changeset 7767:6d98f29867e8

Additional connections reuse. If ngx_drain_connections() fails to immediately reuse any connections and there are no free connections, it now additionally tries to reuse a connection again. This helps to provide at least one free connection in case of HTTP/2 with lingering close, where merely trying to reuse a connection once does not free it, but makes it reusable again, waiting for lingering close.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 11 Feb 2021 21:52:11 +0300
parents 3e83336cda5b
children fc536dcdbbf7
files src/core/ngx_connection.c
diffstat 1 files changed, 16 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- a/src/core/ngx_connection.c
+++ b/src/core/ngx_connection.c
@@ -1310,6 +1310,7 @@ ngx_drain_connections(ngx_cycle_t *cycle
                       cycle->connection_n);
     }
 
+    c = NULL;
     n = ngx_max(ngx_min(32, cycle->reusable_connections_n / 8), 1);
 
     for (i = 0; i < n; i++) {
@@ -1326,6 +1327,21 @@ ngx_drain_connections(ngx_cycle_t *cycle
         c->close = 1;
         c->read->handler(c->read);
     }
+
+    if (cycle->free_connection_n == 0 && c && c->reusable) {
+
+        /*
+         * if no connections were freed, try to reuse the last
+         * connection again: this should free it as long as
+         * previous reuse moved it to lingering close
+         */
+
+        ngx_log_debug0(NGX_LOG_DEBUG_CORE, c->log, 0,
+                       "reusing connection again");
+
+        c->close = 1;
+        c->read->handler(c->read);
+    }
 }