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posix_cpu_timer: consolidate expiry time type 

The posix cpu timer expiry time is stored in a union of two types: a 64
bits field if we rely on scheduler precise accounting, or a cputime_t if
we rely on jiffies.

This results in quite some duplicate code and special cases to handle the
two types.

Just unify this into a single 64 bits field.  cputime_t can always fit
into it.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Olivier Langlois <olivier@trillion01.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Frederic Weisbecker 2013-06-28 00:06:42 +00:00
parent 8bb495e3f0
commit 55ccb616a6
2 changed files with 117 additions and 165 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
include/linux/posix-timers.h
View File

@ -7,14 +7,20 @@
#include <linux/timex.h>
#include <linux/alarmtimer.h>
union cpu_time_count {
cputime_t cpu;
unsigned long long sched;
};
static inline unsigned long long cputime_to_expires(cputime_t expires)
{
return (__force unsigned long long)expires;
}
static inline cputime_t expires_to_cputime(unsigned long long expires)
{
return (__force cputime_t)expires;
}
struct cpu_timer_list {
struct list_head entry;
union cpu_time_count expires, incr;
unsigned long long expires, incr;
struct task_struct *task;
int firing;
};

266
kernel/posix-cpu-timers.c
View File

@ -51,59 +51,28 @@ static int check_clock(const clockid_t which_clock)
return error;
}
static inline union cpu_time_count
static inline unsigned long long
timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
{
union cpu_time_count ret;
ret.sched = 0; /* high half always zero when .cpu used */
unsigned long long ret;
ret = 0; /* high half always zero when .cpu used */
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
ret = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
} else {
ret.cpu = timespec_to_cputime(tp);
ret = cputime_to_expires(timespec_to_cputime(tp));
}
return ret;
}
static void sample_to_timespec(const clockid_t which_clock,
union cpu_time_count cpu,
unsigned long long expires,
struct timespec *tp)
{
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
*tp = ns_to_timespec(cpu.sched);
*tp = ns_to_timespec(expires);
else
cputime_to_timespec(cpu.cpu, tp);
}
static inline int cpu_time_before(const clockid_t which_clock,
union cpu_time_count now,
union cpu_time_count then)
{
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
return now.sched < then.sched;
} else {
return now.cpu < then.cpu;
}
}
static inline void cpu_time_add(const clockid_t which_clock,
union cpu_time_count *acc,
union cpu_time_count val)
{
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
acc->sched += val.sched;
} else {
acc->cpu += val.cpu;
}
}
static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
union cpu_time_count a,
union cpu_time_count b)
{
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
a.sched -= b.sched;
} else {
a.cpu -= b.cpu;
}
return a;
cputime_to_timespec((__force cputime_t)expires, tp);
}
/*
@ -111,47 +80,31 @@ static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
* given the current clock sample.
*/
static void bump_cpu_timer(struct k_itimer *timer,
union cpu_time_count now)
unsigned long long now)
{
int i;
unsigned long long delta, incr;
if (timer->it.cpu.incr.sched == 0)
if (timer->it.cpu.incr == 0)
return;
if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
unsigned long long delta, incr;
if (now < timer->it.cpu.expires)
return;
if (now.sched < timer->it.cpu.expires.sched)
return;
incr = timer->it.cpu.incr.sched;
delta = now.sched + incr - timer->it.cpu.expires.sched;
/* Don't use (incr*2 < delta), incr*2 might overflow. */
for (i = 0; incr < delta - incr; i++)
incr = incr << 1;
for (; i >= 0; incr >>= 1, i--) {
if (delta < incr)
continue;
timer->it.cpu.expires.sched += incr;
timer->it_overrun += 1 << i;
delta -= incr;
}
} else {
cputime_t delta, incr;
incr = timer->it.cpu.incr;
delta = now + incr - timer->it.cpu.expires;
if (now.cpu < timer->it.cpu.expires.cpu)
return;
incr = timer->it.cpu.incr.cpu;
delta = now.cpu + incr - timer->it.cpu.expires.cpu;
/* Don't use (incr*2 < delta), incr*2 might overflow. */
for (i = 0; incr < delta - incr; i++)
incr += incr;
for (; i >= 0; incr = incr >> 1, i--) {
if (delta < incr)
continue;
timer->it.cpu.expires.cpu += incr;
timer->it_overrun += 1 << i;
delta -= incr;
}
/* Don't use (incr*2 < delta), incr*2 might overflow. */
for (i = 0; incr < delta - incr; i++)
incr = incr << 1;
for (; i >= 0; incr >>= 1, i--) {
if (delta < incr)
continue;
timer->it.cpu.expires += incr;
timer->it_overrun += 1 << i;
delta -= incr;
}
}
@ -170,21 +123,21 @@ static inline int task_cputime_zero(const struct task_cputime *cputime)
return 0;
}
static inline cputime_t prof_ticks(struct task_struct *p)
static inline unsigned long long prof_ticks(struct task_struct *p)
{
cputime_t utime, stime;
task_cputime(p, &utime, &stime);
return utime + stime;
return cputime_to_expires(utime + stime);
}
static inline cputime_t virt_ticks(struct task_struct *p)
static inline unsigned long long virt_ticks(struct task_struct *p)
{
cputime_t utime;
task_cputime(p, &utime, NULL);
return utime;
return cputime_to_expires(utime);
}
static int
@ -225,19 +178,19 @@ posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
* Sample a per-thread clock for the given task.
