Re: [PATCH 4/7] posix-timers: CPU clock support for POSIX timers

[Christoph Lameter]

On Mon, 24 Jan 2005, Christoph Lameter wrote:

> It would be great to have a kind of private field that other clocks (like
> clock drivers) could use for their purposes. mmtimer f.e. does use some
> of the fields for the tick based timers for its purposes.

On that note:

Your patch breaks the mmtimer driver because it used k_itimer values for
its own purposes. Here is a fix by defining an additional structure
in k_itimer (same approach for mmtimer as the cpu timers):

Signed-off-by: Christoph Lameter <clameter@xxxxxxx>

Index: linux-2.6.10/include/linux/posix-timers.h
===================================================================
--- linux-2.6.10.orig/include/linux/posix-timers.h	2005-01-25 14:35:11.000000000 -0800
+++ linux-2.6.10/include/linux/posix-timers.h	2005-01-25 14:35:16.000000000 -0800
@@ -57,6 +57,12 @@ struct k_itimer {
 			unsigned long incr; /* interval in jiffies */
 		} real;
 		struct cpu_timer_list cpu;
+		struct {
+			unsigned int clock;
+			unsigned int node;
+			unsigned long incr;
+			unsigned long expires;
+		} mmtimer;
 	} it;
 };

Index: linux-2.6.10/drivers/char/mmtimer.c
===================================================================
--- linux-2.6.10.orig/drivers/char/mmtimer.c	2005-01-25 14:35:09.000000000 -0800
+++ linux-2.6.10/drivers/char/mmtimer.c	2005-01-25 14:34:41.000000000 -0800
@@ -420,19 +420,19 @@ static int inline reschedule_periodic_ti
 	int n;
 	struct k_itimer *t = x->timer;

-	t->it_timer.magic = x->i;
+	t->it.mmtimer.clock = x->i;
 	t->it_overrun--;

 	n = 0;
 	do {

-		t->it_timer.expires += t->it_incr << n;
+		t->it.mmtimer.expires += t->it.mmtimer.incr << n;
 		t->it_overrun += 1 << n;
 		n++;
 		if (n > 20)
 			return 1;

-	} while (mmtimer_setup(x->i, t->it_timer.expires));
+	} while (mmtimer_setup(x->i, t->it.mmtimer.expires));

 	return 0;
 }
@@ -468,7 +468,7 @@ mmtimer_interrupt(int irq, void *dev_id,
 		spin_lock(&base[i].lock);
 		if (base[i].cpu == smp_processor_id()) {
 			if (base[i].timer)
-				expires = base[i].timer->it_timer.expires;
+				expires = base[i].timer->it.mmtimer.expires;
 			/* expires test won't work with shared irqs */
 			if ((mmtimer_int_pending(i) > 0) ||
 				(expires && (expires < rtc_time()))) {
@@ -505,7 +505,7 @@ void mmtimer_tasklet(unsigned long data)

 		t->it_overrun++;
 	}
-	if(t->it_incr) {
+	if(t->it.mmtimer.incr) {
 		/* Periodic timer */
 		if (reschedule_periodic_timer(x)) {
 			printk(KERN_WARNING "mmtimer: unable to reschedule\n");
@@ -513,7 +513,7 @@ void mmtimer_tasklet(unsigned long data)
 		}
 	} else {
 		/* Ensure we don't false trigger in mmtimer_interrupt */
-		t->it_timer.expires = 0;
+		t->it.mmtimer.expires = 0;
 	}
 	t->it_overrun_last = t->it_overrun;
 out:
@@ -524,7 +524,7 @@ out:
 static int sgi_timer_create(struct k_itimer *timer)
 {
 	/* Insure that a newly created timer is off */
-	timer->it_timer.magic = TIMER_OFF;
+	timer->it.mmtimer.clock = TIMER_OFF;
 	return 0;
 }

@@ -535,8 +535,8 @@ static int sgi_timer_create(struct k_iti
  */
 static int sgi_timer_del(struct k_itimer *timr)
 {
-	int i = timr->it_timer.magic;
-	cnodeid_t nodeid = timr->it_timer.data;
+	int i = timr->it.mmtimer.clock;
+	cnodeid_t nodeid = timr->it.mmtimer.node;
 	mmtimer_t *t = timers + nodeid * NUM_COMPARATORS +i;
 	unsigned long irqflags;

@@ -544,8 +544,8 @@ static int sgi_timer_del(struct k_itimer
 		spin_lock_irqsave(&t->lock, irqflags);
 		mmtimer_disable_int(cnodeid_to_nasid(nodeid),i);
 		t->timer = NULL;
-		timr->it_timer.magic = TIMER_OFF;
-		timr->it_timer.expires = 0;
+		timr->it.mmtimer.clock = TIMER_OFF;
+		timr->it.mmtimer.expires = 0;
 		spin_unlock_irqrestore(&t->lock, irqflags);
 	}
 	return 0;
@@ -558,7 +558,7 @@ static int sgi_timer_del(struct k_itimer
 static void sgi_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
 {

-	if (timr->it_timer.magic == TIMER_OFF) {
+	if (timr->it.mmtimer.clock == TIMER_OFF) {
 		cur_setting->it_interval.tv_nsec = 0;
 		cur_setting->it_interval.tv_sec = 0;
 		cur_setting->it_value.tv_nsec = 0;
@@ -566,8 +566,8 @@ static void sgi_timer_get(struct k_itime
 		return;
 	}

-	ns_to_timespec(cur_setting->it_interval, timr->it_incr * sgi_clock_period);
-	ns_to_timespec(cur_setting->it_value, (timr->it_timer.expires - rtc_time())* sgi_clock_period);
+	ns_to_timespec(cur_setting->it_interval, timr->it.mmtimer.incr * sgi_clock_period);
+	ns_to_timespec(cur_setting->it_value, (timr->it.mmtimer.expires - rtc_time())* sgi_clock_period);
 	return;
 }

@@ -640,19 +640,19 @@ retry:
 	base[i].timer = timr;
 	base[i].cpu = smp_processor_id();

-	timr->it_timer.magic = i;
-	timr->it_timer.data = nodeid;
-	timr->it_incr = period;
-	timr->it_timer.expires = when;
+	timr->it.mmtimer.clock = i;
+	timr->it.mmtimer.node = nodeid;
+	timr->it.mmtimer.incr = period;
+	timr->it.mmtimer.expires = when;

 	if (period == 0) {
 		if (mmtimer_setup(i, when)) {
 			mmtimer_disable_int(-1, i);
 			posix_timer_event(timr, 0);
-			timr->it_timer.expires = 0;
+			timr->it.mmtimer.expires = 0;
 		}
 	} else {
-		timr->it_timer.expires -= period;
+		timr->it.mmtimer.expires -= period;
 		if (reschedule_periodic_timer(base+i))
 			err = -EINVAL;
 	}
>
-
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