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Commit f54fe962 authored by Jeff Layton's avatar Jeff Layton Committed by J. Bruce Fields
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nfsd: give block_delegation and delegation_blocked its own spinlock 



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@suse.de>
Signed-off-by: default avatarJeff Layton <jlayton@primarydata.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 0b26693c

fs/nfsd/nfs4state.c

+11 −10
Original line number Diff line number Diff line
@@ -517,10 +517,11 @@ 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,

 * 'blocked_delegations_lock', which is always taken in block_delegations(),

 * 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;
@@ -536,7 +537,7 @@ 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;
@@ -545,7 +546,7 @@ 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]) &&
@@ -566,16 +567,16 @@ 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);



	spin_lock(&blocked_delegations_lock);

	__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]);

	if (bd->entries == 0)

		bd->swap_time = seconds_since_boot();

	bd->entries += 1;

	spin_unlock(&blocked_delegations_lock);

}



static struct nfs4_delegation *
@@ -3096,16 +3097,16 @@ 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);