*/
static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
union cpu_time_count *cpu)
unsigned long long *sample)
{
switch (CPUCLOCK_WHICH(which_clock)) {
default:
return -EINVAL;
case CPUCLOCK_PROF:
cpu->cpu = prof_ticks(p);
*sample = prof_ticks(p);
break;
case CPUCLOCK_VIRT:
cpu->cpu = virt_ticks(p);
*sample = virt_ticks(p);
break;
case CPUCLOCK_SCHED:
cpu->sched = task_sched_runtime(p);
*sample = task_sched_runtime(p);
break;
}
return 0;
@ -284,7 +237,7 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
*/
static int cpu_clock_sample_group(const clockid_t which_clock,
struct task_struct *p,
union cpu_time_count *cpu)
unsigned long long *sample)
{
struct task_cputime cputime;
@ -293,15 +246,15 @@ static int cpu_clock_sample_group(const clockid_t which_clock,
return -EINVAL;
case CPUCLOCK_PROF:
thread_group_cputime(p, &cputime);
cpu->cpu = cputime.utime + cputime.stime;
*sample = cputime_to_expires(cputime.utime + cputime.stime);
break;
case CPUCLOCK_VIRT:
thread_group_cputime(p, &cputime);
cpu->cpu = cputime.utime;
*sample = cputime_to_expires(cputime.utime);
break;
case CPUCLOCK_SCHED:
thread_group_cputime(p, &cputime);
cpu->sched = cputime.sum_exec_runtime;
*sample = cputime.sum_exec_runtime;
break;
}
return 0;
@ -312,7 +265,7 @@ static int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
{
const pid_t pid = CPUCLOCK_PID(which_clock);
int error = -EINVAL;
union cpu_time_count rtn;
unsigned long long rtn;
if (pid == 0) {
/*
@ -461,30 +414,30 @@ static void cleanup_timers(struct list_head *head,
list_for_each_entry_safe(timer, next, head, entry) {
list_del_init(&timer->entry);
if (timer->expires.cpu < ptime) {
timer->expires.cpu = 0;
if (timer->expires < cputime_to_expires(ptime)) {
timer->expires = 0;
} else {
timer->expires.cpu -= ptime;
timer->expires -= cputime_to_expires(ptime);
}
}
++head;
list_for_each_entry_safe(timer, next, head, entry) {
list_del_init(&timer->entry);
if (timer->expires.cpu < utime) {
timer->expires.cpu = 0;
if (timer->expires < cputime_to_expires(utime)) {
timer->expires = 0;
} else {
timer->expires.cpu -= utime;
timer->expires -= cputime_to_expires(utime);
}
}
++head;
list_for_each_entry_safe(timer, next, head, entry) {
list_del_init(&timer->entry);
if (timer->expires.sched < sum_exec_runtime) {
timer->expires.sched = 0;
if (timer->expires < sum_exec_runtime) {
timer->expires = 0;
} else {
timer->expires.sched -= sum_exec_runtime;
timer->expires -= sum_exec_runtime;
}
}
}
@ -516,7 +469,7 @@ void posix_cpu_timers_exit_group(struct task_struct *tsk)
tsk->se.sum_exec_runtime + sig->sum_sched_runtime);
}
static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
static void clear_dead_task(struct k_itimer *timer, unsigned long long now)
{
/*
* That's all for this thread or process.
