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	nfsd: split DRC global spinlock into per-bucket locks
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
		
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					 1 changed files with 20 additions and 23 deletions
				
			
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			@ -29,6 +29,7 @@
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struct nfsd_drc_bucket {
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	struct list_head lru_head;
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	spinlock_t cache_lock;
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};
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static struct nfsd_drc_bucket	*drc_hashtbl;
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			@ -79,7 +80,6 @@ static struct shrinker nfsd_reply_cache_shrinker = {
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 * A cache entry is "single use" if c_state == RC_INPROG
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 * Otherwise, it when accessing _prev or _next, the lock must be held.
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 */
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static DEFINE_SPINLOCK(cache_lock);
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static DECLARE_DELAYED_WORK(cache_cleaner, cache_cleaner_func);
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/*
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			@ -154,11 +154,11 @@ nfsd_reply_cache_free_locked(struct svc_cacherep *rp)
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}
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static void
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nfsd_reply_cache_free(struct svc_cacherep *rp)
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nfsd_reply_cache_free(struct nfsd_drc_bucket *b, struct svc_cacherep *rp)
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{
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	spin_lock(&cache_lock);
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	spin_lock(&b->cache_lock);
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	nfsd_reply_cache_free_locked(rp);
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	spin_unlock(&cache_lock);
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	spin_unlock(&b->cache_lock);
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}
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int nfsd_reply_cache_init(void)
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			@ -180,8 +180,10 @@ int nfsd_reply_cache_init(void)
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	drc_hashtbl = kcalloc(hashsize, sizeof(*drc_hashtbl), GFP_KERNEL);
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	if (!drc_hashtbl)
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		goto out_nomem;
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	for (i = 0; i < hashsize; i++)
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	for (i = 0; i < hashsize; i++) {
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		INIT_LIST_HEAD(&drc_hashtbl[i].lru_head);
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		spin_lock_init(&drc_hashtbl[i].cache_lock);
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	}
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	drc_hashsize = hashsize;
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	return 0;
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			@ -265,9 +267,13 @@ prune_cache_entries(void)
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	for (i = 0; i < drc_hashsize; i++) {
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		struct nfsd_drc_bucket *b = &drc_hashtbl[i];
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		if (list_empty(&b->lru_head))
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			continue;
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		spin_lock(&b->cache_lock);
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		freed += prune_bucket(b);
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		if (!list_empty(&b->lru_head))
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			cancel = false;
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		spin_unlock(&b->cache_lock);
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	}
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	/*
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			@ -282,9 +288,7 @@ prune_cache_entries(void)
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static void
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cache_cleaner_func(struct work_struct *unused)
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{
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	spin_lock(&cache_lock);
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	prune_cache_entries();
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	spin_unlock(&cache_lock);
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}
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static unsigned long
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			@ -296,12 +300,7 @@ nfsd_reply_cache_count(struct shrinker *shrink, struct shrink_control *sc)
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static unsigned long
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nfsd_reply_cache_scan(struct shrinker *shrink, struct shrink_control *sc)
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{
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	unsigned long freed;
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	spin_lock(&cache_lock);
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	freed = prune_cache_entries();
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	spin_unlock(&cache_lock);
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	return freed;
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	return prune_cache_entries();
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}
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/*
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 * Walk an xdr_buf and get a CRC for at most the first RC_CSUMLEN bytes
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			@ -426,14 +425,14 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
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	 * preallocate an entry.
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	 */
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	rp = nfsd_reply_cache_alloc();
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	spin_lock(&cache_lock);
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	spin_lock(&b->cache_lock);
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	if (likely(rp)) {
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		atomic_inc(&num_drc_entries);
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		drc_mem_usage += sizeof(*rp);
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	}
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	/* go ahead and prune the cache */
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	prune_cache_entries();
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	prune_bucket(b);
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	found = nfsd_cache_search(b, rqstp, csum);
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	if (found) {
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			@ -470,7 +469,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
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	}
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	rp->c_type = RC_NOCACHE;
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 out:
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	spin_unlock(&cache_lock);
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	spin_unlock(&b->cache_lock);
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	return rtn;
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found_entry:
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			@ -548,7 +547,7 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp)
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	/* Don't cache excessive amounts of data and XDR failures */
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	if (!statp || len > (256 >> 2)) {
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		nfsd_reply_cache_free(rp);
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		nfsd_reply_cache_free(b, rp);
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		return;
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	}
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			@ -563,23 +562,23 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp)
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		bufsize = len << 2;
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		cachv->iov_base = kmalloc(bufsize, GFP_KERNEL);
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		if (!cachv->iov_base) {
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			nfsd_reply_cache_free(rp);
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			nfsd_reply_cache_free(b, rp);
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			return;
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		}
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		cachv->iov_len = bufsize;
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		memcpy(cachv->iov_base, statp, bufsize);
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		break;
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	case RC_NOCACHE:
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		nfsd_reply_cache_free(rp);
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		nfsd_reply_cache_free(b, rp);
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		return;
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	}
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	spin_lock(&cache_lock);
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	spin_lock(&b->cache_lock);
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	drc_mem_usage += bufsize;
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	lru_put_end(b, rp);
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	rp->c_secure = rqstp->rq_secure;
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	rp->c_type = cachetype;
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	rp->c_state = RC_DONE;
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	spin_unlock(&cache_lock);
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	spin_unlock(&b->cache_lock);
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	return;
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}
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			@ -610,7 +609,6 @@ nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *data)
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 */
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static int nfsd_reply_cache_stats_show(struct seq_file *m, void *v)
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{
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	spin_lock(&cache_lock);
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	seq_printf(m, "max entries:           %u\n", max_drc_entries);
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	seq_printf(m, "num entries:           %u\n",
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			atomic_read(&num_drc_entries));
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			@ -622,7 +620,6 @@ static int nfsd_reply_cache_stats_show(struct seq_file *m, void *v)
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	seq_printf(m, "payload misses:        %u\n", payload_misses);
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	seq_printf(m, "longest chain len:     %u\n", longest_chain);
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	seq_printf(m, "cachesize at longest:  %u\n", longest_chain_cachesize);
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	spin_unlock(&cache_lock);
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	return 0;
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}
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