rculfhash: Remove unneed branches

By the effect of previous patch, some unneed branches can be removed.
One of them is in the fast path.

These branches are mostly special-cases for the node "0", which is
always populated after hash table new.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/rculfhash.c b/rculfhash.c
index 8644f9c3f23ed184117eb2f74264cd9df121f19d..0bcbb1e832a5ab41c4d4357c0dafa4ff87832db7 100644 (file)
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -871,12 +871,6 @@ void _cds_lfht_add(struct cds_lfht *ht,
 
        assert(!is_dummy(node));
        assert(!is_removed(node));
 
        assert(!is_dummy(node));
        assert(!is_removed(node));

-       if (!size) {
-               assert(dummy);
-               assert(!unique_ret);
-               node->p.next = flag_dummy(get_end());
-               return;         /* Initial first add (head) */
-       }

        lookup = lookup_bucket(ht, size, bit_reverse_ulong(node->p.reverse_hash));
        for (;;) {
                uint32_t chain_len = 0;
        lookup = lookup_bucket(ht, size, bit_reverse_ulong(node->p.reverse_hash));
        for (;;) {
                uint32_t chain_len = 0;


@@ -1084,16 +1078,17 @@ void init_table_populate_partition(struct cds_lfht *ht, unsigned long i,
 {
        unsigned long j;
 
 {
        unsigned long j;
 

+       assert(i > 0);

        ht->cds_lfht_rcu_read_lock();
        for (j = start; j < start + len; j++) {
                struct cds_lfht_node *new_node =
                        (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j];
 
                dbg_printf("init populate: i %lu j %lu hash %lu\n",
        ht->cds_lfht_rcu_read_lock();
        for (j = start; j < start + len; j++) {
                struct cds_lfht_node *new_node =
                        (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j];
 
                dbg_printf("init populate: i %lu j %lu hash %lu\n",

-                          i, j, !i ? 0 : (1UL << (i - 1)) + j);
+                          i, j, (1UL << (i - 1)) + j);

                new_node->p.reverse_hash =
                new_node->p.reverse_hash =

-                       bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j);
-               _cds_lfht_add(ht, !i ? 0 : (1UL << (i - 1)),
+                               bit_reverse_ulong((1UL << (i - 1)) + j);
+               _cds_lfht_add(ht, 1UL << (i - 1),

                                new_node, NULL, 1);
        }
        ht->cds_lfht_rcu_read_unlock();
                                new_node, NULL, 1);
        }
        ht->cds_lfht_rcu_read_unlock();


@@ -1121,14 +1116,15 @@ void init_table(struct cds_lfht *ht,
 
        dbg_printf("init table: first_order %lu last_order %lu\n",
                   first_order, last_order);
 
        dbg_printf("init table: first_order %lu last_order %lu\n",
                   first_order, last_order);

+       assert(first_order > 0);

        for (i = first_order; i <= last_order; i++) {
                unsigned long len;
 
        for (i = first_order; i <= last_order; i++) {
                unsigned long len;
 

-               len = !i ? 1 : 1UL << (i - 1);
+               len = 1UL << (i - 1);

                dbg_printf("init order %lu len: %lu\n", i, len);
 
                /* Stop expand if the resize target changes under us */
                dbg_printf("init order %lu len: %lu\n", i, len);
 
                /* Stop expand if the resize target changes under us */

-               if (CMM_LOAD_SHARED(ht->t.resize_target) < (!i ? 1 : (1UL << i)))
+               if (CMM_LOAD_SHARED(ht->t.resize_target) < (1UL << i))

                        break;
 
                ht->t.tbl[i] = calloc(1, len * sizeof(struct _cds_lfht_node));
                        break;
 
                ht->t.tbl[i] = calloc(1, len * sizeof(struct _cds_lfht_node));


@@ -1144,9 +1140,9 @@ void init_table(struct cds_lfht *ht,
                 * Update table size.
                 */
                cmm_smp_wmb();  /* populate data before RCU size */
                 * Update table size.
                 */
                cmm_smp_wmb();  /* populate data before RCU size */

-               CMM_STORE_SHARED(ht->t.size, !i ? 1 : (1UL << i));
+               CMM_STORE_SHARED(ht->t.size, 1UL << i);

 
 

-               dbg_printf("init new size: %lu\n", !i ? 1 : (1UL << i));
+               dbg_printf("init new size: %lu\n", 1UL << i);

                if (CMM_LOAD_SHARED(ht->in_progress_destroy))
                        break;
        }
                if (CMM_LOAD_SHARED(ht->in_progress_destroy))
                        break;
        }


@@ -1183,17 +1179,17 @@ void remove_table_partition(struct cds_lfht *ht, unsigned long i,
 {
        unsigned long j;
 
 {
        unsigned long j;
 

+       assert(i > 0);

        ht->cds_lfht_rcu_read_lock();
        for (j = start; j < start + len; j++) {
                struct cds_lfht_node *fini_node =
                        (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j];
 
                dbg_printf("remove entry: i %lu j %lu hash %lu\n",
        ht->cds_lfht_rcu_read_lock();
        for (j = start; j < start + len; j++) {
                struct cds_lfht_node *fini_node =
                        (struct cds_lfht_node *) &ht->t.tbl[i]->nodes[j];
 
                dbg_printf("remove entry: i %lu j %lu hash %lu\n",

-                          i, j, !i ? 0 : (1UL << (i - 1)) + j);
+                          i, j, (1UL << (i - 1)) + j);

                fini_node->p.reverse_hash =
                fini_node->p.reverse_hash =

-                       bit_reverse_ulong(!i ? 0 : (1UL << (i - 1)) + j);
-               (void) _cds_lfht_del(ht, !i ? 0 : (1UL << (i - 1)),
-                               fini_node, 1);
+                       bit_reverse_ulong((1UL << (i - 1)) + j);
+               (void) _cds_lfht_del(ht, 1UL << (i - 1), fini_node, 1);

        }
        ht->cds_lfht_rcu_read_unlock();
 }
        }
        ht->cds_lfht_rcu_read_unlock();
 }


@@ -1225,7 +1221,7 @@ void fini_table(struct cds_lfht *ht,
        for (i = last_order; i >= first_order; i--) {
                unsigned long len;
 
        for (i = last_order; i >= first_order; i--) {
                unsigned long len;
 

-               len = !i ? 1 : 1UL << (i - 1);
+               len = 1UL << (i - 1);

                dbg_printf("fini order %lu len: %lu\n", i, len);
 
                /* Stop shrink if the resize target changes under us */
                dbg_printf("fini order %lu len: %lu\n", i, len);
 
                /* Stop shrink if the resize target changes under us */