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| author | Srikar Dronamraju <srikar@linux.vnet.ibm.com> | 2020-08-10 12:48:30 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-09-16 22:13:31 +1000 |
| commit | caa8e29da59926bef099b46ab6280333d583e944 (patch) | |
| tree | e98dec4cceb4be5accf376178f731feeadbff113 /arch/powerpc/kernel/smp.c | |
| parent | f6606cfdfbcda00ce8a6e63c8fc13c93e73ac059 (diff) | |
| download | linux-caa8e29da59926bef099b46ab6280333d583e944.tar.gz | |
powerpc/smp: Optimize start_secondary
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.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200810071834.92514-7-srikar@linux.vnet.ibm.com
Diffstat (limited to 'arch/powerpc/kernel/smp.c')
| -rw-r--r-- | arch/powerpc/kernel/smp.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 168532e37305..016a822eb8c4 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -852,7 +852,7 @@ 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 @@ -1319,7 +1319,6 @@ 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; @@ -1345,14 +1344,20 @@ 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])); |