#include <linux/kernel_stat.h>
/*
- * Allocate the thread_group_cputime structure appropriately and fill in the
- * current values of the fields. Called from copy_signal() via
- * thread_group_cputime_clone_thread() when adding a second or subsequent
- * thread to a thread group. Assumes interrupts are enabled when called.
- */
-int thread_group_cputime_alloc(struct task_struct *tsk)
-{
- struct signal_struct *sig = tsk->signal;
- struct task_cputime *cputime;
-
- /*
- * If we have multiple threads and we don't already have a
- * per-CPU task_cputime struct (checked in the caller), allocate
- * one and fill it in with the times accumulated so far. We may
- * race with another thread so recheck after we pick up the sighand
- * lock.
- */
- cputime = alloc_percpu(struct task_cputime);
- if (cputime == NULL)
- return -ENOMEM;
- spin_lock_irq(&tsk->sighand->siglock);
- if (sig->cputime.totals) {
- spin_unlock_irq(&tsk->sighand->siglock);
- free_percpu(cputime);
- return 0;
- }
- sig->cputime.totals = cputime;
- cputime = per_cpu_ptr(sig->cputime.totals, smp_processor_id());
- cputime->utime = tsk->utime;
- cputime->stime = tsk->stime;
- cputime->sum_exec_runtime = tsk->se.sum_exec_runtime;
- spin_unlock_irq(&tsk->sighand->siglock);
- return 0;
-}
-
-/**
- * thread_group_cputime - Sum the thread group time fields across all CPUs.
- *
- * @tsk: The task we use to identify the thread group.
- * @times: task_cputime structure in which we return the summed fields.
- *
- * Walk the list of CPUs to sum the per-CPU time fields in the thread group
- * time structure.
- */
-void thread_group_cputime(
- struct task_struct *tsk,
- struct task_cputime *times)
-{
- struct signal_struct *sig;
- int i;
- struct task_cputime *tot;
-
- sig = tsk->signal;
- if (unlikely(!sig) || !sig->cputime.totals) {
- times->utime = tsk->utime;
- times->stime = tsk->stime;
- times->sum_exec_runtime = tsk->se.sum_exec_runtime;
- return;
- }
- times->stime = times->utime = cputime_zero;
- times->sum_exec_runtime = 0;
- for_each_possible_cpu(i) {
- tot = per_cpu_ptr(tsk->signal->cputime.totals, i);
- times->utime = cputime_add(times->utime, tot->utime);
- times->stime = cputime_add(times->stime, tot->stime);
- times->sum_exec_runtime += tot->sum_exec_runtime;
- }
-}
-
-/*
* Called after updating RLIMIT_CPU to set timer expiration if necessary.
*/
void update_rlimit_cpu(unsigned long rlim_new)
return 0;
}
+void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
+{
+ struct sighand_struct *sighand;
+ struct signal_struct *sig;
+ struct task_struct *t;
+
+ *times = INIT_CPUTIME;
+
+ rcu_read_lock();
+ sighand = rcu_dereference(tsk->sighand);
+ if (!sighand)
+ goto out;
+
+ sig = tsk->signal;
+
+ t = tsk;
+ do {
+ times->utime = cputime_add(times->utime, t->utime);
+ times->stime = cputime_add(times->stime, t->stime);
+ times->sum_exec_runtime += t->se.sum_exec_runtime;
+
+ t = next_thread(t);
+ } while (t != tsk);
+
+ times->utime = cputime_add(times->utime, sig->utime);
+ times->stime = cputime_add(times->stime, sig->stime);
+ times->sum_exec_runtime += sig->sum_sched_runtime;
+out:
+ rcu_read_unlock();
+}
+
+static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
+{
+ if (cputime_gt(b->utime, a->utime))
+ a->utime = b->utime;
+
+ if (cputime_gt(b->stime, a->stime))
+ a->stime = b->stime;
+
+ if (b->sum_exec_runtime > a->sum_exec_runtime)
+ a->sum_exec_runtime = b->sum_exec_runtime;
+}
+
+void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
+{
+ struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+ struct task_cputime sum;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cputimer->lock, flags);
+ if (!cputimer->running) {
+ cputimer->running = 1;
+ /*
+ * The POSIX timer interface allows for absolute time expiry
+ * values through the TIMER_ABSTIME flag, therefore we have
+ * to synchronize the timer to the clock every time we start
+ * it.
+ */
+ thread_group_cputime(tsk, &sum);
+ update_gt_cputime(&cputimer->cputime, &sum);
+ }
+ *times = cputimer->cputime;
+ spin_unlock_irqrestore(&cputimer->lock, flags);
+}
+
/*
* Sample a process (thread group) clock for the given group_leader task.
* Must be called with tasklist_lock held for reading.
struct task_cputime cputime;
thread_group_cputime(p, &cputime);
- switch (which_clock) {
+ switch (CPUCLOCK_WHICH(which_clock)) {
default:
return -EINVAL;
case CPUCLOCK_PROF:
{
struct task_cputime cputime;
- thread_group_cputime(tsk, &cputime);
+ thread_group_cputimer(tsk, &cputime);
cleanup_timers(tsk->signal->cpu_timers,
cputime.utime, cputime.stime, cputime.sum_exec_runtime);
}
}
/*
+ * 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
if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
cpu_clock_sample(timer->it_clock, p, &val);
} else {
- cpu_clock_sample_group(timer->it_clock, p, &val);
+ cpu_timer_sample_group(timer->it_clock, p, &val);
}
if (old) {
read_unlock(&tasklist_lock);
goto dead;
} else {
- cpu_clock_sample_group(timer->it_clock, p, &now);
+ cpu_timer_sample_group(timer->it_clock, p, &now);
clear_dead = (unlikely(p->exit_state) &&
thread_group_empty(p));
}
}
}
+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
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]))
+ list_empty(&timers[CPUCLOCK_SCHED])) {
+ stop_process_timers(tsk);
return;
+ }
/*
* Collect the current process totals.
*/
- thread_group_cputime(tsk, &cputime);
+ thread_group_cputimer(tsk, &cputime);
utime = cputime.utime;
ptime = cputime_add(utime, cputime.stime);
sum_sched_runtime = cputime.sum_exec_runtime;
clear_dead_task(timer, now);
goto out_unlock;
}
- cpu_clock_sample_group(timer->it_clock, p, &now);
+ cpu_timer_sample_group(timer->it_clock, p, &now);
bump_cpu_timer(timer, now);
/* Leave the tasklist_lock locked for the call below. */
}
*/
static inline int fastpath_timer_check(struct task_struct *tsk)
{
- struct signal_struct *sig = tsk->signal;
+ struct signal_struct *sig;
- if (unlikely(!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)) {
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_cputime(tsk, &group_sample);
+ thread_group_cputimer(tsk, &group_sample);
if (task_cputime_expired(&group_sample, &sig->cputime_expires))
return 1;
}
- return 0;
+
+ return sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY;
}
/*
struct list_head *head;
BUG_ON(clock_idx == CPUCLOCK_SCHED);
- cpu_clock_sample_group(clock_idx, tsk, &now);
+ cpu_timer_sample_group(clock_idx, tsk, &now);
if (oldval) {
if (!cputime_eq(*oldval, cputime_zero)) {
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