From: Willy Tarreau <w@1wt.eu>
Date: Fri, 11 Jul 2025 06:40:17 +0000 (+0200)
Subject: MEDIUM: proxy: no longer allocate the default-server entry by default
X-Git-Tag: v3.3-dev4~84
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=49a619acae49321681b8e1b2b42d480a6a75ef46;p=thirdparty%2Fhaproxy.git

MEDIUM: proxy: no longer allocate the default-server entry by default

The default-server entry used to always be allocated. Now we'll postpone
its allocation for the first time we need it, i.e. during a "default-server"
directive, or when inheriting a defaults section which has one. The memory
savings are significant, on a large configuration with 100k backends and
no default-server directive, the memory usage dropped from 800MB RSS to
420MB (380 MB saved). It should be possible to also address configs using
default-server by releasing this entry when leaving the proxy section,
which is not done yet.
---

diff --git a/src/proxy.c b/src/proxy.c
index 0eea5de2d..c6f17eb19 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -1685,16 +1685,6 @@ int setup_new_proxy(struct proxy *px, const char *name, unsigned int cap, char *
 {
 	init_new_proxy(px);
 
-	/* allocate the default server section */
-	px->defsrv = calloc(1, sizeof(*px->defsrv));
-	if (!px->defsrv) {
-		memprintf(errmsg, "out of memory");
-		goto fail;
-	}
-
-	px->defsrv->id = "default-server";
-	srv_settings_init(px->defsrv);
-
 	if (name) {
 		px->id = strdup(name);
 		if (!px->id) {
@@ -1807,8 +1797,24 @@ static int proxy_defproxy_cpy(struct proxy *curproxy, const struct proxy *defpro
 	struct eb32_node *node;
 
 	/* set default values from the specified default proxy */
-	if (curproxy->defsrv)
+
+	if (defproxy->defsrv) {
+		if (!curproxy->defsrv) {
+			/* there's a default-server in the defaults proxy but
+			 * none allocated yet in the current proxy so we have
+			 * to allocate and pre-initialize it right now.
+			 */
+			curproxy->defsrv = calloc(1, sizeof(*curproxy->defsrv));
+			if (!curproxy->defsrv) {
+				memprintf(errmsg, "proxy '%s': out of memory allocating default-server", curproxy->id);
+				return 1;
+			}
+
+			curproxy->defsrv->id = "default-server";
+			srv_settings_init(curproxy->defsrv);
+		}
 		srv_settings_cpy(curproxy->defsrv, defproxy->defsrv, 0);
+	}
 
 	curproxy->flags = (defproxy->flags & PR_FL_DISABLED); /* Only inherit from disabled flag */
 	curproxy->options = defproxy->options;