diff options
Diffstat (limited to 'kernel/time/posix-cpu-timers.c')
| -rw-r--r-- | kernel/time/posix-cpu-timers.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index baeeaef3b721..59ceedbb03f0 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -789,6 +789,7 @@ check_timers_list(struct list_head *timers, return t->expires; t->firing = 1; + t->firing_cpu = smp_processor_id(); list_move_tail(&t->entry, firing); } @@ -1134,6 +1135,20 @@ static inline int fastpath_timer_check(struct task_struct *tsk) return 0; } +static DEFINE_PER_CPU(spinlock_t, cpu_timer_expiry_lock) = __SPIN_LOCK_UNLOCKED(cpu_timer_expiry_lock); + +void cpu_timers_grab_expiry_lock(struct k_itimer *timer) +{ + int cpu = timer->it.cpu.firing_cpu; + + if (cpu >= 0) { + spinlock_t *expiry_lock = per_cpu_ptr(&cpu_timer_expiry_lock, cpu); + + spin_lock_irq(expiry_lock); + spin_unlock_irq(expiry_lock); + } +} + /* * 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. @@ -1144,6 +1159,7 @@ static void __run_posix_cpu_timers(struct task_struct *tsk) LIST_HEAD(firing); struct k_itimer *timer, *next; unsigned long flags; + spinlock_t *expiry_lock; /* * The fast path checks that there are no expired thread or thread @@ -1152,6 +1168,9 @@ static void __run_posix_cpu_timers(struct task_struct *tsk) if (!fastpath_timer_check(tsk)) return; + expiry_lock = this_cpu_ptr(&cpu_timer_expiry_lock); + spin_lock(expiry_lock); + if (!lock_task_sighand(tsk, &flags)) return; /* @@ -1186,6 +1205,7 @@ static void __run_posix_cpu_timers(struct task_struct *tsk) list_del_init(&timer->it.cpu.entry); cpu_firing = timer->it.cpu.firing; timer->it.cpu.firing = 0; + timer->it.cpu.firing_cpu = -1; /* * The firing flag is -1 if we collided with a reset * of the timer, which already reported this @@ -1195,6 +1215,7 @@ static void __run_posix_cpu_timers(struct task_struct *tsk) cpu_timer_fire(timer); spin_unlock(&timer->it_lock); } + spin_unlock(expiry_lock); } #ifdef CONFIG_PREEMPT_RT_BASE @@ -1460,6 +1481,8 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags, spin_unlock_irq(&timer.it_lock); while (error == TIMER_RETRY) { + + cpu_timers_grab_expiry_lock(&timer); /* * We need to handle case when timer was or is in the * middle of firing. In other cases we already freed |