X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftimer%2Ftimer.c;h=2c58a4e5238df00b7bd88abc8cee76feb284eab2;hp=c30c6227ab9a7fc2b672e3319605d0d66ed3a35d;hb=63f770591286a5a61ef2857377eeab5e0e75d115;hpb=daf9ee7d8e2b683ff05283beb1843611ad8c9e8a

diff --git a/ccan/timer/timer.c b/ccan/timer/timer.c
index c30c6227..2c58a4e5 100644
--- a/ccan/timer/timer.c
+++ b/ccan/timer/timer.c
@@ -63,8 +63,20 @@ static void timer_add_raw(struct timers *timers, struct timer *t)
 	list_add_tail(l, &t->list);
 }
 
+void timer_init(struct timer *t)
+{
+	list_node_init(&t->list);
+}
+
+static bool list_node_initted(const struct list_node *n)
+{
+	return n->prev == n;
+}
+
 void timer_add(struct timers *timers, struct timer *t, struct timeabs when)
 {
+	assert(list_node_initted(&t->list));
+
 	t->time = time_to_grains(when);
 
 	/* Added in the past?  Treat it as imminent. */
@@ -79,7 +91,7 @@ void timer_add(struct timers *timers, struct timer *t, struct timeabs when)
 /* FIXME: inline */
 void timer_del(struct timers *timers, struct timer *t)
 {
-	list_del(&t->list);
+	list_del_init(&t->list);
 }
 
 static void timers_far_get(struct timers *timers,
@@ -119,7 +131,10 @@ static void add_level(struct timers *timers, unsigned int level)
 		timer_add_raw(timers, t);
 }
 
+/* We don't need to search past the first at level 0, since the
+ * bucket range is 1; they're all the same. */
 static const struct timer *find_first(const struct list_head *list,
+				      unsigned int level,
 				      const struct timer *prev)
 {
 	struct timer *t;
@@ -127,67 +142,56 @@ static const struct timer *find_first(const struct list_head *list,
 	list_for_each(list, t, list) {
 		if (!prev || t->time < prev->time)
 			prev = t;
+		if (level == 0)
+			break;
 	}
 	return prev;
 }
 
-static const struct timer *get_first(const struct timers *timers)
+/* FIXME: Suboptimal */
+static const struct timer *brute_force_first(const struct timers *timers)
 {
-	unsigned int level, i, off;
-	bool need_next;
-	uint64_t base;
+	unsigned int l, i;
 	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 find_first(&timers->far, NULL);
-
-	need_next = false;
-	off = base % PER_LEVEL;
-	for (i = 0; i < PER_LEVEL; i++) {
-		h = &timers->level[level]->list[(i+off) % PER_LEVEL];
 
-		if (!list_empty(h))
-			break;
-
-		/* We haven't cascaded yet, so if we wrap, we'll need to
-		 * check next level, too. */
-		if (i + off == PER_LEVEL)
-			need_next = true;
-	}
-	if (i == PER_LEVEL) {
-		level++;
-		base >>= TIMER_LEVEL_BITS;
-		goto next;
+	for (l = 0; l < ARRAY_SIZE(timers->level) && timers->level[l]; l++) {
+		for (i = 0; i < PER_LEVEL; i++)
+			found = find_first(&timers->level[l]->list[i], l,
+					   found);
 	}
 
-	/* Level 0 is exact, so they're all the same. */
-	if (level == 0)
-		found = list_top(h, struct timer, list);
+	found = find_first(&timers->far, -1U, found);
+	return found;
+}
+			
+static const struct timer *get_first(const struct timers *timers)
+{
+	uint64_t time;
+	
+	/* Where can we start from? */
+	if (timers->first < timers->base)
+		time = timers->base;
 	else
-		found = find_first(h, NULL);
-
-	if (need_next) {
-		if (!timers->level[level+1]) {
-			found = find_first(&timers->far, found);
-		} else {
-			base >>= TIMER_LEVEL_BITS;
-			off = base % PER_LEVEL;
-			h = &timers->level[level+1]->list[off];
-			found = find_first(h, found);
+		time = timers->first;
+
+	/* We can have just far timers, for example. */
+	if (timers->level[0]) {
+		/* First search rest of lower buckets; we've already spilled
+		 * so if we find one there we don't need to search further. */
+		unsigned int i, off = time % PER_LEVEL;
+
+		for (i = off; i < PER_LEVEL; i++) {
+			struct list_head *h = &timers->level[0]->list[i];
+			if (!list_empty(h))
+				return find_first(h, 0, NULL);
 		}
 	}
-	return found;
+
+	/* From here on, we're searching non-normalized parts of the
+	 * data structure, which is much subtler.
+	 *
+	 * So we brute force. */
+	return brute_force_first(timers);
 }
 
 static bool update_first(struct timers *timers)
@@ -259,37 +263,37 @@ 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 timeabs 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;
+	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);
 	}
 
 	do {
 		if (timers->first > now) {
 			timer_fast_forward(timers, now);
-			break;
+			return NULL;
 		}
 
