order to be able to turn hrtimers into range based, we need to provide accessor functions for getting to the "expires" ktime_t member of the struct hrtimer. This patch adds a set of accessors for this purpose: * hrtimer_set_expires * hrtimer_set_expires_tv64 * hrtimer_add_expires * hrtimer_add_expires_ns * hrtimer_get_expires * hrtimer_get_expires_tv64 * hrtimer_get_expires_ns * hrtimer_expires_remaining * hrtimer_start_expires No users of these new accessors are added yet; these follow in later patches. Hopefully this patch can even go into 2.6.27-rc so that the conversions will not have a bottleneck in -next Signed-off-by: Arjan van de Ven --- include/linux/hrtimer.h | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index becd17db1a1a..9900e998ea8f 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -217,6 +217,45 @@ static inline int hrtimer_is_hres_active(struct hrtimer *timer) return timer->base->cpu_base->hres_active; } +static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) +{ + timer->expires = time; +} +static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) +{ + timer->expires.tv64 = tv64; +} + +static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) +{ + timer->expires = ktime_add_safe(timer->expires, time); +} + +static inline void hrtimer_add_expires_ns(struct hrtimer *timer, unsigned long ns) +{ + timer->expires = ktime_add_ns(timer->expires, ns); +} + +static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) +{ + return timer->expires; +} + +static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer) +{ + return timer->expires.tv64; +} + +static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) +{ + return ktime_to_ns(timer->expires); +} + +static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) +{ + return ktime_sub(timer->expires, timer->base->get_time()); +} + /* * The resolution of the clocks. The resolution value is returned in * the clock_getres() system call to give application programmers an @@ -287,6 +326,12 @@ extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, extern int hrtimer_cancel(struct hrtimer *timer); extern int hrtimer_try_to_cancel(struct hrtimer *timer); +static inline int hrtimer_start_expires(struct hrtimer *timer, + enum hrtimer_mode mode) +{ + return hrtimer_start(timer, hrtimer_get_expires(timer), mode); +} + static inline int hrtimer_restart(struct hrtimer *timer) { return hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS); -- cgit v1.2.3 From 799b64de256ea68fbb5db63bb55f61c305870643 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Mon, 1 Sep 2008 15:27:58 -0700 Subject: hrtimer: rename the "expires" struct member to avoid accidental usage To catch code that still touches the "expires" memory directly, rename it to have the compiler complain rather than get nasty, hard to explain, runtime behavior Signed-off-by: Arjan van de Ven --- include/linux/hrtimer.h | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 9900e998ea8f..485a634fd6e2 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -111,7 +111,7 @@ enum hrtimer_cb_mode { */ struct hrtimer { struct rb_node node; - ktime_t expires; + ktime_t _expires; enum hrtimer_restart (*function)(struct hrtimer *); struct hrtimer_clock_base *base; unsigned long state; @@ -219,41 +219,41 @@ static inline int hrtimer_is_hres_active(struct hrtimer *timer) static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) { - timer->expires = time; + timer->_expires = time; } static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) { - timer->expires.tv64 = tv64; + timer->_expires.tv64 = tv64; } static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time) { - timer->expires = ktime_add_safe(timer->expires, time); + timer->_expires = ktime_add_safe(timer->_expires, time); } static inline void hrtimer_add_expires_ns(struct hrtimer *timer, unsigned long ns) { - timer->expires = ktime_add_ns(timer->expires, ns); + timer->_expires = ktime_add_ns(timer->_expires, ns); } static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) { - return timer->expires; + return timer->_expires; } static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer) { - return timer->expires.tv64; + return timer->_expires.tv64; } static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) { - return ktime_to_ns(timer->expires); + return ktime_to_ns(timer->_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->_expires, timer->base->get_time()); } /* @@ -334,7 +334,7 @@ static inline int hrtimer_start_expires(struct hrtimer *timer, static inline int hrtimer_restart(struct hrtimer *timer) { - return hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS); + return hrtimer_start(timer, timer->_expires, HRTIMER_MODE_ABS); } /* Query timers: */ -- cgit v1.2.3 From 654c8e0b1c623b156c5b92f28d914ab38c9c2c90 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Mon, 1 Sep 2008 15:47:08 -0700 Subject: hrtimer: turn hrtimers into range timers this patch turns hrtimers into range timers; they have 2 expire points 1) the soft expire point 2) the hard expire point the kernel will do it's regular best effort attempt to get the timer run at the hard expire point. However, if some other time fires after the soft expire point, the kernel now has the freedom to fire this timer at this point, and thus grouping the events and preventing a power-expensive wakeup in the future. Signed-off-by: Arjan van de Ven --- include/linux/hrtimer.h | 31 ++++++++++++++++++++++++++- kernel/hrtimer.c | 56 +++++++++++++++++++++++++++++++++++++++++++++---- 2 files changed, 82 insertions(+), 5 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 485a634fd6e2..28259c336679 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -112,6 +112,7 @@ enum hrtimer_cb_mode { struct hrtimer { struct rb_node node; ktime_t _expires; + ktime_t _softexpires; enum hrtimer_restart (*function)(struct hrtimer *); struct hrtimer_clock_base *base; unsigned long state; @@ -220,20 +221,37 @@ static inline int hrtimer_is_hres_active(struct hrtimer *timer) static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) { timer->_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); +} + +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)); +} + static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64) { timer->_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->_softexpires = ktime_add_safe(timer->_softexpires, time); } static inline void hrtimer_add_expires_ns(struct hrtimer *timer, unsigned long ns) { timer->_expires = ktime_add_ns(timer->_expires, ns); + timer->_softexpires = ktime_add_ns(timer->_softexpires, ns); } static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) @@ -241,10 +259,19 @@ static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer) return timer->_expires; } +static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer) +{ + return timer->_softexpires; +} + static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer) { return timer->_expires.tv64; } +static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer) +{ + return timer->_softexpires.tv64; +} static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) { @@ -334,7 +361,7 @@ static inline int hrtimer_start_expires(struct hrtimer *timer, static inline int hrtimer_restart(struct hrtimer *timer) { - return hrtimer_start(timer, timer->_expires, HRTIMER_MODE_ABS); + return hrtimer_start_expires(timer, HRTIMER_MODE_ABS); } /* Query timers: */ @@ -391,6 +418,8 @@ extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *tsk); +extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta, + const enum hrtimer_mode mode); extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode); /* Soft interrupt function to run the hrtimer queues: */ diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index ae307feec74c..01483004183d 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -1309,7 +1309,20 @@ void hrtimer_interrupt(struct clock_event_device *dev) timer = rb_entry(node, struct hrtimer, node); - if (basenow.tv64 < hrtimer_get_expires_tv64(timer)) { + /* + * The immediate goal for using the softexpires is + * minimizing wakeups, not running timers at the + * earliest interrupt after their soft expiration. + * This allows us to avoid using a Priority Search + * Tree, which can answer a stabbing querry for + * overlapping intervals and instead use the simple + * BST we already have. + * We don't add extra wakeups by delaying timers that + * are right-of a not yet expired timer, because that + * timer will have to trigger a wakeup anyway. + */ + + if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) { ktime_t expires; expires = ktime_sub(hrtimer_get_expires(timer), @@ -1681,14 +1694,20 @@ void __init hrtimers_init(void) } /** - * schedule_hrtimeout - sleep until timeout + * schedule_hrtimeout_range - sleep until timeout * @expires: timeout value (ktime_t) + * @delta: slack in expires timeout (ktime_t) * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL * * Make the current task sleep until the given expiry time has * elapsed. The routine will return immediately unless * the current task state has been set (see set_current_state()). * + * The @delta argument gives the kernel the freedom to schedule the + * actual wakeup to a time that is both power and performance friendly. + * The kernel give the normal best effort behavior for "@expires+@delta", + * but may decide to fire the timer earlier, but no earlier than @expires. + * * You can set the task state