Commit 2ff678b8 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Linus Torvalds
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[PATCH] hrtimer: switch itimers to hrtimer



switch itimers to a hrtimers-based implementation
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent df78488d
...@@ -632,10 +632,10 @@ static inline int de_thread(struct task_struct *tsk) ...@@ -632,10 +632,10 @@ static inline int de_thread(struct task_struct *tsk)
* synchronize with any firing (by calling del_timer_sync) * synchronize with any firing (by calling del_timer_sync)
* before we can safely let the old group leader die. * before we can safely let the old group leader die.
*/ */
sig->real_timer.data = (unsigned long)current; sig->real_timer.data = current;
spin_unlock_irq(lock); spin_unlock_irq(lock);
if (del_timer_sync(&sig->real_timer)) if (hrtimer_cancel(&sig->real_timer))
add_timer(&sig->real_timer); hrtimer_restart(&sig->real_timer);
spin_lock_irq(lock); spin_lock_irq(lock);
} }
while (atomic_read(&sig->count) > count) { while (atomic_read(&sig->count) > count) {
......
...@@ -330,7 +330,7 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole) ...@@ -330,7 +330,7 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
unsigned long min_flt = 0, maj_flt = 0; unsigned long min_flt = 0, maj_flt = 0;
cputime_t cutime, cstime, utime, stime; cputime_t cutime, cstime, utime, stime;
unsigned long rsslim = 0; unsigned long rsslim = 0;
unsigned long it_real_value = 0; DEFINE_KTIME(it_real_value);
struct task_struct *t; struct task_struct *t;
char tcomm[sizeof(task->comm)]; char tcomm[sizeof(task->comm)];
...@@ -386,7 +386,7 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole) ...@@ -386,7 +386,7 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
utime = cputime_add(utime, task->signal->utime); utime = cputime_add(utime, task->signal->utime);
stime = cputime_add(stime, task->signal->stime); stime = cputime_add(stime, task->signal->stime);
} }
it_real_value = task->signal->it_real_value; it_real_value = task->signal->real_timer.expires;
} }
ppid = pid_alive(task) ? task->group_leader->real_parent->tgid : 0; ppid = pid_alive(task) ? task->group_leader->real_parent->tgid : 0;
read_unlock(&tasklist_lock); read_unlock(&tasklist_lock);
...@@ -435,7 +435,7 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole) ...@@ -435,7 +435,7 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
priority, priority,
nice, nice,
num_threads, num_threads,
jiffies_to_clock_t(it_real_value), (long) ktime_to_clock_t(it_real_value),
start_time, start_time,
vsize, vsize,
mm ? get_mm_rss(mm) : 0, mm ? get_mm_rss(mm) : 0,
......
...@@ -105,6 +105,7 @@ extern unsigned long nr_iowait(void); ...@@ -105,6 +105,7 @@ extern unsigned long nr_iowait(void);
#include <linux/param.h> #include <linux/param.h>
#include <linux/resource.h> #include <linux/resource.h>
#include <linux/timer.h> #include <linux/timer.h>
#include <linux/hrtimer.h>
#include <asm/processor.h> #include <asm/processor.h>
...@@ -398,8 +399,8 @@ struct signal_struct { ...@@ -398,8 +399,8 @@ struct signal_struct {
struct list_head posix_timers; struct list_head posix_timers;
/* ITIMER_REAL timer for the process */ /* ITIMER_REAL timer for the process */
struct timer_list real_timer; struct hrtimer real_timer;
unsigned long it_real_value, it_real_incr; ktime_t it_real_incr;
/* ITIMER_PROF and ITIMER_VIRTUAL timers for the process */ /* ITIMER_PROF and ITIMER_VIRTUAL timers for the process */
cputime_t it_prof_expires, it_virt_expires; cputime_t it_prof_expires, it_virt_expires;
......
...@@ -96,6 +96,6 @@ static inline void add_timer(struct timer_list *timer) ...@@ -96,6 +96,6 @@ static inline void add_timer(struct timer_list *timer)
extern void init_timers(void); extern void init_timers(void);
extern void run_local_timers(void); extern void run_local_timers(void);
extern void it_real_fn(unsigned long); extern int it_real_fn(void *);
#endif #endif
...@@ -842,7 +842,7 @@ fastcall NORET_TYPE void do_exit(long code) ...@@ -842,7 +842,7 @@ fastcall NORET_TYPE void do_exit(long code)
} }
group_dead = atomic_dec_and_test(&tsk->signal->live); group_dead = atomic_dec_and_test(&tsk->signal->live);
if (group_dead) { if (group_dead) {
del_timer_sync(&tsk->signal->real_timer); hrtimer_cancel(&tsk->signal->real_timer);
exit_itimers(tsk->signal); exit_itimers(tsk->signal);
acct_process(code); acct_process(code);
} }
......
...@@ -801,10 +801,10 @@ static inline int copy_signal(unsigned long clone_flags, struct task_struct * ts ...@@ -801,10 +801,10 @@ static inline int copy_signal(unsigned long clone_flags, struct task_struct * ts
init_sigpending(&sig->shared_pending); init_sigpending(&sig->shared_pending);
INIT_LIST_HEAD(&sig->posix_timers); INIT_LIST_HEAD(&sig->posix_timers);
sig->it_real_value = sig->it_real_incr = 0; hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC);
sig->it_real_incr.tv64 = 0;
sig->real_timer.function = it_real_fn; sig->real_timer.function = it_real_fn;
sig->real_timer.data = (unsigned long) tsk; sig->real_timer.data = tsk;
init_timer(&sig->real_timer);
sig->it_virt_expires = cputime_zero; sig->it_virt_expires = cputime_zero;
sig->it_virt_incr = cputime_zero; sig->it_virt_incr = cputime_zero;
......
