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authorLinus Torvalds <torvalds@linux-foundation.org>2021-08-30 15:31:33 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-08-30 15:31:33 -0700
commit8596e589b787732c8346f0482919e83cc9362db1 (patch)
tree9cab365d272edc26e506daa0a89aec1adf3b02d7 /kernel
parentbed91667415be768be4e5d7691011f2b5e16d796 (diff)
parentd25a025201ed98f4b93775e0999a3f2135702106 (diff)
downloadlinux-8596e589b787732c8346f0482919e83cc9362db1.tar.bz2
Merge tag 'timers-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner: "Updates for timekeeping, timers and related drivers: Core code: - Cure a couple of correctness issues in the posix CPU timer code to prevent that the tick dependency for NOHZ full is kept alive for no reason. - Avoid expensive double reprogramming of the clockevent device in hrtimer_start_range_ns(). - Avoid pointless SMP function calls when the clock was set to avoid disturbing CPUs which do not have any affected timers queued. - Make the clocksource watchdog test work correctly when CONFIG_HZ is less than 100. Drivers: - Prefer the ARM architected timer over the Exynos timer which is way more expensive to access. - Add device tree bindings for new Ingenic SoCs - The usual improvements and cleanups all over the place" * tag 'timers-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (29 commits) clocksource: Make clocksource watchdog test safe for slow-HZ systems dt-bindings: timer: Add ABIs for new Ingenic SoCs clocksource/drivers/fttmr010: Pass around less pointers clocksource/drivers/mediatek: Optimize systimer irq clear flow on shutdown clocksource/drivers/ingenic: Use bitfield macro helpers clocksource/drivers/sh_cmt: Fix wrong setting if don't request IRQ for clock source channel dt-bindings: timer: convert rockchip,rk-timer.txt to YAML clocksource/drivers/exynos_mct: Mark MCT device as CLOCK_EVT_FEAT_PERCPU clocksource/drivers/exynos_mct: Prioritise Arm arch timer on arm64 hrtimer: Unbreak hrtimer_force_reprogram() hrtimer: Use raw_cpu_ptr() in clock_was_set() hrtimer: Avoid more SMP function calls in clock_was_set() hrtimer: Avoid unnecessary SMP function calls in clock_was_set() hrtimer: Add bases argument to clock_was_set() time/timekeeping: Avoid invoking clock_was_set() twice timekeeping: Distangle resume and clock-was-set events timerfd: Provide timerfd_resume() hrtimer: Force clock_was_set() handling for the HIGHRES=n, NOHZ=y case hrtimer: Ensure timerfd notification for HIGHRES=n hrtimer: Consolidate reprogramming code ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/signal.c15
-rw-r--r--kernel/time/clocksource-wdtest.c5
-rw-r--r--kernel/time/clocksource.c6
-rw-r--r--kernel/time/hrtimer.c340
-rw-r--r--kernel/time/jiffies.c21
-rw-r--r--kernel/time/posix-cpu-timers.c90
-rw-r--r--kernel/time/posix-timers.c2
-rw-r--r--kernel/time/tick-common.c7
-rw-r--r--kernel/time/tick-internal.h32
-rw-r--r--kernel/time/timekeeping.c36
10 files changed, 398 insertions, 156 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index a3229add4455..52b6abec0ff8 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1413,6 +1413,21 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
return sighand;
}
+#ifdef CONFIG_LOCKDEP
+void lockdep_assert_task_sighand_held(struct task_struct *task)
+{
+ struct sighand_struct *sighand;
+
+ rcu_read_lock();
+ sighand = rcu_dereference(task->sighand);
+ if (sighand)
+ lockdep_assert_held(&sighand->siglock);
+ else
+ WARN_ON_ONCE(1);
+ rcu_read_unlock();
+}
+#endif
+
/*
* send signal info to all the members of a group
*/
diff --git a/kernel/time/clocksource-wdtest.c b/kernel/time/clocksource-wdtest.c
index 01df12395c0e..df922f49d171 100644
--- a/kernel/time/clocksource-wdtest.c
+++ b/kernel/time/clocksource-wdtest.c
@@ -19,6 +19,8 @@
#include <linux/prandom.h>
#include <linux/cpu.h>
