#include <asm/uaccess.h>
#include <linux/errno.h>
-static int check_clock(clockid_t which_clock)
+static int check_clock(const clockid_t which_clock)
{
int error = 0;
struct task_struct *p;
}
static inline union cpu_time_count
-timespec_to_sample(clockid_t which_clock, const struct timespec *tp)
+timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
{
union cpu_time_count ret;
ret.sched = 0; /* high half always zero when .cpu used */
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
- ret.sched = tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
+ ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
} else {
ret.cpu = timespec_to_cputime(tp);
}
return ret;
}
-static void sample_to_timespec(clockid_t which_clock,
+static void sample_to_timespec(const clockid_t which_clock,
union cpu_time_count cpu,
struct timespec *tp)
{
}
}
-static inline int cpu_time_before(clockid_t which_clock,
+static inline int cpu_time_before(const clockid_t which_clock,
union cpu_time_count now,
union cpu_time_count then)
{
return cputime_lt(now.cpu, then.cpu);
}
}
-static inline void cpu_time_add(clockid_t which_clock,
+static inline void cpu_time_add(const clockid_t which_clock,
union cpu_time_count *acc,
union cpu_time_count val)
{
acc->cpu = cputime_add(acc->cpu, val.cpu);
}
}
-static inline union cpu_time_count cpu_time_sub(clockid_t which_clock,
+static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
union cpu_time_count a,
union cpu_time_count b)
{
return a;
}
+/*
+ * Divide and limit the result to res >= 1
+ *
+ * This is necessary to prevent signal delivery starvation, when the result of
+ * the division would be rounded down to 0.
+ */
+static inline cputime_t cputime_div_non_zero(cputime_t time, unsigned long div)
+{
+ cputime_t res = cputime_div(time, div);
+
+ return max_t(cputime_t, res, 1);
+}
+
/*
* Update expiry time from increment, and increase overrun count,
* given the current clock sample.
*/
-static inline void bump_cpu_timer(struct k_itimer *timer,
+static void bump_cpu_timer(struct k_itimer *timer,
union cpu_time_count now)
{
int i;
for (i = 0; incr < delta - incr; i++)
incr = incr << 1;
for (; i >= 0; incr >>= 1, i--) {
- if (delta <= incr)
+ if (delta < incr)
continue;
timer->it.cpu.expires.sched += incr;
timer->it_overrun += 1 << i;
for (i = 0; cputime_lt(incr, cputime_sub(delta, incr)); i++)
incr = cputime_add(incr, incr);
for (; i >= 0; incr = cputime_halve(incr), i--) {
- if (cputime_le(delta, incr))
+ if (cputime_lt(delta, incr))
continue;
timer->it.cpu.expires.cpu =
cputime_add(timer->it.cpu.expires.cpu, incr);
return (p == current) ? current_sched_time(p) : p->sched_time;
}
-int posix_cpu_clock_getres(clockid_t which_clock, struct timespec *tp)
+int posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
{
int error = check_clock(which_clock);
if (!error) {
return error;
}
-int posix_cpu_clock_set(clockid_t which_clock, const struct timespec *tp)
+int posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
{
/*
* You can never reset a CPU clock, but we check for other errors
/*
* Sample a per-thread clock for the given task.
*/
-static int cpu_clock_sample(clockid_t which_clock, struct task_struct *p,
+static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
union cpu_time_count *cpu)
{
switch (CPUCLOCK_WHICH(which_clock)) {
while ((t = next_thread(t)) != p) {
cpu->sched += t->sched_time;
}
- if (p->tgid == current->tgid) {
- /*
- * We're sampling ourselves, so include the
- * cycles not yet banked. We still omit
- * other threads running on other CPUs,
- * so the total can always be behind as
- * much as max(nthreads-1,ncpus) * (NSEC_PER_SEC/HZ).
- */
- cpu->sched += current_sched_time(current);
- } else {
- cpu->sched += p->sched_time;
- }
+ cpu->sched += sched_ns(p);
break;
}
return 0;
* Sample a process (thread group) clock for the given group_leader task.
