Linux-Kernel Archive: [PATCH] mips: micro-optimize calculate_cpu_foreign_map() [PATCH] mips: micro-optimize calculate_cpu_foreign_map() From: Yury Norov Date: Tue Jun 21 2022 - 10:47:37 EST Next message: Lu Baolu: "[PATCH v9 00/11] iommu: SVA and IOPF refactoring" Previous message: Wolfram Sang: "[PATCH] ufs: core: fix typos in error messages" Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] The inner loop in calculate_cpu_foreign_map() walks the whole cpumask to check if we have siblings for a given cpu. We can just break after a 1st match and avoid useless traversing the rest of mask. Loongarch has an identical function, so fix it here as well. Signed-off-by: Yury Norov --- It looks like loongarch copied quite a lot from arch/mips/kernel/smp.c. For loongarch folks: Guys, can you consider moving shared code into a shared file(s)? arch/loongarch/kernel/smp.c | 7 +++---- arch/mips/kernel/smp.c | 7 +++---- 2 files changed, 6 insertions(+), 8 deletions(-) diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c index b8c53b755a25..c1c91df3c8ac 100644 --- a/arch/loongarch/kernel/smp.c +++ b/arch/loongarch/kernel/smp.c @@ -463,17 +463,16 @@ static inline void set_cpu_core_map(int cpu) */ void calculate_cpu_foreign_map(void) { - int i, k, core_present; + int i, k; cpumask_t temp_foreign_map; /* Re-calculate the mask */ cpumask_clear(&temp_foreign_map); for_each_online_cpu(i) { - core_present = 0; for_each_cpu(k, &temp_foreign_map) if (cpus_are_siblings(i, k)) - core_present = 1; - if (!core_present) + break; + if (k >= nr_cpu_ids) cpumask_set_cpu(i, &temp_foreign_map); } diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c index 1d93b85271ba..a2ce641f5f18 100644 --- a/arch/mips/kernel/smp.c +++ b/arch/mips/kernel/smp.c @@ -115,17 +115,16 @@ static inline void set_cpu_core_map(int cpu) */ void calculate_cpu_foreign_map(void) { - int i, k, core_present; + int i, k; cpumask_t temp_foreign_map; /* Re-calculate the mask */ cpumask_clear(&temp_foreign_map); for_each_online_cpu(i) { - core_present = 0; for_each_cpu(k, &temp_foreign_map) if (cpus_are_siblings(i, k)) - core_present = 1; - if (!core_present) + break; + if (k >= nr_cpu_ids) cpumask_set_cpu(i, &temp_foreign_map); } -- 2.32.0 Next message: Lu Baolu: "[PATCH v9 00/11] iommu: SVA and IOPF refactoring" Previous message: Wolfram Sang: "[PATCH] ufs: core: fix typos in error messages" Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
