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![Ingo Molnar](/assets/img/avatar_default.png)
update the posix-cpu-timers code to use CFS's CPU accounting information. Signed-off-by: Ingo Molnar <mingo@elte.hu>
1629 lines
43 KiB
C
1629 lines
43 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 <asm/uaccess.h>
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#include <linux/errno.h>
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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_pid(pid);
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if (!p || (CPUCLOCK_PERTHREAD(which_clock) ?
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p->tgid != current->tgid : p->tgid != pid)) {
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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->tv_sec = div_long_long_rem(cpu.sched,
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NSEC_PER_SEC, &tp->tv_nsec);
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} else {
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cputime_to_timespec(cpu.cpu, tp);
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}
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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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static inline unsigned long long sched_ns(struct task_struct *p)
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{
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return task_sched_runtime(p);
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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 = sched_ns(p);
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break;
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}
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return 0;
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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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* Must be called with tasklist_lock held for reading, and p->sighand->siglock.
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*/
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static int cpu_clock_sample_group_locked(unsigned int clock_idx,
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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_struct *t = p;
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switch (clock_idx) {
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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(p->signal->utime, p->signal->stime);
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do {
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cpu->cpu = cputime_add(cpu->cpu, prof_ticks(t));
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t = next_thread(t);
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} while (t != p);
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break;
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case CPUCLOCK_VIRT:
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cpu->cpu = p->signal->utime;
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do {
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cpu->cpu = cputime_add(cpu->cpu, virt_ticks(t));
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t = next_thread(t);
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} while (t != p);
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break;
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case CPUCLOCK_SCHED:
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cpu->sched = p->signal->sum_sched_runtime;
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/* Add in each other live thread. */
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while ((t = next_thread(t)) != p) {
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cpu->sched += t->se.sum_exec_runtime;
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}
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cpu->sched += sched_ns(p);
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break;
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}
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return 0;
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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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int ret;
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unsigned long flags;
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spin_lock_irqsave(&p->sighand->siglock, flags);
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ret = cpu_clock_sample_group_locked(CPUCLOCK_WHICH(which_clock), p,
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cpu);
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spin_unlock_irqrestore(&p->sighand->siglock, flags);
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return ret;
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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_pid(pid);
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if (p) {
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if (CPUCLOCK_PERTHREAD(which_clock)) {
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if (p->tgid == current->tgid) {
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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 (p->tgid == pid && 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_pid(pid);
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if (p && p->tgid != current->tgid)
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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_pid(pid);
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if (p && p->tgid != pid)
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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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* 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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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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if (!ret)
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put_task_struct(p);
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}
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return ret;
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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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*/
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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)
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{
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struct cpu_timer_list *timer, *next;
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cputime_t ptime = cputime_add(utime, stime);
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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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++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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++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;
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} else {
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timer->expires.sched -= sum_exec_runtime;
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}
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}
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}
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/*
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* These are both called with the siglock held, when the current thread
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* is being reaped. When the final (leader) thread in the group is reaped,
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* posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
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*/
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void posix_cpu_timers_exit(struct task_struct *tsk)
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{
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cleanup_timers(tsk->cpu_timers,
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tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);
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}
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void posix_cpu_timers_exit_group(struct task_struct *tsk)
|
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{
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cleanup_timers(tsk->signal->cpu_timers,
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cputime_add(tsk->utime, tsk->signal->utime),
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cputime_add(tsk->stime, tsk->signal->stime),
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tsk->se.sum_exec_runtime + tsk->signal->sum_sched_runtime);
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}
|
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|
|
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/*
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* Set the expiry times of all the threads in the process so one of them
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* will go off before the process cumulative expiry total is reached.
