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Commit 1cd07c0b authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

posix-cpu-timers: Consolidate timer expiry further 



With the array based samples and expiry cache, the expiry function can use
a loop to collect timers from the clock specific lists.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192922.365469982@linutronix.de
parent 2bbdbdae

kernel/time/posix-cpu-timers.c

+30 −33
Original line number Diff line number Diff line
@@ -752,6 +752,18 @@ check_timers_list(struct list_head *timers, 
	return U64_MAX;

}



static void collect_posix_cputimers(struct posix_cputimers *pct,

				    u64 *samples, struct list_head *firing)

{

	struct posix_cputimer_base *base = pct->bases;

	int i;



	for (i = 0; i < CPUCLOCK_MAX; i++, base++) {

		base->nextevt = check_timers_list(&base->cpu_timers, firing,

						   samples[i]);

	}

}



static inline void check_dl_overrun(struct task_struct *tsk)

{

	if (tsk->dl.dl_overrun) {
@@ -768,25 +780,18 @@ static inline void check_dl_overrun(struct task_struct *tsk) 
static void check_thread_timers(struct task_struct *tsk,

				struct list_head *firing)

{

	struct posix_cputimer_base *base = tsk->posix_cputimers.bases;

	struct posix_cputimers *pct = &tsk->posix_cputimers;

	u64 samples[CPUCLOCK_MAX];

	unsigned long soft;

	u64 stime, utime;



	if (dl_task(tsk))

		check_dl_overrun(tsk);



	if (expiry_cache_is_inactive(&tsk->posix_cputimers))

	if (expiry_cache_is_inactive(pct))

		return;



	task_cputime(tsk, &utime, &stime);



	base->nextevt = check_timers_list(&base->cpu_timers, firing,

					  utime + stime);

	base++;

	base->nextevt = check_timers_list(&base->cpu_timers, firing, utime);

	base++;

	base->nextevt = check_timers_list(&base->cpu_timers, firing,

					  tsk->se.sum_exec_runtime);

	task_sample_cputime(tsk, samples);

	collect_posix_cputimers(pct, samples, firing);



	/*

	 * Check for the special case thread timers.
@@ -825,7 +830,7 @@ static void check_thread_timers(struct task_struct *tsk, 
		}

	}



	if (expiry_cache_is_inactive(&tsk->posix_cputimers))

	if (expiry_cache_is_inactive(pct))

		tick_dep_clear_task(tsk, TICK_DEP_BIT_POSIX_TIMER);

}
@@ -869,15 +874,15 @@ static void check_process_timers(struct task_struct *tsk, 
				 struct list_head *firing)

{

	struct signal_struct *const sig = tsk->signal;

	struct posix_cputimer_base *base = sig->posix_cputimers.bases;

	u64 virt_exp, prof_exp, sched_exp, samples[CPUCLOCK_MAX];

	struct posix_cputimers *pct = &sig->posix_cputimers;

	u64 samples[CPUCLOCK_MAX];

	unsigned long soft;



	/*

	 * If cputimer is not running, then there are no active

	 * process wide timers (POSIX 1.b, itimers, RLIMIT_CPU).

	 */

	if (!READ_ONCE(tsk->signal->cputimer.running))

	if (!READ_ONCE(sig->cputimer.running))

		return;



       /*
@@ -891,21 +896,17 @@ static void check_process_timers(struct task_struct *tsk, 
	 * so the sample can be taken directly.

	 */

	proc_sample_cputime_atomic(&sig->cputimer.cputime_atomic, samples);



	prof_exp = check_timers_list(&base[CPUCLOCK_PROF].cpu_timers,

				     firing, samples[CPUCLOCK_PROF]);

	virt_exp = check_timers_list(&base[CPUCLOCK_VIRT].cpu_timers,

				     firing, samples[CPUCLOCK_VIRT]);

	sched_exp = check_timers_list(&base[CPUCLOCK_SCHED].cpu_timers,

				      firing, samples[CPUCLOCK_SCHED]);

	collect_posix_cputimers(pct, samples, firing);



	/*

	 * Check for the special case process timers.

	 */

	check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_exp,

	check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF],

			 &pct->bases[CPUCLOCK_PROF].nextevt,

			 samples[CPUCLOCK_PROF], SIGPROF);

	check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_exp,

			 samples[CPUCLOCK_PROF], SIGVTALRM);

	check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT],

			 &pct->bases[CPUCLOCK_VIRT].nextevt,

			 samples[CPUCLOCK_VIRT], SIGVTALRM);



	soft = task_rlimit(tsk, RLIMIT_CPU);

	if (soft != RLIM_INFINITY) {
@@ -940,15 +941,11 @@ static void check_process_timers(struct task_struct *tsk, 
			}

		}

		softns = soft * NSEC_PER_SEC;

		if (softns < prof_exp)

			prof_exp = softns;

		if (softns < pct->bases[CPUCLOCK_PROF].nextevt)

			pct->bases[CPUCLOCK_PROF].nextevt = softns;

	}



	base[CPUCLOCK_PROF].nextevt = prof_exp;

	base[CPUCLOCK_VIRT].nextevt = virt_exp;

	base[CPUCLOCK_SCHED].nextevt = sched_exp;



	if (expiry_cache_is_inactive(&sig->posix_cputimers))

	if (expiry_cache_is_inactive(pct))

		stop_process_timers(sig);



	sig->cputimer.checking_timer = false;