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Commit 89a26b3d authored by Trond Myklebust's avatar Trond Myklebust Committed by J. Bruce Fields
Browse files

nfsd: split DRC global spinlock into per-bucket locks 



Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 31e60f52

fs/nfsd/nfscache.c

+20 −23
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 


struct nfsd_drc_bucket {

	struct list_head lru_head;

	spinlock_t cache_lock;

};



static struct nfsd_drc_bucket	*drc_hashtbl;
@@ -79,7 +80,6 @@ static struct shrinker nfsd_reply_cache_shrinker = { 
 * A cache entry is "single use" if c_state == RC_INPROG

 * Otherwise, it when accessing _prev or _next, the lock must be held.

 */

static DEFINE_SPINLOCK(cache_lock);

static DECLARE_DELAYED_WORK(cache_cleaner, cache_cleaner_func);



/*
@@ -154,11 +154,11 @@ nfsd_reply_cache_free_locked(struct svc_cacherep *rp) 
}



static void

nfsd_reply_cache_free(struct svc_cacherep *rp)

nfsd_reply_cache_free(struct nfsd_drc_bucket *b, struct svc_cacherep *rp)

{

	spin_lock(&cache_lock);

	spin_lock(&b->cache_lock);

	nfsd_reply_cache_free_locked(rp);

	spin_unlock(&cache_lock);

	spin_unlock(&b->cache_lock);

}



int nfsd_reply_cache_init(void)
@@ -180,8 +180,10 @@ int nfsd_reply_cache_init(void) 
	drc_hashtbl = kcalloc(hashsize, sizeof(*drc_hashtbl), GFP_KERNEL);

	if (!drc_hashtbl)

		goto out_nomem;

	for (i = 0; i < hashsize; i++)

	for (i = 0; i < hashsize; i++) {

		INIT_LIST_HEAD(&drc_hashtbl[i].lru_head);

		spin_lock_init(&drc_hashtbl[i].cache_lock);

	}

	drc_hashsize = hashsize;



	return 0;
@@ -265,9 +267,13 @@ prune_cache_entries(void) 
	for (i = 0; i < drc_hashsize; i++) {

		struct nfsd_drc_bucket *b = &drc_hashtbl[i];



		if (list_empty(&b->lru_head))

			continue;

		spin_lock(&b->cache_lock);

		freed += prune_bucket(b);

		if (!list_empty(&b->lru_head))

			cancel = false;

		spin_unlock(&b->cache_lock);

	}



	/*
@@ -282,9 +288,7 @@ prune_cache_entries(void) 
static void

cache_cleaner_func(struct work_struct *unused)

{

	spin_lock(&cache_lock);

	prune_cache_entries();

	spin_unlock(&cache_lock);

}



static unsigned long
@@ -296,12 +300,7 @@ nfsd_reply_cache_count(struct shrinker *shrink, struct shrink_control *sc) 
static unsigned long

nfsd_reply_cache_scan(struct shrinker *shrink, struct shrink_control *sc)

{

	unsigned long freed;



	spin_lock(&cache_lock);

	freed = prune_cache_entries();

	spin_unlock(&cache_lock);

	return freed;

	return prune_cache_entries();

}

/*

 * Walk an xdr_buf and get a CRC for at most the first RC_CSUMLEN bytes
@@ -426,14 +425,14 @@ nfsd_cache_lookup(struct svc_rqst *rqstp) 
	 * preallocate an entry.

	 */

	rp = nfsd_reply_cache_alloc();

	spin_lock(&cache_lock);

	spin_lock(&b->cache_lock);

	if (likely(rp)) {

		atomic_inc(&num_drc_entries);

		drc_mem_usage += sizeof(*rp);

	}



	/* go ahead and prune the cache */

	prune_cache_entries();

	prune_bucket(b);



	found = nfsd_cache_search(b, rqstp, csum);

	if (found) {
@@ -470,7 +469,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp) 
	}

	rp->c_type = RC_NOCACHE;

 out:

	spin_unlock(&cache_lock);

	spin_unlock(&b->cache_lock);

	return rtn;



found_entry:
@@ -548,7 +547,7 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp) 


	/* Don't cache excessive amounts of data and XDR failures */

	if (!statp || len > (256 >> 2)) {

		nfsd_reply_cache_free(rp);

		nfsd_reply_cache_free(b, rp);

		return;

	}
@@ -563,23 +562,23 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp) 
		bufsize = len << 2;

		cachv->iov_base = kmalloc(bufsize, GFP_KERNEL);

		if (!cachv->iov_base) {

			nfsd_reply_cache_free(rp);

			nfsd_reply_cache_free(b, rp);

			return;

		}

		cachv->iov_len = bufsize;

		memcpy(cachv->iov_base, statp, bufsize);

		break;

	case RC_NOCACHE:

		nfsd_reply_cache_free(rp);

		nfsd_reply_cache_free(b, rp);

		return;

	}

	spin_lock(&cache_lock);

	spin_lock(&b->cache_lock);

	drc_mem_usage += bufsize;

	lru_put_end(b, rp);

	rp->c_secure = rqstp->rq_secure;

	rp->c_type = cachetype;

	rp->c_state = RC_DONE;

	spin_unlock(&cache_lock);

	spin_unlock(&b->cache_lock);

	return;

}
@@ -610,7 +609,6 @@ nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *data) 
 */

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",

			atomic_read(&num_drc_entries));
@@ -622,7 +620,6 @@ static int nfsd_reply_cache_stats_show(struct seq_file *m, void *v) 
	seq_printf(m, "payload misses:        %u\n", payload_misses);

	seq_printf(m, "longest chain len:     %u\n", longest_chain);

	seq_printf(m, "cachesize at longest:  %u\n", longest_chain_cachesize);

	spin_unlock(&cache_lock);

	return 0;

}