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authorThomas Gleixner <tglx@linutronix.de>2014-06-22 12:06:40 +0200
committerThomas Gleixner <tglx@linutronix.de>2014-06-23 11:22:35 +0200
commit5cee964597260237dd2cabb3ec22bba0da24b25d (patch)
treef548efb4181a4cffb026adf43178e65330533e87 /kernel/posix-cpu-timers.c
parentclocksource: Add a Kconfig menu (diff)
downloadlinux-dev-5cee964597260237dd2cabb3ec22bba0da24b25d.tar.xz
linux-dev-5cee964597260237dd2cabb3ec22bba0da24b25d.zip
time/timers: Move all time(r) related files into kernel/time
Except for Kconfig.HZ. That needs a separate treatment. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/posix-cpu-timers.c')
-rw-r--r--kernel/posix-cpu-timers.c1490
1 files changed, 0 insertions, 1490 deletions
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
deleted file mode 100644
index 3b8946416a5f..000000000000
--- a/kernel/posix-cpu-timers.c
+++ /dev/null
@@ -1,1490 +0,0 @@
-/*
- * Implement CPU time clocks for the POSIX clock interface.
- */
-
-#include <linux/sched.h>
-#include <linux/posix-timers.h>
-#include <linux/errno.h>
-#include <linux/math64.h>
-#include <asm/uaccess.h>
-#include <linux/kernel_stat.h>
-#include <trace/events/timer.h>
-#include <linux/random.h>
-#include <linux/tick.h>
-#include <linux/workqueue.h>
-
-/*
- * Called after updating RLIMIT_CPU to run cpu timer and update
- * tsk->signal->cputime_expires expiration cache if necessary. Needs
- * siglock protection since other code may update expiration cache as
- * well.
- */
-void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
-{
- cputime_t cputime = secs_to_cputime(rlim_new);
-
- spin_lock_irq(&task->sighand->siglock);
- set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL);
- spin_unlock_irq(&task->sighand->siglock);
-}
-
-static int check_clock(const clockid_t which_clock)
-{
- int error = 0;
- struct task_struct *p;
- const pid_t pid = CPUCLOCK_PID(which_clock);
-
- if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
- return -EINVAL;
-
- if (pid == 0)
- return 0;
-
- rcu_read_lock();
- p = find_task_by_vpid(pid);
- if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
- same_thread_group(p, current) : has_group_leader_pid(p))) {
- error = -EINVAL;
- }
- rcu_read_unlock();
-
- return error;
-}
-
-static inline unsigned long long
-timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
-{
- unsigned long long ret;
-
- ret = 0; /* high half always zero when .cpu used */
- if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
- ret = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
- } else {
- ret = cputime_to_expires(timespec_to_cputime(tp));
- }
- return ret;
-}
-
-static void sample_to_timespec(const clockid_t which_clock,
- unsigned long long expires,
- struct timespec *tp)
-{
- if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
- *tp = ns_to_timespec(expires);
- else
- cputime_to_timespec((__force cputime_t)expires, tp);
-}
-
-/*
- * Update expiry time from increment, and increase overrun count,
- * given the current clock sample.
- */
-static void bump_cpu_timer(struct k_itimer *timer,
- unsigned long long now)
-{
- int i;
- unsigned long long delta, incr;
-
- if (timer->it.cpu.incr == 0)
- return;
-
- if (now < timer->it.cpu.expires)
- return;
-
- incr = timer->it.cpu.incr;
- delta = now + incr - timer->it.cpu.expires;
-
- /* Don't use (incr*2 < delta), incr*2 might overflow. */
- for (i = 0; incr < delta - incr; i++)
- incr = incr << 1;
-
- for (; i >= 0; incr >>= 1, i--) {
- if (delta < incr)
- continue;
-
- timer->it.cpu.expires += incr;
- timer->it_overrun += 1 << i;
- delta -= incr;
- }
-}
-
-/**
- * task_cputime_zero - Check a task_cputime struct for all zero fields.
- *
- * @cputime: The struct to compare.
- *
- * Checks @cputime to see if all fields are zero. Returns true if all fields
- * are zero, false if any field is nonzero.
- */
-static inline int task_cputime_zero(const struct task_cputime *cputime)
-{
- if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime)
- return 1;
- return 0;
-}
-
-static inline unsigned long long prof_ticks(struct task_struct *p)
-{
- cputime_t utime, stime;
-
- task_cputime(p, &utime, &stime);
-
- return cputime_to_expires(utime + stime);
-}
-static inline unsigned long long virt_ticks(struct task_struct *p)
-{
- cputime_t utime;
-
- task_cputime(p, &utime, NULL);
-
- return cputime_to_expires(utime);
-}
-
-static int
-posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
-{
- int error = check_clock(which_clock);
- if (!error) {
- tp->tv_sec = 0;
- tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
- if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
- /*
- * If sched_clock is using a cycle counter, we
- * don't have any idea of its true resolution
- * exported, but it is much more than 1s/HZ.
- */
- tp->tv_nsec = 1;
- }
- }
- return error;
-}
-
-static int
-posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
-{
- /*
- * You can never reset a CPU clock, but we check for other errors
- * in the call before failing with EPERM.
- */
- int error = check_clock(which_clock);
- if (error == 0) {
- error = -EPERM;
- }
- return error;
-}
-
-
-/*
- * Sample a per-thread clock for the given task.
