Commit 35308e7f authored by Chuck Lever's avatar Chuck Lever
Browse files

NFSD: Refactor nfsd_reply_cache_free_locked() 



To reduce contention on the bucket locks, we must avoid calling
kfree() while each bucket lock is held.

Start by refactoring nfsd_reply_cache_free_locked() into a helper
that removes an entry from the bucket (and must therefore run under
the lock) and a second helper that frees the entry (which does not
need to hold the lock).

For readability, rename the helpers nfsd_cacherep_<verb>.

Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 2a9893f7

fs/nfsd/nfscache.c

+20 −7
Original line number Original line Diff line number Diff line
@@ -110,21 +110,33 @@ nfsd_reply_cache_alloc(struct svc_rqst *rqstp, __wsum csum, 
	return rp;

	return rp;

}

}





static void

static void nfsd_cacherep_free(struct svc_cacherep *rp)

nfsd_reply_cache_free_locked(struct nfsd_drc_bucket *b, struct svc_cacherep *rp,

				struct nfsd_net *nn)

{

{

	if (rp->c_type == RC_REPLBUFF && rp->c_replvec.iov_base) {

	if (rp->c_type == RC_REPLBUFF)

		nfsd_stats_drc_mem_usage_sub(nn, rp->c_replvec.iov_len);

		kfree(rp->c_replvec.iov_base);

		kfree(rp->c_replvec.iov_base);

	kmem_cache_free(drc_slab, rp);

}

}



static void

nfsd_cacherep_unlink_locked(struct nfsd_net *nn, struct nfsd_drc_bucket *b,

			    struct svc_cacherep *rp)

{

	if (rp->c_type == RC_REPLBUFF && rp->c_replvec.iov_base)

		nfsd_stats_drc_mem_usage_sub(nn, rp->c_replvec.iov_len);

	if (rp->c_state != RC_UNUSED) {

	if (rp->c_state != RC_UNUSED) {

		rb_erase(&rp->c_node, &b->rb_head);

		rb_erase(&rp->c_node, &b->rb_head);

		list_del(&rp->c_lru);

		list_del(&rp->c_lru);

		atomic_dec(&nn->num_drc_entries);

		atomic_dec(&nn->num_drc_entries);

		nfsd_stats_drc_mem_usage_sub(nn, sizeof(*rp));

		nfsd_stats_drc_mem_usage_sub(nn, sizeof(*rp));

	}

	}

	kmem_cache_free(drc_slab, rp);

}



static void

nfsd_reply_cache_free_locked(struct nfsd_drc_bucket *b, struct svc_cacherep *rp,

				struct nfsd_net *nn)

{

	nfsd_cacherep_unlink_locked(nn, b, rp);

	nfsd_cacherep_free(rp);

}

}





static void

static void
@@ -132,8 +144,9 @@ nfsd_reply_cache_free(struct nfsd_drc_bucket *b, struct svc_cacherep *rp, 
			struct nfsd_net *nn)

			struct nfsd_net *nn)

{

{

	spin_lock(&b->cache_lock);

	spin_lock(&b->cache_lock);

	nfsd_reply_cache_free_locked(b, rp, nn);

	nfsd_cacherep_unlink_locked(nn, b, rp);

	spin_unlock(&b->cache_lock);

	spin_unlock(&b->cache_lock);

	nfsd_cacherep_free(rp);

}

}





int nfsd_drc_slab_create(void)

int nfsd_drc_slab_create(void)