@ -524,9 +477,7 @@ static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
*/
put_task_struct(timer->it.cpu.task);
timer->it.cpu.task = NULL;
timer->it.cpu.expires = cpu_time_sub(timer->it_clock,
timer->it.cpu.expires,
now);
timer->it.cpu.expires -= now;
}
static inline int expires_gt(cputime_t expires, cputime_t new_exp)
@ -558,14 +509,14 @@ static void arm_timer(struct k_itimer *timer)
listpos = head;
list_for_each_entry(next, head, entry) {
if (cpu_time_before(timer->it_clock, nt->expires, next->expires))
if (nt->expires < next->expires)
break;
listpos = &next->entry;
}
list_add(&nt->entry, listpos);
if (listpos == head) {
union cpu_time_count *exp = &nt->expires;
unsigned long long exp = nt->expires;
/*
* We are the new earliest-expiring POSIX 1.b timer, hence
@ -576,17 +527,17 @@ static void arm_timer(struct k_itimer *timer)
switch (CPUCLOCK_WHICH(timer->it_clock)) {
case CPUCLOCK_PROF:
if (expires_gt(cputime_expires->prof_exp, exp->cpu))
cputime_expires->prof_exp = exp->cpu;
if (expires_gt(cputime_expires->prof_exp, expires_to_cputime(exp)))
cputime_expires->prof_exp = expires_to_cputime(exp);
break;
case CPUCLOCK_VIRT:
if (expires_gt(cputime_expires->virt_exp, exp->cpu))
cputime_expires->virt_exp = exp->cpu;
if (expires_gt(cputime_expires->virt_exp, expires_to_cputime(exp)))
cputime_expires->virt_exp = expires_to_cputime(exp);
break;
case CPUCLOCK_SCHED:
if (cputime_expires->sched_exp == 0 ||
cputime_expires->sched_exp > exp->sched)
cputime_expires->sched_exp = exp->sched;
cputime_expires->sched_exp > exp)
cputime_expires->sched_exp = exp;
break;
}
}
@ -601,20 +552,20 @@ static void cpu_timer_fire(struct k_itimer *timer)
/*
* User don't want any signal.
*/
timer->it.cpu.expires.sched = 0;
timer->it.cpu.expires = 0;
} else if (unlikely(timer->sigq == NULL)) {
/*
* This a special case for clock_nanosleep,
* not a normal timer from sys_timer_create.
*/
wake_up_process(timer->it_process);
timer->it.cpu.expires.sched = 0;
} else if (timer->it.cpu.incr.sched == 0) {
timer->it.cpu.expires = 0;
} else if (timer->it.cpu.incr == 0) {
/*
* One-shot timer. Clear it as soon as it's fired.
*/
posix_timer_event(timer, 0);
timer->it.cpu.expires.sched = 0;
timer->it.cpu.expires = 0;
} else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
/*
* The signal did not get queued because the signal
@ -632,7 +583,7 @@ static void cpu_timer_fire(struct k_itimer *timer)
*/
static int cpu_timer_sample_group(const clockid_t which_clock,
struct task_struct *p,
union cpu_time_count *cpu)
unsigned long long *sample)
{
struct task_cputime cputime;
@ -641,13 +592,13 @@ static int cpu_timer_sample_group(const clockid_t which_clock,
default:
return -EINVAL;
case CPUCLOCK_PROF:
cpu->cpu = cputime.utime + cputime.stime;
*sample = cputime_to_expires(cputime.utime + cputime.stime);
break;
case CPUCLOCK_VIRT:
cpu->cpu = cputime.utime;
*sample = cputime_to_expires(cputime.utime);
break;
case CPUCLOCK_SCHED:
cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
*sample = cputime.sum_exec_runtime + task_delta_exec(p);
break;
}
return 0;
@ -694,7 +645,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
struct itimerspec *new, struct itimerspec *old)
{
struct task_struct *p = timer->it.cpu.task;
union cpu_time_count old_expires, new_expires, old_incr, val;
unsigned long long old_expires, new_expires, old_incr, val;
int ret;
if (unlikely(p == NULL)) {
@ -749,7 +700,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
}
if (old) {
if (old_expires.sched == 0) {
if (old_expires == 0) {
old->it_value.tv_sec = 0;
old->it_value.tv_nsec = 0;
} else {
@ -764,11 +715,8 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
* new setting.
