From c3ad24da01c062eaa4eb096f85f9be2312316821 Mon Sep 17 00:00:00 2001 From: Maxim Dounin Date: Fri, 20 Jan 2017 14:03:20 +0300 Subject: Improved connection draining with small number of connections. Closing up to 32 connections might be too aggressive if worker_connections is set to a comparable number (and/or there are only a small number of reusable connections). If an occasional connection shorage happens in such a configuration, it leads to closing all reusable connections instead of gradually reducing keepalive timeout to a smaller value. To improve granularity in such configurations we now close no more than 1/8 of all reusable connections at once. Suggested by Joel Cunningham. --- src/core/ngx_connection.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'src/core/ngx_connection.c') diff --git a/src/core/ngx_connection.c b/src/core/ngx_connection.c index c43163f18..2af287614 100644 --- a/src/core/ngx_connection.c +++ b/src/core/ngx_connection.c @@ -1204,6 +1204,7 @@ ngx_reusable_connection(ngx_connection_t *c, ngx_uint_t reusable) if (c->reusable) { ngx_queue_remove(&c->queue); + ngx_cycle->reusable_connections_n--; #if (NGX_STAT_STUB) (void) ngx_atomic_fetch_add(ngx_stat_waiting, -1); @@ -1217,6 +1218,7 @@ ngx_reusable_connection(ngx_connection_t *c, ngx_uint_t reusable) ngx_queue_insert_head( (ngx_queue_t *) &ngx_cycle->reusable_connections_queue, &c->queue); + ngx_cycle->reusable_connections_n++; #if (NGX_STAT_STUB) (void) ngx_atomic_fetch_add(ngx_stat_waiting, 1); @@ -1228,11 +1230,13 @@ ngx_reusable_connection(ngx_connection_t *c, ngx_uint_t reusable) static void ngx_drain_connections(ngx_cycle_t *cycle) { - ngx_int_t i; + ngx_uint_t i, n; ngx_queue_t *q; ngx_connection_t *c; - for (i = 0; i < 32; i++) { + n = ngx_max(ngx_min(32, cycle->reusable_connections_n / 8), 1); + + for (i = 0; i < n; i++) { if (ngx_queue_empty(&cycle->reusable_connections_queue)) { break; } -- cgit