From 4f6e90b73cb103d7d49b8b4838c5f48c3d15b02e Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Fri, 28 Oct 2011 08:02:12 +0200 Subject: [PATCH] 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 Signed-off-by: Mathieu Desnoyers --- rculfhash.c | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-) diff --git a/rculfhash.c b/rculfhash.c index 8644f9c..0bcbb1e 100644 --- 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)); - 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; @@ -1084,16 +1078,17 @@ void init_table_populate_partition(struct cds_lfht *ht, unsigned long i, { 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", - i, j, !i ? 0 : (1UL << (i - 1)) + j); + i, j, (1UL << (i - 1)) + j); 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(); @@ -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); + assert(first_order > 0); 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 */ - 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)); @@ -1144,9 +1140,9 @@ void init_table(struct cds_lfht *ht, * 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; } @@ -1183,17 +1179,17 @@ void remove_table_partition(struct cds_lfht *ht, unsigned long i, { 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", - i, j, !i ? 0 : (1UL << (i - 1)) + j); + i, j, (1UL << (i - 1)) + j); 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(); } @@ -1225,7 +1221,7 @@ void fini_table(struct cds_lfht *ht, 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 */ -- 2.34.1