Commit a0ef5e19 authored by Jeff Layton's avatar Jeff Layton Committed by J. Bruce Fields
Browse files

nfsd: don't try to reuse an expired DRC entry off the list 



Currently when we are processing a request, we try to scrape an expired
or over-limit entry off the list in preference to allocating a new one
from the slab.

This is unnecessarily complicated. Just use the slab layer.

Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 28303ca3

fs/nfsd/nfscache.c

+4 −32
Original line number Diff line number Diff line
@@ -131,13 +131,6 @@ nfsd_reply_cache_alloc(void) 
	return rp;

}



static void

nfsd_reply_cache_unhash(struct svc_cacherep *rp)

{

	hlist_del_init(&rp->c_hash);

	list_del_init(&rp->c_lru);

}



static void

nfsd_reply_cache_free_locked(struct svc_cacherep *rp)

{
@@ -416,22 +409,8 @@ nfsd_cache_lookup(struct svc_rqst *rqstp) 


	/*

	 * Since the common case is a cache miss followed by an insert,

	 * preallocate an entry. First, try to reuse the first entry on the LRU

	 * if it works, then go ahead and prune the LRU list.

	 * preallocate an entry.

	 */

	spin_lock(&cache_lock);

	if (!list_empty(&lru_head)) {

		rp = list_first_entry(&lru_head, struct svc_cacherep, c_lru);

		if (nfsd_cache_entry_expired(rp) ||

		    num_drc_entries >= max_drc_entries) {

			nfsd_reply_cache_unhash(rp);

			prune_cache_entries();

			goto search_cache;

		}

	}



	/* No expired ones available, allocate a new one. */

	spin_unlock(&cache_lock);

	rp = nfsd_reply_cache_alloc();

	spin_lock(&cache_lock);

	if (likely(rp)) {
@@ -439,7 +418,9 @@ nfsd_cache_lookup(struct svc_rqst *rqstp) 
		drc_mem_usage += sizeof(*rp);

	}



search_cache:

	/* go ahead and prune the cache */

	prune_cache_entries();



	found = nfsd_cache_search(rqstp, csum);

	if (found) {

		if (likely(rp))
@@ -453,15 +434,6 @@ nfsd_cache_lookup(struct svc_rqst *rqstp) 
		goto out;

	}



	/*

	 * We're keeping the one we just allocated. Are we now over the

	 * limit? Prune one off the tip of the LRU in trade for the one we

	 * just allocated if so.

	 */

	if (num_drc_entries >= max_drc_entries)

		nfsd_reply_cache_free_locked(list_first_entry(&lru_head,

						struct svc_cacherep, c_lru));



	nfsdstats.rcmisses++;

	rqstp->rq_cacherep = rp;

	rp->c_state = RC_INPROG;