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| author | Srikar Dronamraju <srikar@linux.vnet.ibm.com> | 2020-09-21 15:26:46 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-10-06 23:22:26 +1100 |
| commit | 70edd4a7c753ba18e3e4bb9e97b6d85156cea738 (patch) | |
| tree | 11c780d909f7301ee5c6af159f58ca19cecd154e /arch/powerpc/kernel | |
| parent | e29e9ed665eeb6f98cd88672994ecf4aaefdb943 (diff) | |
| download | linux-70edd4a7c753ba18e3e4bb9e97b6d85156cea738.tar.bz2 | |
powerpc/smp: Optimize remove_cpu_from_masks
While offlining a CPU, system currently iterate through all the CPUs in
the DIE to clear sibling, l2_cache and smallcore maps. However if there
are more cores in a DIE, system can end up spending more time iterating
through CPUs which are completely unrelated.
Optimize this by only iterating through smaller but relevant cpumap.
If shared_cache is set, cpu_l2_cache_map should be relevant else
cpu_sibling_map would be relevant.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200921095653.9701-5-srikar@linux.vnet.ibm.com
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/smp.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index aecc01f0e95e..9cdb966f00b3 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -1263,14 +1263,21 @@ static bool update_mask_by_l2(int cpu, struct cpumask *(*mask_fn)(int)) #ifdef CONFIG_HOTPLUG_CPU static void remove_cpu_from_masks(int cpu) { + struct cpumask *(*mask_fn)(int) = cpu_sibling_mask; int i; - for_each_cpu(i, cpu_cpu_mask(cpu)) { + if (shared_caches) + mask_fn = cpu_l2_cache_mask; + + for_each_cpu(i, mask_fn(cpu)) { set_cpus_unrelated(cpu, i, cpu_l2_cache_mask); set_cpus_unrelated(cpu, i, cpu_sibling_mask); if (has_big_cores) set_cpus_unrelated(cpu, i, cpu_smallcore_mask); - if (has_coregroup_support()) + } + + if (has_coregroup_support()) { + for_each_cpu(i, cpu_coregroup_mask(cpu)) set_cpus_unrelated(cpu, i, cpu_coregroup_mask); } } |