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[CLEANUP] backend: move LB algos to individual files

Browse Source 
It was becoming painful to have all the LB algos in backend.c.
Let's move them to their own files. A few hashing functions still
need be broken in two parts, one for the contents and one for the
map position.
This commit is contained in:
Willy Tarreau 2009-10-01 11:19:37 +02:00
parent 78ff5d0a9e
commit f89c1873f8
12 changed files with 1290 additions and 1075 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Makefile
View File

@ -459,6 +459,7 @@ OBJS = src/haproxy.o src/sessionhash.o src/base64.o src/protocols.o \
src/time.o src/fd.o src/pipe.o src/regex.o src/cfgparse.o src/server.o \
src/checks.o src/queue.o src/client.o src/proxy.o src/proto_uxst.o \
src/proto_http.o src/stream_sock.o src/appsession.o src/backend.o \
src/lb_fwlc.o src/lb_fwrr.o src/lb_map.o \
src/stream_interface.o src/dumpstats.o src/proto_tcp.o \
src/session.o src/hdr_idx.o src/ev_select.o src/signal.o \
src/acl.o src/memory.o src/freq_ctr.o \

1
Makefile.bsd
View File

@ -105,6 +105,7 @@ OBJS = src/haproxy.o src/sessionhash.o src/base64.o src/protocols.o \
src/proto_http.o src/stream_sock.o src/appsession.o src/backend.o \
src/stream_interface.o src/dumpstats.o src/proto_tcp.o \
src/session.o src/hdr_idx.o src/ev_select.o src/signal.o \
src/lb_fwlc.o src/lb_fwrr.o src/lb_map.o \
src/ev_poll.o src/ev_kqueue.o \
src/acl.o src/memory.o src/freq_ctr.o \
src/ebtree.o src/eb32tree.o

1
Makefile.osx
View File

@ -102,6 +102,7 @@ OBJS = src/haproxy.o src/sessionhash.o src/base64.o src/protocols.o \
src/proto_http.o src/stream_sock.o src/appsession.o src/backend.o \
src/stream_interface.o src/dumpstats.o src/proto_tcp.o \
src/session.o src/hdr_idx.o src/ev_select.o src/signal.o \
src/lb_fwlc.o src/lb_fwrr.o src/lb_map.o \
src/ev_poll.o \
src/acl.o src/memory.o src/freq_ctr.o \
src/ebtree.o src/eb32tree.o

11
include/proto/backend.h
View File

@ -2,7 +2,7 @@
include/proto/backend.h
Functions prototypes for the backend.
Copyright (C) 2000-2008 Willy Tarreau - w@1wt.eu
Copyright (C) 2000-2009 Willy Tarreau - w@1wt.eu
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
@ -25,10 +25,10 @@
#include <common/config.h>
#include <types/backend.h>
#include <types/proxy.h>
#include <types/server.h>
#include <types/session.h>
#include <proto/queue.h>
int assign_server(struct session *s);
int assign_server_address(struct session *s);
int assign_server_and_queue(struct session *s);
@ -37,14 +37,9 @@ int srv_redispatch_connect(struct session *t);
int backend_parse_balance(const char **args, char *err,
int errlen, struct proxy *curproxy);
void recalc_server_map(struct proxy *px);
int be_downtime(struct proxy *px);
void init_server_map(struct proxy *p);
void fwrr_init_server_groups(struct proxy *p);
void fwlc_init_server_tree(struct proxy *p);
void recount_servers(struct proxy *px);
void update_backend_weight(struct proxy *px);
struct server *get_server_rr_with_conns(struct proxy *px, struct server *srvtoavoid);
struct server *get_server_sh(struct proxy *px, const char *addr, int len);
struct server *get_server_uh(struct proxy *px, char *uri, int uri_len);

39
include/proto/lb_fwlc.h Normal file
View File

@ -0,0 +1,39 @@
/*
* include/proto/lb_fwlc.h
* Fast Weighted Least Connection load balancing algorithm.
*
* Copyright (C) 2000-2009 Willy Tarreau - w@1wt.eu
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, version 2.1
* exclusively.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _PROTO_LB_FWLC_H
#define _PROTO_LB_FWLC_H
#include <common/config.h>
#include <types/proxy.h>
#include <types/server.h>
struct server *fwlc_get_next_server(struct proxy *p, struct server *srvtoavoid);
void fwlc_init_server_tree(struct proxy *p);
#endif /* _PROTO_LB_FWLC_H */
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/

