powerpc/smp: Add cpu_l2_cache_map

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 <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index 8ea9850..fac963e 100644 (file)
--- 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 a29c23b..b42c868 100644 (file)
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -75,9 +75,11 @@ 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 */
@@ -610,6 +612,8 @@ 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));
                /*
@@ -624,6 +628,7 @@ 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)
@@ -907,6 +912,7 @@ 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);
        }
 }
@@ -929,17 +935,22 @@ 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)