diff options
Diffstat (limited to 'modules/proxy/balancers/mod_lbmethod_bybusyness.c')
| -rw-r--r-- | modules/proxy/balancers/mod_lbmethod_bybusyness.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/modules/proxy/balancers/mod_lbmethod_bybusyness.c b/modules/proxy/balancers/mod_lbmethod_bybusyness.c new file mode 100644 index 00000000..9185f22f --- /dev/null +++ b/modules/proxy/balancers/mod_lbmethod_bybusyness.c @@ -0,0 +1,161 @@ +/* Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "mod_proxy.h" +#include "scoreboard.h" +#include "ap_mpm.h" +#include "apr_version.h" +#include "ap_hooks.h" + +module AP_MODULE_DECLARE_DATA lbmethod_bybusyness_module; + +static int (*ap_proxy_retry_worker_fn)(const char *proxy_function, + proxy_worker *worker, server_rec *s) = NULL; + +static proxy_worker *find_best_bybusyness(proxy_balancer *balancer, + request_rec *r) +{ + + int i; + proxy_worker **worker; + proxy_worker *mycandidate = NULL; + int cur_lbset = 0; + int max_lbset = 0; + int checking_standby; + int checked_standby; + + int total_factor = 0; + + if (!ap_proxy_retry_worker_fn) { + ap_proxy_retry_worker_fn = + APR_RETRIEVE_OPTIONAL_FN(ap_proxy_retry_worker); + if (!ap_proxy_retry_worker_fn) { + /* can only happen if mod_proxy isn't loaded */ + return NULL; + } + } + + ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01211) + "proxy: Entering bybusyness for BALANCER (%s)", + balancer->s->name); + + /* First try to see if we have available candidate */ + do { + + checking_standby = checked_standby = 0; + while (!mycandidate && !checked_standby) { + + worker = (proxy_worker **)balancer->workers->elts; + for (i = 0; i < balancer->workers->nelts; i++, worker++) { + if (!checking_standby) { /* first time through */ + if ((*worker)->s->lbset > max_lbset) + max_lbset = (*worker)->s->lbset; + } + if ( + ((*worker)->s->lbset != cur_lbset) || + (checking_standby ? !PROXY_WORKER_IS_STANDBY(*worker) : PROXY_WORKER_IS_STANDBY(*worker)) || + (PROXY_WORKER_IS_DRAINING(*worker)) + ) { + continue; + } + + /* If the worker is in error state run + * retry on that worker. It will be marked as + * operational if the retry timeout is elapsed. + * The worker might still be unusable, but we try + * anyway. + */ + if (!PROXY_WORKER_IS_USABLE(*worker)) { + ap_proxy_retry_worker_fn("BALANCER", *worker, r->server); + } + + /* Take into calculation only the workers that are + * not in error state or not disabled. + */ + if (PROXY_WORKER_IS_USABLE(*worker)) { + + (*worker)->s->lbstatus += (*worker)->s->lbfactor; + total_factor += (*worker)->s->lbfactor; + + if (!mycandidate + || (*worker)->s->busy < mycandidate->s->busy + || ((*worker)->s->busy == mycandidate->s->busy && (*worker)->s->lbstatus > mycandidate->s->lbstatus)) + mycandidate = *worker; + + } + + } + + checked_standby = checking_standby++; + + } + + cur_lbset++; + + } while (cur_lbset <= max_lbset && !mycandidate); + + if (mycandidate) { + mycandidate->s->lbstatus -= total_factor; + ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, APLOGNO(01212) + "proxy: bybusyness selected worker \"%s\" : busy %" APR_SIZE_T_FMT " : lbstatus %d", + mycandidate->s->name, mycandidate->s->busy, mycandidate->s->lbstatus); + + } + + return mycandidate; + +} + +/* assumed to be mutex protected by caller */ +static apr_status_t reset(proxy_balancer *balancer, server_rec *s) { + int i; + proxy_worker **worker; + worker = (proxy_worker **)balancer->workers->elts; + for (i = 0; i < balancer->workers->nelts; i++, worker++) { + (*worker)->s->lbstatus = 0; + (*worker)->s->busy = 0; + } + return APR_SUCCESS; +} + +static apr_status_t age(proxy_balancer *balancer, server_rec *s) { + return APR_SUCCESS; +} + +static const proxy_balancer_method bybusyness = +{ + "bybusyness", + &find_best_bybusyness, + NULL, + &reset, + &age +}; + + +static void register_hook(apr_pool_t *p) +{ + ap_register_provider(p, PROXY_LBMETHOD, "bybusyness", "0", &bybusyness); +} + +AP_DECLARE_MODULE(lbmethod_bybusyness) = { + STANDARD20_MODULE_STUFF, + NULL, /* create per-directory config structure */ + NULL, /* merge per-directory config structures */ + NULL, /* create per-server config structure */ + NULL, /* merge per-server config structures */ + NULL, /* command apr_table_t */ + register_hook /* register hooks */ +}; |