nfsd: optimize destroy_lockowner cl_lock thrashing
Reduce the cl_lock trashing in destroy_lockowner. Unhash all of the
lockstateids on the lockowner's list. Put the reference under the lock
and see if it was the last one. If so, then add it to a private list
to be destroyed after we drop the lock.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 9b342e1..9358cbe 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -983,14 +983,23 @@
nfs4_free_ol_stateid(stid);
}
+static void unhash_lock_stateid(struct nfs4_ol_stateid *stp)
+{
+ struct nfs4_openowner *oo = openowner(stp->st_openstp->st_stateowner);
+
+ lockdep_assert_held(&oo->oo_owner.so_client->cl_lock);
+
+ list_del_init(&stp->st_locks);
+ unhash_generic_stateid(stp);
+ unhash_stid(&stp->st_stid);
+}
+
static void release_lock_stateid(struct nfs4_ol_stateid *stp)
{
struct nfs4_openowner *oo = openowner(stp->st_openstp->st_stateowner);
spin_lock(&oo->oo_owner.so_client->cl_lock);
- list_del(&stp->st_locks);
- unhash_generic_stateid(stp);
- unhash_stid(&stp->st_stid);
+ unhash_lock_stateid(stp);
spin_unlock(&oo->oo_owner.so_client->cl_lock);
nfs4_put_stid(&stp->st_stid);
}
@@ -1004,30 +1013,38 @@
list_del_init(&lo->lo_owner.so_strhash);
}
-static void release_lockowner_stateids(struct nfs4_lockowner *lo)
-{
- struct nfs4_client *clp = lo->lo_owner.so_client;
- struct nfs4_ol_stateid *stp;
-
- lockdep_assert_held(&clp->cl_lock);
-
- while (!list_empty(&lo->lo_owner.so_stateids)) {
- stp = list_first_entry(&lo->lo_owner.so_stateids,
- struct nfs4_ol_stateid, st_perstateowner);
- spin_unlock(&clp->cl_lock);
- release_lock_stateid(stp);
- spin_lock(&clp->cl_lock);
- }
-}
-
static void release_lockowner(struct nfs4_lockowner *lo)
{
struct nfs4_client *clp = lo->lo_owner.so_client;
+ struct nfs4_ol_stateid *stp;
+ struct list_head reaplist;
+
+ INIT_LIST_HEAD(&reaplist);
spin_lock(&clp->cl_lock);
unhash_lockowner_locked(lo);
- release_lockowner_stateids(lo);
+ while (!list_empty(&lo->lo_owner.so_stateids)) {
+ stp = list_first_entry(&lo->lo_owner.so_stateids,
+ struct nfs4_ol_stateid, st_perstateowner);
+ unhash_lock_stateid(stp);
+ /*
+ * We now know that no new references can be added to the
+ * stateid. If ours is the last one, finish the unhashing
+ * and put it on the list to be reaped.
+ */
+ if (atomic_dec_and_test(&stp->st_stid.sc_count)) {
+ idr_remove(&clp->cl_stateids,
+ stp->st_stid.sc_stateid.si_opaque.so_id);
+ list_add(&stp->st_locks, &reaplist);
+ }
+ }
spin_unlock(&clp->cl_lock);
+ while (!list_empty(&reaplist)) {
+ stp = list_first_entry(&reaplist, struct nfs4_ol_stateid,
+ st_locks);
+ list_del(&stp->st_locks);
+ stp->st_stid.sc_free(&stp->st_stid);
+ }
nfs4_put_stateowner(&lo->lo_owner);
}