- */
-static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
- unsigned long long *sample)
-{
- switch (CPUCLOCK_WHICH(which_clock)) {
- default:
- return -EINVAL;
- case CPUCLOCK_PROF:
- *sample = prof_ticks(p);
- break;
- case CPUCLOCK_VIRT:
- *sample = virt_ticks(p);
- break;
- case CPUCLOCK_SCHED:
- *sample = task_sched_runtime(p);
- break;
- }
- return 0;
-}
-
-static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
-{
- if (b->utime > a->utime)
- a->utime = b->utime;
-
- if (b->stime > a->stime)
- a->stime = b->stime;
-
- if (b->sum_exec_runtime > a->sum_exec_runtime)
- a->sum_exec_runtime = b->sum_exec_runtime;
-}
-
-void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
-{
- struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
- struct task_cputime sum;
- unsigned long flags;
-
- if (!cputimer->running) {
- /*
- * The POSIX timer interface allows for absolute time expiry
- * values through the TIMER_ABSTIME flag, therefore we have
- * to synchronize the timer to the clock every time we start
- * it.
- */
- thread_group_cputime(tsk, &sum);
- raw_spin_lock_irqsave(&cputimer->lock, flags);
- cputimer->running = 1;
- update_gt_cputime(&cputimer->cputime, &sum);
- } else
- raw_spin_lock_irqsave(&cputimer->lock, flags);
- *times = cputimer->cputime;
- raw_spin_unlock_irqrestore(&cputimer->lock, flags);
-}
-
-/*
- * Sample a process (thread group) clock for the given group_leader task.
- * Must be called with task sighand lock held for safe while_each_thread()
- * traversal.
- */
-static int cpu_clock_sample_group(const clockid_t which_clock,
- struct task_struct *p,
- unsigned long long *sample)
-{
- struct task_cputime cputime;
-
- switch (CPUCLOCK_WHICH(which_clock)) {
- default:
- return -EINVAL;
- case CPUCLOCK_PROF:
- thread_group_cputime(p, &cputime);
- *sample = cputime_to_expires(cputime.utime + cputime.stime);
- break;
- case CPUCLOCK_VIRT:
- thread_group_cputime(p, &cputime);
- *sample = cputime_to_expires(cputime.utime);
- break;
- case CPUCLOCK_SCHED:
- thread_group_cputime(p, &cputime);
- *sample = cputime.sum_exec_runtime;
- break;
- }
- return 0;
-}
-
-static int posix_cpu_clock_get_task(struct task_struct *tsk,
- const clockid_t which_clock,
- struct timespec *tp)
-{
- int err = -EINVAL;
- unsigned long long rtn;
-
- if (CPUCLOCK_PERTHREAD(which_clock)) {
- if (same_thread_group(tsk, current))
- err = cpu_clock_sample(which_clock, tsk, &rtn);
- } else {
- unsigned long flags;
- struct sighand_struct *sighand;
-
- /*
- * while_each_thread() is not yet entirely RCU safe,
- * keep locking the group while sampling process
- * clock for now.
- */
- sighand = lock_task_sighand(tsk, &flags);
- if (!sighand)
- return err;
-
- if (tsk == current || thread_group_leader(tsk))
- err = cpu_clock_sample_group(which_clock, tsk, &rtn);
-
- unlock_task_sighand(tsk, &flags);
- }
-
- if (!err)
- sample_to_timespec(which_clock, rtn, tp);
-
- return err;
-}
-
-
-static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
-{
- const pid_t pid = CPUCLOCK_PID(which_clock);
- int err = -EINVAL;
-
- if (pid == 0) {
- /*
- * Special case constant value for our own clocks.
- * We don't have to do any lookup to find ourselves.
- */
- err = posix_cpu_clock_get_task(current, which_clock, tp);
- } else {
- /*
- * Find the given PID, and validate that the caller
- * should be able to see it.
- */
- struct task_struct *p;
- rcu_read_lock();
- p = find_task_by_vpid(pid);
- if (p)
- err = posix_cpu_clock_get_task(p, which_clock, tp);
- rcu_read_unlock();
- }
-
- return err;
-}
-
-
-/*
- * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
- * This is called from sys_timer_create() and do_cpu_nanosleep() with the
- * new timer already all-zeros initialized.
- */
-static int posix_cpu_timer_create(struct k_itimer *new_timer)
-{
- int ret = 0;
- const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
- struct task_struct *p;
-
- if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
- return -EINVAL;
-
- INIT_LIST_HEAD(&new_timer->it.cpu.entry);
-
- rcu_read_lock();
- if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
- if (pid == 0) {
- p = current;
- } else {
- p = find_task_by_vpid(pid);
- if (p && !same_thread_group(p, current))
- p = NULL;
- }
- } else {
- if (pid == 0) {
- p = current->group_leader;
- } else {
- p = find_task_by_vpid(pid);
- if (p && !has_group_leader_pid(p))
- p = NULL;
- }
- }
- new_timer->it.cpu.task = p;
- if (p) {
- get_task_struct(p);
- } else {
- ret = -EINVAL;
- }
- rcu_read_unlock();
-
- return ret;
-}
-
-/*
- * Clean up a CPU-clock timer that is about to be destroyed.
- * This is called from timer deletion with the timer already locked.
- * If we return TIMER_RETRY, it's necessary to release the timer's lock
- * and try again. (This happens when the timer is in the middle of firing.)