as follows - * * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to @@ -1702,7 +1721,7 @@ void __init hrtimers_init(void) * * Returns 0 when the timer has expired otherwise -EINTR */ -int __sched schedule_hrtimeout(ktime_t *expires, +int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta, const enum hrtimer_mode mode) { struct hrtimer_sleeper t; @@ -1726,7 +1745,7 @@ int __sched schedule_hrtimeout(ktime_t *expires, } hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, mode); - hrtimer_set_expires(&t.timer, *expires); + hrtimer_set_expires_range_ns(&t.timer, *expires, delta); hrtimer_init_sleeper(&t, current); @@ -1744,4 +1763,33 @@ int __sched schedule_hrtimeout(ktime_t *expires, return !t.task ? 0 : -EINTR; } +EXPORT_SYMBOL_GPL(schedule_hrtimeout_range); + +/** + * schedule_hrtimeout - sleep until timeout + * @expires: timeout value (ktime_t) + * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL + * + * Make the current task sleep until the given expiry time has + * elapsed. The routine will return immediately unless + * the current task state has been set (see set_current_state()). + * + * You can set the task state as follows - + * + * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to + * pass before the routine returns. + * + * %TASK_INTERRUPTIBLE - the routine may return early if a signal is + * delivered to the current task. + * + * The current task state is guaranteed to be TASK_RUNNING when this + * routine returns. + * + * Returns 0 when the timer has expired otherwise -EINTR + */ +int __sched schedule_hrtimeout(ktime_t *expires, + const enum hrtimer_mode mode) +{ + return schedule_hrtimeout_range(expires, 0, mode); +} EXPORT_SYMBOL_GPL(schedule_hrtimeout); -- cgit v1.2.3 From 584fb4a76413ec9215741e075e0dfb69173b213f Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Sat, 6 Sep 2008 08:32:57 -0700 Subject: hrtimer: fix build bug found by Ingo in some randconfig configurations, hrtimers are used even though the hrtimer config if off; and it broke the build due to some of the new functions being on the wrong side of the ifdef. This patch moves the functions to the other side of the ifdef, fixing the build bug. Signed-off-by: Arjan van de Ven --- include/linux/hrtimer.h | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 28259c336679..c407b33ef844 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -198,13 +198,6 @@ struct hrtimer_cpu_base { #endif }; -#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); - /* * In high resolution mode the time reference must be read accurate */ @@ -283,6 +276,13 @@ static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) return ktime_sub(timer->_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); + /* * The resolution of the clocks. The resolution value is returned in * the clock_getres() system call to give application programmers an -- cgit v1.2.3 From 2ec02270c00f94b08fddfb68c37510a9fb47ac7c Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Sat, 6 Sep 2008 09:36:56 -0700 Subject: hrtimer: another build fix More randconfig testing Signed-off-by: Arjan van de Ven --- include/linux/hrtimer.h | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index c407b33ef844..4c1a834b9849 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -198,19 +198,6 @@ struct hrtimer_cpu_base { #endif }; -/* - * In high resolution mode the time reference must be read accurate - */ -static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) -{ - return timer->base->get_time(); -} - -static inline int hrtimer_is_hres_active(struct hrtimer *timer) -{ - return timer->base->cpu_base->hres_active; -} - static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time) { timer->_expires = time; @@ -283,6 +270,19 @@ extern void clock_was_set(void); extern void hres_timers_resume(void); extern void hrtimer_interrupt(struct clock_event_device *dev); +/* + * In high resolution mode the time reference must be read accurate + */ +static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) +{ + return timer->base->get_time(); +} + +static inline int hrtimer_is_hres_active(struct hrtimer *timer) +{ + return timer->base->cpu_base->hres_active; +} + /* * The resolution of the clocks. The resolution value is returned in * the clock_getres() system call to give application programmers an -- cgit v1.2.3 From da8f2e170ea94cc20f8ebbc8ee8d127edb8f12f1 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Sun, 7 Sep 2008 10:47:46 -0700 Subject: hrtimer: add a hrtimer_start_range() function this patch adds a _range version of hrtimer_start() so that range timers can be created; the hrtimer_start() function is just a wrapper around this. In addition, hrtimer_start_expires() will now preserve existing ranges. Signed-off-by: Arjan van de Ven --- include/linux/hrtimer.h | 9 ++++++++- kernel/hrtimer.c | 26 +++++++++++++++++++++++--- 2 files changed, 31 insertions(+), 4 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 4c1a834b9849..1c0473e8ecb4 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -350,13 +350,20 @@ static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { } /* Basic timer operations: */ extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode); +extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, + unsigned long range_ns, const enum hrtimer_mode mode); extern int hrtimer_cancel(struct hrtimer *timer); extern int hrtimer_try_to_cancel(struct hrtimer *timer); static inline int hrtimer_start_expires(struct hrtimer *timer, enum hrtimer_mode mode) { - return hrtimer_start(timer, hrtimer_get_expires(timer), mode); + unsigned long delta; + ktime_t soft, hard; + soft = hrtimer_get_softexpires(timer); + hard = hrtimer_get_expires(timer); + delta = ktime_to_ns(ktime_sub(hard, soft)); + return hrtimer_start_range_ns(timer, hrtimer_get_expires(timer), delta, mode); } static inline int hrtimer_restart(struct hrtimer *timer) diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 01483004183d..a0222097c57e 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -945,9 +945,10 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base) } /** - * hrtimer_start - (re)start an relative timer on the current CPU + * hrtimer_start_range_ns - (re)start an relative timer on the current CPU * @timer: the timer to be added * @tim: expiry time + * @delta_ns: "slack" range for the timer * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL) * * Returns: @@ -955,7 +956,8 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base) * 1 when the timer was active */ int -hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) +hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, unsigned long delta_ns, + const enum hrtimer_mode mode) { struct hrtimer_clock_base *base, *new_base; unsigned long flags; @@ -983,7 +985,7 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) #endif } - hrtimer_set_expires(timer, tim); + hrtimer_set_expires_range_ns(timer, tim, delta_ns); timer_stats_hrtimer_set_start_info(timer); @@ -1016,8 +1018,26 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) return ret; } +EXPORT_SYMBOL_GPL(hrtimer_start_range_ns); + +/** + * hrtimer_start - (re)start an relative timer on the current CPU + * @timer: the timer to be added + * @tim: expiry time + * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL) + * + * Returns: + * 0 on success + * 1 when the timer was active + */ +int +hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode) +{ + return hrtimer_start_range_ns(timer, tim, 0, mode); +} EXPORT_SYMBOL_GPL(hrtimer_start); + /** * hrtimer_try_to_cancel - try to deactivate a timer * @timer: hrtimer to stop -- cgit v1.2.3 From 4ce105d30e08fb8a1783c55a0e48aa3fa200c455 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Sun, 7 Sep 2008 15:31:39 -0700 Subject: hrtimer: incorporate feedback from Peter Zijlstra (based on lkml review) * use rt_task() * task_nice() has a sign Signed-off-by: Arjan van de Ven --- fs/select.c | 5 ++--- include/linux/hrtimer.h | 2 +- 2 files changed, 3 insertions(+), 4 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/fs/select.c b/fs/select.c index 5e61b43d0766..fdd8584e536d 100644 --- a/fs/select.c +++ b/fs/select.c @@ -46,7 +46,7 @@ static unsigned long __estimate_accuracy(struct timespec *tv) unsigned long slack; int divfactor = 1000; - if (task_nice(current)) + if (task_nice(current) > 0) divfactor = divfactor / 5; slack = tv->tv_nsec / divfactor; @@ -66,8 +66,7 @@ static unsigned long estimate_accuracy(struct timespec *tv) * Realtime tasks get a slack of 0 for obvious reasons. */ - if (current->policy == SCHED_FIFO || - current->policy == SCHED_RR) + if (rt_task(current)) return 0; ktime_get_ts(&now); diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 1c0473e8ecb4..95db11f62ff2 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -363,7 +363,7 @@ static inline int hrtimer_start_expires(struct hrtimer *timer, soft = hrtimer_get_softexpires(timer); hard = hrtimer_get_expires(timer); delta = ktime_to_ns(ktime_sub(hard, soft)); - return hrtimer_start_range_ns(timer, hrtimer_get_expires(timer), delta, mode); + return hrtimer_start_range_ns(timer, soft, delta, mode); } static inline int hrtimer_restart(struct hrtimer *timer) -- cgit v1.2.3 From 2e94d1f71f7e4404d997e6fb4f1618aa147d76f9 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Wed, 10 Sep 2008 16:06:00 -0700 Subject: hrtimer: peek at the timer queue just before going idle As part of going idle, we already look at the time of the next timer event to