39
include/proto/lb_fwrr.h Normal file
View File

@ -0,0 +1,39 @@
/*
* include/proto/lb_fwrr.h
* Fast Weighted Round Robin load balancing algorithm.
*
* Copyright (C) 2000-2009 Willy Tarreau - w@1wt.eu
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, version 2.1
* exclusively.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _PROTO_LB_FWRR_H
#define _PROTO_LB_FWRR_H
#include <common/config.h>
#include <types/proxy.h>
#include <types/server.h>
void fwrr_init_server_groups(struct proxy *p);
struct server *fwrr_get_next_server(struct proxy *p, struct server *srvtoavoid);
#endif /* _PROTO_LB_FWRR_H */
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/

42
include/proto/lb_map.h Normal file
View File

@ -0,0 +1,42 @@
/*
* include/proto/lb_map.h
* Map-based load-balancing (RR and HASH)
*
* Copyright (C) 2000-2009 Willy Tarreau - w@1wt.eu
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, version 2.1
* exclusively.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _PROTO_LB_MAP_H
#define _PROTO_LB_MAP_H
#include <common/config.h>
#include <types/proxy.h>
#include <types/server.h>
void map_set_server_status_down(struct server *srv);
void map_set_server_status_up(struct server *srv);
void recalc_server_map(struct proxy *px);
void init_server_map(struct proxy *p);
struct server *map_get_server_rr(struct proxy *px, struct server *srvtoavoid);
#endif /* _PROTO_LB_MAP_H */
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/

1074
src/backend.c
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File diff suppressed because it is too large Load Diff

3
src/cfgparse.c
View File

@ -42,6 +42,9 @@
#include <proto/checks.h>
#include <proto/dumpstats.h>
#include <proto/httperr.h>
#include <proto/lb_fwlc.h>
#include <proto/lb_fwrr.h>
#include <proto/lb_map.h>
#include <proto/log.h>
#include <proto/port_range.h>
#include <proto/protocols.h>