* Must be called with tasklist_lock held for reading.
*/
-static int cpu_clock_sample_group(clockid_t which_clock,
+static int cpu_clock_sample_group(const clockid_t which_clock,
struct task_struct *p,
union cpu_time_count *cpu)
{
}
-int posix_cpu_clock_get(clockid_t which_clock, struct timespec *tp)
+int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
{
const pid_t pid = CPUCLOCK_PID(which_clock);
int error = -EINVAL;
int posix_cpu_timer_del(struct k_itimer *timer)
{
struct task_struct *p = timer->it.cpu.task;
+ int ret = 0;
- if (timer->it.cpu.firing)
- return TIMER_RETRY;
-
- if (unlikely(p == NULL))
- return 0;
-
- if (!list_empty(&timer->it.cpu.entry)) {
+ if (likely(p != NULL)) {
read_lock(&tasklist_lock);
if (unlikely(p->signal == NULL)) {
/*
*/
BUG_ON(!list_empty(&timer->it.cpu.entry));
} else {
- /*
- * Take us off the task's timer list.
- */
spin_lock(&p->sighand->siglock);
- list_del(&timer->it.cpu.entry);
+ if (timer->it.cpu.firing)
+ ret = TIMER_RETRY;
+ else
+ list_del(&timer->it.cpu.entry);
spin_unlock(&p->sighand->siglock);
}
read_unlock(&tasklist_lock);
+
+ if (!ret)
+ put_task_struct(p);
}
- put_task_struct(p);
- return 0;
+ return ret;
}
/*
cputime_t ptime = cputime_add(utime, stime);
list_for_each_entry_safe(timer, next, head, entry) {
- timer->task = NULL;
list_del_init(&timer->entry);
if (cputime_lt(timer->expires.cpu, ptime)) {
timer->expires.cpu = cputime_zero;
++head;
list_for_each_entry_safe(timer, next, head, entry) {
- timer->task = NULL;
list_del_init(&timer->entry);
if (cputime_lt(timer->expires.cpu, utime)) {
timer->expires.cpu = cputime_zero;
++head;
list_for_each_entry_safe(timer, next, head, entry) {
- timer->task = NULL;
list_del_init(&timer->entry);
if (timer->expires.sched < sched_time) {
timer->expires.sched = 0;
struct task_struct *t = p;
unsigned int nthreads = atomic_read(&p->signal->live);
+ if (!nthreads)
+ return;
+
switch (clock_idx) {
default:
BUG();
break;
case CPUCLOCK_PROF:
- left = cputime_div(cputime_sub(expires.cpu, val.cpu),
- nthreads);
+ left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
+ nthreads);
do {
- if (!unlikely(t->exit_state)) {
+ if (likely(!(t->flags & PF_EXITING))) {
ticks = cputime_add(prof_ticks(t), left);
if (cputime_eq(t->it_prof_expires,
cputime_zero) ||
} while (t != p);
break;
case CPUCLOCK_VIRT:
- left = cputime_div(cputime_sub(expires.cpu, val.cpu),
- nthreads);
+ left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
+ nthreads);
do {
- if (!unlikely(t->exit_state)) {
+ if (likely(!(t->flags & PF_EXITING))) {
ticks = cputime_add(virt_ticks(t), left);
if (cputime_eq(t->it_virt_expires,
cputime_zero) ||
case CPUCLOCK_SCHED:
nsleft = expires.sched - val.sched;
do_div(nsleft, nthreads);
+ nsleft = max_t(unsigned long long, nsleft, 1);
do {
- if (!unlikely(t->exit_state)) {
+ if (likely(!(t->flags & PF_EXITING))) {
ns = t->sched_time + nsleft;
if (t->it_sched_expires == 0 ||
t->it_sched_expires > ns) {
listpos = head;
if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
list_for_each_entry(next, head, entry) {
- if (next->expires.sched > nt->expires.sched) {
- listpos = &next->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)) {
- listpos = &next->entry;
+ if (cputime_gt(next->expires.cpu, nt->expires.cpu))
break;
- }
+ listpos = &next->entry;
}
}
list_add(&nt->entry, listpos);
* 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;
- list_del_init(&timer->it.cpu.entry);
+ 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);
/*
}
}
- if (unlikely(timer->it.cpu.firing)) {
+ if (unlikely(ret)) {
/*
* We are colliding with the timer actually firing.
