X-Git-Url: http://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Ftimer%2Ftimer.c;h=c1979fd32d97244a52b930e04ef50bc51733319a;hb=fe6bc8c530795a6c718f7e8fd1a6643d9f3024a1;hp=9486e6b92872ac22a50f38fd14f5077b2fd220e3;hpb=606cca7b0ed5236d1df1c4436ca79db6e3fd5321;p=ccan

diff --git a/ccan/timer/timer.c b/ccan/timer/timer.c
index 9486e6b9..c1979fd3 100644
--- a/ccan/timer/timer.c
+++ b/ccan/timer/timer.c
@@ -12,41 +12,46 @@ struct timer_level {
 	struct list_head list[PER_LEVEL];
 };
 
-static uint64_t time_to_grains(struct timespec ts)
+static uint64_t time_to_grains(struct timeabs t)
 {
-	return ts.tv_sec * ((uint64_t)1000000000 / TIMER_GRANULARITY)
-		+ (ts.tv_nsec / TIMER_GRANULARITY);
+	return t.ts.tv_sec * ((uint64_t)1000000000 / TIMER_GRANULARITY)
+		+ (t.ts.tv_nsec / TIMER_GRANULARITY);
 }
 
-static struct timespec grains_to_time(uint64_t grains)
+static struct timeabs grains_to_time(uint64_t grains)
 {
-	struct timespec ts;
+	struct timeabs t;
 
-	ts.tv_sec = grains / (1000000000 / TIMER_GRANULARITY);
-	ts.tv_nsec = (grains % (1000000000 / TIMER_GRANULARITY))
+	t.ts.tv_sec = grains / (1000000000 / TIMER_GRANULARITY);
+	t.ts.tv_nsec = (grains % (1000000000 / TIMER_GRANULARITY))
 		* TIMER_GRANULARITY;
-	return ts;
+	return t;
 }
 
-void timers_init(struct timers *timers, struct timespec start)
+void timers_init(struct timers *timers, struct timeabs start)
 {
 	unsigned int i;
 
 	list_head_init(&timers->far);
 	timers->base = time_to_grains(start);
+	timers->first = -1ULL;
 	for (i = 0; i < ARRAY_SIZE(timers->level); i++)
 		timers->level[i] = NULL;
 }
 
-static void timer_add_raw(struct timers *timers, struct timer *t)
+static unsigned int level_of(const struct timers *timers, uint64_t time)
 {
-	struct list_head *l;
 	uint64_t diff;
-	unsigned int level;
 
 	/* Level depends how far away it is. */
-	diff = t->time - timers->base;
-	level = ilog64(diff / 2) / TIMER_LEVEL_BITS;
+	diff = time - timers->base;
+	return ilog64(diff / 2) / TIMER_LEVEL_BITS;
+}
+
+static void timer_add_raw(struct timers *timers, struct timer *t)
+{
+	struct list_head *l;
+	unsigned int level = level_of(timers, t->time);
 
 	if (!timers->level[level])
 		l = &timers->far;
@@ -58,13 +63,15 @@ static void timer_add_raw(struct timers *timers, struct timer *t)
 	list_add_tail(l, &t->list);
 }
 
-void timer_add(struct timers *timers, struct timer *t, struct timespec when)
+void timer_add(struct timers *timers, struct timer *t, struct timeabs when)
 {
 	t->time = time_to_grains(when);
 
 	/* Added in the past?  Treat it as imminent. */
 	if (t->time < timers->base)
 		t->time = timers->base;
+	if (t->time < timers->first)
+		timers->first = t->time;
 
 	timer_add_raw(timers, t);
 }
@@ -112,41 +119,6 @@ static void add_level(struct timers *timers, unsigned int level)
 		timer_add_raw(timers, t);
 }
 
-/* Take timers from level and distribute them down one. */
-static void cascade(struct timers *timers, unsigned int level)
-{
-	struct timer *i;
-	struct list_head from_far, *list;
-
-	if (level == ARRAY_SIZE(timers->level) || !timers->level[level]) {
-		list_head_init(&from_far);
-		timers_far_get(timers, &from_far,
-			       timers->base
-			       + (1ULL << (level*TIMER_LEVEL_BITS))-1);
-		list = &from_far;
-		if (level != ARRAY_SIZE(timers->level))
-			add_level(timers, level);
-	} else {
-		unsigned src;
-
-		src = (timers->base >> (level * TIMER_LEVEL_BITS)) % PER_LEVEL;
-		if (src == 0)
-			cascade(timers, level + 1);
-		list = &timers->level[level]->list[src];
-	}
-
-	while ((i = list_pop(list, struct timer, list)) != NULL) {
-		unsigned dst;
-
-		assert(i->time >= timers->base);
-		assert(i->time < (timers->base
-				  + (1ULL << ((level+1)*TIMER_LEVEL_BITS))));
-
-		dst = (i->time >> ((level-1)*TIMER_LEVEL_BITS)) % PER_LEVEL;
-		list_add_tail(&timers->level[level-1]->list[dst], &i->list);
-	}
-}
-
 static const struct timer *find_first(const struct list_head *list,
 				      const struct timer *prev)
 {
@@ -159,17 +131,26 @@ static const struct timer *find_first(const struct list_head *list,
 	return prev;
 }
 
-static struct timer *get_first(const struct timers *timers)
+static const struct timer *get_first(const struct timers *timers)
 {
-	unsigned int level = 0, i, off;
+	unsigned int level, i, off;
 	bool need_next;
-	uint64_t base = timers->base;
+	uint64_t base;
 	const struct timer *found = NULL;
 	struct list_head *h;
 
