LU-8130 ldlm: simplify ldlm_ns_hash_defs[]

As the ldlm_ns_types are dense, we can use the type as
the index to the array, rather than searching through
the array for a match.
We can also discard nsd_hops as all hash tables now
use the same hops.
This makes the table smaller and the code simpler.

Change-Id: I2aebb9d533d676bed51a7422801545be4fbb7e1e
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-on: https://review.whamcloud.com/36220
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Mike Pershin <mpershin@whamcloud.com>
Reviewed-by: Neil Brown <neilb@suse.de>

diff --git a/lustre/ldlm/ldlm_resource.c b/lustre/ldlm/ldlm_resource.c
index 735ea3d..d1ace7a 100644 (file)
--- a/lustre/ldlm/ldlm_resource.c
+++ b/lustre/ldlm/ldlm_resource.c
@@ -834,56 +834,35 @@ static struct cfs_hash_ops ldlm_ns_hash_ops = {
        .hs_put         = ldlm_res_hop_put
 };
 
-typedef struct ldlm_ns_hash_def {
-       enum ldlm_ns_type       nsd_type;
+static struct {
        /** hash bucket bits */
        unsigned                nsd_bkt_bits;
        /** hash bits */
        unsigned                nsd_all_bits;
-       /** hash operations */
-       struct cfs_hash_ops *nsd_hops;
-} ldlm_ns_hash_def_t;
-
-static struct ldlm_ns_hash_def ldlm_ns_hash_defs[] =
-{
-       {
-               .nsd_type       = LDLM_NS_TYPE_MDC,
+} ldlm_ns_hash_defs[] = {
+       [LDLM_NS_TYPE_MDC] = {
                .nsd_bkt_bits   = 11,
                .nsd_all_bits   = 16,
-               .nsd_hops       = &ldlm_ns_hash_ops,
        },
-       {
-               .nsd_type       = LDLM_NS_TYPE_MDT,
+       [LDLM_NS_TYPE_MDT] = {
                .nsd_bkt_bits   = 14,
                .nsd_all_bits   = 21,
-               .nsd_hops       = &ldlm_ns_hash_ops,
        },
-       {
-               .nsd_type       = LDLM_NS_TYPE_OSC,
+       [LDLM_NS_TYPE_OSC] = {
                .nsd_bkt_bits   = 8,
                .nsd_all_bits   = 12,
-               .nsd_hops       = &ldlm_ns_hash_ops,
        },
-       {
-               .nsd_type       = LDLM_NS_TYPE_OST,
+       [LDLM_NS_TYPE_OST] = {
                .nsd_bkt_bits   = 11,
                .nsd_all_bits   = 17,
-               .nsd_hops       = &ldlm_ns_hash_ops,
        },
-       {
-               .nsd_type       = LDLM_NS_TYPE_MGC,
+       [LDLM_NS_TYPE_MGC] = {
                .nsd_bkt_bits   = 3,
                .nsd_all_bits   = 4,
-               .nsd_hops       = &ldlm_ns_hash_ops,
        },
-       {
-               .nsd_type       = LDLM_NS_TYPE_MGT,
+       [LDLM_NS_TYPE_MGT] = {
                .nsd_bkt_bits   = 3,
                .nsd_all_bits   = 4,
-               .nsd_hops       = &ldlm_ns_hash_ops,
-       },
-       {
-               .nsd_type       = LDLM_NS_TYPE_UNKNOWN,
        },
 };
 
@@ -896,7 +875,6 @@ struct ldlm_namespace *ldlm_namespace_new(struct obd_device *obd, char *name,
                                          enum ldlm_ns_type ns_type)
 {
        struct ldlm_namespace *ns = NULL;
-       struct ldlm_ns_hash_def *nsd;
        int idx;
        int rc;
 
@@ -909,15 +887,10 @@ struct ldlm_namespace *ldlm_namespace_new(struct obd_device *obd, char *name,
                RETURN(NULL);
        }
 
-       for (idx = 0; ; idx++) {
-               nsd = &ldlm_ns_hash_defs[idx];
-               if (nsd->nsd_type == LDLM_NS_TYPE_UNKNOWN) {
-                       CERROR("Unknown type %d for ns %s\n", ns_type, name);
-                       GOTO(out_ref, NULL);
-               }
-
-               if (nsd->nsd_type == ns_type)
-                       break;
+       if (ns_type >= ARRAY_SIZE(ldlm_ns_hash_defs) ||
+           ldlm_ns_hash_defs[ns_type].nsd_bkt_bits == 0) {
+               CERROR("Unknown type %d for ns %s\n", ns_type, name);
+               GOTO(out_ref, NULL);
        }
 
        OBD_ALLOC_PTR(ns);
@@ -925,11 +898,13 @@ struct ldlm_namespace *ldlm_namespace_new(struct obd_device *obd, char *name,
                GOTO(out_ref, NULL);
 
        ns->ns_rs_hash = cfs_hash_create(name,
-                                        nsd->nsd_all_bits, nsd->nsd_all_bits,
-                                        nsd->nsd_bkt_bits, 0,
+                                        ldlm_ns_hash_defs[ns_type].nsd_all_bits,
+                                        ldlm_ns_hash_defs[ns_type].nsd_all_bits,
+                                        ldlm_ns_hash_defs[ns_type].nsd_bkt_bits,
+                                        0,
                                         CFS_HASH_MIN_THETA,
                                         CFS_HASH_MAX_THETA,
-                                        nsd->nsd_hops,
+                                        &ldlm_ns_hash_ops,
                                         CFS_HASH_DEPTH |
                                         CFS_HASH_BIGNAME |
                                         CFS_HASH_SPIN_BKTLOCK |
@@ -937,7 +912,9 @@ struct ldlm_namespace *ldlm_namespace_new(struct obd_device *obd, char *name,
        if (ns->ns_rs_hash == NULL)
                GOTO(out_ns, NULL);
 
-       ns->ns_bucket_bits = nsd->nsd_all_bits - nsd->nsd_bkt_bits;
+       ns->ns_bucket_bits = ldlm_ns_hash_defs[ns_type].nsd_all_bits -
+                            ldlm_ns_hash_defs[ns_type].nsd_bkt_bits;
+
        OBD_ALLOC_LARGE(ns->ns_rs_buckets,
                        BIT(ns->ns_bucket_bits) * sizeof(ns->ns_rs_buckets[0]));
        if (!ns->ns_rs_buckets)