determine which C-state to select etc. This patch adds functionality that causes the timers that are past their soft expire time, to fire at this time, before we calculate the next wakeup time. This functionality will thus avoid wakeups by running timers before going idle rather than specially waking up for it. Signed-off-by: Arjan van de Ven --- drivers/cpuidle/cpuidle.c | 7 +++++++ include/linux/hrtimer.h | 5 +++++ kernel/hrtimer.c | 30 ++++++++++++++++++++++++++++++ 3 files changed, 42 insertions(+) (limited to 'include/linux/hrtimer.h') diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 5ce07b517c58..2e3148499368 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -16,6 +16,7 @@ #include #include #include +#include #include "cpuidle.h" @@ -60,6 +61,12 @@ static void cpuidle_idle_call(void) return; } + /* + * run any timers that can be run now, at this point + * before calculating the idle duration etc. + */ + hrtimer_peek_ahead_timers(); + /* ask the governor for the next state */ next_state = cpuidle_curr_governor->select(dev); if (need_resched()) diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 95db11f62ff2..d93b1e1dc169 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -326,6 +326,11 @@ static inline int hrtimer_is_hres_active(struct hrtimer *timer) extern ktime_t ktime_get(void); extern ktime_t ktime_get_real(void); + +DECLARE_PER_CPU(struct tick_device, tick_cpu_device); +extern void hrtimer_peek_ahead_timers(void); + + /* Exported timer functions: */ /* Initialize timers: */ diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 9a4c90185566..eb2cf984959f 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -1381,6 +1381,36 @@ void hrtimer_interrupt(struct clock_event_device *dev) raise_softirq(HRTIMER_SOFTIRQ); } +/** + * hrtimer_peek_ahead_timers -- run soft-expired timers now + * + * hrtimer_peek_ahead_timers will peek at the timer queue of + * the current cpu and check if there are any timers for which + * the soft expires time has passed. If any such timers exist, + * they are run immediately and then removed from the timer queue. + * + */ +void hrtimer_peek_ahead_timers(void) +{ + unsigned long flags; + struct tick_device *td; + struct clock_event_device *dev; + + if (hrtimer_hres_active()) + return; + + local_irq_save(flags); + td = &__get_cpu_var(tick_cpu_device); + if (!td) + goto out; + dev = td->evtdev; + if (!dev) + goto out; + hrtimer_interrupt(dev); +out: + local_irq_restore(flags); +} + static void run_hrtimer_softirq(struct softirq_action *h) { run_hrtimer_pending(&__get_cpu_var(hrtimer_bases)); -- cgit v1.2.3 From d7cfb60c5cf904ecf1e0ae23ec178175b86f0d4a Mon Sep 17 00:00:00 2001 From: Mark McLoughlin Date: Fri, 19 Sep 2008 13:13:44 +0100 Subject: hrtimer: remove hrtimer_clock_base::get_softirq_time() Peter Zijlstra noticed this 8 months ago and I just noticed it again. hrtimer_clock_base::get_softirq_time() is currently unused in the entire tree. In fact, looking at the logs, it appears as if it was never used. Remove it. Signed-off-by: Mark McLoughlin Signed-off-by: Ingo Molnar --- include/linux/hrtimer.h | 2 -- kernel/hrtimer.c | 4 +--- 2 files changed, 1 insertion(+), 5 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 6d93dce61cbb..1b079bd29c35 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -145,7 +145,6 @@ struct hrtimer_sleeper { * @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 - * @get_softirq_time: function to retrieve the current time from the softirq * @softirq_time: the time when running the hrtimer queue in the softirq * @offset: offset of this clock to the monotonic base * @reprogram: function to reprogram the timer event @@ -157,7 +156,6 @@ struct hrtimer_clock_base { struct rb_node *first; ktime_t resolution; ktime_t (*get_time)(void); - ktime_t (*get_softirq_time)(void); ktime_t softirq_time; #ifdef CONFIG_HIGH_RES_TIMERS ktime_t offset; diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 03ea1378c43b..4d761d50c529 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -1401,9 +1401,7 @@ void hrtimer_run_queues(void) if (!base->first) continue; - if (base->get_softirq_time) - base->softirq_time = base->get_softirq_time(); - else if (gettime) { + if (gettime) { hrtimer_get_softirq_time(cpu_base); gettime = 0; } -- cgit v1.2.3 From b91c4996df56fcd201f85c392a1de7bc3f6641f5 Mon Sep 17 00:00:00 2001 From: Mark McLoughlin Date: Fri, 19 Sep 2008 13:13:48 +0100 Subject: hrtimer: remove hrtimer_clock_base::reprogram() hrtimer_clock_base::reprogram() also appears to never have been used, so remove it. Signed-off-by: Mark McLoughlin Signed-off-by: Ingo Molnar --- include/linux/hrtimer.h | 4 ---- 1 file changed, 4 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 1b079bd29c35..68b0196d8696 