- */
-static int posix_cpu_timer_del(struct k_itimer *timer)
-{
- int ret = 0;
- unsigned long flags;
- struct sighand_struct *sighand;
- struct task_struct *p = timer->it.cpu.task;
-
- WARN_ON_ONCE(p == NULL);
-
- /*
- * Protect against sighand release/switch in exit/exec and process/
- * thread timer list entry concurrent read/writes.
- */
- sighand = lock_task_sighand(p, &flags);
- if (unlikely(sighand == NULL)) {
- /*
- * We raced with the reaping of the task.
- * The deletion should have cleared us off the list.
- */
- WARN_ON_ONCE(!list_empty(&timer->it.cpu.entry));
- } else {
- if (timer->it.cpu.firing)
- ret = TIMER_RETRY;
- else
- list_del(&timer->it.cpu.entry);
-
- unlock_task_sighand(p, &flags);
- }
-
- if (!ret)
- put_task_struct(p);
-
- return ret;
-}
-
-static void cleanup_timers_list(struct list_head *head)
-{
- struct cpu_timer_list *timer, *next;
-
- list_for_each_entry_safe(timer, next, head, entry)
- list_del_init(&timer->entry);
-}
-
-/*
- * Clean out CPU timers still ticking when a thread exited. The task
- * pointer is cleared, and the expiry time is replaced with the residual
- * time for later timer_gettime calls to return.
- * This must be called with the siglock held.
- */
-static void cleanup_timers(struct list_head *head)
-{
- cleanup_timers_list(head);
- cleanup_timers_list(++head);
- cleanup_timers_list(++head);
-}
-
-/*
- * These are both called with the siglock held, when the current thread
- * is being reaped. When the final (leader) thread in the group is reaped,
- * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
- */
-void posix_cpu_timers_exit(struct task_struct *tsk)
-{
- add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
- sizeof(unsigned long long));
- cleanup_timers(tsk->cpu_timers);
-
-}
-void posix_cpu_timers_exit_group(struct task_struct *tsk)
-{
- cleanup_timers(tsk->signal->cpu_timers);
-}
-
-static inline int expires_gt(cputime_t expires, cputime_t new_exp)
-{
- return expires == 0 || expires > new_exp;
-}
-
-/*
- * Insert the timer on the appropriate list before any timers that
- * expire later. This must be called with the sighand lock held.
- */
-static void arm_timer(struct k_itimer *timer)
-{
- struct task_struct *p = timer->it.cpu.task;
- struct list_head *head, *listpos;
- struct task_cputime *cputime_expires;
- struct cpu_timer_list *const nt = &timer->it.cpu;
- struct cpu_timer_list *next;
-
- if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
- head = p->cpu_timers;
- cputime_expires = &p->cputime_expires;
- } else {
- head = p->signal->cpu_timers;
- cputime_expires = &p->signal->cputime_expires;
- }
- head += CPUCLOCK_WHICH(timer->it_clock);
-
- listpos = head;
- list_for_each_entry(next, head, entry) {
- if (nt->expires < next->expires)
- break;
- listpos = &next->entry;
- }
- list_add(&nt->entry, listpos);
-
- if (listpos == head) {
- unsigned long long exp = nt->expires;
-
- /*
- * We are the new earliest-expiring POSIX 1.b timer, hence
- * need to update expiration cache. Take into account that
- * for process timers we share expiration cache with itimers
- * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
- */
-
- switch (CPUCLOCK_WHICH(timer->it_clock)) {
- case CPUCLOCK_PROF:
- if (expires_gt(cputime_expires->prof_exp, expires_to_cputime(exp)))
- cputime_expires->prof_exp = expires_to_cputime(exp);
- break;
- case CPUCLOCK_VIRT:
- if (expires_gt(cputime_expires->virt_exp, expires_to_cputime(exp)))
- cputime_expires->virt_exp = expires_to_cputime(exp);
- break;
- case CPUCLOCK_SCHED:
- if (cputime_expires->sched_exp == 0 ||
- cputime_expires->sched_exp > exp)
- cputime_expires->sched_exp = exp;
- break;
- }
- }
-}
-
-/*
- * The timer is locked, fire it and arrange for its reload.
- */
-static void cpu_timer_fire(struct k_itimer *timer)
-{
- if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
- /*
- * User don't want any signal.
- */
- timer->it.cpu.expires = 0;
- } else if (unlikely(timer->sigq == NULL)) {
- /*
- * This a special case for clock_nanosleep,
- * not a normal timer from sys_timer_create.
- */
- wake_up_process(timer->it_process);
- timer->it.cpu.expires = 0;
- } else if (timer->it.cpu.incr == 0) {
- /*
- * One-shot timer. Clear it as soon as it's fired.
- */
- posix_timer_event(timer, 0);
- timer->it.cpu.expires = 0;
- } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
- /*
- * The signal did not get queued because the signal
- * was ignored, so we won't get any callback to
- * reload the timer. But we need to keep it
- * ticking in case the signal is deliverable next time.
- */
- posix_cpu_timer_schedule(timer);
- }
-}
-
-/*
- * Sample a process (thread group) timer for the given group_leader task.
- * Must be called with task sighand lock held for safe while_each_thread()
- * traversal.
