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Commit ebc54f27 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull timer fixes from Thomas Gleixner:
 "Three fixlets from the timer departement:

   - Update the timekeeper before updating vsyscall and pvclock.  This
     fixes the kvm-clock regression reported by Chris and Paolo.

   - Use the proper irq work interface from NMI.  This fixes the
     regression reported by Catalin and Dave.

   - Clarify the compat_nanosleep error handling mechanism to avoid
     future confusion"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Update timekeeper before updating vsyscall and pvclock
  compat: nanosleep: Clarify error handling
  nohz: Restore NMI safe local irq work for local nohz kick
parents 2b12164b 9bf2419f

include/linux/tick.h

+1 −6
Original line number Diff line number Diff line
@@ -183,13 +183,8 @@ static inline bool tick_nohz_full_cpu(int cpu) 


extern void tick_nohz_init(void);

extern void __tick_nohz_full_check(void);

extern void tick_nohz_full_kick(void);

extern void tick_nohz_full_kick_cpu(int cpu);



static inline void tick_nohz_full_kick(void)

{

	tick_nohz_full_kick_cpu(smp_processor_id());

}



extern void tick_nohz_full_kick_all(void);

extern void __tick_nohz_task_switch(struct task_struct *tsk);

#else

kernel/compat.c

+21 −3
Original line number Diff line number Diff line
@@ -226,7 +226,7 @@ static long compat_nanosleep_restart(struct restart_block *restart) 
	ret = hrtimer_nanosleep_restart(restart);

	set_fs(oldfs);



	if (ret) {

	if (ret == -ERESTART_RESTARTBLOCK) {

		rmtp = restart->nanosleep.compat_rmtp;



		if (rmtp && compat_put_timespec(&rmt, rmtp))
@@ -256,7 +256,26 @@ COMPAT_SYSCALL_DEFINE2(nanosleep, struct compat_timespec __user *, rqtp, 
				HRTIMER_MODE_REL, CLOCK_MONOTONIC);

	set_fs(oldfs);



	if (ret) {

	/*

	 * hrtimer_nanosleep() can only return 0 or

	 * -ERESTART_RESTARTBLOCK here because:

	 *

	 * - we call it with HRTIMER_MODE_REL and therefor exclude the

	 *   -ERESTARTNOHAND return path.

	 *

	 * - we supply the rmtp argument from the task stack (due to

	 *   the necessary compat conversion. So the update cannot

	 *   fail, which excludes the -EFAULT return path as well. If

	 *   it fails nevertheless we have a bigger problem and wont

	 *   reach this place anymore.

	 *

	 * - if the return value is 0, we do not have to update rmtp

	 *    because there is no remaining time.

	 *

	 * We check for -ERESTART_RESTARTBLOCK nevertheless if the

	 * core implementation decides to return random nonsense.

	 */

	if (ret == -ERESTART_RESTARTBLOCK) {

		struct restart_block *restart

			= &current_thread_info()->restart_block;
@@ -266,7 +285,6 @@ COMPAT_SYSCALL_DEFINE2(nanosleep, struct compat_timespec __user *, rqtp, 
		if (rmtp && compat_put_timespec(&rmt, rmtp))

			return -EFAULT;

	}



	return ret;

}

kernel/time/tick-sched.c

+14 −0
Original line number Diff line number Diff line
@@ -224,6 +224,20 @@ static DEFINE_PER_CPU(struct irq_work, nohz_full_kick_work) = { 
	.func = nohz_full_kick_work_func,

};



/*

 * Kick this CPU if it's full dynticks in order to force it to

 * re-evaluate its dependency on the tick and restart it if necessary.

 * This kick, unlike tick_nohz_full_kick_cpu() and tick_nohz_full_kick_all(),

 * is NMI safe.

 */

void tick_nohz_full_kick(void)

{

	if (!tick_nohz_full_cpu(smp_processor_id()))

		return;



	irq_work_queue(&__get_cpu_var(nohz_full_kick_work));

}



/*

 * Kick the CPU if it's full dynticks in order to force it to

 * re-evaluate its dependency on the tick and restart it if necessary.

kernel/time/timekeeping.c

+3 −2
Original line number Diff line number Diff line
@@ -442,11 +442,12 @@ static void timekeeping_update(struct timekeeper *tk, unsigned int action) 
		tk->ntp_error = 0;

		ntp_clear();

	}

	update_vsyscall(tk);

	update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);



	tk_update_ktime_data(tk);



	update_vsyscall(tk);

	update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);



	if (action & TK_MIRROR)

		memcpy(&shadow_timekeeper, &tk_core.timekeeper,

		       sizeof(tk_core.timekeeper));