From: Chuck Lever chuck.lever@oracle.com
[ Upstream commit 35308e7f0fc3942edc87d9c6dc78c4a096428957 ]
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: Jeff Layton jlayton@kernel.org Stable-dep-of: a9507f6af145 ("NFSD: Replace nfsd_prune_bucket()") Signed-off-by: Chuck Lever chuck.lever@oracle.com --- fs/nfsd/nfscache.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-)
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c index 587ff31deb6e..d078366fd0f8 100644 --- a/fs/nfsd/nfscache.c +++ b/fs/nfsd/nfscache.c @@ -110,21 +110,33 @@ nfsd_reply_cache_alloc(struct svc_rqst *rqstp, __wsum csum, return rp; }
-static void -nfsd_reply_cache_free_locked(struct nfsd_drc_bucket *b, struct svc_cacherep *rp, - struct nfsd_net *nn) +static void nfsd_cacherep_free(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_type == RC_REPLBUFF) 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) { rb_erase(&rp->c_node, &b->rb_head); list_del(&rp->c_lru); atomic_dec(&nn->num_drc_entries); 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 @@ -132,8 +144,9 @@ nfsd_reply_cache_free(struct nfsd_drc_bucket *b, struct svc_cacherep *rp, struct nfsd_net *nn) { 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); + nfsd_cacherep_free(rp); }
int nfsd_drc_slab_create(void)