[PATCH 11/20] staging: lustre: lu_object: discard extra lru count.

From: NeilBrown
Date: Wed Apr 11 2018 - 17:56:45 EST


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.

Signed-off-by: NeilBrown <neilb@xxxxxxxx>
---
drivers/staging/lustre/lustre/obdclass/lu_object.c | 24 ++++++++------------
1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/drivers/staging/lustre/lustre/obdclass/lu_object.c b/drivers/staging/lustre/lustre/obdclass/lu_object.c
index 2a8a25d6edb5..2bf089817157 100644
--- 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.
@@ -187,10 +183,9 @@ 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;
}
@@ -238,7 +233,6 @@ 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);
@@ -422,7 +416,6 @@ 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;
@@ -621,7 +614,6 @@ 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);
@@ -1834,19 +1826,21 @@ 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_read_positive() won't accept a const pointer */
+ struct lu_site *s2 = (struct lu_site *)s;

+ stats->lss_busy += cfs_hash_size_get(hs) -
+ percpu_counter_read_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));
@@ -2039,7 +2033,7 @@ 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,