From: Willy Tarreau <w@1wt.eu>
Date: Tue, 13 May 2014 17:27:31 +0000 (+0200)
Subject: MINOR: server: use functions to detect state changes and to update them
X-Git-Tag: v1.5-dev26~47
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c5150dafd82f70882fc379d145e8cf25625d815d;p=thirdparty%2Fhaproxy.git

MINOR: server: use functions to detect state changes and to update them

Detecting that a server's status has changed is a bit messy, as well
as it is to commit the status changes. We'll have to add new conditions
soon and we'd better avoid to multiply the number of touched locations
with the high risk of forgetting them.

This commit introduces :
  - srv_lb_status_changed() to report if the status changed from the
    previously committed one ;
  - svr_lb_commit_status() to commit the current status

The function is now used by all load-balancing algorithms.
---

diff --git a/include/proto/backend.h b/include/proto/backend.h
index 68ba3d6175..7af92e263e 100644
--- a/include/proto/backend.h
+++ b/include/proto/backend.h
@@ -66,6 +66,24 @@ static inline int srv_is_usable(int state, int weight)
 	return 1;
 }
 
+/* This function commits the current server state and weight onto the previous
+ * ones in order to detect future changes.
+ */
+static inline void srv_lb_commit_status(struct server *srv)
+{
+	srv->prev_state = srv->state;
+	srv->prev_eweight = srv->eweight;
+}
+
+/* This function returns true when a server has experienced a change since last
+ * commit on its state or weight, otherwise zero.
+ */
+static inline int srv_lb_status_changed(const struct server *srv)
+{
+	return (srv->state != srv->prev_state ||
+		srv->eweight != srv->prev_eweight);
+}
+
 #endif /* _PROTO_BACKEND_H */
 
 /*
diff --git a/src/lb_chash.c b/src/lb_chash.c
index 41e06c7ffa..fb10c72bed 100644
--- a/src/lb_chash.c
+++ b/src/lb_chash.c
@@ -98,8 +98,7 @@ static void chash_set_server_status_down(struct server *srv)
 {
 	struct proxy *p = srv->proxy;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	if (srv_is_usable(srv->state, srv->eweight))
@@ -136,8 +135,7 @@ out_update_backend:
 	/* check/update tot_used, tot_weight */
 	update_backend_weight(p);
  out_update_state:
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function updates the server trees according to server <srv>'s new
@@ -151,8 +149,7 @@ static void chash_set_server_status_up(struct server *srv)
 {
 	struct proxy *p = srv->proxy;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	if (!srv_is_usable(srv->state, srv->eweight))
@@ -194,8 +191,7 @@ static void chash_set_server_status_up(struct server *srv)
 	/* check/update tot_used, tot_weight */
 	update_backend_weight(p);
  out_update_state:
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function must be called after an update to server <srv>'s effective
@@ -206,8 +202,7 @@ static void chash_update_server_weight(struct server *srv)
 	int old_state, new_state;
 	struct proxy *p = srv->proxy;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	/* If changing the server's weight changes its state, we simply apply
@@ -222,8 +217,7 @@ static void chash_update_server_weight(struct server *srv)
 	new_state = srv_is_usable(srv->state, srv->eweight);
 
 	if (!old_state && !new_state) {
-		srv->prev_state = srv->state;
-		srv->prev_eweight = srv->eweight;
+		srv_lb_commit_status(srv);
 		return;
 	}
 	else if (!old_state && new_state) {
@@ -244,8 +238,7 @@ static void chash_update_server_weight(struct server *srv)
 		p->lbprm.tot_wact += srv->eweight - srv->prev_eweight;
 
 	update_backend_weight(p);
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /*
@@ -383,8 +376,7 @@ void chash_init_server_tree(struct proxy *p)
 	p->lbprm.wdiv = BE_WEIGHT_SCALE;
 	for (srv = p->srv; srv; srv = srv->next) {
 		srv->eweight = (srv->uweight * p->lbprm.wdiv + p->lbprm.wmult - 1) / p->lbprm.wmult;
-		srv->prev_eweight = srv->eweight;
-		srv->prev_state = srv->state;
+		srv_lb_commit_status(srv);
 	}
 