316
src/lb_fwlc.c Normal file
View File

@ -0,0 +1,316 @@
/*
* Fast Weighted Least Connection load balancing algorithm.
*
* Copyright 2000-2009 Willy Tarreau <w@1wt.eu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <common/compat.h>
#include <common/config.h>
#include <common/debug.h>
#include <common/eb32tree.h>
#include <types/global.h>
#include <types/server.h>
#include <proto/backend.h>
#include <proto/queue.h>
/* Remove a server from a tree. It must have previously been dequeued. This
* function is meant to be called when a server is going down or has its
* weight disabled.
*/
static inline void fwlc_remove_from_tree(struct server *s)
{
s->lb_tree = NULL;
}
/* simply removes a server from a tree */
static inline void fwlc_dequeue_srv(struct server *s)
{
eb32_delete(&s->lb_node);
}
/* Queue a server in its associated tree, assuming the weight is >0.
* Servers are sorted by #conns/weight. To ensure maximum accuracy,
* we use #conns*SRV_EWGHT_MAX/eweight as the sorting key.
*/
static inline void fwlc_queue_srv(struct server *s)
{
s->lb_node.key = s->served * SRV_EWGHT_MAX / s->eweight;
eb32_insert(s->lb_tree, &s->lb_node);
}
/* Re-position the server in the FWLC tree after it has been assigned one
* connection or after it has released one. Note that it is possible that
* the server has been moved out of the tree due to failed health-checks.
*/
static void fwlc_srv_reposition(struct server *s)
{
if (!s->lb_tree)
return;
fwlc_dequeue_srv(s);
fwlc_queue_srv(s);
}
/* This function updates the server trees according to server <srv>'s new
* state. It should be called when server <srv>'s status changes to down.
* It is not important whether the server was already down or not. It is not
* important either that the new state is completely down (the caller may not
* know all the variables of a server's state).
*/
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)
return;
if (srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
if (!srv_is_usable(srv->prev_state, srv->prev_eweight))
/* server was already down */
goto out_update_backend;
if (srv->state & SRV_BACKUP) {
p->lbprm.tot_wbck -= srv->prev_eweight;
p->srv_bck--;
if (srv == p->lbprm.fbck) {
/* we lost the first backup server in a single-backup
* configuration, we must search another one.
*/
struct server *srv2 = p->lbprm.fbck;
do {
srv2 = srv2->next;
} while (srv2 &&
!((srv2->state & SRV_BACKUP) &&
srv_is_usable(srv2->state, srv2->eweight)));
p->lbprm.fbck = srv2;
}
} else {
p->lbprm.tot_wact -= srv->prev_eweight;
p->srv_act--;
}
fwlc_dequeue_srv(srv);
fwlc_remove_from_tree(srv);
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;
}
/* This function updates the server trees according to server <srv>'s new
* state. It should be called when server <srv>'s status changes to up.
* It is not important whether the server was already down or not. It is not
* important either that the new state is completely UP (the caller may not
* know all the variables of a server's state). This function will not change
* the weight of a server which was already up.
*/
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)
return;
if (!srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
if (srv_is_usable(srv->prev_state, srv->prev_eweight))
/* server was already up */
goto out_update_backend;
if (srv->state & SRV_BACKUP) {
srv->lb_tree = &p->lbprm.fwlc.bck;
p->lbprm.tot_wbck += srv->eweight;
p->srv_bck++;
if (!(p->options & PR_O_USE_ALL_BK)) {
if (!p->lbprm.fbck) {
/* there was no backup server anymore */
p->lbprm.fbck = srv;
} else {
/* we may have restored a backup server prior to fbck,
* in which case it should replace it.
*/
struct server *srv2 = srv;
do {
srv2 = srv2->next;
} while (srv2 && (srv2 != p->lbprm.fbck));