- */
-static int cpu_timer_sample_group(const clockid_t which_clock,
- struct task_struct *p,
- unsigned long long *sample)
-{
- struct task_cputime cputime;
-
- thread_group_cputimer(p, &cputime);
- switch (CPUCLOCK_WHICH(which_clock)) {
- default:
- return -EINVAL;
- case CPUCLOCK_PROF:
- *sample = cputime_to_expires(cputime.utime + cputime.stime);
- break;
- case CPUCLOCK_VIRT:
- *sample = cputime_to_expires(cputime.utime);
- break;
- case CPUCLOCK_SCHED:
- *sample = cputime.sum_exec_runtime + task_delta_exec(p);
- break;
- }
- return 0;
-}
-
-#ifdef CONFIG_NO_HZ_FULL
-static void nohz_kick_work_fn(struct work_struct *work)
-{
- tick_nohz_full_kick_all();
-}
-
-static DECLARE_WORK(nohz_kick_work, nohz_kick_work_fn);
-
-/*
- * We need the IPIs to be sent from sane process context.
- * The posix cpu timers are always set with irqs disabled.
- */
-static void posix_cpu_timer_kick_nohz(void)
-{
- if (context_tracking_is_enabled())
- schedule_work(&nohz_kick_work);
-}
-
-bool posix_cpu_timers_can_stop_tick(struct task_struct *tsk)
-{
- if (!task_cputime_zero(&tsk->cputime_expires))
- return false;
-
- if (tsk->signal->cputimer.running)
- return false;
-
- return true;
-}
-#else
-static inline void posix_cpu_timer_kick_nohz(void) { }
-#endif
-
-/*
- * Guts of sys_timer_settime for CPU timers.
- * This is called with the timer locked and interrupts disabled.
- * If we return TIMER_RETRY, it's necessary to release the timer's lock
- * and try again. (This happens when the timer is in the middle of firing.)
- */
-static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
- struct itimerspec *new, struct itimerspec *old)
-{
- unsigned long flags;
- struct sighand_struct *sighand;
- struct task_struct *p = timer->it.cpu.task;
- unsigned long long old_expires, new_expires, old_incr, val;
- int ret;
-
- WARN_ON_ONCE(p == NULL);
-
- new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
-
- /*
- * Protect against sighand release/switch in exit/exec and p->cpu_timers
- * and p->signal->cpu_timers read/write in arm_timer()
- */
- sighand = lock_task_sighand(p, &flags);
- /*
- * If p has just been reaped, we can no
- * longer get any information about it at all.
- */
- if (unlikely(sighand == NULL)) {
- return -ESRCH;
- }
-
- /*
- * Disarm any old timer after extracting its expiry time.
- */
- WARN_ON_ONCE(!irqs_disabled());
-
- ret = 0;
- old_incr = timer->it.cpu.incr;
- old_expires = timer->it.cpu.expires;
- if (unlikely(timer->it.cpu.firing)) {
- timer->it.cpu.firing = -1;
- ret = TIMER_RETRY;
- } else
- list_del_init(&timer->it.cpu.entry);
-
- /*
- * We need to sample the current value to convert the new
- * value from to relative and absolute, and to convert the
- * old value from absolute to relative. To set a process
- * timer, we need a sample to balance the thread expiry
- * times (in arm_timer). With an absolute time, we must
- * check if it's already passed. In short, we need a sample.
- */
- if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
- cpu_clock_sample(timer->it_clock, p, &val);
- } else {
- cpu_timer_sample_group(timer->it_clock, p, &val);
- }
-
- if (old) {
- if (old_expires == 0) {
- old->it_value.tv_sec = 0;
- old->it_value.tv_nsec = 0;
- } else {
- /*
- * Update the timer in case it has
- * overrun already. If it has,
- * we'll report it as having overrun
- * and with the next reloaded timer
- * already ticking, though we are
- * swallowing that pending
- * notification here to install the
- * new setting.
- */
- bump_cpu_timer(timer, val);
- if (val < timer->it.cpu.expires) {
- old_expires = timer->it.cpu.expires - val;
- sample_to_timespec(timer->it_clock,
- old_expires,
- &old->it_value);
- } else {
- old->it_value.tv_nsec = 1;
- old->it_value.tv_sec = 0;
- }
- }
- }
-
- if (unlikely(ret)) {
- /*
- * We are colliding with the timer actually firing.
- * Punt after filling in the timer's old value, and
- * disable this firing since we are already reporting
- * it as an overrun (thanks to bump_cpu_timer above).
- */
- unlock_task_sighand(p, &flags);
- goto out;
- }
-
- if (new_expires != 0 && !(timer_flags & TIMER_ABSTIME)) {
- new_expires += val;
- }
-
- /*
- * Install the new expiry time (or zero).
- * For a timer with no notification action, we don't actually
- * arm the timer (we'll just fake it for timer_gettime).
- */
- timer->it.cpu.expires = new_expires;
- if (new_expires != 0 && val < new_expires) {
- arm_timer(timer);
- }
-
- unlock_task_sighand(p, &flags);
- /*
- * Install the new reload setting, and
- * set up the signal and overrun bookkeeping.
- */
- timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
- &new->it_interval);
-
- /*
- * This acts as a modification timestamp for the timer,
- * so any automatic reload attempt will punt on seeing
- * that we have reset the timer manually.
