On 10/17/2011 10:54 PM, Mathieu Desnoyers wrote:
> * Lai Jiangshan ([email protected]) wrote:
>> make cds_lfht_new() can be called earlier(before rcu is initialized ..etc)
>> If caller want to *parallelly* init the dummy nodes with large init_size,
>> he can use cds_lfht_new()+cds_lfht_resize() combination.
>>
>> Signed-off-by: Lai Jiangshan <[email protected]>
>> ---
>> rculfhash.c | 50 +++++++++++++++++++++++++++++++++++++++++++-------
>> 1 files changed, 43 insertions(+), 7 deletions(-)
>>
>> diff --git a/rculfhash.c b/rculfhash.c
>> index f412c6f..5dcae1f 100644
>> --- a/rculfhash.c
>> +++ b/rculfhash.c
>> @@ -1240,6 +1240,45 @@ void fini_table(struct cds_lfht *ht,
>> }
>> }
>>
>> +static
>> +void cds_lfht_create_dummy(struct cds_lfht *ht, unsigned long size)
>> +{
>> + struct _cds_lfht_node *prev, *node;
>> + unsigned long order, len, i, j;
>> +
>> + ht->t.tbl[0] = calloc(1, sizeof(struct _cds_lfht_node));
>> + assert(ht->t.tbl[0]);
>> +
>> + dbg_printf("create dummy: order %lu index %lu hash %lu\n", 0, 0, 0);
>> + ht->t.tbl[0]->nodes[0].next = flag_dummy(get_end());
>> + ht->t.tbl[0]->nodes[0].reverse_hash = 0;
>> +
>> + for (order = 1; order < get_count_order_ulong(size) + 1; order++) {
/* create the last table for the order */
>
> see other comment below about the semantic of order changing. Maybe
> "index" or "order_idx" would be more appropriate here, because there is
> a + 1 offset compared to the actual order, to deal with the 0
> special-case.
order ht_size last_table_size number_of_tables
0 1 1 1
1 2 1 2
2 4 2 3
3 8 4 4
4 16 8 5
5 32 16 6
The @order equals the actual order in the loop.
the name and semantic are correct here.
Or I miss your meaning?
>
>> + len = 1UL << (order - 1);
>> + ht->t.tbl[order] = calloc(1, len * sizeof(struct
>> _cds_lfht_node));
>> + assert(ht->t.tbl[order]);
>> +
>> + i = 0;
>> + prev = ht->t.tbl[i]->nodes;
>> + for (j = 0; j < len; j++) {
>> + if (j & (j - 1)) {
>> + prev++;
>> + } else if (j) {
>> + i++;
>> + prev = ht->t.tbl[i]->nodes;
>> + }
>> +
>> + node = &ht->t.tbl[order]->nodes[j];
>> + dbg_printf("create dummy: order %lu index %lu hash
>> %lu\n",
>> + order, j, j + len);
>> + node->next = prev->next;
>> + assert(is_dummy(node->next));
>> + node->reverse_hash = bit_reverse_ulong(j + len);
>> + prev->next = flag_dummy((struct cds_lfht_node *)node);
>> + }
>> + }
>> +}
>> +
>> struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
>> cds_lfht_compare_fct compare_fct,
>> unsigned long hash_seed,
>> @@ -1279,14 +1318,11 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct
>> hash_fct,
>> ht->percpu_count = alloc_per_cpu_items_count();
>> /* this mutex should not nest in read-side C.S. */
>> pthread_mutex_init(&ht->resize_mutex, NULL);
>> - order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE)) + 1;
>
The old "order" is incorrect for me, it is actually "number of tables"
> The line above,
>
>> ht->flags = flags;
>> - ht->cds_lfht_rcu_thread_offline();
>> - pthread_mutex_lock(&ht->resize_mutex);
>> - ht->t.resize_target = 1UL << (order - 1);
>> - init_table(ht, 0, order);
>> - pthread_mutex_unlock(&ht->resize_mutex);
>> - ht->cds_lfht_rcu_thread_online();
>> + order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE));
>
> and this line:
>
> notice that the semantic of "order" is changing, and I think this is
> good: The order really becomes the power of 2 order of the size, rather
> than the "index" in the "order array" which is offset by + 1 compared to
> the actual order value to deal with the 0 special-case.
>
> We should also make sure that this semantic change does not affect the
> rest of the code. Given that we communicate the target size and size
> with "resize_target" and "size", I think we should be fine for this.
>
Any problem of the code?
How about the next patches?
>
>> + ht->t.resize_target = 1UL << order;
>> + cds_lfht_create_dummy(ht, 1UL << order);
>> + ht->t.size = 1UL << order;
>> return ht;
>> }
>>
>> --
>> 1.7.4.4
>>
>
_______________________________________________
ltt-dev mailing list
[email protected]
http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