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -147,7 +147,6 @@ struct hrtimer_sleeper { * @get_time: function to retrieve the current time of the clock * @softirq_time: the time when running the hrtimer queue in the softirq * @offset: offset of this clock to the monotonic base - * @reprogram: function to reprogram the timer event */ struct hrtimer_clock_base { struct hrtimer_cpu_base *cpu_base; @@ -159,9 +158,6 @@ struct hrtimer_clock_base { ktime_t softirq_time; #ifdef CONFIG_HIGH_RES_TIMERS ktime_t offset; - int (*reprogram)(struct hrtimer *t, - struct hrtimer_clock_base *b, - ktime_t n); #endif }; -- cgit v1.2.3 From 1b02469088ac7a13d7e622b618b7410d0f1ce5ec Mon Sep 17 00:00:00 2001 From: Richard Kennedy Date: Mon, 22 Sep 2008 14:42:43 -0700 Subject: hrtimer: reorder struct hrtimer to save 8 bytes on 64bit builds reorder struct hrtimer to save 8 bytes on 64 bit builds when CONFIG_TIMER_STATS selected. (also removes 8 bytes from signal_struct) Signed-off-by: Richard Kennedy Signed-off-by: Andrew Morton Signed-off-by: Thomas Gleixner --- include/linux/hrtimer.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 68b0196d8696..8730b60c9432 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -115,12 +115,12 @@ struct hrtimer { enum hrtimer_restart (*function)(struct hrtimer *); struct hrtimer_clock_base *base; unsigned long state; - enum hrtimer_cb_mode cb_mode; struct list_head cb_entry; + enum hrtimer_cb_mode cb_mode; #ifdef CONFIG_TIMER_STATS + int start_pid; void *start_site; char start_comm[16]; - int start_pid; #endif }; -- cgit v1.2.3 From b00c1a99e7758f794923c61e5cd55268d61c9469 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 29 Sep 2008 15:44:46 +0200 Subject: hrtimer: mark migration state Impact: during migration active hrtimers can be seen as inactive The migration code removes the hrtimers from the queues of the dead CPU and sets the state temporary to INACTIVE. The enqueue code sets it to ACTIVE/PENDING again. Prevent that the wrong state can be seen by using a separate migration state bit. Signed-off-by: Thomas Gleixner --- include/linux/hrtimer.h | 4 +++- kernel/hrtimer.c | 12 ++++++++++-- 2 files changed, 13 insertions(+), 3 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 6d93dce61cbb..bdd88df1b4e5 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -67,9 +67,10 @@ enum hrtimer_cb_mode { * 0x02 callback function running * 0x04 callback pending (high resolution mode) * - * Special case: + * Special cases: * 0x03 callback function running and enqueued * (was requeued on another CPU) + * 0x09 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 @@ -87,6 +88,7 @@ enum hrtimer_cb_mode { #define HRTIMER_STATE_ENQUEUED 0x01 #define HRTIMER_STATE_CALLBACK 0x02 #define HRTIMER_STATE_PENDING 0x04 +#define HRTIMER_STATE_MIGRATE 0x08 /** * struct hrtimer - the basic hrtimer structure diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index ac2f6d6d4868..ace723dd1e52 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -1602,7 +1602,13 @@ static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base, timer = rb_entry(node, struct hrtimer, node); BUG_ON(hrtimer_callback_running(timer)); debug_hrtimer_deactivate(timer); - __remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE, 0); + + /* + * Mark it as STATE_MIGRATE not INACTIVE otherwise the + * timer could be seen as !active and just vanish away + * under us on another CPU + */ + __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0); timer->base = new_base; /* * Enqueue the timer. Allow reprogramming of the event device @@ -1620,13 +1626,15 @@ static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base, * state, we need to do that otherwise we end up with * a stale timer. */ - if (timer->state == HRTIMER_STATE_INACTIVE) { + if (timer->state == HRTIMER_STATE_MIGRATE) { timer->state = HRTIMER_STATE_PENDING; list_add_tail(&timer->cb_entry, &new_base->cpu_base->cb_pending); raise = 1; } #endif + /* Clear the migration state bit */ + timer->state &= ~HRTIMER_STATE_MIGRATE; } return raise; } -- cgit v1.2.3 From ccc7dadf736639da86f3e0c86832c11a66fc8221 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 29 Sep 2008 15:47:42 +0200 Subject: hrtimer: prevent migration of per CPU hrtimers Impact: per CPU hrtimers can be migrated from a dead CPU The hrtimer code has no knowledge about per CPU timers, but we need to prevent the migration of such timers and warn when such a timer is active at migration time. Explicitely mark the timers as per CPU and use a more understandable mode descriptor for the interrupts safe unlocked callback mode, which is used by hrtimer_sleeper and the scheduler code. Signed-off-by: Thomas Gleixner --- include/linux/hrtimer.h | 14 +++++++++++--- kernel/hrtimer.c | 37 +++++++++++++++++++++++++------------ kernel/sched.c | 4 ++-- kernel/time/tick-sched.c | 2 +- kernel/trace/trace_sysprof.c | 2 +- 5 files changed, 40 insertions(+), 19 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index bdd88df1b4e5..2f245fe63bda 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -47,14 +47,22 @@ enum hrtimer_restart { * HRTIMER_CB_IRQSAFE: Callback may run in hardirq context * HRTIMER_CB_IRQSAFE_NO_RESTART: Callback may run in hardirq context and * does not restart the timer - * HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: Callback must run in hardirq context - * Special mode for tick emultation + * HRTIMER_CB_IRQSAFE_PERCPU: Callback must run in hardirq context + * Special mode for tick emulation and + * scheduler timer. Such timers are per + * cpu and not allowed to be migrated on + * cpu unplug. + * HRTIMER_CB_IRQSAFE_UNLOCKED: Callback should run in hardirq context + * with timer->base lock unlocked + * used for timers which call wakeup to + * avoid lock order problems with rq->lock */ enum hrtimer_cb_mode { HRTIMER_CB_SOFTIRQ, HRTIMER_CB_IRQSAFE, HRTIMER_CB_IRQSAFE_NO_RESTART, - HRTIMER_CB_IRQSAFE_NO_SOFTIRQ, + HRTIMER_CB_IRQSAFE_PERCPU, + HRTIMER_CB_IRQSAFE_UNLOCKED, }; /* diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index ace723dd1e52..cdec83e722fa 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -672,13 +672,14 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, */ BUG_ON(timer->function(timer) != HRTIMER_NORESTART); return 1; - case HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: + case HRTIMER_CB_IRQSAFE_PERCPU: + case HRTIMER_CB_IRQSAFE_UNLOCKED: /* * This is solely for the sched tick emulation with * dynamic tick support to ensure that we do not * restart the tick right on the edge and end up with * the tick timer in the softirq ! The calling site - * takes care of this. + * takes care of this. Also used for hrtimer sleeper ! */ debug_hrtimer_deactivate(timer); return 1; @@ -1245,7 +1246,8 @@ static void __run_hrtimer(struct hrtimer *timer) timer_stats_account_hrtimer(timer); fn = timer->function; - if (timer->cb_mode == HRTIMER_CB_IRQSAFE_NO_SOFTIRQ) { + if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU || + timer->cb_mode == HRTIMER_CB_IRQSAFE_UNLOCKED) { /* * Used for scheduler timers, avoid lock inversion with * rq->lock and tasklist_lock. @@ -1452,7 +1454,7 @@ void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task) sl->timer.function = hrtimer_wakeup; sl->task = task; #ifdef CONFIG_HIGH_RES_TIMERS - sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ; + sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_UNLOCKED; #endif } @@ -1592,7 +1594,7 @@ static void __cpuinit init_hrtimers_cpu(int cpu) #ifdef CONFIG_HOTPLUG_CPU static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base, - struct hrtimer_clock_base *new_base) + struct hrtimer_clock_base *new_base, int dcpu) { struct hrtimer *timer; struct rb_node *node; @@ -1603,6 +1605,18 @@ static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base, BUG_ON(hrtimer_callback_running(timer)); debug_hrtimer_deactivate(timer); + /* + * Should not happen. Per CPU timers should be + * canceled _before_ the migration code is called + */ + if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU) { + __remove_hrtimer(timer, old_base, + HRTIMER_STATE_INACTIVE, 0); + WARN(1, "hrtimer (%p %p)active but cpu %d dead\n", + timer, timer->function, dcpu); + continue; + } + /* * Mark it as STATE_MIGRATE not INACTIVE otherwise the * timer could be seen as !active and just vanish away @@ -1619,12 +1633,11 @@ static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base, /* * Happens with high res enabled when the timer was * already expired and the callback mode is - * HRTIMER_CB_IRQSAFE_NO_SOFTIRQ - * (hrtimer_sleeper). The enqueue code does not move - * them to the soft irq pending list for - * performance/latency reasons, but in the migration - * state, we need to do that otherwise we end up with - * a stale timer. + * HRTIMER_CB_IRQSAFE_UNLOCKED (hrtimer_sleeper). The + * enqueue code does not move them to the soft irq + * pending list for performance/latency reasons, but + * in the migration state, we need to do that + * otherwise we end up with a stale timer. */ if (timer->state == HRTIMER_STATE_MIGRATE) { timer->state = HRTIMER_STATE_PENDING; @@ -1682,7 +1695,7 @@ static void migrate_hrtimers(int cpu) for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) { if (migrate_hrtimer_list(&old_base->clock_base[i], - &new_base->clock_base[i])) + &new_base->clock_base[i], cpu)) raise = 1; } diff --git a/kernel/sched.c b/kernel/sched.c index 13dd2db9fb2d..ad1962dc0aa2 