knfsd: Improve lookup performance in the duplicate reply cache using an rbtree (736c6625) · Commits · 戴 / test

fs/nfsd/cache.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -30,6 +30,7 @@ struct svc_cacherep {
		struct sockaddr_in6 k_addr;
		} c_key;

		struct rb_node c_node;
		struct list_head c_lru;
		unsigned char c_state, /* unused, inprog, done */
		c_type, /* status, buffer */

fs/nfsd/nfscache.c

+26 −11

Original line number	Diff line number	Diff line
		@@ -30,6 +30,7 @@
		#define TARGET_BUCKET_SIZE 64

		struct nfsd_drc_bucket {
		struct rb_root rb_head;
		struct list_head lru_head;
		spinlock_t cache_lock;
		};
		@@ -129,6 +130,7 @@ nfsd_reply_cache_alloc(struct svc_rqst *rqstp, __wsum csum)
		if (rp) {
		rp->c_state = RC_UNUSED;
		rp->c_type = RC_NOCACHE;
		RB_CLEAR_NODE(&rp->c_node);
		INIT_LIST_HEAD(&rp->c_lru);

		memset(&rp->c_key, 0, sizeof(rp->c_key));
		@@ -145,13 +147,14 @@ nfsd_reply_cache_alloc(struct svc_rqst *rqstp, __wsum csum)
		}

		static void
		nfsd_reply_cache_free_locked(struct svc_cacherep *rp)
		nfsd_reply_cache_free_locked(struct nfsd_drc_bucket b, struct svc_cacherep rp)
		{
		if (rp->c_type == RC_REPLBUFF && rp->c_replvec.iov_base) {
		drc_mem_usage -= rp->c_replvec.iov_len;
		kfree(rp->c_replvec.iov_base);
		}
		if (rp->c_state != RC_UNUSED) {
		rb_erase(&rp->c_node, &b->rb_head);
		list_del(&rp->c_lru);
		atomic_dec(&num_drc_entries);
		drc_mem_usage -= sizeof(*rp);
		@@ -163,7 +166,7 @@ static void
		nfsd_reply_cache_free(struct nfsd_drc_bucket b, struct svc_cacherep rp)
		{
		spin_lock(&b->cache_lock);
		nfsd_reply_cache_free_locked(rp);
		nfsd_reply_cache_free_locked(b, rp);
		spin_unlock(&b->cache_lock);
		}

		@@ -219,7 +222,7 @@ void nfsd_reply_cache_shutdown(void)
		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);
		nfsd_reply_cache_free_locked(&drc_hashtbl[i], rp);
		}
		}

		@@ -258,7 +261,7 @@ prune_bucket(struct nfsd_drc_bucket *b)
		if (atomic_read(&num_drc_entries) <= max_drc_entries &&
		time_before(jiffies, rp->c_timestamp + RC_EXPIRE))
		break;
		nfsd_reply_cache_free_locked(rp);
		nfsd_reply_cache_free_locked(b, rp);
		freed++;
		}
		return freed;
		@@ -349,17 +352,29 @@ static struct svc_cacherep *
		nfsd_cache_insert(struct nfsd_drc_bucket b, struct svc_cacherep key)
		{
		struct svc_cacherep rp, ret = key;
		struct list_head *rh = &b->lru_head;
		struct rb_node **p = &b->rb_head.rb_node,
		*parent = NULL;
		unsigned int entries = 0;
		int cmp;

		list_for_each_entry(rp, rh, c_lru) {
		while (*p != NULL) {
		++entries;
		if (nfsd_cache_key_cmp(key, rp) == 0) {
		parent = *p;
		rp = rb_entry(parent, struct svc_cacherep, c_node);

		cmp = nfsd_cache_key_cmp(key, rp);
		if (cmp < 0)
		p = &parent->rb_left;
		else if (cmp > 0)
		p = &parent->rb_right;
		else {
		ret = rp;
		break;
		goto out;
		}
		}

		rb_link_node(&key->c_node, parent, p);
		rb_insert_color(&key->c_node, &b->rb_head);
		out:
		/* tally hash chain length stats */
		if (entries > longest_chain) {
		longest_chain = entries;
		@@ -414,7 +429,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
		spin_lock(&b->cache_lock);
		found = nfsd_cache_insert(b, rp);
		if (found != rp) {
		nfsd_reply_cache_free_locked(rp);
		nfsd_reply_cache_free_locked(NULL, rp);
		rp = found;
		goto found_entry;
		}
		@@ -462,7 +477,7 @@ found_entry:
		break;
		default:
		printk(KERN_WARNING "nfsd: bad repcache type %d\n", rp->c_type);
		nfsd_reply_cache_free_locked(rp);
		nfsd_reply_cache_free_locked(b, rp);
		}

		goto out;

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