| Message ID | 20220621144729.533026-1-yury.norov@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mips: micro-optimize calculate_cpu_foreign_map() | expand |
On Tue, Jun 21, 2022 at 07:47:29AM -0700, Yury Norov wrote: > 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 <yury.norov@gmail.com> Ping? > --- > > 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
On Thu, Jun 30, 2022 at 07:59:04PM -0700, Yury Norov wrote: > On Tue, Jun 21, 2022 at 07:47:29AM -0700, Yury Norov wrote: > > 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 <yury.norov@gmail.com> > > Ping? as this is touching two different archs, it would have been easier to send this in two different patches. Huacai, should I take the patch ? Thomas.
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); }
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 <yury.norov@gmail.com> --- 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(-)