[PATCH] hrtimer: switch itimers to hrtimer
switch itimers to a hrtimers-based implementation Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Thomas Gleixner
committed by
Linus Torvalds
Linus Torvalds
parent
df78488de7
commit
2ff678b8da
106
kernel/itimer.c
106
kernel/itimer.c
@@ -12,36 +12,46 @@
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#include <linux/syscalls.h>
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#include <linux/time.h>
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#include <linux/posix-timers.h>
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#include <linux/hrtimer.h>
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#include <asm/uaccess.h>
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static unsigned long it_real_value(struct signal_struct *sig)
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/**
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* itimer_get_remtime - get remaining time for the timer
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*
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* @timer: the timer to read
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*
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* Returns the delta between the expiry time and now, which can be
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* less than zero or 1usec for an pending expired timer
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*/
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static struct timeval itimer_get_remtime(struct hrtimer *timer)
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{
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unsigned long val = 0;
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if (timer_pending(&sig->real_timer)) {
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val = sig->real_timer.expires - jiffies;
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ktime_t rem = hrtimer_get_remaining(timer);
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/* look out for negative/zero itimer.. */
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if ((long) val <= 0)
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val = 1;
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}
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return val;
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/*
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* Racy but safe: if the itimer expires after the above
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* hrtimer_get_remtime() call but before this condition
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* then we return 0 - which is correct.
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*/
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if (hrtimer_active(timer)) {
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if (rem.tv64 <= 0)
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rem.tv64 = NSEC_PER_USEC;
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} else
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rem.tv64 = 0;
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return ktime_to_timeval(rem);
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}
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int do_getitimer(int which, struct itimerval *value)
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{
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struct task_struct *tsk = current;
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unsigned long interval, val;
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cputime_t cinterval, cval;
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switch (which) {
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case ITIMER_REAL:
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spin_lock_irq(&tsk->sighand->siglock);
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interval = tsk->signal->it_real_incr;
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val = it_real_value(tsk->signal);
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spin_unlock_irq(&tsk->sighand->siglock);
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jiffies_to_timeval(val, &value->it_value);
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jiffies_to_timeval(interval, &value->it_interval);
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value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
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value->it_interval =
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ktime_to_timeval(tsk->signal->it_real_incr);
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break;
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case ITIMER_VIRTUAL:
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read_lock(&tasklist_lock);
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@@ -113,59 +123,45 @@ asmlinkage long sys_getitimer(int which, struct itimerval __user *value)
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}
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void it_real_fn(unsigned long __data)
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/*
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* The timer is automagically restarted, when interval != 0
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*/
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int it_real_fn(void *data)
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{
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struct task_struct * p = (struct task_struct *) __data;
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unsigned long inc = p->signal->it_real_incr;
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struct task_struct *tsk = (struct task_struct *) data;
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send_group_sig_info(SIGALRM, SEND_SIG_PRIV, p);
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send_group_sig_info(SIGALRM, SEND_SIG_PRIV, tsk);
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/*
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* Now restart the timer if necessary. We don't need any locking
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* here because do_setitimer makes sure we have finished running
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* before it touches anything.
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* Note, we KNOW we are (or should be) at a jiffie edge here so
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* we don't need the +1 stuff. Also, we want to use the prior
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* expire value so as to not "slip" a jiffie if we are late.
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* Deal with requesting a time prior to "now" here rather than
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* in add_timer.
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*/
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if (!inc)
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return;
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while (time_before_eq(p->signal->real_timer.expires, jiffies))
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p->signal->real_timer.expires += inc;
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add_timer(&p->signal->real_timer);
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if (tsk->signal->it_real_incr.tv64 != 0) {
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hrtimer_forward(&tsk->signal->real_timer,
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tsk->signal->it_real_incr);
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return HRTIMER_RESTART;
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}
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return HRTIMER_NORESTART;
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}
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int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
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{
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struct task_struct *tsk = current;
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unsigned long val, interval, expires;
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struct hrtimer *timer;
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ktime_t expires;
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cputime_t cval, cinterval, nval, ninterval;
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switch (which) {
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case ITIMER_REAL:
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again:
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spin_lock_irq(&tsk->sighand->siglock);
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interval = tsk->signal->it_real_incr;
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val = it_real_value(tsk->signal);
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/* We are sharing ->siglock with it_real_fn() */
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if (try_to_del_timer_sync(&tsk->signal->real_timer) < 0) {
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spin_unlock_irq(&tsk->sighand->siglock);
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goto again;
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timer = &tsk->signal->real_timer;
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hrtimer_cancel(timer);
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if (ovalue) {
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ovalue->it_value = itimer_get_remtime(timer);
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ovalue->it_interval
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= ktime_to_timeval(tsk->signal->it_real_incr);
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}
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tsk->signal->it_real_incr =
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timeval_to_jiffies(&value->it_interval);
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expires = timeval_to_jiffies(&value->it_value);
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if (expires)
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mod_timer(&tsk->signal->real_timer,
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jiffies + 1 + expires);
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spin_unlock_irq(&tsk->sighand->siglock);
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if (ovalue) {
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jiffies_to_timeval(val, &ovalue->it_value);
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jiffies_to_timeval(interval,
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&ovalue->it_interval);
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}
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timeval_to_ktime(value->it_interval);
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expires = timeval_to_ktime(value->it_value);
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if (expires.tv64 != 0)
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hrtimer_start(timer, expires, HRTIMER_REL);
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break;
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case ITIMER_VIRTUAL:
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nval = timeval_to_cputime(&value->it_value);
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