+#include "tick-internal.h"
+
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul E. McKenney <paulmck@kernel.org>");
@@ -34,9 +36,6 @@ static u64 wdtest_jiffies_read(struct clocksource *cs)
return (u64)jiffies;
}
-/* Assume HZ > 100. */
-#define JIFFIES_SHIFT 8
-
static struct clocksource clocksource_wdtest_jiffies = {
.name = "wdtest-jiffies",
.rating = 1, /* lowest valid rating*/
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index b89c76e1c02c..b8a14d2fb5ba 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -306,12 +306,12 @@ void clocksource_verify_percpu(struct clocksource *cs)
return;
cpumask_clear(&cpus_ahead);
cpumask_clear(&cpus_behind);
- get_online_cpus();
+ cpus_read_lock();
preempt_disable();
clocksource_verify_choose_cpus();
if (cpumask_weight(&cpus_chosen) == 0) {
preempt_enable();
- put_online_cpus();
+ cpus_read_unlock();
pr_warn("Not enough CPUs to check clocksource '%s'.\n", cs->name);
return;
}
@@ -337,7 +337,7 @@ void clocksource_verify_percpu(struct clocksource *cs)
cs_nsec_min = cs_nsec;
}
preempt_enable();
- put_online_cpus();
+ cpus_read_unlock();
if (!cpumask_empty(&cpus_ahead))
pr_warn(" CPUs %*pbl ahead of CPU %d for clocksource %s.\n",
cpumask_pr_args(&cpus_ahead), testcpu, cs->name);
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 4a66725b1d4a..0ea8702eb516 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -652,21 +652,10 @@ static inline int hrtimer_hres_active(void)
return __hrtimer_hres_active(this_cpu_ptr(&hrtimer_bases));
}
-/*
- * Reprogram the event source with checking both queues for the
- * next event
- * Called with interrupts disabled and base->lock held
- */
-static void
-hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
+static void __hrtimer_reprogram(struct hrtimer_cpu_base *cpu_base,
+ struct hrtimer *next_timer,
+ ktime_t expires_next)
{
- ktime_t expires_next;
-
- expires_next = hrtimer_update_next_event(cpu_base);
-
- if (skip_equal && expires_next == cpu_base->expires_next)
- return;
-
cpu_base->expires_next = expires_next;
/*
@@ -689,7 +678,25 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
if (!__hrtimer_hres_active(cpu_base) || cpu_base->hang_detected)
return;
- tick_program_event(cpu_base->expires_next, 1);
+ tick_program_event(expires_next, 1);
+}
+
+/*
+ * Reprogram the event source with checking both queues for the
+ * next event
+ * Called with interrupts disabled and base->lock held
+ */
+static void
+hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
+{
+ ktime_t expires_next;
+
+ expires_next = hrtimer_update_next_event(cpu_base);
+
+ if (skip_equal && expires_next == cpu_base->expires_next)
+ return;
+
+ __hrtimer_reprogram(cpu_base, cpu_base->next_timer, expires_next);
}
/* High resolution timer related functions */
@@ -720,23 +727,7 @@ static inline int hrtimer_is_hres_enabled(void)
return hrtimer_hres_enabled;
}
-/*
- * Retrigger next event is called after clock was set
- *
- * Called with interrupts disabled via on_each_cpu()
- */
-static void retrigger_next_event(void *arg)
-{
- struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
-
- if (!__hrtimer_hres_active(base))
- return;
-
- raw_spin_lock(&base->lock);
- hrtimer_update_base(base);
- hrtimer_force_reprogram(base, 0);
- raw_spin_unlock(&base->lock);
-}
+static void retrigger_next_event(void *arg);
/*
* Switch to high resolution mode
@@ -758,29 +749,54 @@ static void hrtimer_switch_to_hres(void)
retrigger_next_event(NULL);
}
-static void clock_was_set_work(struct work_struct *work)
-{
- clock_was_set();
-}
+#else
-static DECLARE_WORK(hrtimer_work, clock_was_set_work);
+static inline int hrtimer_is_hres_enabled(void) { return 0; }
+static inline void hrtimer_switch_to_hres(void) { }
+#endif /* CONFIG_HIGH_RES_TIMERS */
/*
- * Called from timekeeping and resume code to reprogram the hrtimer
- * interrupt device on all cpus.
