diff options
| -rw-r--r-- | kernel/time/posix-cpu-timers.c | 59 |
1 files changed, 20 insertions, 39 deletions
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index def225ae069a..a9003b2d614d 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -294,29 +294,37 @@ thread_group_start_cputime(struct task_struct *tsk, struct task_cputime *times) } /* - * Sample a process (thread group) clock for the given group_leader task. - * Must be called with task sighand lock held for safe while_each_thread() - * traversal. + * Sample a process (thread group) clock for the given task clkid. If the + * group's cputime accounting is already enabled, read the atomic + * store. Otherwise a full update is required. Task's sighand lock must be + * held to protect the task traversal on a full update. */ static int cpu_clock_sample_group(const clockid_t which_clock, struct task_struct *p, - u64 *sample) + u64 *sample, bool start) { + struct thread_group_cputimer *cputimer = &p->signal->cputimer; struct task_cputime cputime; + if (!READ_ONCE(cputimer->running)) { + if (start) + thread_group_start_cputime(p, &cputime); + else + thread_group_cputime(p, &cputime); + } else { + sample_cputime_atomic(&cputime, &cputimer->cputime_atomic); + } + switch (CPUCLOCK_WHICH(which_clock)) { default: return -EINVAL; case CPUCLOCK_PROF: - thread_group_cputime(p, &cputime); *sample = cputime.utime + cputime.stime; break; case CPUCLOCK_VIRT: - thread_group_cputime(p, &cputime); *sample = cputime.utime; break; case CPUCLOCK_SCHED: - thread_group_cputime(p, &cputime); *sample = cputime.sum_exec_runtime; break; } @@ -336,7 +344,7 @@ static int posix_cpu_clock_get(const clockid_t clock, struct timespec64 *tp) if (CPUCLOCK_PERTHREAD(clock)) cpu_clock_sample(clkid, tsk, &t); else - cpu_clock_sample_group(clkid, tsk, &t); + cpu_clock_sample_group(clkid, tsk, &t, false); put_task_struct(tsk); *tp = ns_to_timespec64(t); @@ -540,33 +548,6 @@ static void cpu_timer_fire(struct k_itimer *timer) } /* - * Sample a process (thread group) timer for the given group_leader task. - * Must be called with task sighand lock held for safe while_each_thread() - * traversal. - */ -static int cpu_timer_sample_group(const clockid_t which_clock, - struct task_struct *p, u64 *sample) -{ - struct task_cputime cputime; - - thread_group_start_cputime(p, &cputime); - switch (CPUCLOCK_WHICH(which_clock)) { - default: - return -EINVAL; - case CPUCLOCK_PROF: - *sample = cputime.utime + cputime.stime; - break; - case CPUCLOCK_VIRT: - *sample = cputime.utime; - break; - case CPUCLOCK_SCHED: - *sample = cputime.sum_exec_runtime; - 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 @@ -627,7 +608,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags, if (CPUCLOCK_PERTHREAD(timer->it_clock)) { cpu_clock_sample(timer->it_clock, p, &val); } else { - cpu_timer_sample_group(timer->it_clock, p, &val); + cpu_clock_sample_group(timer->it_clock, p, &val, true); } if (old) { @@ -755,7 +736,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp timer->it.cpu.expires = 0; return; } else { - cpu_timer_sample_group(timer->it_clock, p, &now); + cpu_clock_sample_group(timer->it_clock, p, &now, false); unlock_task_sighand(p, &flags); } } @@ -1042,7 +1023,7 @@ static void posix_cpu_timer_rearm(struct k_itimer *timer) /* If the process is dying, no need to rearm */ goto unlock; } - cpu_timer_sample_group(timer->it_clock, p, &now); + cpu_clock_sample_group(timer->it_clock, p, &now, true); bump_cpu_timer(timer, now); /* Leave the sighand locked for the call below. */ } @@ -1211,7 +1192,7 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx, if (WARN_ON_ONCE(clock_idx >= CPUCLOCK_SCHED)) return; - ret = cpu_timer_sample_group(clock_idx, tsk, &now); + ret = cpu_clock_sample_group(clock_idx, tsk, &now, true); if (oldval && ret != -EINVAL) { /* |