- */
- timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
- ~REQUEUE_PENDING;
- timer->it_overrun_last = 0;
- timer->it_overrun = -1;
-
- if (new_expires != 0 && !(val < new_expires)) {
- /*
- * 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);
- }
-
- ret = 0;
- out:
- if (old) {
- sample_to_timespec(timer->it_clock,
- old_incr, &old->it_interval);
- }
- if (!ret)
- posix_cpu_timer_kick_nohz();
- return ret;
-}
-
-static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
-{
- unsigned long long now;
- struct task_struct *p = timer->it.cpu.task;
-
- WARN_ON_ONCE(p == NULL);
-
- /*
- * Easy part: convert the reload time.
- */
- sample_to_timespec(timer->it_clock,
- timer->it.cpu.incr, &itp->it_interval);
-
- if (timer->it.cpu.expires == 0) { /* Timer not armed at all. */
- itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
- return;
- }
-
- /*
- * Sample the clock to take the difference with the expiry time.
- */
- if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
- cpu_clock_sample(timer->it_clock, p, &now);
- } else {
- struct sighand_struct *sighand;
- unsigned long flags;
-
- /*
- * Protect against sighand release/switch in exit/exec and
- * also make timer sampling safe if it ends up calling
- * thread_group_cputime().
- */
- sighand = lock_task_sighand(p, &flags);
- if (unlikely(sighand == NULL)) {
- /*
- * The process has been reaped.
- * We can't even collect a sample any more.
- * Call the timer disarmed, nothing else to do.
- */
- timer->it.cpu.expires = 0;
- sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
- &itp->it_value);
- } else {
- cpu_timer_sample_group(timer->it_clock, p, &now);
- unlock_task_sighand(p, &flags);
- }
- }
-
- if (now < timer->it.cpu.expires) {
- sample_to_timespec(timer->it_clock,
- timer->it.cpu.expires - now,
- &itp->it_value);
- } else {
- /*
- * The timer should have expired already, but the firing
- * hasn't taken place yet. Say it's just about to expire.
- */
- itp->it_value.tv_nsec = 1;
- itp->it_value.tv_sec = 0;
- }
-}
-
-static unsigned long long
-check_timers_list(struct list_head *timers,
- struct list_head *firing,
- unsigned long long curr)
-{
- int maxfire = 20;
-
- while (!list_empty(timers)) {
- struct cpu_timer_list *t;
-
- t = list_first_entry(timers, struct cpu_timer_list, entry);
-
- if (!--maxfire || curr < t->expires)
- return t->expires;
-
- t->firing = 1;
- list_move_tail(&t->entry, firing);
- }
-
- return 0;
-}
-
-/*
- * Check for any per-thread CPU timers that have fired and move them off
- * the tsk->cpu_timers[N] list onto the firing list. Here we update the
- * tsk->it_*_expires values to reflect the remaining thread CPU timers.
- */
-static void check_thread_timers(struct task_struct *tsk,
- struct list_head *firing)
-{
- struct list_head *timers = tsk->cpu_timers;
- struct signal_struct *const sig = tsk->signal;
- struct task_cputime *tsk_expires = &tsk->cputime_expires;
- unsigned long long expires;
- unsigned long soft;
-
- expires = check_timers_list(timers, firing, prof_ticks(tsk));
- tsk_expires->prof_exp = expires_to_cputime(expires);
-
- expires = check_timers_list(++timers, firing, virt_ticks(tsk));
- tsk_expires->virt_exp = expires_to_cputime(expires);
-
- tsk_expires->sched_exp = check_timers_list(++timers, firing,
- tsk->se.sum_exec_runtime);
-
- /*
- * Check for the special case thread timers.
- */
- soft = ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_cur);
- if (soft != RLIM_INFINITY) {
- unsigned long hard =
- ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max);
-
- if (hard != RLIM_INFINITY &&
- tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
- /*
- * At the hard limit, we just die.
- * No need to calculate anything else now.
- */
- __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
- return;
- }
- if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
- /*
- * At the soft limit, send a SIGXCPU every second.
- */
- if (soft < hard) {
- soft += USEC_PER_SEC;
- sig->rlim[RLIMIT_RTTIME].rlim_cur = soft;
- }
- printk(KERN_INFO
- "RT Watchdog Timeout: %s[%d]\n",
- tsk->comm, task_pid_nr(tsk));
- __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
- }
- }
-}
-
-static void stop_process_timers(struct signal_struct *sig)
-{
- struct thread_group_cputimer *cputimer = &sig->cputimer;
- unsigned long flags;
-
- raw_spin_lock_irqsave(&cputimer->lock, flags);
- cputimer->running = 0;
- raw_spin_unlock_irqrestore(&cputimer->lock, flags);
-}
-
-static u32 onecputick;
-
-static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
- unsigned long long *expires,
- unsigned long long cur_time, int signo)
-{
- if (!it->expires)
- return;
-
- if (cur_time >= it->expires) {
- if (it->incr) {
- it->expires += it->incr;
- it->error += it->incr_error;
- if (it->error >= onecputick) {
- it->expires -= cputime_one_jiffy;
- it->error -= onecputick;
- }
- } else {
- it->expires = 0;
- }
-
- trace_itimer_expire(signo == SIGPROF ?
- ITIMER_PROF : ITIMER_VIRTUAL,
- tsk->signal->leader_pid, cur_time);
- __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
- }
-
- if (it->expires && (!*expires || it->expires < *expires)) {
- *expires = it->expires;
- }
-}
-
-/*
- * Check for any per-thread CPU timers that have fired and move them
- * off the tsk->*_timers list onto the firing list. Per-thread timers
- * have already been taken off.