if (srv2)
p->lbprm.fbck = srv;
}
}
} else {
srv->lb_tree = &p->lbprm.fwlc.act;
p->lbprm.tot_wact += srv->eweight;
p->srv_act++;
}
/* note that eweight cannot be 0 here */
fwlc_queue_srv(srv);
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;
}
/* This function must be called after an update to server <srv>'s effective
* weight. It may be called after a state change too.
*/
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)
return;
/* If changing the server's weight changes its state, we simply apply
* the procedures we already have for status change. If the state
* remains down, the server is not in any tree, so it's as easy as
* updating its values. If the state remains up with different weights,
* there are some computations to perform to find a new place and
* possibly a new tree for this server.
*/
old_state = srv_is_usable(srv->prev_state, srv->prev_eweight);
new_state = srv_is_usable(srv->state, srv->eweight);
if (!old_state && !new_state) {
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
return;
}
else if (!old_state && new_state) {
fwlc_set_server_status_up(srv);
return;
}
else if (old_state && !new_state) {
fwlc_set_server_status_down(srv);
return;
}
if (srv->lb_tree)
fwlc_dequeue_srv(srv);
if (srv->state & SRV_BACKUP) {
p->lbprm.tot_wbck += srv->eweight - srv->prev_eweight;
srv->lb_tree = &p->lbprm.fwlc.bck;
} else {
p->lbprm.tot_wact += srv->eweight - srv->prev_eweight;
srv->lb_tree = &p->lbprm.fwlc.act;
}
fwlc_queue_srv(srv);
update_backend_weight(p);
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* This function is responsible for building the trees in case of fast
* weighted least-conns. It also sets p->lbprm.wdiv to the eweight to
* uweight ratio. Both active and backup groups are initialized.
*/
void fwlc_init_server_tree(struct proxy *p)
{
struct server *srv;
struct eb_root init_head = EB_ROOT;
p->lbprm.set_server_status_up = fwlc_set_server_status_up;
p->lbprm.set_server_status_down = fwlc_set_server_status_down;
p->lbprm.update_server_eweight = fwlc_update_server_weight;
p->lbprm.server_take_conn = fwlc_srv_reposition;
p->lbprm.server_drop_conn = fwlc_srv_reposition;
p->lbprm.wdiv = BE_WEIGHT_SCALE;
for (srv = p->srv; srv; srv = srv->next) {
srv->prev_eweight = srv->eweight = srv->uweight * BE_WEIGHT_SCALE;
srv->prev_state = srv->state;
}
recount_servers(p);
update_backend_weight(p);
p->lbprm.fwlc.act = init_head;
p->lbprm.fwlc.bck = init_head;
/* queue active and backup servers in two distinct groups */
for (srv = p->srv; srv; srv = srv->next) {
if (!srv_is_usable(srv->state, srv->eweight))
continue;
srv->lb_tree = (srv->state & SRV_BACKUP) ? &p->lbprm.fwlc.bck : &p->lbprm.fwlc.act;
fwlc_queue_srv(srv);
}
}
/* Return next server from the FWLC tree in backend <p>. If the tree is empty,
* return NULL. Saturated servers are skipped.
*/
struct server *fwlc_get_next_server(struct proxy *p, struct server *srvtoavoid)
{
struct server *srv, *avoided;
struct eb32_node *node;
srv = avoided = NULL;
if (p->srv_act)
node = eb32_first(&p->lbprm.fwlc.act);
else if (p->lbprm.fbck)
return p->lbprm.fbck;
else if (p->srv_bck)
node = eb32_first(&p->lbprm.fwlc.bck);
else
return NULL;
while (node) {
/* OK, we have a server. However, it may be saturated, in which
* case we don't want to reconsider it for now, so we'll simply
* skip it. Same if it's the server we try to avoid, in which
* case we simply remember it for later use if needed.
*/
struct server *s;
s = eb32_entry(node, struct server, lb_node);
if (!s->maxconn || (!s->nbpend && s->served < srv_dynamic_maxconn(s))) {
if (s != srvtoavoid) {
srv = s;
break;
}
avoided = s;
}
node = eb32_next(node);
}
if (!srv)
srv = avoided;
return srv;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/