+ * Retrigger next event is called after clock was set with interrupts
+ * disabled through an SMP function call or directly from low level
+ * resume code.
+ *
+ * This is only invoked when:
+ * - CONFIG_HIGH_RES_TIMERS is enabled.
+ * - CONFIG_NOHZ_COMMON is enabled
+ *
+ * For the other cases this function is empty and because the call sites
+ * are optimized out it vanishes as well, i.e. no need for lots of
+ * #ifdeffery.
*/
-void clock_was_set_delayed(void)
+static void retrigger_next_event(void *arg)
{
- schedule_work(&hrtimer_work);
-}
-
-#else
+ struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
-static inline int hrtimer_is_hres_enabled(void) { return 0; }
-static inline void hrtimer_switch_to_hres(void) { }
-static inline void retrigger_next_event(void *arg) { }
+ /*
+ * When high resolution mode or nohz is active, then the offsets of
+ * CLOCK_REALTIME/TAI/BOOTTIME have to be updated. Otherwise the
+ * next tick will take care of that.
+ *
+ * If high resolution mode is active then the next expiring timer
+ * must be reevaluated and the clock event device reprogrammed if
+ * necessary.
+ *
+ * In the NOHZ case the update of the offset and the reevaluation
+ * of the next expiring timer is enough. The return from the SMP
+ * function call will take care of the reprogramming in case the
+ * CPU was in a NOHZ idle sleep.
+ */
+ if (!__hrtimer_hres_active(base) && !tick_nohz_active)
+ return;
-#endif /* CONFIG_HIGH_RES_TIMERS */
+ raw_spin_lock(&base->lock);
+ hrtimer_update_base(base);
+ if (__hrtimer_hres_active(base))
+ hrtimer_force_reprogram(base, 0);
+ else
+ hrtimer_update_next_event(base);
+ raw_spin_unlock(&base->lock);
+}
/*
* When a timer is enqueued and expires earlier than the already enqueued
@@ -835,75 +851,161 @@ static void hrtimer_reprogram(struct hrtimer *timer, bool reprogram)
if (base->cpu_base != cpu_base)
return;
+ if (expires >= cpu_base->expires_next)
+ return;
+
/*
- * If the hrtimer interrupt is running, then it will
- * reevaluate the clock bases and reprogram the clock event
- * device. The callbacks are always executed in hard interrupt
- * context so we don't need an extra check for a running
- * callback.
+ * If the hrtimer interrupt is running, then it will reevaluate the
+ * clock bases and reprogram the clock event device.
*/
if (cpu_base->in_hrtirq)
return;
- if (expires >= cpu_base->expires_next)
- return;
-
- /* Update the pointer to the next expiring timer */
cpu_base->next_timer = timer;
- cpu_base->expires_next = expires;
+
+ __hrtimer_reprogram(cpu_base, timer, expires);
+}
+
+static bool update_needs_ipi(struct hrtimer_cpu_base *cpu_base,
+ unsigned int active)
+{
+ struct hrtimer_clock_base *base;
+ unsigned int seq;
+ ktime_t expires;
/*
- * If hres is not active, hardware does not have to be
- * programmed yet.
+ * Update the base offsets unconditionally so the following
+ * checks whether the SMP function call is required works.
*
- * If a hang was detected in the last timer interrupt then we
- * do not schedule a timer which is earlier than the expiry
- * which we enforced in the hang detection. We want the system
- * to make progress.
+ * The update is safe even when the remote CPU is in the hrtimer
+ * interrupt or the hrtimer soft interrupt and expiring affected
+ * bases. Either it will see the update before handling a base or
+ * it will see it when it finishes the processing and reevaluates
+ * the next expiring timer.
*/
- if (!__hrtimer_hres_active(cpu_base) || cpu_base->hang_detected)
- return;
+ seq = cpu_base->clock_was_set_seq;
+ hrtimer_update_base(cpu_base);
+
+ /*
+ * If the sequence did not change over the update then the
+ * remote CPU already handled it.
