>
> 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 <jlayton@redhat.com>
> Signed-off-by: Neil Brown <neilb@suse.de>
>
> ### 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;
> -
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