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crypto: iaa - Optimize rebalance_wq_table()

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The function opencodes for_each_cpu() by using a plain for-loop. The
loop calls cpumask_weight() inside the conditional section. Because
cpumask_weight() is O(1), the overall complexity of the function is
O(node * node_cpus^2). Also, cpumask_nth() internally calls hweight(),
which, if not hardware accelerated, is slower than cpumask_next() in
for_each_cpu().

If switched to the dedicated for_each_cpu(), the rebalance_wq_table()
can drop calling cpumask_weight(), together with some housekeeping code.
This makes the overall complexity O(node * node_cpus), or simply speaking
O(nr_cpu_ids).

While there, fix opencoded for_each_possible_cpu() too.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Yury Norov
2025-05-08 15:59:50 -04:00
committed by Herbert Xu
parent 33cd93435c
commit 714ca27e9b
1 changed files with 14 additions and 21 deletions
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35
drivers/crypto/intel/iaa/iaa_crypto_main.c
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@@ -894,7 +894,7 @@ out:
static void rebalance_wq_table(void)
{
const struct cpumask *node_cpus;
int node, cpu, iaa = -1;
int node_cpu, node, cpu, iaa = 0;
if (nr_iaa == 0)
return;
@@ -905,36 +905,29 @@ static void rebalance_wq_table(void)
clear_wq_table();
if (nr_iaa == 1) {
for (cpu = 0; cpu < nr_cpus; cpu++) {
if (WARN_ON(wq_table_add_wqs(0, cpu))) {
pr_debug("could not add any wqs for iaa 0 to cpu %d!\n", cpu);
return;
}
for_each_possible_cpu(cpu) {
if (WARN_ON(wq_table_add_wqs(0, cpu)))
goto err;
}
return;
}
for_each_node_with_cpus(node) {
cpu = 0;
node_cpus = cpumask_of_node(node);
for (cpu = 0; cpu < cpumask_weight(node_cpus); cpu++) {
int node_cpu = cpumask_nth(cpu, node_cpus);
if (WARN_ON(node_cpu >= nr_cpu_ids)) {
pr_debug("node_cpu %d doesn't exist!\n", node_cpu);
return;
}
if ((cpu % cpus_per_iaa) == 0)
iaa++;
if (WARN_ON(wq_table_add_wqs(iaa, node_cpu))) {
pr_debug("could not add any wqs for iaa %d to cpu %d!\n", iaa, cpu);
return;
}
for_each_cpu(node_cpu, node_cpus) {
iaa = cpu / cpus_per_iaa;
if (WARN_ON(wq_table_add_wqs(iaa, node_cpu)))
goto err;
cpu++;
}
}
return;
err:
pr_debug("could not add any wqs for iaa %d to cpu %d!\n", iaa, cpu);
}
static inline int check_completion(struct device *dev,