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*/
|
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static void process_timer_rebalance(struct task_struct *p,
|
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unsigned int clock_idx,
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union cpu_time_count expires,
|
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union cpu_time_count val)
|
|
{
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cputime_t ticks, left;
|
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unsigned long long ns, nsleft;
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struct task_struct *t = p;
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unsigned int nthreads = atomic_read(&p->signal->live);
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|
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if (!nthreads)
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return;
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|
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switch (clock_idx) {
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default:
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BUG();
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break;
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case CPUCLOCK_PROF:
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left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
|
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nthreads);
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do {
|
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if (likely(!(t->flags & PF_EXITING))) {
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ticks = cputime_add(prof_ticks(t), left);
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if (cputime_eq(t->it_prof_expires,
|
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cputime_zero) ||
|
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cputime_gt(t->it_prof_expires, ticks)) {
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t->it_prof_expires = ticks;
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|
}
|
|
}
|
|
t = next_thread(t);
|
|
} while (t != p);
|
|
break;
|
|
case CPUCLOCK_VIRT:
|
|
left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
|
|
nthreads);
|
|
do {
|
|
if (likely(!(t->flags & PF_EXITING))) {
|
|
ticks = cputime_add(virt_ticks(t), left);
|
|
if (cputime_eq(t->it_virt_expires,
|
|
cputime_zero) ||
|
|
cputime_gt(t->it_virt_expires, ticks)) {
|
|
t->it_virt_expires = ticks;
|
|
}
|
|
}
|
|
t = next_thread(t);
|
|
} while (t != p);
|
|
break;
|
|
case CPUCLOCK_SCHED:
|
|
nsleft = expires.sched - val.sched;
|
|
do_div(nsleft, nthreads);
|
|
nsleft = max_t(unsigned long long, nsleft, 1);
|
|
do {
|
|
if (likely(!(t->flags & PF_EXITING))) {
|
|
ns = t->se.sum_exec_runtime + nsleft;
|
|
if (t->it_sched_expires == 0 ||
|
|
t->it_sched_expires > ns) {
|
|
t->it_sched_expires = ns;
|
|
}
|
|
}
|
|
t = next_thread(t);
|
|
} while (t != p);
|
|
break;
|
|
}
|
|
}
|
|
|
|
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->it_prof_expires,
|
|
cputime_zero) ||
|
|
cputime_gt(p->it_prof_expires,
|
|
nt->expires.cpu))
|
|
p->it_prof_expires = nt->expires.cpu;
|
|
break;
|
|
case CPUCLOCK_VIRT:
|
|
if (cputime_eq(p->it_virt_expires,
|
|
cputime_zero) ||
|
|
cputime_gt(p->it_virt_expires,
|
|
nt->expires.cpu))
|
|
p->it_virt_expires = nt->expires.cpu;
|
|
break;
|
|
case CPUCLOCK_SCHED:
|
|
if (p->it_sched_expires == 0 ||
|
|
p->it_sched_expires > nt->expires.sched)
|
|
p->it_sched_expires = nt->expires.sched;
|
|
break;
|
|
}
|
|
} else {
|
|
/*
|
|
* For a process timer, we must balance
|
|
* all the live threads' expirations.
|
|
*/
|
|
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;
|
|
goto rebalance;
|
|
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;
|
|
goto rebalance;
|
|
case CPUCLOCK_SCHED:
|
|
rebalance:
|
|
process_timer_rebalance(
|
|
timer->it.cpu.task,
|
|
CPUCLOCK_WHICH(timer->it_clock),
|
|
timer->it.cpu.expires, now);
|
|
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);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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_clock_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_clock_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;
|
|
|
|
maxfire = 20;
|
|
tsk->it_prof_expires = 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->it_prof_expires = t->expires.cpu;
|
|
break;
|
|
}
|
|
t->firing = 1;
|
|
list_move_tail(&t->entry, firing);
|
|
}
|
|
|
|
++timers;
|
|
maxfire = 20;
|
|
tsk->it_virt_expires = 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->it_virt_expires = t->expires.cpu;
|
|
break;
|
|
}
|
|
t->firing = 1;
|
|
list_move_tail(&t->entry, firing);
|
|
}
|
|
|
|
++timers;
|
|
maxfire = 20;
|
|
tsk->it_sched_expires = 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->it_sched_expires = t->expires.sched;
|
|
break;
|
|
}
|
|
t->firing = 1;
|
|
list_move_tail(&t->entry, firing);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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, stime, ptime, virt_expires, prof_expires;
|
|
unsigned long long sum_sched_runtime, sched_expires;
|
|
struct task_struct *t;
|
|
struct list_head *timers = sig->cpu_timers;
|
|
|
|
/*
|
|
* 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]))
|
|
return;
|
|
|
|
/*
|
|
* Collect the current process totals.
|
|
*/
|
|
utime = sig->utime;
|
|
stime = sig->stime;
|
|
sum_sched_runtime = sig->sum_sched_runtime;
|
|
t = tsk;
|
|
do {
|
|
utime = cputime_add(utime, t->utime);
|
|
stime = cputime_add(stime, t->stime);
|
|
sum_sched_runtime += t->se.sum_exec_runtime;
|
|
t = next_thread(t);
|
|
} while (t != tsk);
|
|
ptime = cputime_add(utime, stime);
|
|
|
|
maxfire = 20;
|
|
prof_expires = cputime_zero;
|
|
while (!list_empty(timers)) {
|
|
struct cpu_timer_list *t = list_first_entry(timers,
|
|
struct cpu_timer_list,
|
|
entry);
|
|
if (!--maxfire || cputime_lt(ptime, t->expires.cpu)) {
|
|
prof_expires = t->expires.cpu;
|
|
break;
|
|
}
|
|
t->firing = 1;
|
|
list_move_tail(&t->entry, firing);
|
|
}
|
|
|
|
++timers;
|
|
maxfire = 20;
|
|
virt_expires = cputime_zero;
|
|
while (!list_empty(timers)) {
|
|
struct cpu_timer_list *t = list_first_entry(timers,
|
|
struct cpu_timer_list,
|
|
entry);
|
|
if (!--maxfire || cputime_lt(utime, t->expires.cpu)) {
|
|
virt_expires = t->expires.cpu;
|
|
break;
|
|
}
|
|
t->firing = 1;
|
|
list_move_tail(&t->entry, firing);
|
|
}
|
|
|
|
++timers;
|
|
maxfire = 20;
|
|
sched_expires = 0;
|
|
while (!list_empty(timers)) {
|
|
struct cpu_timer_list *t = list_first_entry(timers,
|
|
struct cpu_timer_list,
|
|
entry);
|
|
if (!--maxfire || sum_sched_runtime < t->expires.sched) {
|
|
sched_expires = t->expires.sched;
|
|
break;
|
|
}
|
|
t->firing = 1;
|
|
list_move_tail(&t->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(virt_expires, cputime_zero) ||
|
|
sched_expires != 0) {
|
|
/*
|
|
* Rebalance the threads' expiry times for the remaining
|
|
* process CPU timers.
