Upstream: track the number of active connections to upstreams.

This also simplifies the implementation of the least_conn module.

1 files changed, 18 insertions, 120 deletions

diff --git a/src/http/modules/ngx_http_upstream_least_conn_module.c b/src/http/modules/ngx_http_upstream_least_conn_module.c
index 623bc9b10..f2a4ec9eb 100644
--- a/src/http/modules/ngx_http_upstream_least_conn_module.c
+++ b/src/http/modules/ngx_http_upstream_least_conn_module.c
@@ -10,29 +10,10 @@
 #include <ngx_http.h>
 
 
-typedef struct {
-    ngx_uint_t                        *conns;
-} ngx_http_upstream_least_conn_conf_t;
-
-
-typedef struct {
-    /* the round robin data must be first */
-    ngx_http_upstream_rr_peer_data_t   rrp;
-
-    ngx_uint_t                        *conns;
-
-    ngx_event_get_peer_pt              get_rr_peer;
-    ngx_event_free_peer_pt             free_rr_peer;
-} ngx_http_upstream_lc_peer_data_t;
-
-
 static ngx_int_t ngx_http_upstream_init_least_conn_peer(ngx_http_request_t *r,
     ngx_http_upstream_srv_conf_t *us);
 static ngx_int_t ngx_http_upstream_get_least_conn_peer(
     ngx_peer_connection_t *pc, void *data);
-static void ngx_http_upstream_free_least_conn_peer(ngx_peer_connection_t *pc,
-    void *data, ngx_uint_t state);
-static void *ngx_http_upstream_least_conn_create_conf(ngx_conf_t *cf);
 static char *ngx_http_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd,
     void *conf);
 
@@ -57,7 +38,7 @@ static ngx_http_module_t  ngx_http_upstream_least_conn_module_ctx = {
     NULL,                                  /* create main configuration */
     NULL,                                  /* init main configuration */
 
-    ngx_http_upstream_least_conn_create_conf, /* create server configuration */
+    NULL,                                  /* create server configuration */
     NULL,                                  /* merge server configuration */
 
     NULL,                                  /* create location configuration */
@@ -85,10 +66,6 @@ static ngx_int_t
 ngx_http_upstream_init_least_conn(ngx_conf_t *cf,
     ngx_http_upstream_srv_conf_t *us)
 {
-    ngx_uint_t                            n;
-    ngx_http_upstream_rr_peers_t         *peers;
-    ngx_http_upstream_least_conn_conf_t  *lcf;
-
     ngx_log_debug0(NGX_LOG_DEBUG_HTTP, cf->log, 0,
                    "init least conn");
 
@@ -96,22 +73,6 @@ ngx_http_upstream_init_least_conn(ngx_conf_t *cf,
         return NGX_ERROR;
     }
 
-    peers = us->peer.data;
-
-    n = peers->number;
-
-    if (peers->next) {
-        n += peers->next->number;
-    }
-
-    lcf = ngx_http_conf_upstream_srv_conf(us,
-                                          ngx_http_upstream_least_conn_module);
-
-    lcf->conns = ngx_pcalloc(cf->pool, sizeof(ngx_uint_t) * n);
-    if (lcf->conns == NULL) {
-        return NGX_ERROR;
-    }
-
     us->peer.init = ngx_http_upstream_init_least_conn_peer;
 
     return NGX_OK;
@@ -122,33 +83,14 @@ static ngx_int_t
 ngx_http_upstream_init_least_conn_peer(ngx_http_request_t *r,
     ngx_http_upstream_srv_conf_t *us)
 {
-    ngx_http_upstream_lc_peer_data_t     *lcp;
-    ngx_http_upstream_least_conn_conf_t  *lcf;
-
     ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                    "init least conn peer");
 
-    lcf = ngx_http_conf_upstream_srv_conf(us,
-                                          ngx_http_upstream_least_conn_module);
-
-    lcp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_lc_peer_data_t));
-    if (lcp == NULL) {
-        return NGX_ERROR;
-    }
-
-    lcp->conns = lcf->conns;
-
-    r->upstream->peer.data = &lcp->rrp;
-
     if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) {
         return NGX_ERROR;
     }
 
     r->upstream->peer.get = ngx_http_upstream_get_least_conn_peer;
-    r->upstream->peer.free = ngx_http_upstream_free_least_conn_peer;
-
-    lcp->get_rr_peer = ngx_http_upstream_get_round_robin_peer;
-    lcp->free_rr_peer = ngx_http_upstream_free_round_robin_peer;
 
     return NGX_OK;
 }
@@ -157,7 +99,7 @@ ngx_http_upstream_init_least_conn_peer(ngx_http_request_t *r,
 static ngx_int_t
 ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
 {
-    ngx_http_upstream_lc_peer_data_t  *lcp = data;
+    ngx_http_upstream_rr_peer_data_t  *rrp = data;
 
     time_t                         now;
     uintptr_t                      m;
@@ -169,8 +111,8 @@ ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                    "get least conn peer, try: %ui", pc->tries);
 
