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synced 2024-08-21 16:29:59 +00:00
![Peter Zijlstra](/assets/img/avatar_default.png)
While reviewing the manpages, I noticed I'd missed some clock vs timer sites. Make sure that all timer functions call cpu_timer_sample_group() and not cpu_clock_sample_group(). This ensures that we enable the process wide timer in time, and therefore pay the O(n) thread group cost from the syscall. Not doing it here, will result in the first jiffy tick after setting the timer doing this, resulting in a very expensive tick (but only once) and a delay in actually starting the timer. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
1709 lines
45 KiB
C
1709 lines
45 KiB
C
/*
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* Implement CPU time clocks for the POSIX clock interface.
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*/
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#include <linux/sched.h>
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#include <linux/posix-timers.h>
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#include <linux/errno.h>
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#include <linux/math64.h>
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#include <asm/uaccess.h>
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#include <linux/kernel_stat.h>
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/*
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* Called after updating RLIMIT_CPU to set timer expiration if necessary.
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*/
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void update_rlimit_cpu(unsigned long rlim_new)
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{
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cputime_t cputime;
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cputime = secs_to_cputime(rlim_new);
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if (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
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cputime_lt(current->signal->it_prof_expires, cputime)) {
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spin_lock_irq(¤t->sighand->siglock);
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set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
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spin_unlock_irq(¤t->sighand->siglock);
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}
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}
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static int check_clock(const clockid_t which_clock)
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{
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int error = 0;
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struct task_struct *p;
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const pid_t pid = CPUCLOCK_PID(which_clock);
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if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
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return -EINVAL;
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if (pid == 0)
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return 0;
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read_lock(&tasklist_lock);
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p = find_task_by_vpid(pid);
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if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
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same_thread_group(p, current) : thread_group_leader(p))) {
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error = -EINVAL;
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}
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read_unlock(&tasklist_lock);
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return error;
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}
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static inline union cpu_time_count
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timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
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{
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union cpu_time_count ret;
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ret.sched = 0; /* high half always zero when .cpu used */
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if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
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ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
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} else {
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ret.cpu = timespec_to_cputime(tp);
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}
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return ret;
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}
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static void sample_to_timespec(const clockid_t which_clock,
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union cpu_time_count cpu,
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struct timespec *tp)
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{
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if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
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*tp = ns_to_timespec(cpu.sched);
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else
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cputime_to_timespec(cpu.cpu, tp);
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}
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static inline int cpu_time_before(const clockid_t which_clock,
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union cpu_time_count now,
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union cpu_time_count then)
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{
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if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
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return now.sched < then.sched;
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} else {
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return cputime_lt(now.cpu, then.cpu);
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}
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}
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static inline void cpu_time_add(const clockid_t which_clock,
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union cpu_time_count *acc,
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union cpu_time_count val)
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{
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if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
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acc->sched += val.sched;
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} else {
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acc->cpu = cputime_add(acc->cpu, val.cpu);
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}
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}
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static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
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union cpu_time_count a,
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union cpu_time_count b)
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{
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if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
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a.sched -= b.sched;
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} else {
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a.cpu = cputime_sub(a.cpu, b.cpu);
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}
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return a;
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}
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/*
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* Divide and limit the result to res >= 1
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*
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* This is necessary to prevent signal delivery starvation, when the result of
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* the division would be rounded down to 0.
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*/
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static inline cputime_t cputime_div_non_zero(cputime_t time, unsigned long div)
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{
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cputime_t res = cputime_div(time, div);
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return max_t(cputime_t, res, 1);
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}
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/*
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* Update expiry time from increment, and increase overrun count,
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* given the current clock sample.
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*/
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static void bump_cpu_timer(struct k_itimer *timer,
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union cpu_time_count now)
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{
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int i;
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if (timer->it.cpu.incr.sched == 0)
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return;
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if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
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unsigned long long delta, incr;
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if (now.sched < timer->it.cpu.expires.sched)
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return;
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incr = timer->it.cpu.incr.sched;
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delta = now.sched + incr - timer->it.cpu.expires.sched;
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/* Don't use (incr*2 < delta), incr*2 might overflow. */
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for (i = 0; incr < delta - incr; i++)
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incr = incr << 1;
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for (; i >= 0; incr >>= 1, i--) {
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if (delta < incr)
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continue;
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timer->it.cpu.expires.sched += incr;
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timer->it_overrun += 1 << i;
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delta -= incr;
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}
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} else {
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cputime_t delta, incr;
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if (cputime_lt(now.cpu, timer->it.cpu.expires.cpu))
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return;
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incr = timer->it.cpu.incr.cpu;
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delta = cputime_sub(cputime_add(now.cpu, incr),
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timer->it.cpu.expires.cpu);
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/* Don't use (incr*2 < delta), incr*2 might overflow. */
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for (i = 0; cputime_lt(incr, cputime_sub(delta, incr)); i++)
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incr = cputime_add(incr, incr);
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for (; i >= 0; incr = cputime_halve(incr), i--) {
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if (cputime_lt(delta, incr))
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continue;
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timer->it.cpu.expires.cpu =
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cputime_add(timer->it.cpu.expires.cpu, incr);
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timer->it_overrun += 1 << i;
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delta = cputime_sub(delta, incr);
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}
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}
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}
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static inline cputime_t prof_ticks(struct task_struct *p)
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{
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return cputime_add(p->utime, p->stime);
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}
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static inline cputime_t virt_ticks(struct task_struct *p)
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{
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return p->utime;
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}
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int posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
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{
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int error = check_clock(which_clock);
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if (!error) {
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tp->tv_sec = 0;
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tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
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if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
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/*
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* If sched_clock is using a cycle counter, we
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* don't have any idea of its true resolution
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* exported, but it is much more than 1s/HZ.
