staging: lustre: lu_object: discard extra lru count.

lu_object maintains 2 lru counts.
One is a per-bucket lsb_lru_len.
The other is the per-cpu ls_lru_len_counter.

The only times the per-bucket counters are use are:
- a debug message when an object is added
- in lu_site_stats_get when all the counters are combined.

The debug message is not essential, and the per-cpu counter
can be used to get the combined total.

So discard the per-bucket lsb_lru_len.

Reviewed-by: Andreas Dilger <andreas.dilger@dilger.ca>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/obdclass/lu_object.c b/drivers/staging/lustre/lustre/obdclass/lu_object.c
index 197dd1eab3456e29bb532e6a4a08ec36d1ef0512..b862c5aba7a61badafc151309cb14b219dcb4b08 100644 (file)
--- a/drivers/staging/lustre/lustre/obdclass/lu_object.c
+++ b/drivers/staging/lustre/lustre/obdclass/lu_object.c
@@ -57,10 +57,6 @@
 #include <linux/list.h>
 
 struct lu_site_bkt_data {
-       /**
-        * number of object in this bucket on the lsb_lru list.
-        */
-       long                    lsb_lru_len;
        /**
         * LRU list, updated on each access to object. Protected by
         * bucket lock of lu_site::ls_obj_hash.
@@ -188,10 +184,9 @@ void lu_object_put(const struct lu_env *env, struct lu_object *o)
        if (!lu_object_is_dying(top)) {
                LASSERT(list_empty(&top->loh_lru));
                list_add_tail(&top->loh_lru, &bkt->lsb_lru);
-               bkt->lsb_lru_len++;
                percpu_counter_inc(&site->ls_lru_len_counter);
-               CDEBUG(D_INODE, "Add %p to site lru. hash: %p, bkt: %p, lru_len: %ld\n",
-                      o, site->ls_obj_hash, bkt, bkt->lsb_lru_len);
+               CDEBUG(D_INODE, "Add %p to site lru. hash: %p, bkt: %p\n",
+                      o, site->ls_obj_hash, bkt);
                cfs_hash_bd_unlock(site->ls_obj_hash, &bd, 1);
                return;
        }
@@ -239,7 +234,6 @@ void lu_object_unhash(const struct lu_env *env, struct lu_object *o)
 
                        list_del_init(&top->loh_lru);
                        bkt = cfs_hash_bd_extra_get(obj_hash, &bd);
-                       bkt->lsb_lru_len--;
                        percpu_counter_dec(&site->ls_lru_len_counter);
                }
                cfs_hash_bd_del_locked(obj_hash, &bd, &top->loh_hash);
@@ -423,7 +417,6 @@ int lu_site_purge_objects(const struct lu_env *env, struct lu_site *s,
                        cfs_hash_bd_del_locked(s->ls_obj_hash,
                                               &bd2, &h->loh_hash);
                        list_move(&h->loh_lru, &dispose);
-                       bkt->lsb_lru_len--;
                        percpu_counter_dec(&s->ls_lru_len_counter);
                        if (did_sth == 0)
                                did_sth = 1;
@@ -622,7 +615,6 @@ static struct lu_object *htable_lookup(struct lu_site *s,
                lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_HIT);
                if (!list_empty(&h->loh_lru)) {
                        list_del_init(&h->loh_lru);
-                       bkt->lsb_lru_len--;
                        percpu_counter_dec(&s->ls_lru_len_counter);
                }
                return lu_object_top(h);
@@ -1858,19 +1850,24 @@ struct lu_site_stats {
        unsigned int    lss_busy;
 };
 
-static void lu_site_stats_get(struct cfs_hash *hs,
+static void lu_site_stats_get(const struct lu_site *s,
                              struct lu_site_stats *stats, int populated)
 {
+       struct cfs_hash *hs = s->ls_obj_hash;
        struct cfs_hash_bd bd;
        unsigned int i;
+       /*
+        * percpu_counter_sum_positive() won't accept a const pointer
+        * as it does modify the struct by taking a spinlock
+        */
+       struct lu_site *s2 = (struct lu_site *)s;
 
+       stats->lss_busy += cfs_hash_size_get(hs) -
+               percpu_counter_sum_positive(&s2->ls_lru_len_counter);
        cfs_hash_for_each_bucket(hs, &bd, i) {
-               struct lu_site_bkt_data *bkt = cfs_hash_bd_extra_get(hs, &bd);
                struct hlist_head       *hhead;
 
                cfs_hash_bd_lock(hs, &bd, 1);
-               stats->lss_busy  +=
-                       cfs_hash_bd_count_get(&bd) - bkt->lsb_lru_len;
                stats->lss_total += cfs_hash_bd_count_get(&bd);
                stats->lss_max_search = max((int)stats->lss_max_search,
                                            cfs_hash_bd_depmax_get(&bd));
@@ -2063,7 +2060,7 @@ int lu_site_stats_print(const struct lu_site *s, struct seq_file *m)
        struct lu_site_stats stats;
 
        memset(&stats, 0, sizeof(stats));
-       lu_site_stats_get(s->ls_obj_hash, &stats, 1);
+       lu_site_stats_get(s, &stats, 1);
 
        seq_printf(m, "%d/%d %d/%ld %d %d %d %d %d %d %d\n",
                   stats.lss_busy,