[PATCH 05/11] powerpc/smp: Dont assume l2-cache to be superset of sibling

[Srikar Dronamraju]

Current code assumes that cpumask of cpus sharing a l2-cache mask will
always be a superset of cpu_sibling_mask.

Lets stop that assumption.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: Michael Ellerman <micha...@au1.ibm.com>
Cc: Nick Piggin <npig...@au1.ibm.com>
Cc: Oliver OHalloran <olive...@au1.ibm.com>
Cc: Nathan Lynch <nath...@linux.ibm.com>
Cc: Michael Neuling <mi...@linux.ibm.com>
Cc: Anton Blanchard <an...@au1.ibm.com>
Cc: Gautham R Shenoy <e...@linux.vnet.ibm.com>
Cc: Vaidyanathan Srinivasan <sva...@linux.ibm.com>
Signed-off-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/smp.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 7d430fc536cc..875f57e41355 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1198,6 +1198,7 @@ static bool update_mask_by_l2(int cpu, struct cpumask 
*(*mask_fn)(int))
        struct device_node *l2_cache, *np;
        int i;
 
+       cpumask_set_cpu(cpu, mask_fn(cpu));
        l2_cache = cpu_to_l2cache(cpu);
        if (!l2_cache)
                return false;
@@ -1284,29 +1285,30 @@ static void add_cpu_to_masks(int cpu)
         * add it to it's own thread sibling mask.
         */
        cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
+       cpumask_set_cpu(cpu, cpu_core_mask(cpu));
 
        for (i = first_thread; i < first_thread + threads_per_core; i++)
                if (cpu_online(i))
                        set_cpus_related(i, cpu, cpu_sibling_mask);
 
        add_cpu_to_smallcore_masks(cpu);
-       /*
-        * 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 (pkg_id == -1) {
+               struct cpumask *(*mask)(int) = cpu_sibling_mask;
+
+               /*
+                * Copy the sibling mask into core sibling mask and
+                * mark any CPUs on the same chip as this CPU.
+                */
+               if (shared_caches)
+                       mask = cpu_l2_cache_mask;
+
+               for_each_cpu(i, mask(cpu))
+                       set_cpus_related(cpu, i, cpu_core_mask);
 
-       if (pkg_id == -1)
                return;
+       }
 
        for_each_cpu(i, cpu_online_mask)
                if (get_physical_package_id(i) == pkg_id)
-- 
2.17.1