576
src/lb_fwrr.c Normal file
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@ -0,0 +1,576 @@
/*
* Fast Weighted Round Robin load balancing algorithm.
*
* Copyright 2000-2009 Willy Tarreau <w@1wt.eu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <common/compat.h>
#include <common/config.h>
#include <common/debug.h>
#include <common/eb32tree.h>
#include <types/global.h>
#include <types/server.h>
#include <proto/backend.h>
#include <proto/queue.h>
static inline void fwrr_remove_from_tree(struct server *s);
static inline void fwrr_queue_by_weight(struct eb_root *root, struct server *s);
static inline void fwrr_dequeue_srv(struct server *s);
static void fwrr_get_srv(struct server *s);
static void fwrr_queue_srv(struct server *s);
/* This function updates the server trees according to server <srv>'s new
* state. It should be called when server <srv>'s status changes to down.
* It is not important whether the server was already down or not. It is not
* important either that the new state is completely down (the caller may not
* know all the variables of a server's state).
*/
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)
return;
if (srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
if (!srv_is_usable(srv->prev_state, srv->prev_eweight))
/* server was already down */
goto out_update_backend;
grp = (srv->state & SRV_BACKUP) ? &p->lbprm.fwrr.bck : &p->lbprm.fwrr.act;
grp->next_weight -= srv->prev_eweight;
if (srv->state & SRV_BACKUP) {
p->lbprm.tot_wbck = p->lbprm.fwrr.bck.next_weight;
p->srv_bck--;
if (srv == p->lbprm.fbck) {
/* we lost the first backup server in a single-backup
* configuration, we must search another one.
*/
struct server *srv2 = p->lbprm.fbck;
do {
srv2 = srv2->next;
} while (srv2 &&
!((srv2->state & SRV_BACKUP) &&
srv_is_usable(srv2->state, srv2->eweight)));
p->lbprm.fbck = srv2;
}
} else {
p->lbprm.tot_wact = p->lbprm.fwrr.act.next_weight;
p->srv_act--;
}
fwrr_dequeue_srv(srv);
fwrr_remove_from_tree(srv);
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;
}
/* This function updates the server trees according to server <srv>'s new
* state. It should be called when server <srv>'s status changes to up.
* It is not important whether the server was already down or not. It is not
* important either that the new state is completely UP (the caller may not
* know all the variables of a server's state). This function will not change
* the weight of a server which was already up.
*/
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)
return;
if (!srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
if (srv_is_usable(srv->prev_state, srv->prev_eweight))
/* server was already up */
goto out_update_backend;
grp = (srv->state & SRV_BACKUP) ? &p->lbprm.fwrr.bck : &p->lbprm.fwrr.act;
grp->next_weight += srv->eweight;
if (srv->state & SRV_BACKUP) {
p->lbprm.tot_wbck = p->lbprm.fwrr.bck.next_weight;
p->srv_bck++;
if (!(p->options & PR_O_USE_ALL_BK)) {
if (!p->lbprm.fbck) {
/* there was no backup server anymore */
p->lbprm.fbck = srv;
} else {
/* we may have restored a backup server prior to fbck,
* in which case it should replace it.
*/
struct server *srv2 = srv;
do {
srv2 = srv2->next;
} while (srv2 && (srv2 != p->lbprm.fbck));
if (srv2)
p->lbprm.fbck = srv;
}
}
} else {
p->lbprm.tot_wact = p->lbprm.fwrr.act.next_weight;
p->srv_act++;
}
/* note that eweight cannot be 0 here */
fwrr_get_srv(srv);
srv->npos = grp->curr_pos + (grp->next_weight + grp->curr_weight - grp->curr_pos) / srv->eweight;
fwrr_queue_srv(srv);
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;
}
/* This function must be called after an update to server <srv>'s effective
* weight. It may be called after a state change too.
*/
static void fwrr_update_server_weight(struct server *srv)
{
int old_state, new_state;
struct proxy *p = srv->proxy;
struct fwrr_group *grp;
if (srv->state == srv->prev_state &&
srv->eweight == srv->prev_eweight)
return;
/* If changing the server's weight changes its state, we simply apply
* the procedures we already have for status change. If the state
* remains down, the server is not in any tree, so it's as easy as
* updating its values. If the state remains up with different weights,
* there are some computations to perform to find a new place and
* possibly a new tree for this server.
*/
old_state = srv_is_usable(srv->prev_state, srv->prev_eweight);
new_state = srv_is_usable(srv->state, srv->eweight);
if (!old_state && !new_state) {
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
return;
}
else if (!old_state && new_state) {
fwrr_set_server_status_up(srv);
return;
}
else if (old_state && !new_state) {
fwrr_set_server_status_down(srv);
return;
}
grp = (srv->state & SRV_BACKUP) ? &p->lbprm.fwrr.bck : &p->lbprm.fwrr.act;
grp->next_weight = grp->next_weight - srv->prev_eweight + srv->eweight;
p->lbprm.tot_wact = p->lbprm.fwrr.act.next_weight;
p->lbprm.tot_wbck = p->lbprm.fwrr.bck.next_weight;
if (srv->lb_tree == grp->init) {
fwrr_dequeue_srv(srv);
fwrr_queue_by_weight(grp->init, srv);
}
else if (!srv->lb_tree) {
