[MEDIUM] now the round-robin load balancer uses two passes to avoid saturated servers...

diff --git a/haproxy.c b/haproxy.c
index d4953ac4f3480fa61f2ad7a345bc61884e3c6ae5..1eb714e70b352248f81dc3508bad99c4c85be8c5 100644 (file)
--- a/haproxy.c
+++ b/haproxy.c
@@ -1972,10 +1972,40 @@ static void recalc_server_map(struct proxy *px) {
     px->srv_map_sz = tot;
 }
 
+/*
+ * This function tries to find a running server with free connection slots for
+ * the proxy <px> following the round-robin method.
+ * If any server is found, it will be returned and px->srv_rr_idx will be updated
+ * to point to the next server. If no valid server is found, NULL is returned.
+ */
+static inline struct server *get_server_rr_with_conns(struct proxy *px) {
+    int newidx;
+    struct server *srv;
+
+    if (px->srv_map_sz == 0)
+       return NULL;
+
+    if (px->srv_rr_idx < 0 || px->srv_rr_idx >= px->srv_map_sz)
+       px->srv_rr_idx = 0;
+    newidx = px->srv_rr_idx;
+
+    do {
+       srv = px->srv_map[newidx++];
+       if (!srv->maxconn || srv->cur_sess < srv->maxconn) {
+           px->srv_rr_idx = newidx;
+           return srv;
+       }
+       if (newidx == px->srv_map_sz)
+           newidx = 0;
+    } while (newidx != px->srv_rr_idx);
+
+    return NULL;
+}
+
+
 /*
  * This function tries to find a running server for the proxy <px> following
- * the round-robin method. Depending on the number of active/backup servers,
- * it will either look for active servers, or for backup servers.
+ * the round-robin method.
  * If any server is found, it will be returned and px->srv_rr_idx will be updated
  * to point to the next server. If no valid server is found, NULL is returned.
  */
@@ -2044,7 +2074,9 @@ int connect_server(struct session *s) {
        if (s->proxy->options & PR_O_BALANCE_RR) {
            struct server *srv;
 
-           srv = get_server_rr(s->proxy);
+           srv = get_server_rr_with_conns(s->proxy);
+           if (!srv)
+               srv = get_server_rr(s->proxy);
            s->srv_addr = srv->addr;
            s->srv = srv;
        }