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Commit d1e3b6d1 authored by Stanislaw Gruszka's avatar Stanislaw Gruszka Committed by Ingo Molnar
Browse files

itimers: Simplify arm_timer() code a bit 



Don't update values in expiration cache when new ones are
equal. Add expire_le() and expire_gt() helpers to simplify the
code.

Signed-off-by: default avatarStanislaw Gruszka <sgruszka@redhat.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
LKML-Reference: <1248862529-6063-4-git-send-email-sgruszka@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 8356b5f9

kernel/posix-cpu-timers.c

+23 −21
Original line number Diff line number Diff line
@@ -541,6 +541,17 @@ static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now) 
					     now);

}



static inline int expires_gt(cputime_t expires, cputime_t new_exp)

{

	return cputime_eq(expires, cputime_zero) ||

	       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
@@ -585,31 +596,26 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now) 
		 */



		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 (cputime_eq(p->cputime_expires.prof_exp,

					       cputime_zero) ||

				    cputime_gt(p->cputime_expires.prof_exp,

					       nt->expires.cpu))

					p->cputime_expires.prof_exp =

						nt->expires.cpu;

				if (expires_gt(p->cputime_expires.prof_exp,

					       exp->cpu))

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

				break;

			case CPUCLOCK_VIRT:

				if (cputime_eq(p->cputime_expires.virt_exp,

					       cputime_zero) ||

				    cputime_gt(p->cputime_expires.virt_exp,

					       nt->expires.cpu))

					p->cputime_expires.virt_exp =

						nt->expires.cpu;

				if (expires_gt(p->cputime_expires.virt_exp,

					       exp->cpu))

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

				break;

			case CPUCLOCK_SCHED:

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

				    p->cputime_expires.sched_exp >

							nt->expires.sched)

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

					p->cputime_expires.sched_exp =

						nt->expires.sched;

								exp->sched;

				break;

			}

		} else {
@@ -623,17 +629,13 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now) 
			default:

				BUG();

			case CPUCLOCK_VIRT:

				if (!cputime_eq(sig->it[CPUCLOCK_VIRT].expires,

						cputime_zero) &&

				    cputime_lt(sig->it[CPUCLOCK_VIRT].expires,

				if (expires_le(sig->it[CPUCLOCK_VIRT].expires,

					       exp->cpu))

					break;

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

				break;

			case CPUCLOCK_PROF:

				if (!cputime_eq(sig->it[CPUCLOCK_PROF].expires,

						cputime_zero) &&

				    cputime_lt(sig->it[CPUCLOCK_PROF].expires,

				if (expires_le(sig->it[CPUCLOCK_PROF].expires,

					       exp->cpu))

					break;

				i = sig->rlim[RLIMIT_CPU].rlim_cur;