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Commit bedd4b61 authored by Trond Myklebust's avatar Trond Myklebust Committed by J. Bruce Fields
Browse files

nfsd: convert the lru list into a per-bucket thing 



Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 7142b98d

fs/nfsd/nfscache.c

+50 −23
Original line number Diff line number Diff line
@@ -29,10 +29,10 @@ 


struct nfsd_drc_bucket {

	struct hlist_head cache_hash;

	struct list_head lru_head;

};



static struct nfsd_drc_bucket	*drc_hashtbl;

static struct list_head 	lru_head;

static struct kmem_cache	*drc_slab;



/* max number of entries allowed in the cache */
@@ -40,6 +40,7 @@ static unsigned int max_drc_entries; 


/* number of significant bits in the hash value */

static unsigned int		maskbits;

static unsigned int		drc_hashsize;



/*

 * Stats and other tracking of on the duplicate reply cache. All of these and
@@ -167,8 +168,8 @@ nfsd_reply_cache_free(struct svc_cacherep *rp) 
int nfsd_reply_cache_init(void)

{

	unsigned int hashsize;

	unsigned int i;



	INIT_LIST_HEAD(&lru_head);

	max_drc_entries = nfsd_cache_size_limit();

	num_drc_entries = 0;

	hashsize = nfsd_hashsize(max_drc_entries);
@@ -183,6 +184,9 @@ 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++)

		INIT_LIST_HEAD(&drc_hashtbl[i].lru_head);

	drc_hashsize = hashsize;



	return 0;

out_nomem:
@@ -194,17 +198,22 @@ int nfsd_reply_cache_init(void) 
void nfsd_reply_cache_shutdown(void)

{

	struct svc_cacherep	*rp;

	unsigned int i;



	unregister_shrinker(&nfsd_reply_cache_shrinker);

	cancel_delayed_work_sync(&cache_cleaner);



	while (!list_empty(&lru_head)) {

		rp = list_entry(lru_head.next, struct svc_cacherep, c_lru);

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

		struct list_head *head = &drc_hashtbl[i].lru_head;

		while (!list_empty(head)) {

			rp = list_first_entry(head, struct svc_cacherep, c_lru);

			nfsd_reply_cache_free_locked(rp);

		}

	}



	kfree (drc_hashtbl);

	drc_hashtbl = NULL;

	drc_hashsize = 0;



	if (drc_slab) {

		kmem_cache_destroy(drc_slab);
@@ -217,10 +226,10 @@ void nfsd_reply_cache_shutdown(void) 
 * not already scheduled.

 */

static void

lru_put_end(struct svc_cacherep *rp)

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

{

	rp->c_timestamp = jiffies;

	list_move_tail(&rp->c_lru, &lru_head);

	list_move_tail(&rp->c_lru, &b->lru_head);

	schedule_delayed_work(&cache_cleaner, RC_EXPIRE);

}
@@ -234,17 +243,13 @@ hash_refile(struct nfsd_drc_bucket *b, struct svc_cacherep *rp) 
	hlist_add_head(&rp->c_hash, &b->cache_hash);

}



/*

 * Walk the LRU list and prune off entries that are older than RC_EXPIRE.

 * Also prune the oldest ones when the total exceeds the max number of entries.

 */

static long

prune_cache_entries(void)

prune_bucket(struct nfsd_drc_bucket *b)

{

	struct svc_cacherep *rp, *tmp;

	long freed = 0;



	list_for_each_entry_safe(rp, tmp, &lru_head, c_lru) {

	list_for_each_entry_safe(rp, tmp, &b->lru_head, c_lru) {

		/*

		 * Don't free entries attached to calls that are still

		 * in-progress, but do keep scanning the list.
@@ -257,16 +262,33 @@ prune_cache_entries(void) 
		nfsd_reply_cache_free_locked(rp);

		freed++;

	}

	return freed;

}



/*

	 * Conditionally rearm the job. If we cleaned out the list, then

	 * cancel any pending run (since there won't be any work to do).

	 * Otherwise, we rearm the job or modify the existing one to run in

	 * RC_EXPIRE since we just ran the pruner.

 * Walk the LRU list and prune off entries that are older than RC_EXPIRE.

 * Also prune the oldest ones when the total exceeds the max number of entries.

 */

	if (list_empty(&lru_head))

		cancel_delayed_work(&cache_cleaner);

	else

static long

prune_cache_entries(void)

{

	unsigned int i;

	long freed = 0;

	bool cancel = true;



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

		struct nfsd_drc_bucket *b = &drc_hashtbl[i];



		freed += prune_bucket(b);

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

			cancel = false;

	}



	/*

	 * Conditionally rearm the job to run in RC_EXPIRE since we just

	 * ran the pruner.

	 */

	if (!cancel)

		mod_delayed_work(system_wq, &cache_cleaner, RC_EXPIRE);

	return freed;

}
@@ -458,7 +480,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp) 
	rp->c_csum = csum;



	hash_refile(b, rp);

	lru_put_end(rp);

	lru_put_end(b, rp);



	/* release any buffer */

	if (rp->c_type == RC_REPLBUFF) {
@@ -475,7 +497,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp) 
	nfsdstats.rchits++;

	/* We found a matching entry which is either in progress or done. */

	age = jiffies - rp->c_timestamp;

	lru_put_end(rp);

	lru_put_end(b, rp);



	rtn = RC_DROPIT;

	/* Request being processed or excessive rexmits */
@@ -530,12 +552,17 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp) 
{

	struct svc_cacherep *rp = rqstp->rq_cacherep;

	struct kvec	*resv = &rqstp->rq_res.head[0], *cachv;

	u32		hash;

	struct nfsd_drc_bucket *b;

	int		len;

	size_t		bufsize = 0;



	if (!rp)

		return;



	hash = nfsd_cache_hash(rp->c_xid);

	b = &drc_hashtbl[hash];



	len = resv->iov_len - ((char*)statp - (char*)resv->iov_base);

	len >>= 2;
@@ -568,7 +595,7 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp) 
	}

	spin_lock(&cache_lock);

	drc_mem_usage += bufsize;

	lru_put_end(rp);

	lru_put_end(b, rp);

	rp->c_secure = rqstp->rq_secure;

	rp->c_type = cachetype;

	rp->c_state = RC_DONE;