- */
-static void check_process_timers(struct task_struct *tsk,
- struct list_head *firing)
-{
- struct signal_struct *const sig = tsk->signal;
- unsigned long long utime, ptime, virt_expires, prof_expires;
- unsigned long long sum_sched_runtime, sched_expires;
- struct list_head *timers = sig->cpu_timers;
- struct task_cputime cputime;
- unsigned long soft;
-
- /*
- * Collect the current process totals.
- */
- thread_group_cputimer(tsk, &cputime);
- utime = cputime_to_expires(cputime.utime);
- ptime = utime + cputime_to_expires(cputime.stime);
- sum_sched_runtime = cputime.sum_exec_runtime;
-
- prof_expires = check_timers_list(timers, firing, ptime);
- virt_expires = check_timers_list(++timers, firing, utime);
- sched_expires = check_timers_list(++timers, firing, sum_sched_runtime);
-
- /*
- * Check for the special case process timers.
- */
- check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime,
- SIGPROF);
- check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
- SIGVTALRM);
- soft = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
- if (soft != RLIM_INFINITY) {
- unsigned long psecs = cputime_to_secs(ptime);
- unsigned long hard =
- ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_max);
- cputime_t x;
- if (psecs >= hard) {
- /*
- * At the hard limit, we just die.
- * No need to calculate anything else now.
- */
- __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
- return;
- }
- if (psecs >= soft) {
- /*
- * At the soft limit, send a SIGXCPU every second.
- */
- __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
- if (soft < hard) {
- soft++;
- sig->rlim[RLIMIT_CPU].rlim_cur = soft;
- }
- }
- x = secs_to_cputime(soft);
- if (!prof_expires || x < prof_expires) {
- prof_expires = x;
- }
- }
-
- sig->cputime_expires.prof_exp = expires_to_cputime(prof_expires);
- sig->cputime_expires.virt_exp = expires_to_cputime(virt_expires);
- sig->cputime_expires.sched_exp = sched_expires;
- if (task_cputime_zero(&sig->cputime_expires))
- stop_process_timers(sig);
-}
-
-/*
- * This is called from the signal code (via do_schedule_next_timer)
- * when the last timer signal was delivered and we have to reload the timer.
- */
-void posix_cpu_timer_schedule(struct k_itimer *timer)
-{
- struct sighand_struct *sighand;
- unsigned long flags;
- struct task_struct *p = timer->it.cpu.task;
- unsigned long long now;
-
- WARN_ON_ONCE(p == NULL);
-
- /*
- * Fetch the current sample and update the timer's expiry time.
- */
- if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
- cpu_clock_sample(timer->it_clock, p, &now);
- bump_cpu_timer(timer, now);
- if (unlikely(p->exit_state))
- goto out;
-
- /* Protect timer list r/w in arm_timer() */
- sighand = lock_task_sighand(p, &flags);
- if (!sighand)
- goto out;
- } else {
- /*
- * Protect arm_timer() and timer sampling in case of call to
- * thread_group_cputime().
- */
- sighand = lock_task_sighand(p, &flags);
- if (unlikely(sighand == NULL)) {
- /*
- * The process has been reaped.
- * We can't even collect a sample any more.
- */
- timer->it.cpu.expires = 0;
- goto out;
- } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
- unlock_task_sighand(p, &flags);
- /* Optimizations: if the process is dying, no need to rearm */
- goto out;
- }
- cpu_timer_sample_group(timer->it_clock, p, &now);
- bump_cpu_timer(timer, now);
- /* Leave the sighand locked for the call below. */
- }
-
- /*
- * Now re-arm for the new expiry time.
- */
- WARN_ON_ONCE(!irqs_disabled());
- arm_timer(timer);
- unlock_task_sighand(p, &flags);
-
- /* Kick full dynticks CPUs in case they need to tick on the new timer */
- posix_cpu_timer_kick_nohz();
-out:
- timer->it_overrun_last = timer->it_overrun;
- timer->it_overrun = -1;
- ++timer->it_requeue_pending;
-}
-
-/**
- * task_cputime_expired - Compare two task_cputime entities.
- *
- * @sample: The task_cputime structure to be checked for expiration.
- * @expires: Expiration times, against which @sample will be checked.
- *
- * Checks @sample against @expires to see if any field of @sample has expired.
- * Returns true if any field of the former is greater than the corresponding
- * field of the latter if the latter field is set. Otherwise returns false.
- */
-static inline int task_cputime_expired(const struct task_cputime *sample,
- const struct task_cputime *expires)
-{
- if (expires->utime && sample->utime >= expires->utime)
- return 1;
- if (expires->stime && sample->utime + sample->stime >= expires->stime)
- return 1;
- if (expires->sum_exec_runtime != 0 &&
- sample->sum_exec_runtime >= expires->sum_exec_runtime)
- return 1;
- return 0;
-}
-
-/**
- * fastpath_timer_check - POSIX CPU timers fast path.
- *
- * @tsk: The task (thread) being checked.
- *
- * Check the task and thread group timers. If both are zero (there are no
- * timers set) return false. Otherwise snapshot the task and thread group
- * timers and compare them with the corresponding expiration times. Return
- * true if a timer has expired, else return false.
