How and when do ALIGNED_PROXY_BALANCER_SHARED_SIZE and conf->max_balancers change???
> On Aug 21, 2015, at 8:34 AM, yla...@apache.org wrote: > > Author: ylavic > Date: Fri Aug 21 12:34:02 2015 > New Revision: 1696960 > > URL: http://svn.apache.org/r1696960 > Log: > mod_proxy_balancer: Fix balancers and balancer members reuse on > restart when new ones are added. PR 58024. > > Since slotmem_create() issues a strict check on the size of an existing > slot before reusing it, it won't reuse existing balancers and members when > new ones are added during restart (whereas growth margins would allow it). > Fix this by using slotmem_attach() first and if it succeeds do the checks > based on the returned previous number of existing entries. > > Modified: > httpd/httpd/trunk/CHANGES > httpd/httpd/trunk/docs/log-message-tags/next-number > httpd/httpd/trunk/modules/proxy/mod_proxy_balancer.c > > Modified: httpd/httpd/trunk/CHANGES > URL: > http://svn.apache.org/viewvc/httpd/httpd/trunk/CHANGES?rev=1696960&r1=1696959&r2=1696960&view=diff > ============================================================================== > --- httpd/httpd/trunk/CHANGES [utf-8] (original) > +++ httpd/httpd/trunk/CHANGES [utf-8] Fri Aug 21 12:34:02 2015 > @@ -1,6 +1,9 @@ > -*- coding: utf-8 -*- > Changes with Apache 2.5.0 > > + *) mod_proxy_balancer: Fix balancers and balancer members reuse on > + restart when new ones are added. PR 58024. [Yann Ylavic] > + > *) mod_socache_memcache: Add the 'MemcacheConnTTL' directive to control how > long to keep idle connections with the memcache server(s). > Change default value from 600 usec (!) to 15 sec. PR 58091 > > Modified: httpd/httpd/trunk/docs/log-message-tags/next-number > URL: > http://svn.apache.org/viewvc/httpd/httpd/trunk/docs/log-message-tags/next-number?rev=1696960&r1=1696959&r2=1696960&view=diff > ============================================================================== > --- httpd/httpd/trunk/docs/log-message-tags/next-number (original) > +++ httpd/httpd/trunk/docs/log-message-tags/next-number Fri Aug 21 12:34:02 > 2015 > @@ -1 +1 @@ > -2964 > +2966 > > Modified: httpd/httpd/trunk/modules/proxy/mod_proxy_balancer.c > URL: > http://svn.apache.org/viewvc/httpd/httpd/trunk/modules/proxy/mod_proxy_balancer.c?rev=1696960&r1=1696959&r2=1696960&view=diff > ============================================================================== > --- httpd/httpd/trunk/modules/proxy/mod_proxy_balancer.c (original) > +++ httpd/httpd/trunk/modules/proxy/mod_proxy_balancer.c Fri Aug 21 12:34:02 > 2015 > @@ -761,8 +761,11 @@ static int balancer_post_config(apr_pool > char *id; > proxy_balancer *balancer; > ap_slotmem_type_t type; > + apr_size_t attached_size; > + unsigned int attached_num; > void *sconf = s->module_config; > conf = (proxy_server_conf *)ap_get_module_config(sconf, > &proxy_module); > + > /* > * During create_proxy_config() we created a dummy id. Now that > * we have identifying info, we can create the real id > @@ -794,11 +797,39 @@ static int balancer_post_config(apr_pool > (int)ALIGNED_PROXY_BALANCER_SHARED_SIZE, > (int)conf->balancers->nelts, conf->max_balancers); > > - rv = storage->create(&new, conf->id, > - ALIGNED_PROXY_BALANCER_SHARED_SIZE, > - conf->max_balancers, type, pconf); > + /* First try to attach() since the number of configured balancers > + * may have changed during restart, and we don't want create() to > + * fail because the overall size * number of entries is not > stricly > + * identical to the previous run. There may still be enough room > + * for this new run thanks to bgrowth margin, so if attach() > + * succeeds we can only check for the number of available entries > + * to be *greater or* equal to what we need now. If attach() > fails > + * we simply fall back to create(). > + */ > + rv = storage->attach(&new, conf->id, > + &attached_size, &attached_num, > + pconf); > + if (rv != APR_SUCCESS) { > + rv = storage->create(&new, conf->id, > + ALIGNED_PROXY_BALANCER_SHARED_SIZE, > + conf->max_balancers, type, pconf); > + } > + else { > + ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(02964) > + "Balancers attached: %d, %d (%d)", > + (int)ALIGNED_PROXY_BALANCER_SHARED_SIZE, > + (int)attached_num, conf->max_balancers); > + if (attached_size == ALIGNED_PROXY_BALANCER_SHARED_SIZE > + && attached_num >= conf->balancers->nelts) { > + conf->max_balancers = attached_num; > + } > + else { > + rv = APR_ENOSPC; > + } > + } > if (rv != APR_SUCCESS) { > - ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01179) > "balancer slotmem_create failed"); > + ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01179) > + "balancer slotmem create or attach failed"); > return !OK; > } > conf->bslot = new; > @@ -864,11 +895,32 @@ static int balancer_post_config(apr_pool > (int)ALIGNED_PROXY_WORKER_SHARED_SIZE, > (int)balancer->max_workers, i); > > - rv = storage->create(&new, balancer->s->sname, > - ALIGNED_PROXY_WORKER_SHARED_SIZE, > - balancer->max_workers, type, pconf); > + /* try to attach first (see rationale from balancers above) */ > + rv = storage->attach(&new, balancer->s->sname, > + &attached_size, &attached_num, > + pconf); > + if (rv != APR_SUCCESS) { > + rv = storage->create(&new, balancer->s->sname, > + ALIGNED_PROXY_WORKER_SHARED_SIZE, > + balancer->max_workers, type, pconf); > + } > + else { > + ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(02965) > + "Workers attached: %s (%s), %d, %d (%d) [%u]", > + balancer->s->name, balancer->s->sname, > + (int)ALIGNED_PROXY_WORKER_SHARED_SIZE, > + (int)attached_num, balancer->max_workers, i); > + if (attached_size == ALIGNED_PROXY_WORKER_SHARED_SIZE > + && attached_num >= balancer->workers->nelts) { > + balancer->max_workers = attached_num; > + } > + else { > + rv = APR_ENOSPC; > + } > + } > if (rv != APR_SUCCESS) { > - ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01185) > "worker slotmem_create failed"); > + ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01185) > + "worker slotmem create or attach failed"); > return !OK; > } > balancer->wslot = new; > >