+ */
+ if (seq == cpu_base->clock_was_set_seq)
+ return false;
+
+ /*
+ * If the remote CPU is currently handling an hrtimer interrupt, it
+ * will reevaluate the first expiring timer of all clock bases
+ * before reprogramming. Nothing to do here.
+ */
+ if (cpu_base->in_hrtirq)
+ return false;
/*
- * Program the timer hardware. We enforce the expiry for
- * events which are already in the past.
+ * Walk the affected clock bases and check whether the first expiring
+ * timer in a clock base is moving ahead of the first expiring timer of
+ * @cpu_base. If so, the IPI must be invoked because per CPU clock
+ * event devices cannot be remotely reprogrammed.
*/
- tick_program_event(expires, 1);
+ active &= cpu_base->active_bases;
+
+ for_each_active_base(base, cpu_base, active) {
+ struct timerqueue_node *next;
+
+ next = timerqueue_getnext(&base->active);
+ expires = ktime_sub(next->expires, base->offset);
+ if (expires < cpu_base->expires_next)
+ return true;
+
+ /* Extra check for softirq clock bases */
+ if (base->clockid < HRTIMER_BASE_MONOTONIC_SOFT)
+ continue;
+ if (cpu_base->softirq_activated)
+ continue;
+ if (expires < cpu_base->softirq_expires_next)
+ return true;
+ }
+ return false;
}
/*
- * Clock realtime was set
- *
- * Change the offset of the realtime clock vs. the monotonic
- * clock.
+ * Clock was set. This might affect CLOCK_REALTIME, CLOCK_TAI and
+ * CLOCK_BOOTTIME (for late sleep time injection).
*
- * We might have to reprogram the high resolution timer interrupt. On
- * SMP we call the architecture specific code to retrigger _all_ high
- * resolution timer interrupts. On UP we just disable interrupts and
- * call the high resolution interrupt code.
+ * This requires to update the offsets for these clocks
+ * vs. CLOCK_MONOTONIC. When high resolution timers are enabled, then this
+ * also requires to eventually reprogram the per CPU clock event devices
+ * when the change moves an affected timer ahead of the first expiring
+ * timer on that CPU. Obviously remote per CPU clock event devices cannot
+ * be reprogrammed. The other reason why an IPI has to be sent is when the
+ * system is in !HIGH_RES and NOHZ mode. The NOHZ mode updates the offsets
+ * in the tick, which obviously might be stopped, so this has to bring out
+ * the remote CPU which might sleep in idle to get this sorted.
*/
-void clock_was_set(void)
+void clock_was_set(unsigned int bases)
{
-#ifdef CONFIG_HIGH_RES_TIMERS
- /* Retrigger the CPU local events everywhere */
- on_each_cpu(retrigger_next_event, NULL, 1);
-#endif
+ struct hrtimer_cpu_base *cpu_base = raw_cpu_ptr(&hrtimer_bases);
+ cpumask_var_t mask;
+ int cpu;
+
+ if (!__hrtimer_hres_active(cpu_base) && !tick_nohz_active)
+ goto out_timerfd;
+
+ if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) {
+ on_each_cpu(retrigger_next_event, NULL, 1);
+ goto out_timerfd;
+ }
+
+ /* Avoid interrupting CPUs if possible */
+ cpus_read_lock();
+ for_each_online_cpu(cpu) {
+ unsigned long flags;
+
+ cpu_base = &per_cpu(hrtimer_bases, cpu);
+ raw_spin_lock_irqsave(&cpu_base->lock, flags);
+
+ if (update_needs_ipi(cpu_base, bases))
+ cpumask_set_cpu(cpu, mask);
+
+ raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
+ }
+
+ preempt_disable();
+ smp_call_function_many(mask, retrigger_next_event, NULL, 1);
+ preempt_enable();
+ cpus_read_unlock();
+ free_cpumask_var(mask);
+
+out_timerfd:
timerfd_clock_was_set();
}
+static void clock_was_set_work(struct work_struct *work)
+{
+ clock_was_set(CLOCK_SET_WALL);
+}
+
+static DECLARE_WORK(hrtimer_work, clock_was_set_work);
+
+/*
+ * Called from timekeeping code to reprogram the hrtimer interrupt device
+ * on all cpus and to notify timerfd.