...@@ -12,36 +12,46 @@ ...@@ -12,36 +12,46 @@
#include <linux/syscalls.h> #include <linux/syscalls.h>
#include <linux/time.h> #include <linux/time.h>
#include <linux/posix-timers.h> #include <linux/posix-timers.h>
#include <linux/hrtimer.h>
#include <asm/uaccess.h> #include <asm/uaccess.h>
static unsigned long it_real_value(struct signal_struct *sig) /**
* itimer_get_remtime - get remaining time for the timer
*
* @timer: the timer to read
*
* Returns the delta between the expiry time and now, which can be
* less than zero or 1usec for an pending expired timer
*/
static struct timeval itimer_get_remtime(struct hrtimer *timer)
{ {
unsigned long val = 0; ktime_t rem = hrtimer_get_remaining(timer);
if (timer_pending(&sig->real_timer)) {
val = sig->real_timer.expires - jiffies;
/* look out for negative/zero itimer.. */ /*
if ((long) val <= 0) * Racy but safe: if the itimer expires after the above
val = 1; * hrtimer_get_remtime() call but before this condition
} * then we return 0 - which is correct.
return val; */
if (hrtimer_active(timer)) {
if (rem.tv64 <= 0)
rem.tv64 = NSEC_PER_USEC;
} else
rem.tv64 = 0;
return ktime_to_timeval(rem);
} }
int do_getitimer(int which, struct itimerval *value) int do_getitimer(int which, struct itimerval *value)
{ {
struct task_struct *tsk = current; struct task_struct *tsk = current;
unsigned long interval, val;
cputime_t cinterval, cval; cputime_t cinterval, cval;
switch (which) { switch (which) {
case ITIMER_REAL: case ITIMER_REAL:
spin_lock_irq(&tsk->sighand->siglock); value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
interval = tsk->signal->it_real_incr; value->it_interval =
val = it_real_value(tsk->signal); ktime_to_timeval(tsk->signal->it_real_incr);
spin_unlock_irq(&tsk->sighand->siglock);
jiffies_to_timeval(val, &value->it_value);
jiffies_to_timeval(interval, &value->it_interval);
break; break;
case ITIMER_VIRTUAL: case ITIMER_VIRTUAL:
read_lock(&tasklist_lock); read_lock(&tasklist_lock);
...@@ -113,59 +123,45 @@ asmlinkage long sys_getitimer(int which, struct itimerval __user *value) ...@@ -113,59 +123,45 @@ asmlinkage long sys_getitimer(int which, struct itimerval __user *value)
} }
void it_real_fn(unsigned long __data) /*
* The timer is automagically restarted, when interval != 0
*/
int it_real_fn(void *data)
{ {
struct task_struct * p = (struct task_struct *) __data; struct task_struct *tsk = (struct task_struct *) data;
unsigned long inc = p->signal->it_real_incr;
send_group_sig_info(SIGALRM, SEND_SIG_PRIV, p); send_group_sig_info(SIGALRM, SEND_SIG_PRIV, tsk);
/* if (tsk->signal->it_real_incr.tv64 != 0) {
* Now restart the timer if necessary. We don't need any locking hrtimer_forward(&tsk->signal->real_timer,
* here because do_setitimer makes sure we have finished running tsk->signal->it_real_incr);
* before it touches anything.
* Note, we KNOW we are (or should be) at a jiffie edge here so return HRTIMER_RESTART;
* we don't need the +1 stuff. Also, we want to use the prior }
* expire value so as to not "slip" a jiffie if we are late. return HRTIMER_NORESTART;
* Deal with requesting a time prior to "now" here rather than
* in add_timer.
*/
if (!inc)
return;
while (time_before_eq(p->signal->real_timer.expires, jiffies))
p->signal->real_timer.expires += inc;
add_timer(&p->signal->real_timer);
} }
int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
{ {
struct task_struct *tsk = current; struct task_struct *tsk = current;
unsigned long val, interval, expires; struct hrtimer *timer;
ktime_t expires;
cputime_t cval, cinterval, nval, ninterval; cputime_t cval, cinterval, nval, ninterval;
switch (which) { switch (which) {
case ITIMER_REAL: case ITIMER_REAL:
again: timer = &tsk->signal->real_timer;
spin_lock_irq(&tsk->sighand->siglock); hrtimer_cancel(timer);
interval = tsk->signal->it_real_incr;
val = it_real_value(tsk->signal);
/* We are sharing ->siglock with it_real_fn() */
if (try_to_del_timer_sync(&tsk->signal->real_timer) < 0) {
spin_unlock_irq(&tsk->sighand->siglock);
goto again;
}
tsk->signal->it_real_incr =
timeval_to_jiffies(&value->it_interval);
expires = timeval_to_jiffies(&value->it_value);
if (expires)
mod_timer(&tsk->signal->real_timer,
jiffies + 1 + expires);
spin_unlock_irq(&tsk->sighand->siglock);
if (ovalue) { if (ovalue) {
jiffies_to_timeval(val, &ovalue->it_value); ovalue->it_value = itimer_get_remtime(timer);
jiffies_to_timeval(interval, ovalue->it_interval
&ovalue->it_interval); = ktime_to_timeval(tsk->signal->it_real_incr);
} }
tsk->signal->it_real_incr =
timeval_to_ktime(value->it_interval);
expires = timeval_to_ktime(value->it_value);
if (expires.tv64 != 0)
hrtimer_start(timer, expires, HRTIMER_REL);
break; break;
case ITIMER_VIRTUAL: case ITIMER_VIRTUAL:
nval = timeval_to_cputime(&value->it_value); nval = timeval_to_cputime(&value->it_value);
......
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