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*/
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tp->tv_nsec = 1;
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}
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}
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return error;
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}
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int posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
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{
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/*
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* You can never reset a CPU clock, but we check for other errors
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* in the call before failing with EPERM.
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*/
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int error = check_clock(which_clock);
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if (error == 0) {
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error = -EPERM;
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}
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return error;
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}
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/*
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* Sample a per-thread clock for the given task.
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*/
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static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
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union cpu_time_count *cpu)
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{
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switch (CPUCLOCK_WHICH(which_clock)) {
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default:
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return -EINVAL;
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case CPUCLOCK_PROF:
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cpu->cpu = prof_ticks(p);
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break;
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case CPUCLOCK_VIRT:
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cpu->cpu = virt_ticks(p);
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break;
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case CPUCLOCK_SCHED:
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cpu->sched = p->se.sum_exec_runtime + task_delta_exec(p);
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break;
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}
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return 0;
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}
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void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
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{
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struct sighand_struct *sighand;
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struct signal_struct *sig;
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struct task_struct *t;
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*times = INIT_CPUTIME;
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rcu_read_lock();
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sighand = rcu_dereference(tsk->sighand);
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if (!sighand)
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goto out;
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sig = tsk->signal;
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t = tsk;
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do {
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times->utime = cputime_add(times->utime, t->utime);
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times->stime = cputime_add(times->stime, t->stime);
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times->sum_exec_runtime += t->se.sum_exec_runtime;
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t = next_thread(t);
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} while (t != tsk);
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times->utime = cputime_add(times->utime, sig->utime);
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times->stime = cputime_add(times->stime, sig->stime);
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times->sum_exec_runtime += sig->sum_sched_runtime;
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out:
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rcu_read_unlock();
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}
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static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
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{
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if (cputime_gt(b->utime, a->utime))
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a->utime = b->utime;
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if (cputime_gt(b->stime, a->stime))
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a->stime = b->stime;
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if (b->sum_exec_runtime > a->sum_exec_runtime)
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a->sum_exec_runtime = b->sum_exec_runtime;
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}
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void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
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{
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struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
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struct task_cputime sum;
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unsigned long flags;
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spin_lock_irqsave(&cputimer->lock, flags);
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if (!cputimer->running) {
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cputimer->running = 1;
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/*
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* The POSIX timer interface allows for absolute time expiry
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* values through the TIMER_ABSTIME flag, therefore we have
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* to synchronize the timer to the clock every time we start
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* it.
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*/
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thread_group_cputime(tsk, &sum);
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update_gt_cputime(&cputimer->cputime, &sum);
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}
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*times = cputimer->cputime;
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spin_unlock_irqrestore(&cputimer->lock, flags);
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}
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/*
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* Sample a process (thread group) clock for the given group_leader task.
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* Must be called with tasklist_lock held for reading.
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*/
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static int cpu_clock_sample_group(const clockid_t which_clock,
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struct task_struct *p,
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union cpu_time_count *cpu)
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{
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struct task_cputime cputime;
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thread_group_cputime(p, &cputime);
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switch (CPUCLOCK_WHICH(which_clock)) {
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default:
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return -EINVAL;
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case CPUCLOCK_PROF:
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cpu->cpu = cputime_add(cputime.utime, cputime.stime);
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break;
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case CPUCLOCK_VIRT:
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cpu->cpu = cputime.utime;
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break;
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case CPUCLOCK_SCHED:
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cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
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break;
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}
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return 0;
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}
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int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
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{
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const pid_t pid = CPUCLOCK_PID(which_clock);
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int error = -EINVAL;
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union cpu_time_count rtn;
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if (pid == 0) {
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/*
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* Special case constant value for our own clocks.
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* We don't have to do any lookup to find ourselves.
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*/
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if (CPUCLOCK_PERTHREAD(which_clock)) {
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/*
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* Sampling just ourselves we can do with no locking.
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*/
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error = cpu_clock_sample(which_clock,
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current, &rtn);
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} else {
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read_lock(&tasklist_lock);
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error = cpu_clock_sample_group(which_clock,
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current, &rtn);
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read_unlock(&tasklist_lock);
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}
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} else {
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/*
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* Find the given PID, and validate that the caller
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* should be able to see it.
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*/
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struct task_struct *p;
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rcu_read_lock();
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p = find_task_by_vpid(pid);
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if (p) {
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if (CPUCLOCK_PERTHREAD(which_clock)) {
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if (same_thread_group(p, current)) {
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error = cpu_clock_sample(which_clock,
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p, &rtn);
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}
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} else {
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read_lock(&tasklist_lock);
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if (thread_group_leader(p) && p->signal) {
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error =
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cpu_clock_sample_group(which_clock,
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p, &rtn);
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}
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read_unlock(&tasklist_lock);
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}
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}
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rcu_read_unlock();
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}
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if (error)
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return error;
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sample_to_timespec(which_clock, rtn, tp);
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return 0;
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}
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/*
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* Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
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* This is called from sys_timer_create with the new timer already locked.