+ */
+void clock_was_set_delayed(void)
+{
+ schedule_work(&hrtimer_work);
+}
+
/*
- * During resume we might have to reprogram the high resolution timer
- * interrupt on all online CPUs. However, all other CPUs will be
- * stopped with IRQs interrupts disabled so the clock_was_set() call
- * must be deferred.
+ * Called during resume either directly from via timekeeping_resume()
+ * or in the case of s2idle from tick_unfreeze() to ensure that the
+ * hrtimers are up to date.
*/
-void hrtimers_resume(void)
+void hrtimers_resume_local(void)
{
lockdep_assert_irqs_disabled();
/* Retrigger on the local CPU */
retrigger_next_event(NULL);
- /* And schedule a retrigger for all others */
- clock_was_set_delayed();
}
/*
@@ -1030,12 +1132,13 @@ static void __remove_hrtimer(struct hrtimer *timer,
* remove hrtimer, called with base lock held
*/
static inline int
-remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base, bool restart)
+remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base,
+ bool restart, bool keep_local)
{
u8 state = timer->state;
if (state & HRTIMER_STATE_ENQUEUED) {
- int reprogram;
+ bool reprogram;
/*
* Remove the timer and force reprogramming when high
@@ -1048,8 +1151,16 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base, bool rest
debug_deactivate(timer);
reprogram = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
+ /*
+ * If the timer is not restarted then reprogramming is
+ * required if the timer is local. If it is local and about
+ * to be restarted, avoid programming it twice (on removal
+ * and a moment later when it's requeued).
+ */
if (!restart)
state = HRTIMER_STATE_INACTIVE;
+ else
+ reprogram &= !keep_local;
__remove_hrtimer(timer, base, state, reprogram);
return 1;
@@ -1103,9 +1214,31 @@ static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
struct hrtimer_clock_base *base)
{
struct hrtimer_clock_base *new_base;
+ bool force_local, first;
- /* Remove an active timer from the queue: */
- remove_hrtimer(timer, base, true);
+ /*
+ * If the timer is on the local cpu base and is the first expiring
+ * timer then this might end up reprogramming the hardware twice
+ * (on removal and on enqueue). To avoid that by prevent the
+ * reprogram on removal, keep the timer local to the current CPU
+ * and enforce reprogramming after it is queued no matter whether
+ * it is the new first expiring timer again or not.
+ */
+ force_local = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
+ force_local &= base->cpu_base->next_timer == timer;
+
+ /*
+ * Remove an active timer from the queue. In case it is not queued
+ * on the current CPU, make sure that remove_hrtimer() updates the
+ * remote data correctly.
+ *
+ * If it's on the current CPU and the first expiring timer, then
+ * skip reprogramming, keep the timer local and enforce
+ * reprogramming later if it was the first expiring timer. This
+ * avoids programming the underlying clock event twice (once at
+ * removal and once after enqueue).
+ */
+ remove_hrtimer(timer, base, true, force_local);
if (mode & HRTIMER_MODE_REL)
tim = ktime_add_safe(tim, base->get_time());
@@ -1115,9 +1248,24 @@ static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
hrtimer_set_expires_range_ns(timer, tim, delta_ns);
/* Switch the timer base, if necessary: */
- new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
+ if (!force_local) {
+ new_base = switch_hrtimer_base(timer, base,
+ mode & HRTIMER_MODE_PINNED);
+ } else {
+ new_base = base;
+ }
- return enqueue_hrtimer(timer, new_base, mode);
+ first = enqueue_hrtimer(timer, new_base, mode);
+ if (!force_local)
+ return first;
+
+ /*
+ * Timer was forced to stay on the current CPU to avoid
+ * reprogramming on removal and enqueue. Force reprogram the
+ * hardware by evaluating the new first expiring timer.
