From: "J. Bruce Fields" Subject: Re: [PATCH] knfsd: Remove NLM_HOST_MAX and associated logic. Date: Thu, 7 Feb 2008 22:55:08 -0500 Message-ID: <20080208035508.GC7117@fieldses.org> References: <20080208130300.14320.patches@notabene> <1080208020337.14371@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: J.Bruce@suse.de, Fields@suse.de, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, Jeff Layton To: NeilBrown Return-path: Received: from pie.citi.umich.edu ([141.211.133.115]:50486 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756174AbYBHDzM (ORCPT ); Thu, 7 Feb 2008 22:55:12 -0500 In-Reply-To: <1080208020337.14371@suse.de> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Fri, Feb 08, 2008 at 01:03:37PM +1100, NeilBrown wrote: > > Lockd caches information about hosts that have recently held locks it > expedite the taking of further locks. Applied, thanks!--b. > > It periodically discards this information for hosts that have not been > used for a few minutes. > > lockd currently has a value NLM_HOST_MAX, and changes the 'garbage > collection' behaviour when the number of hosts exceeds this threshold. > > However it's behaviour in strange an likely not what was intended. > When the number of hosts exceeds the max, it scans *less* often (every > 2 minutes vs every minute) and allows unused host information to > remain around longer (5 minutes instead of 2). > > Having this limit is of dubious value anyway, and we have not > suffered from the code not getting the limit right, so remove the > limit altogether. We go with the larger values (discard 5 minute old > hosts every 2 minutes) as that is probably safer. > > Maybe the periodic garbage collection should be replace to with > 'shrinker' handler so we just respond to memory pressure.... > > Acked-by: Jeff Layton > Signed-off-by: Neil Brown > > ### Diffstat output > ./fs/lockd/host.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff .prev/fs/lockd/host.c ./fs/lockd/host.c > --- .prev/fs/lockd/host.c 2008-02-07 14:20:54.000000000 +1100 > +++ ./fs/lockd/host.c 2008-02-08 12:54:28.000000000 +1100 > @@ -19,12 +19,11 @@ > > > #define NLMDBG_FACILITY NLMDBG_HOSTCACHE > -#define NLM_HOST_MAX 64 > #define NLM_HOST_NRHASH 32 > #define NLM_ADDRHASH(addr) (ntohl(addr) & (NLM_HOST_NRHASH-1)) > #define NLM_HOST_REBIND (60 * HZ) > -#define NLM_HOST_EXPIRE ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ) > -#define NLM_HOST_COLLECT ((nrhosts > NLM_HOST_MAX)? 120 * HZ : 60 * HZ) > +#define NLM_HOST_EXPIRE (300 * HZ) > +#define NLM_HOST_COLLECT (120 * HZ) > > static struct hlist_head nlm_hosts[NLM_HOST_NRHASH]; > static unsigned long next_gc; > @@ -142,9 +141,7 @@ nlm_lookup_host(int server, const struct > INIT_LIST_HEAD(&host->h_granted); > INIT_LIST_HEAD(&host->h_reclaim); > > - if (++nrhosts > NLM_HOST_MAX) > - next_gc = 0; > - > + nrhosts++; > out: > mutex_unlock(&nlm_host_mutex); > return host; > - > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html