-    if (lcp->rrp.peers->single) {
-        return lcp->get_rr_peer(pc, &lcp->rrp);
+    if (rrp->peers->single) {
+        return ngx_http_upstream_get_round_robin_peer(pc, rrp);
     }
 
     pc->cached = 0;
@@ -178,7 +120,7 @@ ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
 
     now = ngx_time();
 
-    peers = lcp->rrp.peers;
+    peers = rrp->peers;
 
     best = NULL;
     total = 0;
@@ -193,7 +135,7 @@ ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
         n = i / (8 * sizeof(uintptr_t));
         m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
 
-        if (lcp->rrp.tried[n] & m) {
+        if (rrp->tried[n] & m) {
             continue;
         }
 
@@ -217,15 +159,13 @@ ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
          */
 
         if (best == NULL
-            || lcp->conns[i] * best->weight < lcp->conns[p] * peer->weight)
+            || peer->conns * best->weight < best->conns * peer->weight)
         {
             best = peer;
             many = 0;
             p = i;
 
-        } else if (lcp->conns[i] * best->weight
-                   == lcp->conns[p] * peer->weight)
-        {
+        } else if (peer->conns * best->weight == best->conns * peer->weight) {
             many = 1;
         }
     }
@@ -246,7 +186,7 @@ ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
             n = i / (8 * sizeof(uintptr_t));
             m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
 
-            if (lcp->rrp.tried[n] & m) {
+            if (rrp->tried[n] & m) {
                 continue;
             }
 
@@ -256,7 +196,7 @@ ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
                 continue;
             }
 
-            if (lcp->conns[i] * best->weight != lcp->conns[p] * peer->weight) {
+            if (peer->conns * best->weight != best->conns * peer->weight) {
                 continue;
             }
 
@@ -291,13 +231,14 @@ ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
     pc->socklen = best->socklen;
     pc->name = &best->name;
 
-    lcp->rrp.current = p;
+    best->conns++;
+
+    rrp->current = p;
 
     n = p / (8 * sizeof(uintptr_t));
     m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));
 
-    lcp->rrp.tried[n] |= m;
-    lcp->conns[p]++;
+    rrp->tried[n] |= m;
 
     return NGX_OK;
 
@@ -307,18 +248,16 @@ failed:
         ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                        "get least conn peer, backup servers");
 
-        lcp->conns += peers->number;
-
-        lcp->rrp.peers = peers->next;
+        rrp->peers = peers->next;
 
-        n = (lcp->rrp.peers->number + (8 * sizeof(uintptr_t) - 1))
+        n = (rrp->peers->number + (8 * sizeof(uintptr_t) - 1))
                 / (8 * sizeof(uintptr_t));
 
         for (i = 0; i < n; i++) {
-             lcp->rrp.tried[i] = 0;
+             rrp->tried[i] = 0;
         }
 
-        rc = ngx_http_upstream_get_least_conn_peer(pc, lcp);
+        rc = ngx_http_upstream_get_least_conn_peer(pc, rrp);
 
         if (rc != NGX_BUSY) {
             return rc;
@@ -337,47 +276,6 @@ failed:
 }
 
 
-static void
-ngx_http_upstream_free_least_conn_peer(ngx_peer_connection_t *pc,
-    void *data, ngx_uint_t state)
-{
-    ngx_http_upstream_lc_peer_data_t  *lcp = data;
-
-    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
-                   "free least conn peer %ui %ui", pc->tries, state);
-
-    if (lcp->rrp.peers->single) {
-        lcp->free_rr_peer(pc, &lcp->rrp, state);
-        return;
-    }
-
-    lcp->conns[lcp->rrp.current]--;
-
-    lcp->free_rr_peer(pc, &lcp->rrp, state);
-}
-
-
-static void *
-ngx_http_upstream_least_conn_create_conf(ngx_conf_t *cf)
-{
-    ngx_http_upstream_least_conn_conf_t  *conf;
-
-    conf = ngx_pcalloc(cf->pool,
-                       sizeof(ngx_http_upstream_least_conn_conf_t));
-    if (conf == NULL) {
-        return NULL;
-    }
-
-    /*
-     * set by ngx_pcalloc():
-     *
-     *     conf->conns = NULL;
-     */
-
-    return conf;
-}
-
-
 static char *
 ngx_http_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 {