- */
-static inline int fastpath_timer_check(struct task_struct *tsk)
-{
- struct signal_struct *sig;
- cputime_t utime, stime;
-
- task_cputime(tsk, &utime, &stime);
-
- if (!task_cputime_zero(&tsk->cputime_expires)) {
- struct task_cputime task_sample = {
- .utime = utime,
- .stime = stime,
- .sum_exec_runtime = tsk->se.sum_exec_runtime
- };
-
- if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
- return 1;
- }
-
- sig = tsk->signal;
- if (sig->cputimer.running) {
- struct task_cputime group_sample;
-
- raw_spin_lock(&sig->cputimer.lock);
- group_sample = sig->cputimer.cputime;
- raw_spin_unlock(&sig->cputimer.lock);
-
- if (task_cputime_expired(&group_sample, &sig->cputime_expires))
- return 1;
- }
-
- return 0;
-}
-
-/*
- * This is called from the timer interrupt handler. The irq handler has
- * already updated our counts. We need to check if any timers fire now.
- * Interrupts are disabled.
- */
-void run_posix_cpu_timers(struct task_struct *tsk)
-{
- LIST_HEAD(firing);
- struct k_itimer *timer, *next;
- unsigned long flags;
-
- WARN_ON_ONCE(!irqs_disabled());
-
- /*
- * The fast path checks that there are no expired thread or thread
- * group timers. If that's so, just return.
- */
- if (!fastpath_timer_check(tsk))
- return;
-
- if (!lock_task_sighand(tsk, &flags))
- return;
- /*
- * Here we take off tsk->signal->cpu_timers[N] and
- * tsk->cpu_timers[N] all the timers that are firing, and
- * put them on the firing list.
- */
- check_thread_timers(tsk, &firing);
- /*
- * If there are any active process wide timers (POSIX 1.b, itimers,
- * RLIMIT_CPU) cputimer must be running.
- */
- if (tsk->signal->cputimer.running)
- check_process_timers(tsk, &firing);
-
- /*
- * We must release these locks before taking any timer's lock.
- * There is a potential race with timer deletion here, as the
- * siglock now protects our private firing list. We have set
- * the firing flag in each timer, so that a deletion attempt
- * that gets the timer lock before we do will give it up and
- * spin until we've taken care of that timer below.
- */
- unlock_task_sighand(tsk, &flags);
-
- /*
- * Now that all the timers on our list have the firing flag,
- * no one will touch their list entries but us. We'll take
- * each timer's lock before clearing its firing flag, so no
- * timer call will interfere.
- */
- list_for_each_entry_safe(timer, next, &firing, it.cpu.entry) {
- int cpu_firing;
-
- spin_lock(&timer->it_lock);
- list_del_init(&timer->it.cpu.entry);
- cpu_firing = timer->it.cpu.firing;
- timer->it.cpu.firing = 0;
- /*
- * The firing flag is -1 if we collided with a reset
- * of the timer, which already reported this
- * almost-firing as an overrun. So don't generate an event.
- */
- if (likely(cpu_firing >= 0))
- cpu_timer_fire(timer);
- spin_unlock(&timer->it_lock);
- }
-}
-
-/*
- * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
- * The tsk->sighand->siglock must be held by the caller.
- */
-void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
- cputime_t *newval, cputime_t *oldval)
-{
- unsigned long long now;
-
- WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED);
- cpu_timer_sample_group(clock_idx, tsk, &now);
-
- if (oldval) {
- /*
- * We are setting itimer. The *oldval is absolute and we update
- * it to be relative, *newval argument is relative and we update
- * it to be absolute.
- */
- if (*oldval) {
- if (*oldval <= now) {
- /* Just about to fire. */
- *oldval = cputime_one_jiffy;
- } else {
- *oldval -= now;
- }
- }
-
- if (!*newval)
- goto out;
- *newval += now;
- }
-
- /*
- * Update expiration cache if we are the earliest timer, or eventually
- * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
- */
- switch (clock_idx) {
- case CPUCLOCK_PROF:
- if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
- tsk->signal->cputime_expires.prof_exp = *newval;
- break;
- case CPUCLOCK_VIRT:
- if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
- tsk->signal->cputime_expires.virt_exp = *newval;
- break;
- }
-out:
- posix_cpu_timer_kick_nohz();
-}
-
-static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
- struct timespec *rqtp, struct itimerspec *it)
-{
- struct k_itimer timer;
- int error;
-
- /*
- * Set up a temporary timer and then wait for it to go off.
- */
- memset(&timer, 0, sizeof timer);
- spin_lock_init(&timer.it_lock);
- timer.it_clock = which_clock;
- timer.it_overrun = -1;
- error = posix_cpu_timer_create(&timer);
- timer.it_process = current;
- if (!error) {
- static struct itimerspec zero_it;
-
- memset(it, 0, sizeof *it);
- it->it_value = *rqtp;
-
- spin_lock_irq(&timer.it_lock);
- error = posix_cpu_timer_set(&timer, flags, it, NULL);
- if (error) {
- spin_unlock_irq(&timer.it_lock);
- return error;
- }
-
- while (!signal_pending(current)) {
- if (timer.it.cpu.expires == 0) {
- /*
- * Our timer fired and was reset, below
- * deletion can not fail.
- */
- posix_cpu_timer_del(&timer);
- spin_unlock_irq(&timer.it_lock);
- return 0;
- }
-
- /*
- * Block until cpu_timer_fire (or a signal) wakes us.
