From: Willy Tarreau <w@1wt.eu>
Date: Mon, 14 Jun 2010 12:53:07 +0000 (+0200)
Subject: [MEDIUM] stick-tables: add a reference counter to each entry
X-Git-Tag: v1.5-dev8~556
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e7f3d7ab9f95584f5bf5154b18fd028ccccd93b9;p=thirdparty%2Fhaproxy.git

[MEDIUM] stick-tables: add a reference counter to each entry

We'll soon have to maintain links from sessions to entries, so let's
add a refcount in entries to avoid purging them if it's not null.
---

diff --git a/include/types/stick_table.h b/include/types/stick_table.h
index 843f5d73ed..25bfbd8c15 100644
--- a/include/types/stick_table.h
+++ b/include/types/stick_table.h
@@ -75,6 +75,7 @@ struct stktable_type {
  */
 struct stksess {
 	unsigned int expire;      /* session expiration date */
+	unsigned int ref_cnt;     /* reference count, can only purge when zero */
 	struct eb32_node exp;     /* ebtree node used to hold the session in expiration tree */
 	struct ebmb_node key;     /* ebtree node used to hold the session in table */
 	/* WARNING! do not put anything after <keys>, it's used by the key */
diff --git a/src/stick_table.c b/src/stick_table.c
index 5723dffd28..09cb96beb1 100644
--- a/src/stick_table.c
+++ b/src/stick_table.c
@@ -64,6 +64,7 @@ void stksess_setkey(struct stktable *t, struct stksess *ts, struct stktable_key
 static struct stksess *stksess_init(struct stktable *t, struct stksess * ts)
 {
 	memset((void *)ts - t->data_size, 0, t->data_size);
+	ts->ref_cnt = 0;
 	ts->key.node.leaf_p = NULL;
 	ts->exp.node.leaf_p = NULL;
 	return ts;
@@ -78,6 +79,7 @@ static int stktable_trash_oldest(struct stktable *t, int to_batch)
 	struct stksess *ts;
 	struct eb32_node *eb;
 	int batched = 0;
+	int looped = 0;
 
 	eb = eb32_lookup_ge(&t->exps, now_ms - TIMER_LOOK_BACK);
 
@@ -86,8 +88,12 @@ static int stktable_trash_oldest(struct stktable *t, int to_batch)
 		if (unlikely(!eb)) {
 			/* we might have reached the end of the tree, typically because
 			 * <now_ms> is in the first half and we're first scanning the last
-			 * half. Let's loop back to the beginning of the tree now.
+			 * half. Let's loop back to the beginning of the tree now if we
+			 * have not yet visited it.
 			 */
+			if (looped)
+				break;
+			looped = 1;
 			eb = eb32_first(&t->exps);
 			if (likely(!eb))
 				break;
@@ -97,6 +103,10 @@ static int stktable_trash_oldest(struct stktable *t, int to_batch)
 		ts = eb32_entry(eb, struct stksess, exp);
 		eb = eb32_next(eb);
 
+		/* don't delete an entry which is currently referenced */
+		if (ts->ref_cnt)
+			continue;
+
 		eb32_delete(&ts->exp);
 
 		if (ts->expire != ts->exp.key) {
@@ -223,6 +233,7 @@ static int stktable_trash_expired(struct stktable *t)
 {
 	struct stksess *ts;
 	struct eb32_node *eb;
+	int looped = 0;
 
 	eb = eb32_lookup_ge(&t->exps, now_ms - TIMER_LOOK_BACK);
 
@@ -230,8 +241,12 @@ static int stktable_trash_expired(struct stktable *t)
 		if (unlikely(!eb)) {
 			/* we might have reached the end of the tree, typically because
 			 * <now_ms> is in the first half and we're first scanning the last
-			 * half. Let's loop back to the beginning of the tree now.
+			 * half. Let's loop back to the beginning of the tree now if we
+			 * have not yet visited it.
 			 */
+			if (looped)
+				break;
+			looped = 1;
 			eb = eb32_first(&t->exps);
 			if (likely(!eb))
 				break;
@@ -247,6 +262,10 @@ static int stktable_trash_expired(struct stktable *t)
 		ts = eb32_entry(eb, struct stksess, exp);
 		eb = eb32_next(eb);
 
+		/* don't delete an entry which is currently referenced */
+		if (ts->ref_cnt)
+			continue;
+
 		eb32_delete(&ts->exp);
 
 		if (!tick_is_expired(ts->expire, now_ms)) {