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*/
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int posix_cpu_timer_create(struct k_itimer *new_timer)
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{
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int ret = 0;
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const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
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struct task_struct *p;
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if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
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return -EINVAL;
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INIT_LIST_HEAD(&new_timer->it.cpu.entry);
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new_timer->it.cpu.incr.sched = 0;
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new_timer->it.cpu.expires.sched = 0;
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read_lock(&tasklist_lock);
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if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
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if (pid == 0) {
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p = current;
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} else {
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p = find_task_by_vpid(pid);
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if (p && !same_thread_group(p, current))
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p = NULL;
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}
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} else {
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if (pid == 0) {
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p = current->group_leader;
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} else {
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p = find_task_by_vpid(pid);
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if (p && !thread_group_leader(p))
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p = NULL;
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}
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}
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new_timer->it.cpu.task = p;
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if (p) {
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get_task_struct(p);
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} else {
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ret = -EINVAL;
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}
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read_unlock(&tasklist_lock);
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return ret;
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}
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|
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/*
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* Clean up a CPU-clock timer that is about to be destroyed.
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* This is called from timer deletion with the timer already locked.
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* If we return TIMER_RETRY, it's necessary to release the timer's lock
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* and try again. (This happens when the timer is in the middle of firing.)
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*/
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int posix_cpu_timer_del(struct k_itimer *timer)
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{
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struct task_struct *p = timer->it.cpu.task;
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int ret = 0;
|
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|
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if (likely(p != NULL)) {
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read_lock(&tasklist_lock);
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if (unlikely(p->signal == NULL)) {
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/*
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* We raced with the reaping of the task.
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* The deletion should have cleared us off the list.
|
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*/
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BUG_ON(!list_empty(&timer->it.cpu.entry));
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} else {
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spin_lock(&p->sighand->siglock);
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if (timer->it.cpu.firing)
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ret = TIMER_RETRY;
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else
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list_del(&timer->it.cpu.entry);
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spin_unlock(&p->sighand->siglock);
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}
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read_unlock(&tasklist_lock);
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|
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if (!ret)
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put_task_struct(p);
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}
|
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|
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return ret;
|
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}
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|
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/*
|
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* Clean out CPU timers still ticking when a thread exited. The task
|
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* pointer is cleared, and the expiry time is replaced with the residual
|
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* time for later timer_gettime calls to return.
|
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* This must be called with the siglock held.
|
|
*/
|
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static void cleanup_timers(struct list_head *head,
|
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cputime_t utime, cputime_t stime,
|
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unsigned long long sum_exec_runtime)
|
|
{
|
|
struct cpu_timer_list *timer, *next;
|
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cputime_t ptime = cputime_add(utime, stime);
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|
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list_for_each_entry_safe(timer, next, head, entry) {
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list_del_init(&timer->entry);
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if (cputime_lt(timer->expires.cpu, ptime)) {
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timer->expires.cpu = cputime_zero;
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} else {
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timer->expires.cpu = cputime_sub(timer->expires.cpu,
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ptime);
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}
|
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}
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|
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++head;
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list_for_each_entry_safe(timer, next, head, entry) {
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list_del_init(&timer->entry);
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if (cputime_lt(timer->expires.cpu, utime)) {
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timer->expires.cpu = cputime_zero;
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} else {
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timer->expires.cpu = cputime_sub(timer->expires.cpu,
|
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utime);
|
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}
|
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}
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|
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++head;
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list_for_each_entry_safe(timer, next, head, entry) {
|
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list_del_init(&timer->entry);
|
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if (timer->expires.sched < sum_exec_runtime) {
|
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timer->expires.sched = 0;
|
|
} else {
|
|
timer->expires.sched -= sum_exec_runtime;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
cleanup_timers(tsk->cpu_timers,
|
|
tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);
|
|
|
|
}
|
|
void posix_cpu_timers_exit_group(struct task_struct *tsk)
|
|
{
|
|
struct task_cputime cputime;
|
|
|
|
thread_group_cputimer(tsk, &cputime);
|
|
cleanup_timers(tsk->signal->cpu_timers,
|
|
cputime.utime, cputime.stime, cputime.sum_exec_runtime);
|
|
}
|
|
|
|
static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
|
|
{
|
|
/*
|
|
* That's all for this thread or process.
|
|
* We leave our residual in expires to be reported.
|
|
*/
|
|
put_task_struct(timer->it.cpu.task);
|
|
timer->it.cpu.task = NULL;
|
|
timer->it.cpu.expires = cpu_time_sub(timer->it_clock,
|
|
timer->it.cpu.expires,
|
|
now);
|
|
}
|
|
|
|
/*
|
|
* Insert the timer on the appropriate list before any timers that
|
|
* expire later. This must be called with the tasklist_lock held
|
|
* for reading, and interrupts disabled.
|
|
*/
|
|
static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
|
|
{
|
|
struct task_struct *p = timer->it.cpu.task;
|
|
struct list_head *head, *listpos;
|
|
struct cpu_timer_list *const nt = &timer->it.cpu;
|
|
struct cpu_timer_list *next;
|
|
unsigned long i;
|
|
|
|
head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
|
|
p->cpu_timers : p->signal->cpu_timers);
|
|
head += CPUCLOCK_WHICH(timer->it_clock);
|
|
|
|
BUG_ON(!irqs_disabled());
|
|
spin_lock(&p->sighand->siglock);
|
|
|
|
listpos = head;
|
|
if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
|
|
list_for_each_entry(next, head, entry) {
|
|
if (next->expires.sched > nt->expires.sched)
|
|
break;
|
|
listpos = &next->entry;
|
|
}
|
|
} else {
|
|
list_for_each_entry(next, head, entry) {
|
|
if (cputime_gt(next->expires.cpu, nt->expires.cpu))
|
|
break;
|
|
listpos = &next->entry;
|
|
}
|
|
}
|
|
list_add(&nt->entry, listpos);
|
|
|
|
if (listpos == head) {
|
|
/*
|
|
* We are the new earliest-expiring timer.