|
|
*/
|
|
|
|
cputime_t prof_left, virt_left, ticks;
|
|
unsigned long long sched_left, sched;
|
|
const unsigned int nthreads = atomic_read(&sig->live);
|
|
|
|
if (!nthreads)
|
|
return;
|
|
|
|
prof_left = cputime_sub(prof_expires, utime);
|
|
prof_left = cputime_sub(prof_left, stime);
|
|
prof_left = cputime_div_non_zero(prof_left, nthreads);
|
|
virt_left = cputime_sub(virt_expires, utime);
|
|
virt_left = cputime_div_non_zero(virt_left, nthreads);
|
|
if (sched_expires) {
|
|
sched_left = sched_expires - sum_sched_runtime;
|
|
do_div(sched_left, nthreads);
|
|
sched_left = max_t(unsigned long long, sched_left, 1);
|
|
} else {
|
|
sched_left = 0;
|
|
}
|
|
t = tsk;
|
|
do {
|
|
if (unlikely(t->flags & PF_EXITING))
|
|
continue;
|
|
|
|
ticks = cputime_add(cputime_add(t->utime, t->stime),
|
|
prof_left);
|
|
if (!cputime_eq(prof_expires, cputime_zero) &&
|
|
(cputime_eq(t->it_prof_expires, cputime_zero) ||
|
|
cputime_gt(t->it_prof_expires, ticks))) {
|
|
t->it_prof_expires = ticks;
|
|
}
|
|
|
|
ticks = cputime_add(t->utime, virt_left);
|
|
if (!cputime_eq(virt_expires, cputime_zero) &&
|
|
(cputime_eq(t->it_virt_expires, cputime_zero) ||
|
|
cputime_gt(t->it_virt_expires, ticks))) {
|
|
t->it_virt_expires = ticks;
|
|
}
|
|
|
|
sched = t->se.sum_exec_runtime + sched_left;
|
|
if (sched_expires && (t->it_sched_expires == 0 ||
|
|
t->it_sched_expires > sched)) {
|
|
t->it_sched_expires = sched;
|
|
}
|
|
} while ((t = next_thread(t)) != tsk);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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_clock_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;
|
|
}
|
|
|
|
/*
|
|
* 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());
|
|
|
|
#define UNEXPIRED(clock) \
|
|
(cputime_eq(tsk->it_##clock##_expires, cputime_zero) || \
|
|
cputime_lt(clock##_ticks(tsk), tsk->it_##clock##_expires))
|
|
|
|
if (UNEXPIRED(prof) && UNEXPIRED(virt) &&
|
|
(tsk->it_sched_expires == 0 ||
|
|
tsk->se.sum_exec_runtime < tsk->it_sched_expires))
|
|
return;
|
|
|
|
#undef UNEXPIRED
|
|
|
|
/*
|
|
* Double-check with locks held.
|
|
*/
|
|
read_lock(&tasklist_lock);
|
|
if (likely(tsk->signal != NULL)) {
|
|
spin_lock(&tsk->sighand->siglock);
|
|
|
|
/*
|
|
* Here we take off tsk->cpu_timers[N] and tsk->signal->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);
|
|
}
|
|
read_unlock(&tasklist_lock);
|
|
|
|
/*
|
|
* 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 tasklist_lock and tsk->sighand->siglock must be held by the caller.
|
|
* The oldval argument is null for the RLIMIT_CPU timer, where *newval is
|
|
* absolute; non-null for ITIMER_*, where *newval 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_clock_sample_group_locked(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)) {
|
|
/*
|
|
* Rejigger each thread's expiry time so that one will
|
|
* notice before we hit the process-cumulative expiry time.
|
|
*/
|
|
union cpu_time_count expires = { .sched = 0 };
|
|
expires.cpu = *newval;
|
|
process_timer_rebalance(tsk, clock_idx, expires, now);
|
|
}
|
|
}
|
|
|
|
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);
|