 		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;
-	} while (update_first(timers));
+		/* This *may* be NULL, if we deleted the first timer */
+		t = list_pop(&timers->level[0]->list[off], struct timer, list);
+		if (t)
+			list_node_init(&t->list);
+	} while (!t && update_first(timers));
+
+	return t;
 }
 
 static bool timer_list_check(const struct list_head *l,
@@ -348,7 +352,7 @@ struct timers *timers_check(const struct timers *timers, const char *abortstr)
 
 	/* For other levels, "current" bucket has been emptied, and may contain
 	 * entries for the current + level_size bucket. */
-	for (l = 1; timers->level[l] && l < PER_LEVEL; l++) {
+	for (l = 1; l < ARRAY_SIZE(timers->level) && timers->level[l]; l++) {
 		uint64_t per_bucket = 1ULL << (TIMER_LEVEL_BITS * l);
 
 		off = ((timers->base >> (l*TIMER_LEVEL_BITS)) % PER_LEVEL);
@@ -377,50 +381,84 @@ past_levels:
 }
 
 #ifdef CCAN_TIMER_DEBUG
-void timers_dump(const struct timers *timers, FILE *fp)
+static void dump_bucket_stats(FILE *fp, const struct list_head *h)
 {
-	unsigned int l, i;
-	uint64_t min, max, num;
+	unsigned long long min, max, num;
 	struct timer *t;
 
-	if (!fp)
-		fp = stderr;
-
-	fprintf(fp, "Base: %llu\n", timers->base);
-
-	for (l = 0; timers->level[l] && l < ARRAY_SIZE(timers->level); l++) {
-		fprintf(fp, "Level %i (+%llu):\n",
-			l, (uint64_t)1 << (TIMER_LEVEL_BITS * l));
-		for (i = 0; i < (1 << TIMER_LEVEL_BITS); i++) {
-
-			if (list_empty(&timers->level[l]->list[i]))
-				continue;
-			min = -1ULL;
-			max = 0;
-			num = 0;
-			list_for_each(&timers->level[l]->list[i], t, list) {
-				if (t->time < min)
-					min = t->time;
-				if (t->time > max)
-					max = t->time;
-				num++;
-			}
-			fprintf(stderr, "  %llu (+%llu-+%llu)\n",
-				num, min - timers->base, max - timers->base);
-		}
+	if (list_empty(h)) {
+		printf("\n");
+		return;
 	}
 
 	min = -1ULL;
 	max = 0;
 	num = 0;
-	list_for_each(&timers->far, t, list) {
+	list_for_each(h, t, list) {
 		if (t->time < min)
 			min = t->time;
 		if (t->time > max)
 			max = t->time;
 		num++;
 	}
-	fprintf(stderr, "Far: %llu (%llu-%llu)\n", num, min, max);
+	fprintf(fp, " %llu (%llu-%llu)\n",
+		num, min, max);
+}
+
+void timers_dump(const struct timers *timers, FILE *fp)
+{
+	unsigned int l, i, off;
+	unsigned long long base;
+
+	if (!fp)
+		fp = stderr;
+
+	fprintf(fp, "Base: %llu\n", (unsigned long long)timers->base);
+
+	if (!timers->level[0])
+		goto past_levels;
+
+	fprintf(fp, "Level 0:\n");
+
+	/* First level is simple. */
+	off = timers->base % PER_LEVEL;
+	for (i = 0; i < PER_LEVEL; i++) {
+		const struct list_head *h;
+
+		fprintf(fp, "  Bucket %llu (%lu):",
+			(i+off) % PER_LEVEL, timers->base + i);
+		h = &timers->level[0]->list[(i+off) % PER_LEVEL];
+		dump_bucket_stats(fp, h);
+	}
+
+	/* For other levels, "current" bucket has been emptied, and may contain
+	 * entries for the current + level_size bucket. */
+	for (l = 1; l < ARRAY_SIZE(timers->level) && timers->level[l]; l++) {
+		uint64_t per_bucket = 1ULL << (TIMER_LEVEL_BITS * l);
+
+		off = ((timers->base >> (l*TIMER_LEVEL_BITS)) % PER_LEVEL);
+		/* We start at *next* bucket. */
+		base = (timers->base & ~(per_bucket - 1)) + per_bucket;
+
+		fprintf(fp, "Level %u:\n", l);
+		for (i = 1; i <= PER_LEVEL; i++) {
+			const struct list_head *h;
+
+			fprintf(fp, "  Bucket %llu (%llu - %llu):",
+				(i+off) % PER_LEVEL,
+				base, base + per_bucket - 1);
+
+			h = &timers->level[l]->list[(i+off) % PER_LEVEL];
+			dump_bucket_stats(fp, h);
+			base += per_bucket;
+		}
+	}
+
+past_levels:
+	if (!list_empty(&timers->far)) {
+		fprintf(fp, "Far timers:");
+		dump_bucket_stats(fp, &timers->far);
+	}
 }
 #endif