|
|
* If we are a thread timer, there can always
|
|
* be a process timer telling us to stop earlier.
|
|
*/
|
|
|
|
if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
|
|
switch (CPUCLOCK_WHICH(timer->it_clock)) {
|
|
default:
|
|
BUG();
|
|
case CPUCLOCK_PROF:
|
|
if (cputime_eq(p->cputime_expires.prof_exp,
|
|
cputime_zero) ||
|
|
cputime_gt(p->cputime_expires.prof_exp,
|
|
nt->expires.cpu))
|
|
p->cputime_expires.prof_exp =
|
|
nt->expires.cpu;
|
|
break;
|
|
case CPUCLOCK_VIRT:
|
|
if (cputime_eq(p->cputime_expires.virt_exp,
|
|
cputime_zero) ||
|
|
cputime_gt(p->cputime_expires.virt_exp,
|
|
nt->expires.cpu))
|
|
p->cputime_expires.virt_exp =
|
|
nt->expires.cpu;
|
|
break;
|
|
case CPUCLOCK_SCHED:
|
|
if (p->cputime_expires.sched_exp == 0 ||
|
|
p->cputime_expires.sched_exp >
|
|
nt->expires.sched)
|
|
p->cputime_expires.sched_exp =
|
|
nt->expires.sched;
|
|
break;
|
|
}
|
|
} else {
|
|
/*
|
|
* For a process timer, set the cached expiration time.
|
|
*/
|
|
switch (CPUCLOCK_WHICH(timer->it_clock)) {
|
|
default:
|
|
BUG();
|
|
case CPUCLOCK_VIRT:
|
|
if (!cputime_eq(p->signal->it_virt_expires,
|
|
cputime_zero) &&
|
|
cputime_lt(p->signal->it_virt_expires,
|
|
timer->it.cpu.expires.cpu))
|
|
break;
|
|
p->signal->cputime_expires.virt_exp =
|
|
timer->it.cpu.expires.cpu;
|
|
break;
|
|
case CPUCLOCK_PROF:
|
|
if (!cputime_eq(p->signal->it_prof_expires,
|
|
cputime_zero) &&
|
|
cputime_lt(p->signal->it_prof_expires,
|
|
timer->it.cpu.expires.cpu))
|
|
break;
|
|
i = p->signal->rlim[RLIMIT_CPU].rlim_cur;
|
|
if (i != RLIM_INFINITY &&
|
|
i <= cputime_to_secs(timer->it.cpu.expires.cpu))
|
|
break;
|
|
p->signal->cputime_expires.prof_exp =
|
|
timer->it.cpu.expires.cpu;
|
|
break;
|
|
case CPUCLOCK_SCHED:
|
|
p->signal->cputime_expires.sched_exp =
|
|
timer->it.cpu.expires.sched;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
spin_unlock(&p->sighand->siglock);
|
|
}
|
|
|
|
/*
|
|
* The timer is locked, fire it and arrange for its reload.
|
|
*/
|
|
static void cpu_timer_fire(struct k_itimer *timer)
|
|
{
|
|
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.sched = 0;
|
|
} else if (timer->it.cpu.incr.sched == 0) {
|
|
/*
|
|
* One-shot timer. Clear it as soon as it's fired.
|
|
*/
|
|
posix_timer_event(timer, 0);
|
|
timer->it.cpu.expires.sched = 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 tasklist_lock held for reading.
|
|
*/
|
|
static int cpu_timer_sample_group(const clockid_t which_clock,
|
|
struct task_struct *p,
|
|
union cpu_time_count *cpu)
|
|
{
|
|
struct task_cputime cputime;
|
|
|
|
thread_group_cputimer(p, &cputime);
|
|
switch (CPUCLOCK_WHICH(which_clock)) {
|
|
default:
|
|
return -EINVAL;
|
|
case CPUCLOCK_PROF:
|
|
cpu->cpu = cputime_add(cputime.utime, cputime.stime);
|
|
break;
|
|
case CPUCLOCK_VIRT:
|
|
cpu->cpu = cputime.utime;
|
|
break;
|
|
case CPUCLOCK_SCHED:
|
|
cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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.)
|
|
*/
|
|
int posix_cpu_timer_set(struct k_itimer *timer, int flags,
|
|
struct itimerspec *new, struct itimerspec *old)
|
|
{
|
|
struct task_struct *p = timer->it.cpu.task;
|
|
union cpu_time_count old_expires, new_expires, val;
|
|
int ret;
|
|
|
|
if (unlikely(p == NULL)) {
|
|
/*
|
|
* Timer refers to a dead task's clock.
|
|
*/
|
|
return -ESRCH;
|
|
}
|
|
|
|
new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
|
|
|
|
read_lock(&tasklist_lock);
|
|
/*
|
|
* We need the tasklist_lock to protect against reaping that
|
|
* clears p->signal. If p has just been reaped, we can no
|
|
* longer get any information about it at all.