*/
bump_cpu_timer(timer, val);
if (cpu_time_before(timer->it_clock, val,
timer->it.cpu.expires)) {
old_expires = cpu_time_sub(
timer->it_clock,
timer->it.cpu.expires, val);
if (val < timer->it.cpu.expires) {
old_expires = timer->it.cpu.expires - val;
sample_to_timespec(timer->it_clock,
old_expires,
&old->it_value);
@ -791,8 +739,8 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
goto out;
}
if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
cpu_time_add(timer->it_clock, &new_expires, val);
if (new_expires != 0 && !(flags & TIMER_ABSTIME)) {
new_expires += val;
}
/*
@ -801,8 +749,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
* arm the timer (we'll just fake it for timer_gettime).
*/
timer->it.cpu.expires = new_expires;
if (new_expires.sched != 0 &&
cpu_time_before(timer->it_clock, val, new_expires)) {
if (new_expires != 0 && val < new_expires) {
arm_timer(timer);
}
@ -826,8 +773,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
timer->it_overrun_last = 0;
timer->it_overrun = -1;
if (new_expires.sched != 0 &&
!cpu_time_before(timer->it_clock, val, new_expires)) {
if (new_expires != 0 && !(val < new_expires)) {
/*
* The designated time already passed, so we notify
* immediately, even if the thread never runs to
@ -849,7 +795,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int flags,
static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
{
union cpu_time_count now;
unsigned long long now;
struct task_struct *p = timer->it.cpu.task;
int clear_dead;
@ -859,7 +805,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
sample_to_timespec(timer->it_clock,
timer->it.cpu.incr, &itp->it_interval);
if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
if (timer->it.cpu.expires == 0) { /* Timer not armed at all. */
itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
return;
}
@ -891,7 +837,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
*/
put_task_struct(p);
timer->it.cpu.task = NULL;
timer->it.cpu.expires.sched = 0;
timer->it.cpu.expires = 0;
read_unlock(&tasklist_lock);
goto dead;
} else {
@ -912,10 +858,9 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
goto dead;
}
if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
if (now < timer->it.cpu.expires) {
sample_to_timespec(timer->it_clock,
cpu_time_sub(timer->it_clock,
timer->it.cpu.expires, now),
timer->it.cpu.expires - now,
&itp->it_value);
} else {
/*
@ -946,8 +891,8 @@ static void check_thread_timers(struct task_struct *tsk,
struct cpu_timer_list *t = list_first_entry(timers,
struct cpu_timer_list,
entry);
if (!--maxfire || prof_ticks(tsk) < t->expires.cpu) {
tsk->cputime_expires.prof_exp = t->expires.cpu;
if (!--maxfire || prof_ticks(tsk) < t->expires) {
tsk->cputime_expires.prof_exp = expires_to_cputime(t->expires);
break;
}
t->firing = 1;
@ -961,8 +906,8 @@ static void check_thread_timers(struct task_struct *tsk,
struct cpu_timer_list *t = list_first_entry(timers,
struct cpu_timer_list,
entry);
if (!--maxfire || virt_ticks(tsk) < t->expires.cpu) {
tsk->cputime_expires.virt_exp = t->expires.cpu;
if (!--maxfire || virt_ticks(tsk) < t->expires) {
tsk->cputime_expires.virt_exp = expires_to_cputime(t->expires);
break;
}
t->firing = 1;
@ -976,8 +921,8 @@ static void check_thread_timers(struct task_struct *tsk,
struct cpu_timer_list *t = list_first_entry(timers,
struct cpu_timer_list,
entry);
if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
tsk->cputime_expires.sched_exp = t->expires.sched;
if (!--maxfire || tsk->se.sum_exec_runtime < t->expires) {
tsk->cputime_expires.sched_exp = t->expires;
break;
}
t->firing = 1;
@ -1030,7 +975,8 @@ static void stop_process_timers(struct signal_struct *sig)
static u32 onecputick;
static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
cputime_t *expires, cputime_t cur_time, int signo)
unsigned long long *expires,
unsigned long long cur_time, int signo)
{
if (!it->expires)
return;
@ -1068,7 +1014,7 @@ static void check_process_timers(struct task_struct *tsk,
{
int maxfire;
struct signal_struct *const sig = tsk->signal;
cputime_t utime, ptime, virt_expires, prof_expires;
unsigned long long utime, ptime, virt_expires, prof_expires;
unsigned long long sum_sched_runtime, sched_expires;
struct list_head *timers = sig->cpu_timers;
struct task_cputime cputime;
@ -1078,8 +1024,8 @@ static void check_process_timers(struct task_struct *tsk,
* Collect the current process totals.
