Commit 2ff678b8 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Linus Torvalds

[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)
* synchronize with any firing (by calling del_timer_sync)
* 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);
if (del_timer_sync(&sig->real_timer))
add_timer(&sig->real_timer);
if (hrtimer_cancel(&sig->real_timer))
hrtimer_restart(&sig->real_timer);
spin_lock_irq(lock);
}
while (atomic_read(&sig->count) > count) {
......
......@@ -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;
cputime_t cutime, cstime, utime, stime;
unsigned long rsslim = 0;
unsigned long it_real_value = 0;
DEFINE_KTIME(it_real_value);
struct task_struct *t;
char tcomm[sizeof(task->comm)];
......@@ -386,7 +386,7 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
utime = cputime_add(utime, task->signal->utime);
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;
read_unlock(&tasklist_lock);
......@@ -435,7 +435,7 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
priority,
nice,
num_threads,
jiffies_to_clock_t(it_real_value),
(long) ktime_to_clock_t(it_real_value),
start_time,
vsize,
mm ? get_mm_rss(mm) : 0,
......
......@@ -105,6 +105,7 @@ extern unsigned long nr_iowait(void);
#include <linux/param.h>
#include <linux/resource.h>
#include <linux/timer.h>
#include <linux/hrtimer.h>
#include <asm/processor.h>
......@@ -398,8 +399,8 @@ struct signal_struct {
struct list_head posix_timers;
/* ITIMER_REAL timer for the process */
struct timer_list real_timer;
unsigned long it_real_value, it_real_incr;
struct hrtimer real_timer;
ktime_t it_real_incr;
/* ITIMER_PROF and ITIMER_VIRTUAL timers for the process */
cputime_t it_prof_expires, it_virt_expires;
......
......@@ -96,6 +96,6 @@ static inline void add_timer(struct timer_list *timer)
extern void init_timers(void);
extern void run_local_timers(void);
extern void it_real_fn(unsigned long);
extern int it_real_fn(void *);
#endif
......@@ -842,7 +842,7 @@ fastcall NORET_TYPE void do_exit(long code)
}
group_dead = atomic_dec_and_test(&tsk->signal->live);
if (group_dead) {
del_timer_sync(&tsk->signal->real_timer);
hrtimer_cancel(&tsk->signal->real_timer);
exit_itimers(tsk->signal);
acct_process(code);
}
......
......@@ -801,10 +801,10 @@ static inline int copy_signal(unsigned long clone_flags, struct task_struct * ts
init_sigpending(&sig->shared_pending);
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.data = (unsigned long) tsk;
init_timer(&sig->real_timer);
sig->real_timer.data = tsk;
sig->it_virt_expires = cputime_zero;
sig->it_virt_incr = cputime_zero;
......
......@@ -12,36 +12,46 @@
#include <linux/syscalls.h>
#include <linux/time.h>
#include <linux/posix-timers.h>
#include <linux/hrtimer.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;
if (timer_pending(&sig->real_timer)) {
val = sig->real_timer.expires - jiffies;
ktime_t rem = hrtimer_get_remaining(timer);
/* look out for negative/zero itimer.. */
if ((long) val <= 0)
val = 1;
}
return val;
/*
* Racy but safe: if the itimer expires after the above
* hrtimer_get_remtime() call but before this condition
* then we return 0 - which is correct.
*/
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)
{
struct task_struct *tsk = current;
unsigned long interval, val;
cputime_t cinterval, cval;
switch (which) {
case ITIMER_REAL:
spin_lock_irq(&tsk->sighand->siglock);
interval = tsk->signal->it_real_incr;
val = it_real_value(tsk->signal);
spin_unlock_irq(&tsk->sighand->siglock);
jiffies_to_timeval(val, &value->it_value);
jiffies_to_timeval(interval, &value->it_interval);
value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
value->it_interval =
ktime_to_timeval(tsk->signal->it_real_incr);
break;
case ITIMER_VIRTUAL:
read_lock(&tasklist_lock);
......@@ -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;
unsigned long inc = p->signal->it_real_incr;
struct task_struct *tsk = (struct task_struct *) data;
send_group_sig_info(SIGALRM, SEND_SIG_PRIV, p);
send_group_sig_info(SIGALRM, SEND_SIG_PRIV, tsk);
/*
* Now restart the timer if necessary. We don't need any locking
* here because do_setitimer makes sure we have finished running
* before it touches anything.
* Note, we KNOW we are (or should be) at a jiffie edge here so
* 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.
* 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);
if (tsk->signal->it_real_incr.tv64 != 0) {
hrtimer_forward(&tsk->signal->real_timer,
tsk->signal->it_real_incr);
return HRTIMER_RESTART;
}
return HRTIMER_NORESTART;
}
int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
{
struct task_struct *tsk = current;
unsigned long val, interval, expires;
struct hrtimer *timer;
ktime_t expires;
cputime_t cval, cinterval, nval, ninterval;
switch (which) {
case ITIMER_REAL:
again:
spin_lock_irq(&tsk->sighand->siglock);
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);
timer = &tsk->signal->real_timer;
hrtimer_cancel(timer);
if (ovalue) {
jiffies_to_timeval(val, &ovalue->it_value);
jiffies_to_timeval(interval,
&ovalue->it_interval);
ovalue->it_value = itimer_get_remtime(timer);
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;
case ITIMER_VIRTUAL:
nval = timeval_to_cputime(&value->it_value);
......
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