+	if (timers->first < timers->base) {
+		base = timers->base;
+		level = 0;
+	} else {
+		/* May not be accurate, due to timer_del / expiry. */
+		level = level_of(timers, timers->first);
+		base = timers->first >> (TIMER_LEVEL_BITS * level);
+	}
+
 next:
 	if (!timers->level[level])
-		return (struct timer *)find_first(&timers->far, NULL);
+		return find_first(&timers->far, NULL);
 
 	need_next = false;
 	off = base % PER_LEVEL;
@@ -206,17 +187,28 @@ next:
 			found = find_first(h, found);
 		}
 	}
-
-	return (struct timer *)found;
+	return found;
 }
 
-bool timer_earliest(const struct timers *timers, struct timespec *first)
+static bool update_first(struct timers *timers)
 {
-	struct timer *found = get_first(timers);
+	const struct timer *found = get_first(timers);
 
-	if (!found)
+	if (!found) {
+		timers->first = -1ULL;
 		return false;
-	*first = grains_to_time(found->time);
+	}
+
+	timers->first = found->time;
+	return true;
+}
+
+bool timer_earliest(struct timers *timers, struct timeabs *first)
+{
+	if (!update_first(timers))
+		return false;
+
+	*first = grains_to_time(timers->first);
 	return true;
 }
 
@@ -267,43 +259,39 @@ static void timer_fast_forward(struct timers *timers, uint64_t time)
 		timer_add_raw(timers, i);
 }
 
-/* Fills list of expired timers. */
-void timers_expire(struct timers *timers,
-		   struct timespec expire,
-		   struct list_head *list)
+/* Returns an expired timer. */
+struct timer *timers_expire(struct timers *timers, struct timeabs expire)
 {
 	uint64_t now = time_to_grains(expire);
 	unsigned int off;
-	const struct timer *first;
+	struct timer *t;
 
 	assert(now >= timers->base);
 
-	list_head_init(list);
-
 	if (!timers->level[0]) {
 		if (list_empty(&timers->far))
-			return;
+			return NULL;
 		add_level(timers, 0);
 	}
 
-	while ((first = get_first(timers)) != NULL) {
-		assert(first->time >= timers->base);
-		if (first->time > now) {
+	do {
+		if (timers->first > now) {
 			timer_fast_forward(timers, now);
-			break;
+			return NULL;
 		}
 
-		timer_fast_forward(timers, first->time);
+		timer_fast_forward(timers, timers->first);
 		off = timers->base % PER_LEVEL;
 
-		list_append_list(list, &timers->level[0]->list[off]);
-		if (timers->base == now)
-			break;
-	}
+		/* This *may* be NULL, if we deleted the first timer */
+		t = list_pop(&timers->level[0]->list[off], struct timer, list);
+	} while (!t && update_first(timers));
+
+	return t;
 }
 
 static bool timer_list_check(const struct list_head *l,
-			     uint64_t min, uint64_t max,
+			     uint64_t min, uint64_t max, uint64_t first,
 			     const char *abortstr)
 {
 	const struct timer *t;
@@ -316,7 +304,18 @@ static bool timer_list_check(const struct list_head *l,
 			if (abortstr) {
 				fprintf(stderr,
 					"%s: timer %p %llu not %llu-%llu\n",
-					abortstr, t, t->time, min, max);
+					abortstr, t, (long long)t->time,
+					(long long)min, (long long)max);
+				abort();
+			}
+			return false;
+		}
+		if (t->time < first) {
+			if (abortstr) {
+				fprintf(stderr,
+					"%s: timer %p %llu < minimum %llu\n",
+					abortstr, t, (long long)t->time,
+					(long long)first);
 				abort();
 			}
 			return false;
@@ -341,7 +340,7 @@ struct timers *timers_check(const struct timers *timers, const char *abortstr)
 
 		h = &timers->level[l]->list[(i+off) % PER_LEVEL];
 		if (!timer_list_check(h, timers->base + i, timers->base + i,
-				      abortstr))
+				      timers->first, abortstr))
 			return NULL;
 	}
 
@@ -359,7 +358,7 @@ struct timers *timers_check(const struct timers *timers, const char *abortstr)
 
 			h = &timers->level[l]->list[(i+off) % PER_LEVEL];
 			if (!timer_list_check(h, base, base + per_bucket - 1,
-					      abortstr))
+					      timers->first, abortstr))
 				return NULL;
 			base += per_bucket;
 		}
@@ -368,13 +367,14 @@ struct timers *timers_check(const struct timers *timers, const char *abortstr)
 past_levels:
 	base = (timers->base & ~((1ULL << (TIMER_LEVEL_BITS * l)) - 1))
 		+ (1ULL << (TIMER_LEVEL_BITS * l)) - 1;
-	if (!timer_list_check(&timers->far, base, -1ULL, abortstr))
+	if (!timer_list_check(&timers->far, base, -1ULL, timers->first,
+			      abortstr))
 		return NULL;
 
 	return (struct timers *)timers;
 }
 
-//#ifdef CCAN_TIMER_DEBUG
+#ifdef CCAN_TIMER_DEBUG
 void timers_dump(const struct timers *timers, FILE *fp)
 {
 	unsigned int l, i;
@@ -420,7 +420,7 @@ void timers_dump(const struct timers *timers, FILE *fp)
 	}
 	fprintf(stderr, "Far: %llu (%llu-%llu)\n", num, min, max);
 }
-//#endif
+#endif
 
 void timers_cleanup(struct timers *timers)
 {