*/
thread_group_cputimer(tsk, &cputime);
utime = cputime.utime;
ptime = utime + cputime.stime;
utime = cputime_to_expires(cputime.utime);
ptime = utime + cputime_to_expires(cputime.stime);
sum_sched_runtime = cputime.sum_exec_runtime;
maxfire = 20;
prof_expires = 0;
@ -1087,8 +1033,8 @@ static void check_process_timers(struct task_struct *tsk,
struct cpu_timer_list *tl = list_first_entry(timers,
struct cpu_timer_list,
entry);
if (!--maxfire || ptime < tl->expires.cpu) {
prof_expires = tl->expires.cpu;
if (!--maxfire || ptime < tl->expires) {
prof_expires = tl->expires;
break;
}
tl->firing = 1;
@ -1102,8 +1048,8 @@ static void check_process_timers(struct task_struct *tsk,
struct cpu_timer_list *tl = list_first_entry(timers,
struct cpu_timer_list,
entry);
if (!--maxfire || utime < tl->expires.cpu) {
virt_expires = tl->expires.cpu;
if (!--maxfire || utime < tl->expires) {
virt_expires = tl->expires;
break;
}
tl->firing = 1;
@ -1117,8 +1063,8 @@ static void check_process_timers(struct task_struct *tsk,
struct cpu_timer_list *tl = list_first_entry(timers,
struct cpu_timer_list,
entry);
if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
sched_expires = tl->expires.sched;
if (!--maxfire || sum_sched_runtime < tl->expires) {
sched_expires = tl->expires;
break;
}
tl->firing = 1;
@ -1162,8 +1108,8 @@ static void check_process_timers(struct task_struct *tsk,
}
}
sig->cputime_expires.prof_exp = prof_expires;
sig->cputime_expires.virt_exp = virt_expires;
sig->cputime_expires.prof_exp = expires_to_cputime(prof_expires);
sig->cputime_expires.virt_exp = expires_to_cputime(virt_expires);
sig->cputime_expires.sched_exp = sched_expires;
if (task_cputime_zero(&sig->cputime_expires))
stop_process_timers(sig);
@ -1176,7 +1122,7 @@ static void check_process_timers(struct task_struct *tsk,
void posix_cpu_timer_schedule(struct k_itimer *timer)
{
struct task_struct *p = timer->it.cpu.task;
union cpu_time_count now;
unsigned long long now;
if (unlikely(p == NULL))
/*
@ -1205,7 +1151,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer)
*/
put_task_struct(p);
timer->it.cpu.task = p = NULL;
timer->it.cpu.expires.sched = 0;
timer->it.cpu.expires = 0;
goto out_unlock;
} else if (unlikely(p->exit_state) && thread_group_empty(p)) {
/*
@ -1387,7 +1333,7 @@ void run_posix_cpu_timers(struct task_struct *tsk)
void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
cputime_t *newval, cputime_t *oldval)
{
union cpu_time_count now;
unsigned long long now;
BUG_ON(clock_idx == CPUCLOCK_SCHED);
cpu_timer_sample_group(clock_idx, tsk, &now);
@ -1399,17 +1345,17 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
* it to be absolute.
*/
if (*oldval) {
if (*oldval <= now.cpu) {
if (*oldval <= now) {
/* Just about to fire. */
*oldval = cputime_one_jiffy;
} else {
*oldval -= now.cpu;
*oldval -= now;
}
}
if (!*newval)
goto out;
*newval += now.cpu;
*newval += now;
}
/*
@ -1459,7 +1405,7 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
}
while (!signal_pending(current)) {
if (timer.it.cpu.expires.sched == 0) {
if (timer.it.cpu.expires == 0) {
/*
* Our timer fired and was reset, below
* deletion can not fail.