/* FIXME: server was down. This is not possible right now but
* may be needed soon for slowstart or graceful shutdown.
*/
fwrr_dequeue_srv(srv);
fwrr_get_srv(srv);
srv->npos = grp->curr_pos + (grp->next_weight + grp->curr_weight - grp->curr_pos) / srv->eweight;
fwrr_queue_srv(srv);
} else {
/* The server is either active or in the next queue. If it's
* still in the active queue and it has not consumed all of its
* places, let's adjust its next position.
*/
fwrr_get_srv(srv);
if (srv->eweight > 0) {
int prev_next = srv->npos;
int step = grp->next_weight / srv->eweight;
srv->npos = srv->lpos + step;
srv->rweight = 0;
if (srv->npos > prev_next)
srv->npos = prev_next;
if (srv->npos < grp->curr_pos + 2)
srv->npos = grp->curr_pos + step;
} else {
/* push it into the next tree */
srv->npos = grp->curr_pos + grp->curr_weight;
}
fwrr_dequeue_srv(srv);
fwrr_queue_srv(srv);
}
update_backend_weight(p);
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* Remove a server from a tree. It must have previously been dequeued. This
* function is meant to be called when a server is going down or has its
* weight disabled.
*/
static inline void fwrr_remove_from_tree(struct server *s)
{
s->lb_tree = NULL;
}
/* Queue a server in the weight tree <root>, assuming the weight is >0.
* We want to sort them by inverted weights, because we need to place
* heavy servers first in order to get a smooth distribution.
*/
static inline void fwrr_queue_by_weight(struct eb_root *root, struct server *s)
{
s->lb_node.key = SRV_EWGHT_MAX - s->eweight;
eb32_insert(root, &s->lb_node);
s->lb_tree = root;
}
/* This function is responsible for building the weight trees in case of fast
* weighted round-robin. It also sets p->lbprm.wdiv to the eweight to uweight
* ratio. Both active and backup groups are initialized.
*/
void fwrr_init_server_groups(struct proxy *p)
{
struct server *srv;
struct eb_root init_head = EB_ROOT;
p->lbprm.set_server_status_up = fwrr_set_server_status_up;
p->lbprm.set_server_status_down = fwrr_set_server_status_down;
p->lbprm.update_server_eweight = fwrr_update_server_weight;
p->lbprm.wdiv = BE_WEIGHT_SCALE;
for (srv = p->srv; srv; srv = srv->next) {
srv->prev_eweight = srv->eweight = srv->uweight * BE_WEIGHT_SCALE;
srv->prev_state = srv->state;
}
recount_servers(p);
update_backend_weight(p);
/* prepare the active servers group */
p->lbprm.fwrr.act.curr_pos = p->lbprm.fwrr.act.curr_weight =
p->lbprm.fwrr.act.next_weight = p->lbprm.tot_wact;
p->lbprm.fwrr.act.curr = p->lbprm.fwrr.act.t0 =
p->lbprm.fwrr.act.t1 = init_head;
p->lbprm.fwrr.act.init = &p->lbprm.fwrr.act.t0;
p->lbprm.fwrr.act.next = &p->lbprm.fwrr.act.t1;
/* prepare the backup servers group */
p->lbprm.fwrr.bck.curr_pos = p->lbprm.fwrr.bck.curr_weight =
p->lbprm.fwrr.bck.next_weight = p->lbprm.tot_wbck;
p->lbprm.fwrr.bck.curr = p->lbprm.fwrr.bck.t0 =
p->lbprm.fwrr.bck.t1 = init_head;
p->lbprm.fwrr.bck.init = &p->lbprm.fwrr.bck.t0;
p->lbprm.fwrr.bck.next = &p->lbprm.fwrr.bck.t1;
/* queue active and backup servers in two distinct groups */
for (srv = p->srv; srv; srv = srv->next) {
if (!srv_is_usable(srv->state, srv->eweight))
continue;
fwrr_queue_by_weight((srv->state & SRV_BACKUP) ?
p->lbprm.fwrr.bck.init :
p->lbprm.fwrr.act.init,
srv);
}
}
/* simply removes a server from a weight tree */
static inline void fwrr_dequeue_srv(struct server *s)
{
eb32_delete(&s->lb_node);
}
/* queues a server into the appropriate group and tree depending on its
* backup status, and ->npos. If the server is disabled, simply assign
* it to the NULL tree.
*/
static void fwrr_queue_srv(struct server *s)
{
struct proxy *p = s->proxy;
struct fwrr_group *grp;
grp = (s->state & SRV_BACKUP) ? &p->lbprm.fwrr.bck : &p->lbprm.fwrr.act;
/* Delay everything which does not fit into the window and everything
* which does not fit into the theorical new window.
*/
if (!srv_is_usable(s->state, s->eweight)) {
fwrr_remove_from_tree(s);
}
else if (s->eweight <= 0 ||
s->npos >= 2 * grp->curr_weight ||
s->npos >= grp->curr_weight + grp->next_weight) {
/* put into next tree, and readjust npos in case we could
* finally take this back to current. */
s->npos -= grp->curr_weight;
fwrr_queue_by_weight(grp->next, s);
}
else {
/* The sorting key is stored in units of s->npos * user_weight
* in order to avoid overflows. As stated in backend.h, the
* lower the scale, the rougher the weights modulation, and the
* higher the scale, the lower the number of servers without
* overflow. With this formula, the result is always positive,
* so we can use eb3é_insert().
*/
s->lb_node.key = SRV_UWGHT_RANGE * s->npos +
(unsigned)(SRV_EWGHT_MAX + s->rweight - s->eweight) / BE_WEIGHT_SCALE;
eb32_insert(&grp->curr, &s->lb_node);
s->lb_tree = &grp->curr;
}
}
/* prepares a server when extracting it from the "init" tree */
static inline void fwrr_get_srv_init(struct server *s)
{
s->npos = s->rweight = 0;
}
/* prepares a server when extracting it from the "next" tree */
static inline void fwrr_get_srv_next(struct server *s)
{
