@@ -47,7 +47,7 @@ static unsigned int drc_hashsize;
*/
/* total number of entries */
-static unsigned int num_drc_entries;
+static atomic_t num_drc_entries;
/* cache misses due only to checksum comparison failures */
static unsigned int payload_misses;
@@ -148,7 +148,7 @@ nfsd_reply_cache_free_locked(struct svc_cacherep *rp)
kfree(rp->c_replvec.iov_base);
}
list_del(&rp->c_lru);
- --num_drc_entries;
+ atomic_dec(&num_drc_entries);
drc_mem_usage -= sizeof(*rp);
kmem_cache_free(drc_slab, rp);
}
@@ -167,7 +167,7 @@ int nfsd_reply_cache_init(void)
unsigned int i;
max_drc_entries = nfsd_cache_size_limit();
- num_drc_entries = 0;
+ atomic_set(&num_drc_entries, 0);
hashsize = nfsd_hashsize(max_drc_entries);
maskbits = ilog2(hashsize);
@@ -242,7 +242,7 @@ prune_bucket(struct nfsd_drc_bucket *b)
*/
if (rp->c_state == RC_INPROG)
continue;
- if (num_drc_entries <= max_drc_entries &&
+ if (atomic_read(&num_drc_entries) <= max_drc_entries &&
time_before(jiffies, rp->c_timestamp + RC_EXPIRE))
break;
nfsd_reply_cache_free_locked(rp);
@@ -290,13 +290,7 @@ cache_cleaner_func(struct work_struct *unused)
static unsigned long
nfsd_reply_cache_count(struct shrinker *shrink, struct shrink_control *sc)
{
- unsigned long num;
-
- spin_lock(&cache_lock);
- num = num_drc_entries;
- spin_unlock(&cache_lock);
-
- return num;
+ return atomic_read(&num_drc_entries);
}
static unsigned long
@@ -386,11 +380,12 @@ nfsd_cache_search(struct nfsd_drc_bucket *b, struct svc_rqst *rqstp,
/* tally hash chain length stats */
if (entries > longest_chain) {
longest_chain = entries;
- longest_chain_cachesize = num_drc_entries;
+ longest_chain_cachesize = atomic_read(&num_drc_entries);
} else if (entries == longest_chain) {
/* prefer to keep the smallest cachesize possible here */
- longest_chain_cachesize = min(longest_chain_cachesize,
- num_drc_entries);
+ longest_chain_cachesize = min_t(unsigned int,
+ longest_chain_cachesize,
+ atomic_read(&num_drc_entries));
}
return ret;
@@ -433,7 +428,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
rp = nfsd_reply_cache_alloc();
spin_lock(&cache_lock);
if (likely(rp)) {
- ++num_drc_entries;
+ atomic_inc(&num_drc_entries);
drc_mem_usage += sizeof(*rp);
}
@@ -617,7 +612,8 @@ static int nfsd_reply_cache_stats_show(struct seq_file *m, void *v)
{
spin_lock(&cache_lock);
seq_printf(m, "max entries: %u\n", max_drc_entries);
- seq_printf(m, "num entries: %u\n", num_drc_entries);
+ seq_printf(m, "num entries: %u\n",
+ atomic_read(&num_drc_entries));
seq_printf(m, "hash buckets: %u\n", 1 << maskbits);
seq_printf(m, "mem usage: %u\n", drc_mem_usage);
seq_printf(m, "cache hits: %u\n", nfsdstats.rchits);
...so we can remove the spinlocking around it. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> --- fs/nfsd/nfscache.c | 28 ++++++++++++---------------- 1 file changed, 12 insertions(+), 16 deletions(-)