Commit 661e3d42 authored Sep 21, 2020 by Srikar Dronamraju Committed by Michael Ellerman Oct 06, 2020

powerpc/smp: Depend on cpu_l1_cache_map when adding CPUs

Currently on hotplug/hotunplug, CPU iterates through all the CPUs in
its core to find threads in its thread group. However this info is
already captured in cpu_l1_cache_map. Hence reduce iterations and
cleanup add_cpu_to_smallcore_masks function.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200921095653.9701-8-srikar@linux.vnet.ibm.com

parent 1f3a4181

arch/powerpc/kernel/smp.c

+3 −4

Original line number	Diff line number	Diff line
		@@ -1285,16 +1285,15 @@ static void remove_cpu_from_masks(int cpu)

		static inline void add_cpu_to_smallcore_masks(int cpu)
		{
		struct cpumask *this_l1_cache_map = per_cpu(cpu_l1_cache_map, cpu);
		int i, first_thread = cpu_first_thread_sibling(cpu);
		int i;

		if (!has_big_cores)
		return;

		cpumask_set_cpu(cpu, cpu_smallcore_mask(cpu));

		for (i = first_thread; i < first_thread + threads_per_core; i++) {
		if (cpu_online(i) && cpumask_test_cpu(i, this_l1_cache_map))
		for_each_cpu(i, per_cpu(cpu_l1_cache_map, cpu)) {
		if (cpu_online(i))
		set_cpus_related(i, cpu, cpu_smallcore_mask);
		}
		}