Hello, Li.
On Tue, Jan 08, 2013 at 03:51:45PM +0800, Li Zefan wrote:
> -static struct hlist_head *css_set_hash(struct cgroup_subsys_state *css[])
> +static unsigned long css_set_hash(struct cgroup_subsys_state *css[])
> {
> int i;
> - int index;
> - unsigned long tmp = 0UL;
> + unsigned long key = 0UL;
>
> for (i = 0; i < CGROUP_SUBSYS_COUNT; i++)
> - tmp += (unsigned long)css[i];
> - tmp = (tmp >> 16) ^ tmp;
> + key += (unsigned long)css[i];
> + key = (key >> 16) ^ key;
@key is gonna go through hash function anyway. Do we still need the
above (key >> 16) ^ key? It's not gonna help anything.
> - index = hash_long(tmp, CSS_SET_HASH_BITS);
> -
> - return &css_set_table[index];
> + return key;
> }
>
> /* We don't maintain the lists running through each css_set to its
> @@ -4503,23 +4498,17 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss)
> * this is all done under the css_set_lock.
> */
> write_lock(&css_set_lock);
> - for (i = 0; i < CSS_SET_TABLE_SIZE; i++) {
> - struct css_set *cg;
> - struct hlist_node *node, *tmp;
> - struct hlist_head *bucket = &css_set_table[i], *new_bucket;
> -
> - hlist_for_each_entry_safe(cg, node, tmp, bucket, hlist) {
> - /* skip entries that we already rehashed */
> - if (cg->subsys[ss->subsys_id])
> - continue;
> - /* remove existing entry */
> - hlist_del(&cg->hlist);
> - /* set new value */
> - cg->subsys[ss->subsys_id] = css;
> - /* recompute hash and restore entry */
> - new_bucket = css_set_hash(cg->subsys);
> - hlist_add_head(&cg->hlist, new_bucket);
> - }
> + hash_for_each_safe(css_set_table, i, node, tmp, cg, hlist) {
> + /* skip entries that we already rehashed */
> + if (cg->subsys[ss->subsys_id])
> + continue;
> + /* remove existing entry */
> + hlist_del(&cg->hlist);
hash_del()?
Thanks.
--
tejun
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