* Punt after filling in the timer's old value, and
* it as an overrun (thanks to bump_cpu_timer above).
*/
read_unlock(&tasklist_lock);
- timer->it.cpu.firing = -1;
- ret = TIMER_RETRY;
goto out;
}
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_entry(timers->next,
struct cpu_timer_list,
entry);
- if (cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
+ if (!--maxfire || cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
tsk->it_prof_expires = t->expires.cpu;
break;
}
}
++timers;
+ maxfire = 20;
tsk->it_virt_expires = cputime_zero;
while (!list_empty(timers)) {
struct cpu_timer_list *t = list_entry(timers->next,
struct cpu_timer_list,
entry);
- if (cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
+ if (!--maxfire || cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
tsk->it_virt_expires = t->expires.cpu;
break;
}
}
++timers;
+ maxfire = 20;
tsk->it_sched_expires = 0;
while (!list_empty(timers)) {
struct cpu_timer_list *t = list_entry(timers->next,
struct cpu_timer_list,
entry);
- if (tsk->sched_time < t->expires.sched) {
+ if (!--maxfire || tsk->sched_time < t->expires.sched) {
tsk->it_sched_expires = t->expires.sched;
break;
}
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 sched_time, sched_expires;
} while (t != tsk);
ptime = cputime_add(utime, stime);
+ maxfire = 20;
prof_expires = cputime_zero;
while (!list_empty(timers)) {
struct cpu_timer_list *t = list_entry(timers->next,
struct cpu_timer_list,
entry);
- if (cputime_lt(ptime, t->expires.cpu)) {
+ if (!--maxfire || cputime_lt(ptime, t->expires.cpu)) {
prof_expires = t->expires.cpu;
break;
}
}
++timers;
+ maxfire = 20;
virt_expires = cputime_zero;
while (!list_empty(timers)) {
struct cpu_timer_list *t = list_entry(timers->next,
struct cpu_timer_list,
entry);
- if (cputime_lt(utime, t->expires.cpu)) {
+ if (!--maxfire || cputime_lt(utime, t->expires.cpu)) {
virt_expires = t->expires.cpu;
break;
}
}
++timers;
+ maxfire = 20;
sched_expires = 0;
while (!list_empty(timers)) {
struct cpu_timer_list *t = list_entry(timers->next,
struct cpu_timer_list,
entry);
- if (sched_time < t->expires.sched) {
+ if (!--maxfire || sched_time < t->expires.sched) {
sched_expires = t->expires.sched;
break;
}
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(prof_left, nthreads);
+ prof_left = cputime_div_non_zero(prof_left, nthreads);
virt_left = cputime_sub(virt_expires, utime);
- virt_left = cputime_div(virt_left, nthreads);
+ virt_left = cputime_div_non_zero(virt_left, nthreads);
if (sched_expires) {
sched_left = sched_expires - sched_time;
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) &&
t->it_sched_expires > sched)) {
t->it_sched_expires = sched;
}
-
- do {
- t = next_thread(t);
- } while (unlikely(t->exit_state));
- } while (t != tsk);
+ } while ((t = next_thread(t)) != tsk);
}
}
/*
* The task was cleaned up already, no future firings.