|
|
*/
|
|
if (unlikely(p->signal == NULL)) {
|
|
read_unlock(&tasklist_lock);
|
|
put_task_struct(p);
|
|
timer->it.cpu.task = NULL;
|
|
return -ESRCH;
|
|
}
|
|
|
|
/*
|
|
* Disarm any old timer after extracting its expiry time.
|
|
*/
|
|
BUG_ON(!irqs_disabled());
|
|
|
|
ret = 0;
|
|
spin_lock(&p->sighand->siglock);
|
|
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);
|
|
spin_unlock(&p->sighand->siglock);
|
|
|
|
/*
|
|
* 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.sched == 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 (cpu_time_before(timer->it_clock, val,
|
|
timer->it.cpu.expires)) {
|
|
old_expires = cpu_time_sub(
|
|
timer->it_clock,
|
|
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).
|
|
*/
|
|
read_unlock(&tasklist_lock);
|
|
goto out;
|
|
}
|
|
|
|
if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
|
|
cpu_time_add(timer->it_clock, &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.sched != 0 &&
|
|
(timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
|
|
cpu_time_before(timer->it_clock, val, new_expires)) {
|
|
arm_timer(timer, val);
|
|
}
|
|
|
|
read_unlock(&tasklist_lock);
|
|
|
|
/*
|
|
* 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.sched != 0 &&
|
|
(timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
|
|
!cpu_time_before(timer->it_clock, 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,
|
|
timer->it.cpu.incr, &old->it_interval);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
|
|
{
|
|
union cpu_time_count now;
|
|
struct task_struct *p = timer->it.cpu.task;
|
|
int clear_dead;
|
|
|
|
/*
|
|
* Easy part: convert the reload time.
|
|
*/
|
|
sample_to_timespec(timer->it_clock,
|
|
timer->it.cpu.incr, &itp->it_interval);
|
|
|
|
if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
|
|
itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
|
|
return;
|
|
}
|
|
|
|
if (unlikely(p == NULL)) {
|
|
/*
|
|
* This task already died and the timer will never fire.
|
|
* In this case, expires is actually the dead value.
|
|
*/
|
|
dead:
|
|
sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
|
|
&itp->it_value);
|
|
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);
|
|
clear_dead = p->exit_state;
|
|
} else {
|
|
read_lock(&tasklist_lock);
|
|
if (unlikely(p->signal == NULL)) {
|
|
/*
|
|
* The process has been reaped.
|
|
* We can't even collect a sample any more.
|
|
* Call the timer disarmed, nothing else to do.
|
|
*/
|
|
put_task_struct(p);
|
|
timer->it.cpu.task = NULL;
|
|
timer->it.cpu.expires.sched = 0;
|
|
read_unlock(&tasklist_lock);
|
|
goto dead;
|
|
} else {
|
|
cpu_timer_sample_group(timer->it_clock, p, &now);
|
|
clear_dead = (unlikely(p->exit_state) &&
|
|
thread_group_empty(p));
|
|
}
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
|
|
if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
|
|
if (timer->it.cpu.incr.sched == 0 &&
|
|
cpu_time_before(timer->it_clock,
|
|
timer->it.cpu.expires, now)) {
|
|
/*
|
|
* Do-nothing timer expired and has no reload,
|
|
* so it's as if it was never set.
|
|
*/
|
|
timer->it.cpu.expires.sched = 0;
|
|
itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
|
|
return;
|
|
}
|
|
/*
|
|
* Account for any expirations and reloads that should
|
|
* have happened.
|
|
*/
|
|
bump_cpu_timer(timer, now);
|
|
}
|
|
|
|
if (unlikely(clear_dead)) {
|
|
/*
|
|
* We've noticed that the thread is dead, but
|
|
* not yet reaped. Take this opportunity to
|
|
* drop our task ref.
|
|
*/
|
|
clear_dead_task(timer, now);
|
|
goto dead;
|
|
}
|
|
|
|
if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
|
|
sample_to_timespec(timer->it_clock,
|
|
cpu_time_sub(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;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
int maxfire;
|
|
struct list_head *timers = tsk->cpu_timers;
|
|
struct signal_struct *const sig = tsk->signal;
|
|
|
|
maxfire = 20;
|
|
tsk->cputime_expires.prof_exp = cputime_zero;
|
|
while (!list_empty(timers)) {
|
|
struct cpu_timer_list *t = list_first_entry(timers,
|
|
struct cpu_timer_list,
|
|
entry);
|
|
if (!--maxfire || cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
|
|
tsk->cputime_expires.prof_exp = t->expires.cpu;
|
|
break;
|
|
}
|
|
t->firing = 1;
|
|
list_move_tail(&t->entry, firing);
|
|
}
|
|
|
|
++timers;
|
|
maxfire = 20;
|
|
tsk->cputime_expires.virt_exp = cputime_zero;
|
|
while (!list_empty(timers)) {
|
|
struct cpu_timer_list *t = list_first_entry(timers,
|
|
struct cpu_timer_list,
|
|
entry);
|
|
if (!--maxfire || cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
|
|
tsk->cputime_expires.virt_exp = t->expires.cpu;
|
|
break;
|
|
}
|
|
t->firing = 1;
|
|
list_move_tail(&t->entry, firing);
|
|
}
|
|
|
|
++timers;
|
|
maxfire = 20;
|
|
tsk->cputime_expires.sched_exp = 0;
|
|
while (!list_empty(timers)) {
|
|
struct cpu_timer_list *t = list_first_entry(timers,
|
|
struct cpu_timer_list,
|
|
entry);
|
|
if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
|
|
tsk->cputime_expires.sched_exp = t->expires.sched;
|
|
break;
|
|
}
|
|
t->firing = 1;
|
|
list_move_tail(&t->entry, firing);
|
|
}
|
|
|
|
/*
|
|
* Check for the special case thread timers.
