From: Aurelien DARRAGON <adarragon@haproxy.com>
Date: Wed, 30 Apr 2025 14:41:16 +0000 (+0200)
Subject: MINOR: hlua_fcn: enforce yield after *_get_stats() methods
X-Git-Tag: v3.2-dev13~12
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7f418ac7d26de77aafd1bd13709d6257038c24e1;p=thirdparty%2Fhaproxy.git

MINOR: hlua_fcn: enforce yield after *_get_stats() methods

{listener,proxy,server}_get_stats() methods are know to be expensive,
expecially if used under an iteration. Indeed, while automatic yield
is performed every X lua instructions (defaults to 10k), computing an
object's stats 10K times in a single cpu loop is not desirable and
could create contention.

In this patch we leverage hlua_yield_asap() at the end of *_get_stats()
methods in order to force the automatic yield to occur ASAP after the
method returns. Hopefully this should help in similar scenarios as the
one described in GH #2903
---

diff --git a/src/hlua_fcn.c b/src/hlua_fcn.c
index 0ad0b7ed0..a340d0d88 100644
--- a/src/hlua_fcn.c
+++ b/src/hlua_fcn.c
@@ -1154,6 +1154,7 @@ int hlua_listener_get_stats(lua_State *L)
 		hlua_fcn_pushfield(L, &stats[i]);
 		lua_settable(L, -3);
 	}
+	hlua_yield_asap(L);
 	return 1;
 
 }
@@ -1200,6 +1201,7 @@ int hlua_server_get_stats(lua_State *L)
 		hlua_fcn_pushfield(L, &stats[i]);
 		lua_settable(L, -3);
 	}
+	hlua_yield_asap(L);
 	return 1;
 
 }
@@ -2053,6 +2055,7 @@ int hlua_proxy_get_stats(lua_State *L)
 		hlua_fcn_pushfield(L, &stats[i]);
 		lua_settable(L, -3);
 	}
+	hlua_yield_asap(L);
 	return 1;
 }