We want to add an extra level to the CPU scheduler topology to account
for cores which share a cache. To do this we need to build a cpumask
for each CPU that indicates which CPUs share this cache to use as an
input to the scheduler.
Signed-off-by: Oliver O'Halloran <ooh...@gmail.com>
---
arch/powerpc/include/asm/smp.h | 6 ++++++
arch/powerpc/kernel/smp.c | 23 +++++++++++++++++------
2 files changed, 23 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index 8ea98504f900..fac963e10d39 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -97,6 +97,7 @@ static inline void set_hard_smp_processor_id(int cpu, int
phys)
#endif
DECLARE_PER_CPU(cpumask_var_t, cpu_sibling_map);
+DECLARE_PER_CPU(cpumask_var_t, cpu_l2_cache_map);
DECLARE_PER_CPU(cpumask_var_t, cpu_core_map);
static inline struct cpumask *cpu_sibling_mask(int cpu)
@@ -109,6 +110,11 @@ static inline struct cpumask *cpu_core_mask(int cpu)
return per_cpu(cpu_core_map, cpu);
}
+static inline struct cpumask *cpu_l2_cache_mask(int cpu)
+{
+ return per_cpu(cpu_l2_cache_map, cpu);
+}
+
extern int cpu_to_core_id(int cpu);
/* Since OpenPIC has only 4 IPIs, we use slightly different message numbers.
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 4c50f5fe5366..46f071cedf31 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -74,9 +74,11 @@ static DEFINE_PER_CPU(int, cpu_state) = { 0 };
struct thread_info *secondary_ti;
DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
+DEFINE_PER_CPU(cpumask_var_t, cpu_l2_cache_map);
DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
+EXPORT_PER_CPU_SYMBOL(cpu_l2_cache_map);
EXPORT_PER_CPU_SYMBOL(cpu_core_map);
/* SMP operations for this machine */
@@ -606,6 +608,8 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
for_each_possible_cpu(cpu) {
zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu),
GFP_KERNEL, cpu_to_node(cpu));
+ zalloc_cpumask_var_node(&per_cpu(cpu_l2_cache_map, cpu),
+ GFP_KERNEL, cpu_to_node(cpu));
zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
GFP_KERNEL, cpu_to_node(cpu));
/*
@@ -620,6 +624,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
/* Init the cpumasks so the boot CPU is related to itself */
cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
+ cpumask_set_cpu(boot_cpuid, cpu_l2_cache_mask(boot_cpuid));
cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
if (smp_ops && smp_ops->probe)
@@ -903,6 +908,7 @@ static void remove_cpu_from_masks(int cpu)
/* NB: cpu_core_mask is a superset of the others */
for_each_cpu(i, cpu_core_mask(cpu)) {
set_cpus_unrelated(cpu, i, cpu_core_mask);
+ set_cpus_unrelated(cpu, i, cpu_l2_cache_mask);
set_cpus_unrelated(cpu, i, cpu_sibling_mask);
}
}
@@ -924,17 +930,22 @@ static void add_cpu_to_masks(int cpu)
set_cpus_related(i, cpu, cpu_sibling_mask);
/*
- * Copy the thread sibling into core sibling mask, and
- * add CPUs that share a chip or an L2 to the core sibling
- * mask.
+ * Copy the thread sibling mask into the cache sibling mask
+ * and mark any CPUs that share an L2 with this CPU.
*/
for_each_cpu(i, cpu_sibling_mask(cpu))
+ set_cpus_related(cpu, i, cpu_l2_cache_mask);
+ update_mask_by_l2(cpu, cpu_l2_cache_mask);
+
+ /*
+ * Copy the cache sibling mask into core sibling mask and mark
+ * any CPUs on the same chip as this CPU.
+ */
+ for_each_cpu(i, cpu_l2_cache_mask(cpu))
set_cpus_related(cpu, i, cpu_core_mask);
- if (chipid == -1) {
- update_mask_by_l2(cpu, cpu_core_mask);
+ if (chipid == -1)
return;
- }
for_each_cpu(i, cpu_online_mask)
if (cpu_to_chip_id(i) == chipid)
--
2.9.4