|
|
*/
|
|
if (sig->rlim[RLIMIT_RTTIME].rlim_cur != RLIM_INFINITY) {
|
|
unsigned long hard = sig->rlim[RLIMIT_RTTIME].rlim_max;
|
|
unsigned long *soft = &sig->rlim[RLIMIT_RTTIME].rlim_cur;
|
|
|
|
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 (sig->rlim[RLIMIT_RTTIME].rlim_cur
|
|
< sig->rlim[RLIMIT_RTTIME].rlim_max) {
|
|
sig->rlim[RLIMIT_RTTIME].rlim_cur +=
|
|
USEC_PER_SEC;
|
|
}
|
|
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 task_struct *tsk)
|
|
{
|
|
struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
|
|
unsigned long flags;
|
|
|
|
if (!cputimer->running)
|
|
return;
|
|
|
|
spin_lock_irqsave(&cputimer->lock, flags);
|
|
cputimer->running = 0;
|
|
spin_unlock_irqrestore(&cputimer->lock, flags);
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
int maxfire;
|
|
struct signal_struct *const sig = tsk->signal;
|
|
cputime_t 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;
|
|
|
|
/*
|
|
* Don't sample the current process CPU clocks if there are no timers.
|
|
*/
|
|
if (list_empty(&timers[CPUCLOCK_PROF]) &&
|
|
cputime_eq(sig->it_prof_expires, cputime_zero) &&
|
|
sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY &&
|
|
list_empty(&timers[CPUCLOCK_VIRT]) &&
|
|
cputime_eq(sig->it_virt_expires, cputime_zero) &&
|
|
list_empty(&timers[CPUCLOCK_SCHED])) {
|
|
stop_process_timers(tsk);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Collect the current process totals.
|
|
*/
|
|
thread_group_cputimer(tsk, &cputime);
|
|
utime = cputime.utime;
|
|
ptime = cputime_add(utime, cputime.stime);
|
|
sum_sched_runtime = cputime.sum_exec_runtime;
|
|
maxfire = 20;
|
|
prof_expires = cputime_zero;
|
|
while (!list_empty(timers)) {
|
|
struct cpu_timer_list *tl = list_first_entry(timers,
|
|
struct cpu_timer_list,
|
|
entry);
|
|
if (!--maxfire || cputime_lt(ptime, tl->expires.cpu)) {
|
|
prof_expires = tl->expires.cpu;
|
|
break;
|
|
}
|
|
tl->firing = 1;
|
|
list_move_tail(&tl->entry, firing);
|
|
}
|
|
|
|
++timers;
|
|
maxfire = 20;
|
|
virt_expires = cputime_zero;
|
|
while (!list_empty(timers)) {
|
|
struct cpu_timer_list *tl = list_first_entry(timers,
|
|
struct cpu_timer_list,
|
|
entry);
|
|
if (!--maxfire || cputime_lt(utime, tl->expires.cpu)) {
|
|
virt_expires = tl->expires.cpu;
|
|
break;
|
|
}
|
|
tl->firing = 1;
|
|
list_move_tail(&tl->entry, firing);
|
|
}
|
|
|
|
++timers;
|
|
maxfire = 20;
|
|
sched_expires = 0;
|
|
while (!list_empty(timers)) {
|
|
struct cpu_timer_list *tl = list_first_entry(timers,
|
|
struct cpu_timer_list,
|
|
entry);
|
|
if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
|
|
sched_expires = tl->expires.sched;
|
|
break;
|
|
}
|
|
tl->firing = 1;
|
|
list_move_tail(&tl->entry, firing);
|
|
}
|
|
|
|
/*
|
|
* Check for the special case process timers.
|
|
*/
|
|
if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
|
|
if (cputime_ge(ptime, sig->it_prof_expires)) {
|
|
/* ITIMER_PROF fires and reloads. */
|
|
sig->it_prof_expires = sig->it_prof_incr;
|
|
if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
|
|
sig->it_prof_expires = cputime_add(
|
|
sig->it_prof_expires, ptime);
|
|
}
|
|
__group_send_sig_info(SIGPROF, SEND_SIG_PRIV, tsk);
|
|
}
|
|
if (!cputime_eq(sig->it_prof_expires, cputime_zero) &&
|
|
(cputime_eq(prof_expires, cputime_zero) ||
|
|
cputime_lt(sig->it_prof_expires, prof_expires))) {
|
|
prof_expires = sig->it_prof_expires;
|
|
}
|
|
}
|
|
if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
|
|
if (cputime_ge(utime, sig->it_virt_expires)) {
|
|
/* ITIMER_VIRTUAL fires and reloads. */
|
|
sig->it_virt_expires = sig->it_virt_incr;
|
|
if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
|
|
sig->it_virt_expires = cputime_add(
|
|
sig->it_virt_expires, utime);
|
|
}
|
|
__group_send_sig_info(SIGVTALRM, SEND_SIG_PRIV, tsk);
|
|
}
|
|
if (!cputime_eq(sig->it_virt_expires, cputime_zero) &&
|
|
(cputime_eq(virt_expires, cputime_zero) ||
|
|
cputime_lt(sig->it_virt_expires, virt_expires))) {
|
|
virt_expires = sig->it_virt_expires;
|
|
}
|
|
}
|
|
if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
|
|
unsigned long psecs = cputime_to_secs(ptime);
|
|
cputime_t x;
|
|
if (psecs >= sig->rlim[RLIMIT_CPU].rlim_max) {
|
|
/*
|
|
* 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 >= sig->rlim[RLIMIT_CPU].rlim_cur) {
|
|
/*
|
|
* At the soft limit, send a SIGXCPU every second.
