reuse keepalive connections if there are no free worker connections
patch by Maxim Dounin
diff --git a/src/core/ngx_connection.c b/src/core/ngx_connection.c
index c495edd..9f19fcc 100644
--- a/src/core/ngx_connection.c
+++ b/src/core/ngx_connection.c
@@ -12,6 +12,9 @@
ngx_os_io_t ngx_io;
+static void ngx_drain_connections(void);
+
+
ngx_listening_t *
ngx_create_listening(ngx_conf_t *cf, void *sockaddr, socklen_t socklen)
{
@@ -719,6 +722,11 @@
c = ngx_cycle->free_connections;
if (c == NULL) {
+ ngx_drain_connections();
+ c = ngx_cycle->free_connections;
+ }
+
+ if (c == NULL) {
ngx_log_error(NGX_LOG_ALERT, log, 0,
"%ui worker_connections are not enough",
ngx_cycle->connection_n);
@@ -861,6 +869,8 @@
#endif
+ ngx_reusable_connection(c, 0);
+
log_error = c->log_error;
ngx_free_connection(c);
@@ -900,6 +910,51 @@
}
+void
+ngx_reusable_connection(ngx_connection_t *c, ngx_uint_t reusable)
+{
+ ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
+ "reusable connection: %ui", reusable);
+
+ if (c->reusable) {
+ ngx_queue_remove(&c->queue);
+ }
+
+ c->reusable = reusable;
+
+ if (reusable) {
+ /* need cast as ngx_cycle is volatile */
+
+ ngx_queue_insert_head(
+ (ngx_queue_t *) &ngx_cycle->reusable_connections_queue, &c->queue);
+ }
+}
+
+
+static void
+ngx_drain_connections(void)
+{
+ ngx_int_t i;
+ ngx_queue_t *q;
+ ngx_connection_t *c;
+
+ for (i = 0; i < 32; i++) {
+ if (ngx_queue_empty(&ngx_cycle->reusable_connections_queue)) {
+ break;
+ }
+
+ q = ngx_queue_last(&ngx_cycle->reusable_connections_queue);
+ c = ngx_queue_data(q, ngx_connection_t, queue);
+
+ ngx_log_debug0(NGX_LOG_DEBUG_CORE, c->log, 0,
+ "reusing connection");
+
+ c->close = 1;
+ c->read->handler(c->read);
+ }
+}
+
+
ngx_int_t
ngx_connection_local_sockaddr(ngx_connection_t *c, ngx_str_t *s,
ngx_uint_t port)
diff --git a/src/core/ngx_connection.h b/src/core/ngx_connection.h
index 3837fd2..f9bf504 100644
--- a/src/core/ngx_connection.h
+++ b/src/core/ngx_connection.h
@@ -135,6 +135,8 @@
ngx_buf_t *buffer;
+ ngx_queue_t queue;
+
ngx_atomic_uint_t number;
ngx_uint_t requests;
@@ -150,6 +152,7 @@
unsigned destroyed:1;
unsigned idle:1;
+ unsigned reusable:1;
unsigned close:1;
unsigned sendfile:1;
@@ -186,5 +189,6 @@
ngx_connection_t *ngx_get_connection(ngx_socket_t s, ngx_log_t *log);
void ngx_free_connection(ngx_connection_t *c);
+void ngx_reusable_connection(ngx_connection_t *c, ngx_uint_t reusable);
#endif /* _NGX_CONNECTION_H_INCLUDED_ */
diff --git a/src/core/ngx_cycle.c b/src/core/ngx_cycle.c
index 357c6b2..7986707 100644
--- a/src/core/ngx_cycle.c
+++ b/src/core/ngx_cycle.c
@@ -181,6 +181,9 @@
cycle->listening.pool = pool;
+ ngx_queue_init(&cycle->reusable_connections_queue);
+
+
cycle->conf_ctx = ngx_pcalloc(pool, ngx_max_module * sizeof(void *));
if (cycle->conf_ctx == NULL) {
ngx_destroy_pool(pool);
diff --git a/src/core/ngx_cycle.h b/src/core/ngx_cycle.h
index d96c85f..e14983d 100644
--- a/src/core/ngx_cycle.h
+++ b/src/core/ngx_cycle.h
@@ -44,6 +44,8 @@
ngx_connection_t *free_connections;
ngx_uint_t free_connection_n;
+ ngx_queue_t reusable_connections_queue;
+
ngx_array_t listening;
ngx_array_t pathes;
ngx_list_t open_files;
diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index bd51e06..2cef4fa 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -2594,6 +2594,7 @@
#endif
c->idle = 1;
+ ngx_reusable_connection(c, 1);
if (rev->ready) {
ngx_post_event(rev, &ngx_posted_events);
@@ -2703,6 +2704,7 @@
c->log->action = "reading client request line";
c->idle = 0;
+ ngx_reusable_connection(c, 0);
ngx_http_init_request(rev);
}
