In start_secondary, even if shared_cache was already set, system does a redundant match for cpumask. This redundant check can be removed by checking if shared_cache is already set.
While here, localize the sibling_mask variable to within the if condition. Cc: linuxppc-dev <[email protected]> Cc: LKML <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Anton Blanchard <[email protected]> Cc: Oliver O'Halloran <[email protected]> Cc: Nathan Lynch <[email protected]> Cc: Michael Neuling <[email protected]> Cc: Gautham R Shenoy <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Valentin Schneider <[email protected]> Cc: Jordan Niethe <[email protected]> Cc: Vaidyanathan Srinivasan <[email protected]> Signed-off-by: Srikar Dronamraju <[email protected]> --- Changelog v4 ->v5: Retain cache domain, no need for generalization (Michael Ellerman, Peter Zijlstra, Valentin Schneider, Gautham R. Shenoy) Changelog v1 -> v2: Moved shared_cache topology fixup to fixup_topology (Gautham) arch/powerpc/kernel/smp.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 0c960ce3be42..91cf5d05e7ec 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -851,7 +851,7 @@ static int powerpc_shared_cache_flags(void) */ static const struct cpumask *shared_cache_mask(int cpu) { - return cpu_l2_cache_mask(cpu); + return per_cpu(cpu_l2_cache_map, cpu); } #ifdef CONFIG_SCHED_SMT @@ -1305,7 +1305,6 @@ static void add_cpu_to_masks(int cpu) void start_secondary(void *unused) { unsigned int cpu = smp_processor_id(); - struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask; mmgrab(&init_mm); current->active_mm = &init_mm; @@ -1331,14 +1330,20 @@ void start_secondary(void *unused) /* Update topology CPU masks */ add_cpu_to_masks(cpu); - if (has_big_cores) - sibling_mask = cpu_smallcore_mask; /* * Check for any shared caches. Note that this must be done on a * per-core basis because one core in the pair might be disabled. */ - if (!cpumask_equal(cpu_l2_cache_mask(cpu), sibling_mask(cpu))) - shared_caches = true; + if (!shared_caches) { + struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask; + struct cpumask *mask = cpu_l2_cache_mask(cpu); + + if (has_big_cores) + sibling_mask = cpu_smallcore_mask; + + if (cpumask_weight(mask) > cpumask_weight(sibling_mask(cpu))) + shared_caches = true; + } set_numa_node(numa_cpu_lookup_table[cpu]); set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu])); -- 2.18.2