 	recount_servers(p);
diff --git a/src/lb_fas.c b/src/lb_fas.c
index b4cfc7949e..b8b0569a8f 100644
--- a/src/lb_fas.c
+++ b/src/lb_fas.c
@@ -77,8 +77,7 @@ static void fas_set_server_status_down(struct server *srv)
 {
 	struct proxy *p = srv->proxy;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	if (srv_is_usable(srv->state, srv->eweight))
@@ -116,8 +115,7 @@ out_update_backend:
 	/* check/update tot_used, tot_weight */
 	update_backend_weight(p);
  out_update_state:
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function updates the server trees according to server <srv>'s new
@@ -131,8 +129,7 @@ static void fas_set_server_status_up(struct server *srv)
 {
 	struct proxy *p = srv->proxy;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	if (!srv_is_usable(srv->state, srv->eweight))
@@ -176,8 +173,7 @@ static void fas_set_server_status_up(struct server *srv)
 	/* check/update tot_used, tot_weight */
 	update_backend_weight(p);
  out_update_state:
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function must be called after an update to server <srv>'s effective
@@ -188,8 +184,7 @@ static void fas_update_server_weight(struct server *srv)
 	int old_state, new_state;
 	struct proxy *p = srv->proxy;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	/* If changing the server's weight changes its state, we simply apply
@@ -204,8 +199,7 @@ static void fas_update_server_weight(struct server *srv)
 	new_state = srv_is_usable(srv->state, srv->eweight);
 
 	if (!old_state && !new_state) {
-		srv->prev_state = srv->state;
-		srv->prev_eweight = srv->eweight;
+		srv_lb_commit_status(srv);
 		return;
 	}
 	else if (!old_state && new_state) {
@@ -231,8 +225,7 @@ static void fas_update_server_weight(struct server *srv)
 	fas_queue_srv(srv);
 
 	update_backend_weight(p);
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function is responsible for building the trees in case of fast
@@ -253,8 +246,7 @@ void fas_init_server_tree(struct proxy *p)
 	p->lbprm.wdiv = BE_WEIGHT_SCALE;
 	for (srv = p->srv; srv; srv = srv->next) {
 		srv->eweight = (srv->uweight * p->lbprm.wdiv + p->lbprm.wmult - 1) / p->lbprm.wmult;
-		srv->prev_eweight = srv->eweight;
-		srv->prev_state = srv->state;
+		srv_lb_commit_status(srv);
 	}
 
 	recount_servers(p);
diff --git a/src/lb_fwlc.c b/src/lb_fwlc.c
index de1896ed67..ca68a33655 100644
--- a/src/lb_fwlc.c
+++ b/src/lb_fwlc.c
@@ -69,8 +69,7 @@ static void fwlc_set_server_status_down(struct server *srv)
 {
 	struct proxy *p = srv->proxy;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	if (srv_is_usable(srv->state, srv->eweight))
@@ -108,8 +107,7 @@ out_update_backend:
 	/* check/update tot_used, tot_weight */
 	update_backend_weight(p);
  out_update_state:
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function updates the server trees according to server <srv>'s new
@@ -123,8 +121,7 @@ static void fwlc_set_server_status_up(struct server *srv)
 {
 	struct proxy *p = srv->proxy;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	if (!srv_is_usable(srv->state, srv->eweight))
@@ -168,8 +165,7 @@ static void fwlc_set_server_status_up(struct server *srv)
 	/* check/update tot_used, tot_weight */
 	update_backend_weight(p);
  out_update_state:
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function must be called after an update to server <srv>'s effective
@@ -180,8 +176,7 @@ static void fwlc_update_server_weight(struct server *srv)
 	int old_state, new_state;
 	struct proxy *p = srv->proxy;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	/* If changing the server's weight changes its state, we simply apply
@@ -196,8 +191,7 @@ static void fwlc_update_server_weight(struct server *srv)
 	new_state = srv_is_usable(srv->state, srv->eweight);
 
 	if (!old_state && !new_state) {
-		srv->prev_state = srv->state;
-		srv->prev_eweight = srv->eweight;
+		srv_lb_commit_status(srv);
 		return;
 	}
 	else if (!old_state && new_state) {
@@ -223,8 +217,7 @@ static void fwlc_update_server_weight(struct server *srv)
 	fwlc_queue_srv(srv);
 
 	update_backend_weight(p);
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function is responsible for building the trees in case of fast
@@ -245,8 +238,7 @@ void fwlc_init_server_tree(struct proxy *p)
 	p->lbprm.wdiv = BE_WEIGHT_SCALE;
 	for (srv = p->srv; srv; srv = srv->next) {
 		srv->eweight = (srv->uweight * p->lbprm.wdiv + p->lbprm.wmult - 1) / p->lbprm.wmult;
-		srv->prev_eweight = srv->eweight;
-		srv->prev_state = srv->state;
+		srv_lb_commit_status(srv);
 	}
 
