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Commit 5eb9aa64 authored by Stanislaw Gruszka's avatar Stanislaw Gruszka Committed by Thomas Gleixner
Browse files

cpu-timers: Cleanup arm_timer() 



Signed-off-by: default avatarStanislaw Gruszka <sgruszka@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent f55db609

kernel/posix-cpu-timers.c

+35 −69
Original line number Diff line number Diff line
@@ -547,98 +547,64 @@ static inline int expires_gt(cputime_t expires, cputime_t new_exp) 
	       cputime_gt(expires, new_exp);

}



static inline int expires_le(cputime_t expires, cputime_t new_exp)

{

	return !cputime_eq(expires, cputime_zero) &&

	       cputime_le(expires, new_exp);

}

/*

 * Insert the timer on the appropriate list before any timers that

 * expire later.  This must be called with the tasklist_lock held

 * for reading, and interrupts disabled.

 */

static void arm_timer(struct k_itimer *timer, union cpu_time_count now)

static void arm_timer(struct k_itimer *timer)

{

	struct task_struct *p = timer->it.cpu.task;

	struct list_head *head, *listpos;

	struct task_cputime *cputime_expires;

	struct cpu_timer_list *const nt = &timer->it.cpu;

	struct cpu_timer_list *next;



	head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?

		p->cpu_timers : p->signal->cpu_timers);

	if (CPUCLOCK_PERTHREAD(timer->it_clock)) {

		head = p->cpu_timers;

		cputime_expires = &p->cputime_expires;

	} else {

		head = p->signal->cpu_timers;

		cputime_expires = &p->signal->cputime_expires;

	}

	head += CPUCLOCK_WHICH(timer->it_clock);



	BUG_ON(!irqs_disabled());

	spin_lock(&p->sighand->siglock);



	listpos = head;

	if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {

		list_for_each_entry(next, head, 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))

		if (cpu_time_before(timer->it_clock, nt->expires, next->expires))

			break;

		listpos = &next->entry;

	}

	}

	list_add(&nt->entry, listpos);



	if (listpos == head) {

		union cpu_time_count *exp = &nt->expires;



		/*

		 * We are the new earliest-expiring timer.

		 * If we are a thread timer, there can always

		 * be a process timer telling us to stop earlier.

		 * We are the new earliest-expiring POSIX 1.b timer, hence

		 * need to update expiration cache. Take into account that

		 * for process timers we share expiration cache with itimers

		 * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.

		 */



		if (CPUCLOCK_PERTHREAD(timer->it_clock)) {

			union cpu_time_count *exp = &nt->expires;



		switch (CPUCLOCK_WHICH(timer->it_clock)) {

			default:

				BUG();

		case CPUCLOCK_PROF:

				if (expires_gt(p->cputime_expires.prof_exp,

					       exp->cpu))

					p->cputime_expires.prof_exp = exp->cpu;

			if (expires_gt(cputime_expires->prof_exp, exp->cpu))

				cputime_expires->prof_exp = exp->cpu;

			break;

		case CPUCLOCK_VIRT:

				if (expires_gt(p->cputime_expires.virt_exp,

					       exp->cpu))

					p->cputime_expires.virt_exp = exp->cpu;

			if (expires_gt(cputime_expires->virt_exp, exp->cpu))

				cputime_expires->virt_exp = exp->cpu;

			break;

		case CPUCLOCK_SCHED:

				if (p->cputime_expires.sched_exp == 0 ||

				    p->cputime_expires.sched_exp > exp->sched)

					p->cputime_expires.sched_exp =

								exp->sched;

			if (cputime_expires->sched_exp == 0 ||

			    cputime_expires->sched_exp > exp->sched)

				cputime_expires->sched_exp = exp->sched;

			break;

		}

		} else {

			struct signal_struct *const sig = p->signal;

			union cpu_time_count *exp = &timer->it.cpu.expires;



			/*

			 * For a process timer, set the cached expiration time.

			 */

			switch (CPUCLOCK_WHICH(timer->it_clock)) {

			default:

				BUG();

			case CPUCLOCK_VIRT:

				if (expires_gt(sig->cputime_expires.virt_exp, exp->cpu))

					sig->cputime_expires.virt_exp = exp->cpu;

			case CPUCLOCK_PROF:

				if (expires_gt(sig->cputime_expires.prof_exp, exp->cpu))

					sig->cputime_expires.prof_exp = exp->cpu;

				break;

			case CPUCLOCK_SCHED:

				sig->cputime_expires.sched_exp = exp->sched;

				break;

			}

		}

	}



	spin_unlock(&p->sighand->siglock);
@@ -819,7 +785,7 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, 
	if (new_expires.sched != 0 &&

	    (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&

	    cpu_time_before(timer->it_clock, val, new_expires)) {

		arm_timer(timer, val);

		arm_timer(timer);

	}



	read_unlock(&tasklist_lock);
@@ -1283,7 +1249,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer) 
	/*

	 * Now re-arm for the new expiry time.

	 */

	arm_timer(timer, now);

	arm_timer(timer);



out_unlock:

	read_unlock(&tasklist_lock);