2020-06-22 23:54:35

by Atish Patra

Subject: [PATCH] RISC-V: Use a local variable instead of smp_processor_id()

From: Greentime Hu <[email protected]>

Store the smp_processor_id() in a local variable to save some
pointer chasing.

Signed-off-by: Greentime Hu <[email protected]>
Signed-off-by: Atish Patra <[email protected]>
---
arch/riscv/kernel/smpboot.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 4e9922790f6e..3e033e97dd08 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -146,6 +146,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
asmlinkage __visible void smp_callin(void)
{
struct mm_struct *mm = &init_mm;
+ unsigned int curr_cpuid = smp_processor_id();

if (!IS_ENABLED(CONFIG_RISCV_SBI))
clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id()));
@@ -155,9 +156,9 @@ asmlinkage __visible void smp_callin(void)
current->active_mm = mm;

trap_init();
- notify_cpu_starting(smp_processor_id());
- update_siblings_masks(smp_processor_id());
- set_cpu_online(smp_processor_id(), 1);
+ notify_cpu_starting(curr_cpuid);
+ update_siblings_masks(curr_cpuid);
+ set_cpu_online(curr_cpuid, 1);
/*
* Remote TLB flushes are ignored while the CPU is offline, so emit
* a local TLB flush right now just in case.
--
2.26.2

2020-06-25 23:39:45

by Palmer Dabbelt

Subject: Re: [PATCH] RISC-V: Use a local variable instead of smp_processor_id()

On Mon, 22 Jun 2020 16:47:25 PDT (-0700), Atish Patra wrote:
> From: Greentime Hu <[email protected]>
>
> Store the smp_processor_id() in a local variable to save some
> pointer chasing.
>
> Signed-off-by: Greentime Hu <[email protected]>
> Signed-off-by: Atish Patra <[email protected]>
> ---
> arch/riscv/kernel/smpboot.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> index 4e9922790f6e..3e033e97dd08 100644
> --- a/arch/riscv/kernel/smpboot.c
> +++ b/arch/riscv/kernel/smpboot.c
> @@ -146,6 +146,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
> asmlinkage __visible void smp_callin(void)
> {
> struct mm_struct *mm = &init_mm;
> + unsigned int curr_cpuid = smp_processor_id();
>
> if (!IS_ENABLED(CONFIG_RISCV_SBI))
> clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id()));
> @@ -155,9 +156,9 @@ asmlinkage __visible void smp_callin(void)
> current->active_mm = mm;
>
> trap_init();
> - notify_cpu_starting(smp_processor_id());
> - update_siblings_masks(smp_processor_id());
> - set_cpu_online(smp_processor_id(), 1);
> + notify_cpu_starting(curr_cpuid);
> + update_siblings_masks(curr_cpuid);
> + set_cpu_online(curr_cpuid, 1);
> /*
> * Remote TLB flushes are ignored while the CPU is offline, so emit
> * a local TLB flush right now just in case.

Thanks. This is on for-next.