 	recount_servers(p);
diff --git a/src/lb_fwrr.c b/src/lb_fwrr.c
index 7cf0cc749b..b8756b68c2 100644
--- a/src/lb_fwrr.c
+++ b/src/lb_fwrr.c
@@ -39,8 +39,7 @@ static void fwrr_set_server_status_down(struct server *srv)
 	struct proxy *p = srv->proxy;
 	struct fwrr_group *grp;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	if (srv_is_usable(srv->state, srv->eweight))
@@ -81,8 +80,7 @@ out_update_backend:
 	/* check/update tot_used, tot_weight */
 	update_backend_weight(p);
  out_update_state:
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function updates the server trees according to server <srv>'s new
@@ -97,8 +95,7 @@ static void fwrr_set_server_status_up(struct server *srv)
 	struct proxy *p = srv->proxy;
 	struct fwrr_group *grp;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	if (!srv_is_usable(srv->state, srv->eweight))
@@ -145,8 +142,7 @@ out_update_backend:
 	/* check/update tot_used, tot_weight */
 	update_backend_weight(p);
  out_update_state:
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function must be called after an update to server <srv>'s effective
@@ -158,8 +154,7 @@ static void fwrr_update_server_weight(struct server *srv)
 	struct proxy *p = srv->proxy;
 	struct fwrr_group *grp;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	/* If changing the server's weight changes its state, we simply apply
@@ -174,8 +169,7 @@ static void fwrr_update_server_weight(struct server *srv)
 	new_state = srv_is_usable(srv->state, srv->eweight);
 
 	if (!old_state && !new_state) {
-		srv->prev_state = srv->state;
-		srv->prev_eweight = srv->eweight;
+		srv_lb_commit_status(srv);
 		return;
 	}
 	else if (!old_state && new_state) {
@@ -233,8 +227,7 @@ static void fwrr_update_server_weight(struct server *srv)
 	}
 
 	update_backend_weight(p);
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* Remove a server from a tree. It must have previously been dequeued. This
@@ -273,8 +266,7 @@ void fwrr_init_server_groups(struct proxy *p)
 	p->lbprm.wdiv = BE_WEIGHT_SCALE;
 	for (srv = p->srv; srv; srv = srv->next) {
 		srv->eweight = (srv->uweight * p->lbprm.wdiv + p->lbprm.wmult - 1) / p->lbprm.wmult;
-		srv->prev_eweight = srv->eweight;
-		srv->prev_state = srv->state;
+		srv_lb_commit_status(srv);
 	}
 
 	recount_servers(p);
diff --git a/src/lb_map.c b/src/lb_map.c
index 7ecd00311d..2d296d7800 100644
--- a/src/lb_map.c
+++ b/src/lb_map.c
@@ -28,8 +28,7 @@ static void map_set_server_status_down(struct server *srv)
 {
 	struct proxy *p = srv->proxy;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	if (srv_is_usable(srv->state, srv->eweight))
@@ -40,8 +39,7 @@ static void map_set_server_status_down(struct server *srv)
 	update_backend_weight(p);
 	p->lbprm.map.state |= LB_MAP_RECALC;
  out_update_state:
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function updates the map according to server <srv>'s new state */
@@ -49,8 +47,7 @@ static void map_set_server_status_up(struct server *srv)
 {
 	struct proxy *p = srv->proxy;
 
-	if (srv->state == srv->prev_state &&
-	    srv->eweight == srv->prev_eweight)
+	if (!srv_lb_status_changed(srv))
 		return;
 
 	if (!srv_is_usable(srv->state, srv->eweight))
@@ -61,8 +58,7 @@ static void map_set_server_status_up(struct server *srv)
 	update_backend_weight(p);
 	p->lbprm.map.state |= LB_MAP_RECALC;
  out_update_state:
-	srv->prev_state = srv->state;
-	srv->prev_eweight = srv->eweight;
+	srv_lb_commit_status(srv);
 }
 
 /* This function recomputes the server map for proxy px. It relies on
@@ -181,8 +177,8 @@ void init_server_map(struct proxy *p)
 	act = bck = 0;
 	for (srv = p->srv; srv; srv = srv->next) {
 		srv->eweight = (srv->uweight * p->lbprm.wdiv + p->lbprm.wmult - 1) / p->lbprm.wmult;
-		srv->prev_eweight = srv->eweight;
-		srv->prev_state = srv->state;
+		srv_lb_commit_status(srv);
+
 		if (srv->state & SRV_BACKUP)
 			bck += srv->eweight;
 		else
diff --git a/src/server.c b/src/server.c
index a903e84c2a..e0b200d6b8 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1143,7 +1143,7 @@ int parse_server(const char *file, int linenum, char **args, struct proxy *curpr
 			else
 				curproxy->srv_act++;
 
-			newsrv->prev_state = newsrv->state;
+			srv_lb_commit_status(newsrv);
 		}
 	}
 	return 0;