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* re-architectured the server round-robin mechanism to ease integration of

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other algorithms. It now relies on the number of active and backup servers.
This commit is contained in:
willy tarreau 2006-03-24 19:36:41 +01:00
parent 62084d4f2d
commit 4c8c2b5f08
1 changed files with 64 additions and 41 deletions
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105
haproxy.c
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@ -1784,41 +1784,6 @@ static inline void session_free(struct session *s) {
}
/*
* This function tries to find a running server for the proxy <px>. A first
* pass looks for active servers, and if none is found, a second pass also
* looks for backup servers.
* If no valid server is found, NULL is returned and px->cursrv is left undefined.
*/
static inline struct server *find_server(struct proxy *px) {
struct server *srv = px->cursrv;
struct server *end;
int ignore_backup = 1;
do {
if (srv == NULL)
srv = px->srv;
end = srv;
do {
if (srv->state & SRV_RUNNING
&& !((srv->state & SRV_BACKUP) && ignore_backup))
return srv;
srv = srv->next;
if (srv == NULL)
srv = px->srv;
} while (srv != end);
/* By default, we look for the first backup server if all others are
* DOWN. But in some cases, it may be desirable to load-balance across
* all backup servers.
*/
if (!(px->options & PR_O_USE_ALL_BK))
srv = px->srv;
} while (ignore_backup--);
return NULL;
}
/*
* This function recounts the number of usable active and backup servers for
* proxy <p>. These numbers are returned into the p->srv_act and p->srv_bck.
@ -1837,6 +1802,65 @@ static inline void recount_servers(struct proxy *px) {
}
}
/*
* This function tries to find a running server for the proxy <px> following
* the round-robin method. Depending on the number of active/backup servers,
* it will either look for active servers, or for backup servers.
* If any server is found, it will be returned and px->cursrv will be updated
* to point to the next server. If no valid server is found, NULL is returned.
*/
static inline struct server *get_server_rr(struct proxy *px) {
struct server *srv;
struct server *end;
if (px->srv_act) {
srv = px->cursrv;
if (srv == NULL)
srv = px->srv;
end = srv;
do {
if ((srv->state & (SRV_RUNNING | SRV_BACKUP)) == SRV_RUNNING) {
px->cursrv = srv->next;
return srv;
}
srv = srv->next;
if (srv == NULL)
srv = px->srv;
} while (srv != end);
/* note that theorically we should not get there */
}
if (px->srv_bck) {
/* By default, we look for the first backup server if all others are
* DOWN. But in some cases, it may be desirable to load-balance across
* all backup servers.
*/
if (px->options & PR_O_USE_ALL_BK)
srv = px->cursrv;
else
srv = px->srv;
if (srv == NULL)
srv = px->srv;
end = srv;
do {
if (srv->state & SRV_RUNNING) {
px->cursrv = srv->next;
return srv;
}
srv = srv->next;
if (srv == NULL)
srv = px->srv;
} while (srv != end);
/* note that theorically we should not get there */
}
/* if we get there, it means there are no available servers at all */
return NULL;
}
/*
* This function initiates a connection to the current server (s->srv) if (s->direct)
* is set, or to the dispatch server if (s->direct) is 0.
@ -1860,17 +1884,16 @@ int connect_server(struct session *s) {
s->srv_addr = s->srv->addr;
}
else if (s->proxy->options & PR_O_BALANCE) {
if (!s->proxy->srv_act && !s->proxy->srv_bck)
return SN_ERR_SRVTO;
if (s->proxy->options & PR_O_BALANCE_RR) {
struct server *srv;
srv = find_server(s->proxy);
if (srv == NULL) /* no server left */
return SN_ERR_SRVTO;
srv = get_server_rr(s->proxy);
/* srv cannot be NULL */
s->srv_addr = srv->addr;
s->srv = srv;
s->proxy->cursrv = srv->next;
}
else /* unknown balancing algorithm */
return SN_ERR_INTERNAL;