[PATCH v2 07/11] powerpc/smp: Depend on cpu_l1_cache_map when adding CPUs

[Srikar Dronamraju]

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.

Cc: linuxppc-dev <linuxppc-dev@xxxxxxxxxxxxxxxx>
Cc: LKML <linux-kernel@xxxxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Anton Blanchard <anton@xxxxxxxxxx>
Cc: Oliver O'Halloran <oohall@xxxxxxxxx>
Cc: Nathan Lynch <nathanl@xxxxxxxxxxxxx>
Cc: Michael Neuling <mikey@xxxxxxxxxxx>
Cc: Gautham R Shenoy <ego@xxxxxxxxxxxxxxxxxx>
Cc: Satheesh Rajendran <sathnaga@xxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Valentin Schneider <valentin.schneider@xxxxxxx>
Signed-off-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Tested-by: Satheesh Rajendran <sathnaga@xxxxxxxxxxxxxxxxxx>
---
 arch/powerpc/kernel/smp.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 441c9c64b1e3..aeb219a4bf7a 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -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);
 	}
 }
-- 
2.17.1