The state lock can be fairly heavily contended, and there's no reason
that nfs4_file lookups and delegation_blocked should be mutually
exclusive. Let's give the new block_delegation code its own spinlock.
It does mean that we'll need to take a different lock in the delegation
break code, but that's not generally as critical to performance.
Cc: Neil Brown <neilb@xxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
---
fs/nfsd/nfs4state.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index a2c6c85adfc7..952def00363b 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -506,10 +506,11 @@ static struct nfs4_ol_stateid * nfs4_alloc_stateid(struct nfs4_client *clp)
* Each filter is 256 bits. We hash the filehandle to 32bit and use the
* low 3 bytes as hash-table indices.
*
- * 'state_lock', which is always held when block_delegations() is called,
- * is used to manage concurrent access. Testing does not need the lock
- * except when swapping the two filters.
+ * 'blocked_delegations_lock', which is always held when block_delegations()
+ * is called, is used to manage concurrent access. Testing does not need the
+ * lock except when swapping the two filters.
*/
+static DEFINE_SPINLOCK(blocked_delegations_lock);
static struct bloom_pair {
int entries, old_entries;
time_t swap_time;
@@ -525,7 +526,7 @@ static int delegation_blocked(struct knfsd_fh *fh)
if (bd->entries == 0)
return 0;
if (seconds_since_boot() - bd->swap_time > 30) {
- spin_lock(&state_lock);
+ spin_lock(&blocked_delegations_lock);
if (seconds_since_boot() - bd->swap_time > 30) {
bd->entries -= bd->old_entries;
bd->old_entries = bd->entries;
@@ -534,7 +535,7 @@ static int delegation_blocked(struct knfsd_fh *fh)
bd->new = 1-bd->new;
bd->swap_time = seconds_since_boot();
}
- spin_unlock(&state_lock);
+ spin_unlock(&blocked_delegations_lock);
}
hash = arch_fast_hash(&fh->fh_base, fh->fh_size, 0);
if (test_bit(hash&255, bd->set[0]) &&
@@ -555,16 +556,16 @@ static void block_delegations(struct knfsd_fh *fh)
u32 hash;
struct bloom_pair *bd = &blocked_delegations;
- lockdep_assert_held(&state_lock);
-
hash = arch_fast_hash(&fh->fh_base, fh->fh_size, 0);
__set_bit(hash&255, bd->set[bd->new]);
__set_bit((hash>>8)&255, bd->set[bd->new]);
__set_bit((hash>>16)&255, bd->set[bd->new]);
+ spin_lock(&blocked_delegations_lock);
if (bd->entries == 0)
bd->swap_time = seconds_since_boot();
bd->entries += 1;
+ spin_unlock(&blocked_delegations_lock);
}
static struct nfs4_delegation *
@@ -3097,16 +3098,16 @@ void nfsd4_prepare_cb_recall(struct nfs4_delegation *dp)
struct nfs4_client *clp = dp->dl_stid.sc_client;
struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
- /*
- * We can't do this in nfsd_break_deleg_cb because it is
- * already holding inode->i_lock
- */
- spin_lock(&state_lock);
block_delegations(&dp->dl_fh);
+
/*
+ * We can't do this in nfsd_break_deleg_cb because it is
+ * already holding inode->i_lock.
+ *
* If the dl_time != 0, then we know that it has already been
* queued for a lease break. Don't queue it again.
*/
+ spin_lock(&state_lock);
if (dp->dl_time == 0) {
dp->dl_time = get_seconds();
list_add_tail(&dp->dl_recall_lru, &nn->del_recall_lru);
--
1.9.3
--
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