From 9a3ec202322b174acb5973d8f55cf570f1177149 Mon Sep 17 00:00:00 2001 From: Maxim Dounin Date: Thu, 11 Feb 2021 21:52:11 +0300 Subject: [PATCH] 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. --- src/core/ngx_connection.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/src/core/ngx_connection.c b/src/core/ngx_connection.c index c082d0dac..8339e2bb7 100644 --- 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); + } }