|
|
*/
|
|
__group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
|
|
if (sig->rlim[RLIMIT_CPU].rlim_cur
|
|
< sig->rlim[RLIMIT_CPU].rlim_max) {
|
|
sig->rlim[RLIMIT_CPU].rlim_cur++;
|
|
}
|
|
}
|
|
x = secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
|
|
if (cputime_eq(prof_expires, cputime_zero) ||
|
|
cputime_lt(x, prof_expires)) {
|
|
prof_expires = x;
|
|
}
|
|
}
|
|
|
|
if (!cputime_eq(prof_expires, cputime_zero) &&
|
|
(cputime_eq(sig->cputime_expires.prof_exp, cputime_zero) ||
|
|
cputime_gt(sig->cputime_expires.prof_exp, prof_expires)))
|
|
sig->cputime_expires.prof_exp = prof_expires;
|
|
if (!cputime_eq(virt_expires, cputime_zero) &&
|
|
(cputime_eq(sig->cputime_expires.virt_exp, cputime_zero) ||
|
|
cputime_gt(sig->cputime_expires.virt_exp, virt_expires)))
|
|
sig->cputime_expires.virt_exp = virt_expires;
|
|
if (sched_expires != 0 &&
|
|
(sig->cputime_expires.sched_exp == 0 ||
|
|
sig->cputime_expires.sched_exp > sched_expires))
|
|
sig->cputime_expires.sched_exp = sched_expires;
|
|
}
|
|
|
|
/*
|
|
* 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 task_struct *p = timer->it.cpu.task;
|
|
union cpu_time_count now;
|
|
|
|
if (unlikely(p == NULL))
|
|
/*
|
|
* The task was cleaned up already, no future firings.
|
|
*/
|
|
goto out;
|
|
|
|
/*
|
|
* 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)) {
|
|
clear_dead_task(timer, now);
|
|
goto out;
|
|
}
|
|
read_lock(&tasklist_lock); /* arm_timer needs it. */
|
|
} else {
|
|
read_lock(&tasklist_lock);
|
|
if (unlikely(p->signal == NULL)) {
|
|
/*
|
|
* The process has been reaped.
|
|
* We can't even collect a sample any more.
|
|
*/
|
|
put_task_struct(p);
|
|
timer->it.cpu.task = p = NULL;
|
|
timer->it.cpu.expires.sched = 0;
|
|
goto out_unlock;
|
|
} else if (unlikely(p->exit_state) && thread_group_empty(p)) {
|
|
/*
|
|
* We've noticed that the thread is dead, but
|
|
* not yet reaped. Take this opportunity to
|
|
* drop our task ref.
|
|
*/
|
|
clear_dead_task(timer, now);
|
|
goto out_unlock;
|
|
}
|
|
cpu_timer_sample_group(timer->it_clock, p, &now);
|
|
bump_cpu_timer(timer, now);
|
|
/* Leave the tasklist_lock locked for the call below. */
|
|
}
|
|
|
|
/*
|
|
* Now re-arm for the new expiry time.
|
|
*/
|
|
arm_timer(timer, now);
|
|
|
|
out_unlock:
|
|
read_unlock(&tasklist_lock);
|
|
|
|
out:
|
|
timer->it_overrun_last = timer->it_overrun;
|
|
timer->it_overrun = -1;
|
|
++timer->it_requeue_pending;
|
|
}
|
|
|
|
/**
|
|
* 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_eq(cputime->utime, cputime_zero) &&
|
|
cputime_eq(cputime->stime, cputime_zero) &&
|
|
cputime->sum_exec_runtime == 0)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* 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 (!cputime_eq(expires->utime, cputime_zero) &&
|
|
cputime_ge(sample->utime, expires->utime))
|
|
return 1;
|
|
if (!cputime_eq(expires->stime, cputime_zero) &&
|
|
cputime_ge(cputime_add(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;
|
|
|
|
/* tsk == current, ensure it is safe to use ->signal/sighand */
|
|
if (unlikely(tsk->exit_state))
|
|
return 0;
|
|
|
|
if (!task_cputime_zero(&tsk->cputime_expires)) {
|
|
struct task_cputime task_sample = {
|
|
.utime = tsk->utime,
|
|
.stime = tsk->stime,
|
|
.sum_exec_runtime = tsk->se.sum_exec_runtime
|
|
};
|
|
|
|
if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
|
|
return 1;
|
|
}
|
|
|
|
sig = tsk->signal;
|
|
if (!task_cputime_zero(&sig->cputime_expires)) {
|
|
struct task_cputime group_sample;
|
|
|
|
thread_group_cputimer(tsk, &group_sample);
|
|
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;
|
|
|
|
BUG_ON(!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;
|
|
|
|
spin_lock(&tsk->sighand->siglock);
|
|
/*
|
|
* 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);
|
|
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.
