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nfsd: give block_delegation and delegation_blocked its own spinlock

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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: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Jeff Layton 2014-07-25 07:34:26 -04:00 committed by J. Bruce Fields
parent 0b26693c56
commit f54fe962b8
1 changed files with 11 additions and 10 deletions
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21
fs/nfsd/nfs4state.c
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@ -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);
block_delegations(&dp->dl_fh);
/*
* 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);
/*
* 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);