+ */
+ hrtimer_force_reprogram(new_base->cpu_base, 1);
+ return 0;
}
/**
@@ -1183,7 +1331,7 @@ int hrtimer_try_to_cancel(struct hrtimer *timer)
base = lock_hrtimer_base(timer, &flags);
if (!hrtimer_callback_running(timer))
- ret = remove_hrtimer(timer, base, false);
+ ret = remove_hrtimer(timer, base, false, false);
unlock_hrtimer_base(timer, &flags);
diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c
index 01935aafdb46..bc4db9e5ab70 100644
--- a/kernel/time/jiffies.c
+++ b/kernel/time/jiffies.c
@@ -10,28 +10,9 @@
#include <linux/init.h>
#include "timekeeping.h"
+#include "tick-internal.h"
-/* Since jiffies uses a simple TICK_NSEC multiplier
- * conversion, the .shift value could be zero. However
- * this would make NTP adjustments impossible as they are
- * in units of 1/2^.shift. Thus we use JIFFIES_SHIFT to
- * shift both the nominator and denominator the same
- * amount, and give ntp adjustments in units of 1/2^8
- *
- * The value 8 is somewhat carefully chosen, as anything
- * larger can result in overflows. TICK_NSEC grows as HZ
- * shrinks, so values greater than 8 overflow 32bits when
- * HZ=100.
- */
-#if HZ < 34
-#define JIFFIES_SHIFT 6
-#elif HZ < 67
-#define JIFFIES_SHIFT 7
-#else
-#define JIFFIES_SHIFT 8
-#endif
-
static u64 jiffies_read(struct clocksource *cs)
{
return (u64) jiffies;
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 517be7fd175e..ee736861b18f 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -291,6 +291,8 @@ static void thread_group_start_cputime(struct task_struct *tsk, u64 *samples)
struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
struct posix_cputimers *pct = &tsk->signal->posix_cputimers;
+ lockdep_assert_task_sighand_held(tsk);
+
/* Check if cputimer isn't running. This is accessed without locking. */
if (!READ_ONCE(pct->timers_active)) {
struct task_cputime sum;
@@ -405,6 +407,55 @@ static int posix_cpu_timer_create(struct k_itimer *new_timer)
return 0;
}
+static struct posix_cputimer_base *timer_base(struct k_itimer *timer,
+ struct task_struct *tsk)
+{
+ int clkidx = CPUCLOCK_WHICH(timer->it_clock);
+
+ if (CPUCLOCK_PERTHREAD(timer->it_clock))
+ return tsk->posix_cputimers.bases + clkidx;
+ else
+ return tsk->signal->posix_cputimers.bases + clkidx;
+}
+
+/*
+ * Force recalculating the base earliest expiration on the next tick.
+ * This will also re-evaluate the need to keep around the process wide
+ * cputime counter and tick dependency and eventually shut these down
+ * if necessary.
+ */
+static void trigger_base_recalc_expires(struct k_itimer *timer,
+ struct task_struct *tsk)
+{
+ struct posix_cputimer_base *base = timer_base(timer, tsk);
+
+ base->nextevt = 0;
+}
+
+/*
+ * Dequeue the timer and reset the base if it was its earliest expiration.
+ * It makes sure the next tick recalculates the base next expiration so we
+ * don't keep the costly process wide cputime counter around for a random
+ * amount of time, along with the tick dependency.
+ *
+ * If another timer gets queued between this and the next tick, its
+ * expiration will update the base next event if necessary on the next
+ * tick.
+ */
+static void disarm_timer(struct k_itimer *timer, struct task_struct *p)
+{
+ struct cpu_timer *ctmr = &timer->it.cpu;
+ struct posix_cputimer_base *base;
+
+ if (!cpu_timer_dequeue(ctmr))
+ return;
+
+ base = timer_base(timer, p);
+ if (cpu_timer_getexpires(ctmr) == base->nextevt)
+ trigger_base_recalc_expires(timer, p);
+}
+
+
/*
* Clean up a CPU-clock timer that is about to be destroyed.
* This is called from timer deletion with the timer already locked.