*/
- return;
+ goto out;
/*
* Fetch the current sample and update the timer's expiry time.
bump_cpu_timer(timer, now);
if (unlikely(p->exit_state)) {
clear_dead_task(timer, now);
- return;
+ goto out;
}
read_lock(&tasklist_lock); /* arm_timer needs it. */
} else {
put_task_struct(p);
timer->it.cpu.task = p = NULL;
timer->it.cpu.expires.sched = 0;
- read_unlock(&tasklist_lock);
- return;
+ goto out_unlock;
} else if (unlikely(p->exit_state) && thread_group_empty(p)) {
/*
* We've noticed that the thread is dead, but
* drop our task ref.
*/
clear_dead_task(timer, now);
- read_unlock(&tasklist_lock);
- return;
+ goto out_unlock;
}
cpu_clock_sample_group(timer->it_clock, p, &now);
bump_cpu_timer(timer, now);
*/
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;
}
/*
#undef UNEXPIRED
- BUG_ON(tsk->exit_state);
-
/*
* Double-check with locks held.
*/
read_lock(&tasklist_lock);
- spin_lock(&tsk->sighand->siglock);
+ 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);
+ /*
+ * 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);
+ /*
+ * 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);
/*
static long posix_cpu_clock_nanosleep_restart(struct restart_block *);
-int posix_cpu_nsleep(clockid_t which_clock, int flags,
- struct timespec *rqtp)
+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;
error = posix_cpu_timer_create(&timer);
timer.it_process = current;
if (!error) {
- struct timespec __user *rmtp;
static struct itimerspec zero_it;
struct itimerspec it = { .it_value = *rqtp,
.it_interval = {} };
/*
* Report back to the user the time still remaining.
*/
- rmtp = (struct timespec __user *) restart_block->arg1;
if (rmtp != NULL && !(flags & TIMER_ABSTIME) &&
copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
return -EFAULT;
restart_block->fn = posix_cpu_clock_nanosleep_restart;
/* Caller already set restart_block->arg1 */
restart_block->arg0 = which_clock;
+ restart_block->arg1 = (unsigned long) rmtp;
restart_block->arg2 = rqtp->tv_sec;
restart_block->arg3 = rqtp->tv_nsec;
posix_cpu_clock_nanosleep_restart(struct restart_block *restart_block)
{
clockid_t which_clock = restart_block->arg0;
- struct timespec t = { .tv_sec = restart_block->arg2,
- .tv_nsec = restart_block->arg3 };
+ struct timespec __user *rmtp;
+ struct timespec t;
+
+ 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;
- return posix_cpu_nsleep(which_clock, TIMER_ABSTIME, &t);
+ return posix_cpu_nsleep(which_clock, TIMER_ABSTIME, &t, rmtp);
}
#define PROCESS_CLOCK MAKE_PROCESS_CPUCLOCK(0, CPUCLOCK_SCHED)
#define THREAD_CLOCK MAKE_THREAD_CPUCLOCK(0, CPUCLOCK_SCHED)
-static int process_cpu_clock_getres(clockid_t which_clock, struct timespec *tp)
+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(clockid_t which_clock, struct timespec *tp)
+static int process_cpu_clock_get(const clockid_t which_clock,
+ struct timespec *tp)
{
return posix_cpu_clock_get(PROCESS_CLOCK, tp);
}
timer->it_clock = PROCESS_CLOCK;
return posix_cpu_timer_create(timer);
}
-static int process_cpu_nsleep(clockid_t which_clock, int flags,
- struct timespec *rqtp)
+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);
+ return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
}
-static int thread_cpu_clock_getres(clockid_t which_clock, struct timespec *tp)
+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(clockid_t which_clock, struct timespec *tp)
+static int thread_cpu_clock_get(const clockid_t which_clock,
+ struct timespec *tp)
{
return posix_cpu_clock_get(THREAD_CLOCK, tp);
}
timer->it_clock = THREAD_CLOCK;
return posix_cpu_timer_create(timer);
}
-static int thread_cpu_nsleep(clockid_t which_clock, int flags,
- struct timespec *rqtp)
+static int thread_cpu_nsleep(const clockid_t which_clock, int flags,
+ struct timespec *rqtp, struct timespec __user *rmtp)
{
return -EINVAL;
}