struct fwrr_group *grp = (s->state & SRV_BACKUP) ?
&s->proxy->lbprm.fwrr.bck :
&s->proxy->lbprm.fwrr.act;
s->npos += grp->curr_weight;
}
/* prepares a server when it was marked down */
static inline void fwrr_get_srv_down(struct server *s)
{
struct fwrr_group *grp = (s->state & SRV_BACKUP) ?
&s->proxy->lbprm.fwrr.bck :
&s->proxy->lbprm.fwrr.act;
s->npos = grp->curr_pos;
}
/* prepares a server when extracting it from its tree */
static void fwrr_get_srv(struct server *s)
{
struct proxy *p = s->proxy;
struct fwrr_group *grp = (s->state & SRV_BACKUP) ?
&p->lbprm.fwrr.bck :
&p->lbprm.fwrr.act;
if (s->lb_tree == grp->init) {
fwrr_get_srv_init(s);
}
else if (s->lb_tree == grp->next) {
fwrr_get_srv_next(s);
}
else if (s->lb_tree == NULL) {
fwrr_get_srv_down(s);
}
}
/* switches trees "init" and "next" for FWRR group <grp>. "init" should be empty
* when this happens, and "next" filled with servers sorted by weights.
*/
static inline void fwrr_switch_trees(struct fwrr_group *grp)
{
struct eb_root *swap;
swap = grp->init;
grp->init = grp->next;
grp->next = swap;
grp->curr_weight = grp->next_weight;
grp->curr_pos = grp->curr_weight;
}
/* return next server from the current tree in FWRR group <grp>, or a server
* from the "init" tree if appropriate. If both trees are empty, return NULL.
*/
static struct server *fwrr_get_server_from_group(struct fwrr_group *grp)
{
struct eb32_node *node;
struct server *s;
node = eb32_first(&grp->curr);
s = eb32_entry(node, struct server, lb_node);
if (!node || s->npos > grp->curr_pos) {
/* either we have no server left, or we have a hole */
struct eb32_node *node2;
node2 = eb32_first(grp->init);
if (node2) {
node = node2;
s = eb32_entry(node, struct server, lb_node);
fwrr_get_srv_init(s);
if (s->eweight == 0) /* FIXME: is it possible at all ? */
node = NULL;
}
}
if (node)
return s;
else
return NULL;
}
/* Computes next position of server <s> in the group. It is mandatory for <s>
* to have a non-zero, positive eweight.
*/
static inline void fwrr_update_position(struct fwrr_group *grp, struct server *s)
{
if (!s->npos) {
/* first time ever for this server */
s->lpos = grp->curr_pos;
s->npos = grp->curr_pos + grp->next_weight / s->eweight;
s->rweight += grp->next_weight % s->eweight;
if (s->rweight >= s->eweight) {
s->rweight -= s->eweight;
s->npos++;
}
} else {
s->lpos = s->npos;
s->npos += grp->next_weight / s->eweight;
s->rweight += grp->next_weight % s->eweight;
if (s->rweight >= s->eweight) {
s->rweight -= s->eweight;
s->npos++;
}
}
}
/* Return next server from the current tree in backend <p>, or a server from
* the init tree if appropriate. If both trees are empty, return NULL.
* Saturated servers are skipped and requeued.
*/
struct server *fwrr_get_next_server(struct proxy *p, struct server *srvtoavoid)
{
struct server *srv, *full, *avoided;
struct fwrr_group *grp;
int switched;
if (p->srv_act)
grp = &p->lbprm.fwrr.act;
else if (p->lbprm.fbck)
return p->lbprm.fbck;
else if (p->srv_bck)
grp = &p->lbprm.fwrr.bck;
else
return NULL;
switched = 0;
avoided = NULL;
full = NULL; /* NULL-terminated list of saturated servers */
while (1) {
/* if we see an empty group, let's first try to collect weights
* which might have recently changed.
*/
if (!grp->curr_weight)
grp->curr_pos = grp->curr_weight = grp->next_weight;
/* get first server from the "current" tree. When the end of
* the tree is reached, we may have to switch, but only once.
*/
while (1) {
srv = fwrr_get_server_from_group(grp);
if (srv)
break;
if (switched) {
if (avoided) {
srv = avoided;
break;
}
goto requeue_servers;
}
switched = 1;
fwrr_switch_trees(grp);
}
/* OK, we have a server. However, it may be saturated, in which
* case we don't want to reconsider it for now. We'll update
* its position and dequeue it anyway, so that we can move it
* to a better place afterwards.
*/
fwrr_update_position(grp, srv);
fwrr_dequeue_srv(srv);
grp->curr_pos++;
if (!srv->maxconn || (!srv->nbpend && srv->served < srv_dynamic_maxconn(srv))) {
/* make sure it is not the server we are trying to exclude... */
if (srv != srvtoavoid || avoided)
break;
avoided = srv; /* ...but remember that is was selected yet avoided */
}
/* the server is saturated or avoided, let's chain it for later reinsertion */
srv->next_full = full;
full = srv;
}
/* OK, we got the best server, let's update it */
fwrr_queue_srv(srv);
requeue_servers:
/* Requeue all extracted servers. If full==srv then it was
* avoided (unsucessfully) and chained, omit it now.
*/
if (unlikely(full != NULL)) {
if (switched) {
/* the tree has switched, requeue all extracted servers
* into "init", because their place was lost, and only
* their weight matters.
*/
do {
if (likely(full != srv))
fwrr_queue_by_weight(grp->init, full);
full = full->next_full;
} while (full);
} else {
/* requeue all extracted servers just as if they were consumed
* so that they regain their expected place.
*/
do {
if (likely(full != srv))
fwrr_queue_srv(full);
full = full->next_full;
} while (full);
}
}
return srv;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/