@@ -439,7 +490,7 @@ static int posix_cpu_timer_del(struct k_itimer *timer)
if (timer->it.cpu.firing)
ret = TIMER_RETRY;
else
- cpu_timer_dequeue(ctmr);
+ disarm_timer(timer, p);
unlock_task_sighand(p, &flags);
}
@@ -498,15 +549,9 @@ void posix_cpu_timers_exit_group(struct task_struct *tsk)
*/
static void arm_timer(struct k_itimer *timer, struct task_struct *p)
{
- int clkidx = CPUCLOCK_WHICH(timer->it_clock);
+ struct posix_cputimer_base *base = timer_base(timer, p);
struct cpu_timer *ctmr = &timer->it.cpu;
u64 newexp = cpu_timer_getexpires(ctmr);
- struct posix_cputimer_base *base;
-
- if (CPUCLOCK_PERTHREAD(timer->it_clock))
- base = p->posix_cputimers.bases + clkidx;
- else
- base = p->signal->posix_cputimers.bases + clkidx;
if (!cpu_timer_enqueue(&base->tqhead, ctmr))
return;
@@ -703,16 +748,29 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
timer->it_overrun_last = 0;
timer->it_overrun = -1;
- if (new_expires != 0 && !(val < new_expires)) {
+ if (val >= new_expires) {
+ if (new_expires != 0) {
+ /*
+ * The designated time already passed, so we notify
+ * immediately, even if the thread never runs to
+ * accumulate more time on this clock.
+ */
+ cpu_timer_fire(timer);
+ }
+
/*
- * The designated time already passed, so we notify
- * immediately, even if the thread never runs to
- * accumulate more time on this clock.
+ * Make sure we don't keep around the process wide cputime
+ * counter or the tick dependency if they are not necessary.
*/
- cpu_timer_fire(timer);
- }
+ sighand = lock_task_sighand(p, &flags);
+ if (!sighand)
+ goto out;
+
+ if (!cpu_timer_queued(ctmr))
+ trigger_base_recalc_expires(timer, p);
- ret = 0;
+ unlock_task_sighand(p, &flags);
+ }
out:
rcu_read_unlock();
if (old)
@@ -1346,8 +1404,6 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clkid,
}
}
- if (!*newval)
- return;
*newval += now;
}
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index dd5697d7347b..3913222e7bcf 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -336,7 +336,7 @@ void posixtimer_rearm(struct kernel_siginfo *info)
int posix_timer_event(struct k_itimer *timr, int si_private)
{
enum pid_type type;
- int ret = -1;
+ int ret;
/*
* FIXME: if ->sigq is queued we can race with
* dequeue_signal()->posixtimer_rearm().
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index d663249652ef..46789356f856 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -470,6 +470,13 @@ void tick_resume_local(void)
else
tick_resume_oneshot();
}
+
+ /*
+ * Ensure that hrtimers are up to date and the clockevents device
+ * is reprogrammed correctly when high resolution timers are
+ * enabled.
+ */
+ hrtimers_resume_local();
}
/**
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 6a742a29e545..649f2b48e8f0 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -165,3 +165,35 @@ DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
extern u64 get_next_timer_interrupt(unsigned long basej, u64 basem);
void timer_clear_idle(void);
+
+#define CLOCK_SET_WALL \
+ (BIT(HRTIMER_BASE_REALTIME) | BIT(HRTIMER_BASE_REALTIME_SOFT) | \
+ BIT(HRTIMER_BASE_TAI) | BIT(HRTIMER_BASE_TAI_SOFT))
+
+#define CLOCK_SET_BOOT \
+ (BIT(HRTIMER_BASE_BOOTTIME) | BIT(HRTIMER_BASE_BOOTTIME_SOFT))
+
+void clock_was_set(unsigned int bases);
+void clock_was_set_delayed(void);
+
+void hrtimers_resume_local(void);
+
+/* Since jiffies uses a simple TICK_NSEC multiplier
+ * conversion, the .shift value could be zero. However
+ * this would make NTP adjustments impossible as they are
+ * in units of 1/2^.shift. Thus we use JIFFIES_SHIFT to
+ * shift both the nominator and denominator the same
+ * amount, and give ntp adjustments in units of 1/2^8
+ *
+ * The value 8 is somewhat carefully chosen, as anything
+ * larger can result in overflows. TICK_NSEC grows as HZ
+ * shrinks, so values greater than 8 overflow 32bits when
+ * HZ=100.