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -201,7 +201,7 @@ void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime) hrtimer_init(&rt_b->rt_period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); rt_b->rt_period_timer.function = sched_rt_period_timer; - rt_b->rt_period_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ; + rt_b->rt_period_timer.cb_mode = HRTIMER_CB_IRQSAFE_UNLOCKED; } static void start_rt_bandwidth(struct rt_bandwidth *rt_b) @@ -1119,7 +1119,7 @@ static void init_rq_hrtick(struct rq *rq) hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); rq->hrtick_timer.function = hrtick; - rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ; + rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_PERCPU; } #else static inline void hrtick_clear(struct rq *rq) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 39019b3f7621..cb02324bdb88 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -625,7 +625,7 @@ void tick_setup_sched_timer(void) */ hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); ts->sched_timer.function = tick_sched_timer; - ts->sched_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ; + ts->sched_timer.cb_mode = HRTIMER_CB_IRQSAFE_PERCPU; /* Get the next period (per cpu) */ ts->sched_timer.expires = tick_init_jiffy_update(); diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c index bb948e52ce20..db58fb66a135 100644 --- a/kernel/trace/trace_sysprof.c +++ b/kernel/trace/trace_sysprof.c @@ -202,7 +202,7 @@ static void start_stack_timer(int cpu) hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); hrtimer->function = stack_trace_timer_fn; - hrtimer->cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ; + hrtimer->cb_mode = HRTIMER_CB_IRQSAFE_PERCPU; hrtimer_start(hrtimer, ns_to_ktime(sample_period), HRTIMER_MODE_REL); } -- cgit v1.2.3 From 2075eb8d95612cadde91ef5be82691d97a2ea6c5 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Tue, 7 Oct 2008 10:57:54 -0700 Subject: rangetimer: fix x86 build failure for the !HRTIMERS case the timer peek function was on the wrong side of an ifdef, breaking for the !HRTIMERs case. Just provide an empty inline for that case since it doesn't make sense in that scenario. Signed-off-by: Arjan van de Ven --- include/linux/hrtimer.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index d93b1e1dc169..508ce20b8f9c 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -283,6 +283,8 @@ static inline int hrtimer_is_hres_active(struct hrtimer *timer) return timer->base->cpu_base->hres_active; } +extern void hrtimer_peek_ahead_timers(void); + /* * The resolution of the clocks. The resolution value is returned in * the clock_getres() system call to give application programmers an @@ -305,6 +307,7 @@ static inline int hrtimer_is_hres_active(struct hrtimer *timer) * 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) { } @@ -328,7 +331,6 @@ extern ktime_t ktime_get_real(void); DECLARE_PER_CPU(struct tick_device, tick_cpu_device); -extern void hrtimer_peek_ahead_timers(void); /* Exported timer functions: */ -- cgit v1.2.3 From 40b8606253552109815786e5d4b0de98782d31f5 Mon Sep 17 00:00:00 2001 From: Stephen Rothwell Date: Wed, 15 Oct 2008 14:20:28 +1100 Subject: DECLARE_PER_CPU needs linux/percpu.h Signed-off-by: Stephen Rothwell --- include/linux/hrtimer.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 508ce20b8f9c..1e6f731381d9 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -20,6 +20,8 @@ #include #include #include +#include + struct hrtimer_clock_base; struct hrtimer_cpu_base; -- cgit v1.2.3 From 592aa999d6a272856c9bfbdaac0cfba1bb37c24c Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 20 Oct 2008 16:38:19 +0200 Subject: hrtimers: add missing docbook comments to struct hrtimer Signed-off-by: Thomas Gleixner --- include/linux/hrtimer.h | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index cb25c1cc2352..58bca8e9bae1 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -103,9 +103,14 @@ enum hrtimer_cb_mode { /** * struct hrtimer - the basic hrtimer structure * @node: red black tree node for time ordered insertion - * @expires: the absolute expiry time in the hrtimers internal + * @_expires: the absolute expiry time in the hrtimers internal * representation. The time is related to the clock on - * which the timer is based. + * which the timer is based. Is setup by adding + * slack to the _softexpires value. For non range timers + * identical to _softexpires. + * @_softexpires: the absolute earliest expiry time of the hrtimer. + * The time which was given as expiry time when the timer + * was armed. * @function: timer expiry callback function * @base: pointer to the timer base (per cpu and per clock) * @state: state information (See bit values above) -- cgit v1.2.3