From 661e3d42f99193b7fdd71467a87e48f6e597c285 Mon Sep 17 00:00:00 2001
From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Date: Mon, 21 Sep 2020 15:26:49 +0530
Subject: [PATCH] powerpc/smp: Depend on cpu_l1_cache_map when adding CPUs
References: jsc#SLE-13615 bsc#1180100 ltc#190257
Patch-mainline: v5.10-rc1
Git-commit: 661e3d42f99193b7fdd71467a87e48f6e597c285
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
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
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 0e96f6687363..3a3e6bbab29c 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);
}
}
--
2.26.2