- */
- __set_current_state(TASK_INTERRUPTIBLE);
- spin_unlock_irq(&timer.it_lock);
- schedule();
- spin_lock_irq(&timer.it_lock);
- }
-
- /*
- * We were interrupted by a signal.
- */
- sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
- error = posix_cpu_timer_set(&timer, 0, &zero_it, it);
- if (!error) {
- /*
- * Timer is now unarmed, deletion can not fail.
- */
- posix_cpu_timer_del(&timer);
- }
- spin_unlock_irq(&timer.it_lock);
-
- while (error == TIMER_RETRY) {
- /*
- * We need to handle case when timer was or is in the
- * middle of firing. In other cases we already freed
- * resources.
- */
- spin_lock_irq(&timer.it_lock);
- error = posix_cpu_timer_del(&timer);
- spin_unlock_irq(&timer.it_lock);
- }
-
- if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
- /*
- * It actually did fire already.
- */
- return 0;
- }
-
- error = -ERESTART_RESTARTBLOCK;
- }
-
- return error;
-}
-
-static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
-
-static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
- struct timespec *rqtp, struct timespec __user *rmtp)
-{
- struct restart_block *restart_block =
- &current_thread_info()->restart_block;
- struct itimerspec it;
- int error;
-
- /*
- * Diagnose required errors first.
- */
- if (CPUCLOCK_PERTHREAD(which_clock) &&
- (CPUCLOCK_PID(which_clock) == 0 ||
- CPUCLOCK_PID(which_clock) == current->pid))
- return -EINVAL;
-
- error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
-
- if (error == -ERESTART_RESTARTBLOCK) {
-
- if (flags & TIMER_ABSTIME)
- return -ERESTARTNOHAND;
- /*
- * Report back to the user the time still remaining.
- */
- if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
- return -EFAULT;
-
- restart_block->fn = posix_cpu_nsleep_restart;
- restart_block->nanosleep.clockid = which_clock;
- restart_block->nanosleep.rmtp = rmtp;
- restart_block->nanosleep.expires = timespec_to_ns(rqtp);
- }
- return error;
-}
-
-static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
-{
- clockid_t which_clock = restart_block->nanosleep.clockid;
- struct timespec t;
- struct itimerspec it;
- int error;
-
- t = ns_to_timespec(restart_block->nanosleep.expires);
-
- error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
-
- if (error == -ERESTART_RESTARTBLOCK) {
- struct timespec __user *rmtp = restart_block->nanosleep.rmtp;
- /*
- * Report back to the user the time still remaining.
- */
- if (rmtp && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
- return -EFAULT;
-
- restart_block->nanosleep.expires = timespec_to_ns(&t);
- }
- return error;
-
-}
-
-#define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
-#define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
-
-static int process_cpu_clock_getres(const clockid_t which_clock,
- struct timespec *tp)
-{
- return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
-}
-static int process_cpu_clock_get(const clockid_t which_clock,
- struct timespec *tp)
-{
- return posix_cpu_clock_get(PROCESS_CLOCK, tp);
-}
-static int process_cpu_timer_create(struct k_itimer *timer)
-{
- timer->it_clock = PROCESS_CLOCK;
- return posix_cpu_timer_create(timer);
-}
-static int process_cpu_nsleep(const clockid_t which_clock, int flags,
- struct timespec *rqtp,
- struct timespec __user *rmtp)
-{
- return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
-}
-static long process_cpu_nsleep_restart(struct restart_block *restart_block)
-{
- return -EINVAL;
-}
-static int thread_cpu_clock_getres(const clockid_t which_clock,
- struct timespec *tp)
-{
- return posix_cpu_clock_getres(THREAD_CLOCK, tp);
-}
-static int thread_cpu_clock_get(const clockid_t which_clock,
- struct timespec *tp)
-{
- return posix_cpu_clock_get(THREAD_CLOCK, tp);
-}
-static int thread_cpu_timer_create(struct k_itimer *timer)
-{
- timer->it_clock = THREAD_CLOCK;
- return posix_cpu_timer_create(timer);
-}
-
-struct k_clock clock_posix_cpu = {
- .clock_getres = posix_cpu_clock_getres,
- .clock_set = posix_cpu_clock_set,
- .clock_get = posix_cpu_clock_get,
- .timer_create = posix_cpu_timer_create,
- .nsleep = posix_cpu_nsleep,
- .nsleep_restart = posix_cpu_nsleep_restart,
- .timer_set = posix_cpu_timer_set,
- .timer_del = posix_cpu_timer_del,
- .timer_get = posix_cpu_timer_get,
-};
-
-static __init int init_posix_cpu_timers(void)
-{
- struct k_clock process = {
- .clock_getres = process_cpu_clock_getres,
- .clock_get = process_cpu_clock_get,
- .timer_create = process_cpu_timer_create,
- .nsleep = process_cpu_nsleep,
- .nsleep_restart = process_cpu_nsleep_restart,
- };
- struct k_clock thread = {
- .clock_getres = thread_cpu_clock_getres,
- .clock_get = thread_cpu_clock_get,
- .timer_create = thread_cpu_timer_create,
- };
- struct timespec ts;
-
- posix_timers_register_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
- posix_timers_register_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
-
- cputime_to_timespec(cputime_one_jiffy, &ts);
- onecputick = ts.tv_nsec;
- WARN_ON(ts.tv_sec != 0);
-
- return 0;
-}
-__initcall(init_posix_cpu_timers);