Commit 31e60f52 authored by Trond Myklebust's avatar Trond Myklebust Committed by J. Bruce Fields
Browse files

nfsd: convert num_drc_entries to an atomic_t 



...so we can remove the spinlocking around it.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 11acf6ef

fs/nfsd/nfscache.c

+12 −16
Original line number Diff line number Diff line
@@ -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);