Commit 40ba13b4 authored by Yury Norov's avatar Yury Norov
Browse files

powerpc/xmon: simplify xmon_batch_next_cpu() 



The function opencodes for_each_cpu_wrap() macro. As a loop termination
condition it uses cpumask_empty(), which is O(N), and it makes the whole
algorithm O(N^2). Switching to for_each_cpu_wrap() simplifies the logic,
and makes the algorithm linear.

Signed-off-by: default avatarYury Norov <yury.norov@gmail.com>
parent 2a402aa6

arch/powerpc/xmon/xmon.c

+1 −5
Original line number Diff line number Diff line
@@ -1271,11 +1271,7 @@ static int xmon_batch_next_cpu(void) 
{

	unsigned long cpu;



	while (!cpumask_empty(&xmon_batch_cpus)) {

		cpu = cpumask_next_wrap(smp_processor_id(), &xmon_batch_cpus,

					xmon_batch_start_cpu, true);

		if (cpu >= nr_cpu_ids)

			break;

	for_each_cpu_wrap(cpu, &xmon_batch_cpus, xmon_batch_start_cpu) {

		if (xmon_batch_start_cpu == -1)

			xmon_batch_start_cpu = cpu;

		if (xmon_switch_cpu(cpu))