262
src/lb_map.c Normal file
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@ -0,0 +1,262 @@
/*
* Map-based load-balancing (RR and HASH)
*
* Copyright 2000-2009 Willy Tarreau <w@1wt.eu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <common/compat.h>
#include <common/config.h>
#include <common/debug.h>
#include <common/eb32tree.h>
#include <types/global.h>
#include <types/server.h>
#include <proto/backend.h>
#include <proto/proto_http.h>
#include <proto/proto_tcp.h>
#include <proto/queue.h>
/* this function updates the map according to server <srv>'s new state */
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)
return;
if (srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
/* FIXME: could be optimized since we know what changed */
recount_servers(p);
update_backend_weight(p);
p->lbprm.map.state |= PR_MAP_RECALC;
out_update_state:
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* This function updates the map according to server <srv>'s new state */
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)
return;
if (!srv_is_usable(srv->state, srv->eweight))
goto out_update_state;
/* FIXME: could be optimized since we know what changed */
recount_servers(p);
update_backend_weight(p);
p->lbprm.map.state |= PR_MAP_RECALC;
out_update_state:
srv->prev_state = srv->state;
srv->prev_eweight = srv->eweight;
}
/* This function recomputes the server map for proxy px. It relies on
* px->lbprm.tot_wact, tot_wbck, tot_used, tot_weight, so it must be
* called after recount_servers(). It also expects px->lbprm.map.srv
* to be allocated with the largest size needed. It updates tot_weight.
*/
void recalc_server_map(struct proxy *px)
{
int o, tot, flag;
struct server *cur, *best;
switch (px->lbprm.tot_used) {
case 0: /* no server */
px->lbprm.map.state &= ~PR_MAP_RECALC;
return;
case 1: /* only one server, just fill first entry */
tot = 1;
break;
default:
tot = px->lbprm.tot_weight;
break;
}
/* here we *know* that we have some servers */
if (px->srv_act)
flag = SRV_RUNNING;
else
flag = SRV_RUNNING | SRV_BACKUP;
/* this algorithm gives priority to the first server, which means that
* it will respect the declaration order for equivalent weights, and
* that whatever the weights, the first server called will always be
* the first declared. This is an important asumption for the backup
* case, where we want the first server only.
*/
for (cur = px->srv; cur; cur = cur->next)
cur->wscore = 0;
for (o = 0; o < tot; o++) {
int max = 0;
best = NULL;
for (cur = px->srv; cur; cur = cur->next) {
if (cur->eweight &&
flag == (cur->state &
(SRV_RUNNING | SRV_GOINGDOWN | SRV_BACKUP))) {
int v;
/* If we are forced to return only one server, we don't want to
* go further, because we would return the wrong one due to
* divide overflow.
*/
if (tot == 1) {
best = cur;
/* note that best->wscore will be wrong but we don't care */
break;
}
cur->wscore += cur->eweight;
v = (cur->wscore + tot) / tot; /* result between 0 and 3 */
if (best == NULL || v > max) {
max = v;
best = cur;
}
}
}
px->lbprm.map.srv[o] = best;
best->wscore -= tot;
}
px->lbprm.map.state &= ~PR_MAP_RECALC;
}
/* This function is responsible of building the server MAP for map-based LB
* algorithms, allocating the map, and setting p->lbprm.wmult to the GCD of the
* weights if applicable. It should be called only once per proxy, at config
* time.
*/
void init_server_map(struct proxy *p)
{
struct server *srv;
int pgcd;
int act, bck;
p->lbprm.set_server_status_up = map_set_server_status_up;
p->lbprm.set_server_status_down = map_set_server_status_down;
p->lbprm.update_server_eweight = NULL;
if (!p->srv)
return;
/* We will factor the weights to reduce the table,
* using Euclide's largest common divisor algorithm.
* Since we may have zero weights, we have to first
* find a non-zero weight server.
*/
pgcd = 1;
srv = p->srv;
while (srv && !srv->uweight)
srv = srv->next;
if (srv) {
pgcd = srv->uweight; /* note: cannot be zero */
while (pgcd > 1 && (srv = srv->next)) {
int w = srv->uweight;
while (w) {
int t = pgcd % w;
pgcd = w;
w = t;
}
}
}
/* It is sometimes useful to know what factor to apply
* to the backend's effective weight to know its real
* weight.
*/
p->lbprm.wmult = pgcd;
act = bck = 0;
for (srv = p->srv; srv; srv = srv->next) {
srv->eweight = srv->uweight / pgcd;
srv->prev_eweight = srv->eweight;
srv->prev_state = srv->state;
if (srv->state & SRV_BACKUP)
bck += srv->eweight;
else
act += srv->eweight;
}
/* this is the largest map we will ever need for this servers list */
if (act < bck)
act = bck;
if (!act)
act = 1;
p->lbprm.map.srv = (struct server **)calloc(act, sizeof(struct server *));
/* recounts servers and their weights */
p->lbprm.map.state = PR_MAP_RECALC;
recount_servers(p);
update_backend_weight(p);
recalc_server_map(p);
}
/*
* This function tries to find a running server with free connection slots for
* the proxy <px> following the round-robin method.
* If any server is found, it will be returned and px->lbprm.map.rr_idx will be updated
* to point to the next server. If no valid server is found, NULL is returned.
*/
struct server *map_get_server_rr(struct proxy *px, struct server *srvtoavoid)
{
int newidx, avoididx;
struct server *srv, *avoided;
if (px->lbprm.tot_weight == 0)
return NULL;
if (px->lbprm.map.state & PR_MAP_RECALC)
recalc_server_map(px);
if (px->lbprm.map.rr_idx < 0 || px->lbprm.map.rr_idx >= px->lbprm.tot_weight)
px->lbprm.map.rr_idx = 0;
newidx = px->lbprm.map.rr_idx;
avoided = NULL;
avoididx = 0; /* shut a gcc warning */
do {
srv = px->lbprm.map.srv[newidx++];
if (!srv->maxconn || srv->cur_sess < srv_dynamic_maxconn(srv)) {
/* make sure it is not the server we are try to exclude... */
if (srv != srvtoavoid) {
px->lbprm.map.rr_idx = newidx;
return srv;
}
avoided = srv; /* ...but remember that is was selected yet avoided */
avoididx = newidx;
}
if (newidx == px->lbprm.tot_weight)
newidx = 0;
} while (newidx != px->lbprm.map.rr_idx);
if (avoided)
px->lbprm.map.rr_idx = avoididx;
/* return NULL or srvtoavoid if found */
return avoided;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/