|
|
*/
|
|
spin_unlock(&tsk->sighand->siglock);
|
|
|
|
/*
|
|
* Now that all the timers on our list have the firing flag,
|
|
* noone 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 firing;
|
|
spin_lock(&timer->it_lock);
|
|
list_del_init(&timer->it.cpu.entry);
|
|
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(firing >= 0)) {
|
|
cpu_timer_fire(timer);
|
|
}
|
|
spin_unlock(&timer->it_lock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Set one of the process-wide special case CPU timers.
|
|
* The tsk->sighand->siglock must be held by the caller.
|
|
* The *newval argument is relative and we update it to be absolute, *oldval
|
|
* is absolute and we update it to be relative.
|
|
*/
|
|
void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
|
|
cputime_t *newval, cputime_t *oldval)
|
|
{
|
|
union cpu_time_count now;
|
|
struct list_head *head;
|
|
|
|
BUG_ON(clock_idx == CPUCLOCK_SCHED);
|
|
cpu_timer_sample_group(clock_idx, tsk, &now);
|
|
|
|
if (oldval) {
|
|
if (!cputime_eq(*oldval, cputime_zero)) {
|
|
if (cputime_le(*oldval, now.cpu)) {
|
|
/* Just about to fire. */
|
|
*oldval = jiffies_to_cputime(1);
|
|
} else {
|
|
*oldval = cputime_sub(*oldval, now.cpu);
|
|
}
|
|
}
|
|
|
|
if (cputime_eq(*newval, cputime_zero))
|
|
return;
|
|
*newval = cputime_add(*newval, now.cpu);
|
|
|
|
/*
|
|
* If the RLIMIT_CPU timer will expire before the
|
|
* ITIMER_PROF timer, we have nothing else to do.
|
|
*/
|
|
if (tsk->signal->rlim[RLIMIT_CPU].rlim_cur
|
|
< cputime_to_secs(*newval))
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Check whether there are any process timers already set to fire
|
|
* before this one. If so, we don't have anything more to do.
|
|
*/
|
|
head = &tsk->signal->cpu_timers[clock_idx];
|
|
if (list_empty(head) ||
|
|
cputime_ge(list_first_entry(head,
|
|
struct cpu_timer_list, entry)->expires.cpu,
|
|
*newval)) {
|
|
switch (clock_idx) {
|
|
case CPUCLOCK_PROF:
|
|
tsk->signal->cputime_expires.prof_exp = *newval;
|
|
break;
|
|
case CPUCLOCK_VIRT:
|
|
tsk->signal->cputime_expires.virt_exp = *newval;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
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.sched == 0) {
|
|
/*
|
|
* Our timer fired and was reset.
|
|
*/
|
|
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);
|
|
posix_cpu_timer_set(&timer, 0, &zero_it, it);
|
|
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;
|
|
}
|
|
|
|
int posix_cpu_nsleep(const clockid_t which_clock, int flags,
|
|
struct timespec *rqtp, struct timespec __user *rmtp)
|
|
{
|
|
struct restart_block *restart_block =
|
|
¤t_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 != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
|
|
return -EFAULT;
|
|
|
|
restart_block->fn = posix_cpu_nsleep_restart;
|
|
restart_block->arg0 = which_clock;
|
|
restart_block->arg1 = (unsigned long) rmtp;
|
|
restart_block->arg2 = rqtp->tv_sec;
|
|
restart_block->arg3 = rqtp->tv_nsec;
|
|
}
|
|
return error;
|
|
}
|
|
|
|
long posix_cpu_nsleep_restart(struct restart_block *restart_block)
|
|
{
|
|
clockid_t which_clock = restart_block->arg0;
|
|
struct timespec __user *rmtp;
|
|
struct timespec t;
|
|
struct itimerspec it;
|
|
int error;
|
|
|
|
rmtp = (struct timespec __user *) restart_block->arg1;
|
|
t.tv_sec = restart_block->arg2;
|
|
t.tv_nsec = restart_block->arg3;
|
|
|
|
restart_block->fn = do_no_restart_syscall;
|
|
error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
|
|
|
|
if (error == -ERESTART_RESTARTBLOCK) {
|
|
/*
|
|
* Report back to the user the time still remaining.
|
|
*/
|
|
if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
|
|
return -EFAULT;
|
|
|
|
restart_block->fn = posix_cpu_nsleep_restart;
|
|
restart_block->arg0 = which_clock;
|
|
restart_block->arg1 = (unsigned long) rmtp;
|
|
restart_block->arg2 = t.tv_sec;
|
|
restart_block->arg3 = t.tv_nsec;
|
|
}
|
|
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);
|
|
}
|
|
static int thread_cpu_nsleep(const clockid_t which_clock, int flags,
|
|
struct timespec *rqtp, struct timespec __user *rmtp)
|
|
{
|
|
return -EINVAL;
|
|
}
|
|
static long thread_cpu_nsleep_restart(struct restart_block *restart_block)
|
|
{
|
|
return -EINVAL;
|
|
}
|
|
|
|
static __init int init_posix_cpu_timers(void)
|
|
{
|
|
struct k_clock process = {
|
|
.clock_getres = process_cpu_clock_getres,
|
|
.clock_get = process_cpu_clock_get,
|
|
.clock_set = do_posix_clock_nosettime,
|
|
.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,
|
|
.clock_set = do_posix_clock_nosettime,
|
|
.timer_create = thread_cpu_timer_create,
|
|
.nsleep = thread_cpu_nsleep,
|
|
.nsleep_restart = thread_cpu_nsleep_restart,
|
|
};
|
|
|
|
register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
|
|
register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
|
|
|
|
return 0;
|
|
}
|
|
__initcall(init_posix_cpu_timers);
|