+ */
+#if HZ < 34
+#define JIFFIES_SHIFT 6
+#elif HZ < 67
+#define JIFFIES_SHIFT 7
+#else
+#define JIFFIES_SHIFT 8
+#endif
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 8a364aa9881a..b348749a9fc6 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1323,8 +1323,8 @@ out:
write_seqcount_end(&tk_core.seq);
raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
- /* signal hrtimers about time change */
- clock_was_set();
+ /* Signal hrtimers about time change */
+ clock_was_set(CLOCK_SET_WALL);
if (!ret)
audit_tk_injoffset(ts_delta);
@@ -1371,8 +1371,8 @@ error: /* even if we error out, we forwarded the time, so call update */
write_seqcount_end(&tk_core.seq);
raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
- /* signal hrtimers about time change */
- clock_was_set();
+ /* Signal hrtimers about time change */
+ clock_was_set(CLOCK_SET_WALL);
return ret;
}
@@ -1746,8 +1746,8 @@ void timekeeping_inject_sleeptime64(const struct timespec64 *delta)
write_seqcount_end(&tk_core.seq);
raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
- /* signal hrtimers about time change */
- clock_was_set();
+ /* Signal hrtimers about time change */
+ clock_was_set(CLOCK_SET_WALL | CLOCK_SET_BOOT);
}
#endif
@@ -1810,8 +1810,10 @@ void timekeeping_resume(void)
touch_softlockup_watchdog();
+ /* Resume the clockevent device(s) and hrtimers */
tick_resume();
- hrtimers_resume();
+ /* Notify timerfd as resume is equivalent to clock_was_set() */
+ timerfd_resume();
}
int timekeeping_suspend(void)
@@ -2125,7 +2127,7 @@ static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
* timekeeping_advance - Updates the timekeeper to the current time and
* current NTP tick length
*/
-static void timekeeping_advance(enum timekeeping_adv_mode mode)
+static bool timekeeping_advance(enum timekeeping_adv_mode mode)
{
struct timekeeper *real_tk = &tk_core.timekeeper;
struct timekeeper *tk = &shadow_timekeeper;
@@ -2196,9 +2198,8 @@ static void timekeeping_advance(enum timekeeping_adv_mode mode)
write_seqcount_end(&tk_core.seq);
out:
raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
- if (clock_set)
- /* Have to call _delayed version, since in irq context*/
- clock_was_set_delayed();
+
+ return !!clock_set;
}
/**
@@ -2207,7 +2208,8 @@ out:
*/
void update_wall_time(void)
{
- timekeeping_advance(TK_ADV_TICK);
+ if (timekeeping_advance(TK_ADV_TICK))
+ clock_was_set_delayed();
}
/**
@@ -2387,8 +2389,9 @@ int do_adjtimex(struct __kernel_timex *txc)
{
struct timekeeper *tk = &tk_core.timekeeper;
struct audit_ntp_data ad;
- unsigned long flags;
+ bool clock_set = false;
struct timespec64 ts;
+ unsigned long flags;
s32 orig_tai, tai;
int ret;
@@ -2423,6 +2426,7 @@ int do_adjtimex(struct __kernel_timex *txc)
if (tai != orig_tai) {
__timekeeping_set_tai_offset(tk, tai);
timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
+ clock_set = true;
}
tk_update_leap_state(tk);
@@ -2433,10 +2437,10 @@ int do_adjtimex(struct __kernel_timex *txc)
/* Update the multiplier immediately if frequency was set directly */
if (txc->modes & (ADJ_FREQUENCY | ADJ_TICK))
- timekeeping_advance(TK_ADV_FREQ);
+ clock_set |= timekeeping_advance(TK_ADV_FREQ);
- if (tai != orig_tai)
- clock_was_set();
+ if (clock_set)
+ clock_was_set(CLOCK_REALTIME);
ntp_notify_cmos_timer();