[prev in list] [next in list] [prev in thread] [next in thread] 

List:       haproxy
Subject:    [PATCH] [CRITICAL] fix server state tracking: it was O(n!)
From:       Krzysztof Piotr Oledzki <ole () ans ! pl>
Date:       2009-01-30 0:38:38
Message-ID: 49824c0e.J40UffmNAx43Dhvo%ole () ans ! pl
[Download RAW message or body]

From 9bb0f6085163991924d99b7c7ff8000ade0ce0b6 Mon Sep 17 00:00:00 2001
From: Krzysztof Piotr Oledzki <ole@ans.pl>
Date: Fri, 30 Jan 2009 00:52:49 +0100
Subject: [CRITICAL] fix server state tracking: it was O(n!) instead of O(n)

Using the wrong operator (&& instead of &) causes DOWN->UP
transition to take longer than it should and to produce a lot of
redundant logs. With typical "track" usage (1-6 tracking servers) it
shouldn't make a big difference but for heavily tracked servers
this bug leads to hang with 100% CPU usage and extremely big
log spam.

---
 src/checks.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/checks.c b/src/checks.c
index d6ce335..ec21e42 100644
--- a/src/checks.c
+++ b/src/checks.c
@@ -161,7 +161,7 @@ static void set_server_down(struct server *s)
 
 		s->down_trans++;
 
-		if (s->state && SRV_CHECKED)
+		if (s->state & SRV_CHECKED)
 			for(srv = s->tracknext; srv; srv = srv->tracknext)
 				set_server_down(srv);
 	}
@@ -226,7 +226,7 @@ static void set_server_up(struct server *s) {
 		Warning("%s", trash);
 		send_log(s->proxy, LOG_NOTICE, "%s", trash);
 
-		if (s->state && SRV_CHECKED)
+		if (s->state & SRV_CHECKED)
 			for(srv = s->tracknext; srv; srv = srv->tracknext)
 				set_server_up(srv);
 	}
@@ -277,7 +277,7 @@ static void set_server_disabled(struct server *s) {
 	if (!s->proxy->srv_bck && !s->proxy->srv_act)
 		set_backend_down(s->proxy);
 
-	if (s->state && SRV_CHECKED)
+	if (s->state & SRV_CHECKED)
 		for(srv = s->tracknext; srv; srv = srv->tracknext)
 			set_server_disabled(srv);
 }
@@ -317,7 +317,7 @@ static void set_server_enabled(struct server *s) {
 	Warning("%s", trash);
 	send_log(s->proxy, LOG_NOTICE, "%s", trash);
 
-	if (s->state && SRV_CHECKED)
+	if (s->state & SRV_CHECKED)
 		for(srv = s->tracknext; srv; srv = srv->tracknext)
 			set_server_enabled(srv);
 }
-- 
1.6.0.4


[prev in list] [next in list] [prev in thread] [next in thread]