diff options
| author | Srikar Dronamraju <srikar@linux.vnet.ibm.com> | 2020-09-13 22:40:38 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-09-16 22:13:31 +1000 |
| commit | f6606cfdfbcda00ce8a6e63c8fc13c93e73ac059 (patch) | |
| tree | 28441bdab758d13b2816c66f27038df228e94ab0 /arch/powerpc/kernel/smp.c | |
| parent | 3c6032a8fe99547d31b2b57715e303a67d1b0c66 (diff) | |
| download | linux-f6606cfdfbcda00ce8a6e63c8fc13c93e73ac059.tar.gz | |
powerpc/smp: Dont assume l2-cache to be superset of sibling
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. cpu_l2_cache_mask is a superset of
cpu_sibling_mask if and only if shared_caches is set.
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200913171038.GB11808@linux.vnet.ibm.com
Diffstat (limited to 'arch/powerpc/kernel/smp.c')
| -rw-r--r-- | arch/powerpc/kernel/smp.c | 43 |
1 files changed, 29 insertions, 14 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 9f4333d0748b30..168532e37305dc 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -1186,9 +1186,23 @@ static bool update_mask_by_l2(int cpu, struct cpumask *(*mask_fn)(int)) int i; l2_cache = cpu_to_l2cache(cpu); - if (!l2_cache) + if (!l2_cache) { + struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask; + + /* + * If no l2cache for this CPU, assume all siblings to share + * cache with this CPU. + */ + if (has_big_cores) + sibling_mask = cpu_smallcore_mask; + + for_each_cpu(i, sibling_mask(cpu)) + set_cpus_related(cpu, i, cpu_l2_cache_mask); + return false; + } + cpumask_set_cpu(cpu, mask_fn(cpu)); for_each_cpu(i, cpu_online_mask) { /* * when updating the marks the current CPU has not been marked @@ -1271,29 +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) |