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>

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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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drivers/crypto/intel/iaa/iaa_crypto_main.c

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