Re: [PATCH 1/3] jump label: add enabled/disabled state to jumplabel key entries

From: Mathieu Desnoyers
Date: Tue Nov 23 2010 - 19:34:08 EST


* Jason Baron (jbaron@xxxxxxxxxx) wrote:
[...]
> +static void update_jump_label_module(struct module *mod)
> +{
> + struct hlist_head *head;
> + struct hlist_node *node, *node_next, *module_node, *module_node_next;
> + struct jump_label_entry *e;
> + struct jump_label_module_entry *e_module;
> + struct jump_entry *iter;
> + int i, count;
> +
> + /* if the module doesn't have jump label entries, just return */
> + if (!mod->num_jump_entries)
> + return;
> +
> + for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) {
> + head = &jump_label_table[i];
> + hlist_for_each_entry_safe(e, node, node_next, head, hlist) {
> + if (!e->enabled)
> + continue;
> + hlist_for_each_entry_safe(e_module, module_node,
> + module_node_next,
> + &(e->modules), hlist) {
> + if (e_module->mod != mod)
> + continue;

Ouch.

Could you iterate on the loaded/unloaded module jump labels and do hash
table lookups rather than doing this O(n^3) iteration ?

Thanks,

Mathieu

--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
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