Re: [PATCH v5 24/25] arm64/mm: __always_inline to improve fork() perf

2024-02-13 Thread Mark Rutland
On Fri, Feb 02, 2024 at 08:07:55AM +, Ryan Roberts wrote:
> As set_ptes() and wrprotect_ptes() become a bit more complex, the
> compiler may choose not to inline them. But this is critical for fork()
> performance. So mark the functions, along with contpte_try_unfold()
> which is called by them, as __always_inline. This is worth ~1% on the
> fork() microbenchmark with order-0 folios (the common case).
> 
> Signed-off-by: Ryan Roberts 

I have no strong feelings either way on this, so:

Acked-by: Mark Rutland 

Mark.

> ---
>  arch/arm64/include/asm/pgtable.h | 10 +-
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/pgtable.h 
> b/arch/arm64/include/asm/pgtable.h
> index 353ea67b5d75..cdc310880a3b 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -1213,8 +1213,8 @@ extern int contpte_ptep_set_access_flags(struct 
> vm_area_struct *vma,
>   unsigned long addr, pte_t *ptep,
>   pte_t entry, int dirty);
>  
> -static inline void contpte_try_unfold(struct mm_struct *mm, unsigned long 
> addr,
> - pte_t *ptep, pte_t pte)
> +static __always_inline void contpte_try_unfold(struct mm_struct *mm,
> + unsigned long addr, pte_t *ptep, pte_t pte)
>  {
>   if (unlikely(pte_valid_cont(pte)))
>   __contpte_try_unfold(mm, addr, ptep, pte);
> @@ -1279,7 +1279,7 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
>  }
>  
>  #define set_ptes set_ptes
> -static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
> +static __always_inline void set_ptes(struct mm_struct *mm, unsigned long 
> addr,
>   pte_t *ptep, pte_t pte, unsigned int nr)
>  {
>   pte = pte_mknoncont(pte);
> @@ -1361,8 +1361,8 @@ static inline int ptep_clear_flush_young(struct 
> vm_area_struct *vma,
>  }
>  
>  #define wrprotect_ptes wrprotect_ptes
> -static inline void wrprotect_ptes(struct mm_struct *mm, unsigned long addr,
> - pte_t *ptep, unsigned int nr)
> +static __always_inline void wrprotect_ptes(struct mm_struct *mm,
> + unsigned long addr, pte_t *ptep, unsigned int 
> nr)
>  {
>   if (likely(nr == 1)) {
>   /*
> -- 
> 2.25.1
> 


[PATCH v5 24/25] arm64/mm: __always_inline to improve fork() perf

2024-02-02 Thread Ryan Roberts
As set_ptes() and wrprotect_ptes() become a bit more complex, the
compiler may choose not to inline them. But this is critical for fork()
performance. So mark the functions, along with contpte_try_unfold()
which is called by them, as __always_inline. This is worth ~1% on the
fork() microbenchmark with order-0 folios (the common case).

Signed-off-by: Ryan Roberts 
---
 arch/arm64/include/asm/pgtable.h | 10 +-
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 353ea67b5d75..cdc310880a3b 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -1213,8 +1213,8 @@ extern int contpte_ptep_set_access_flags(struct 
vm_area_struct *vma,
unsigned long addr, pte_t *ptep,
pte_t entry, int dirty);
 
-static inline void contpte_try_unfold(struct mm_struct *mm, unsigned long addr,
-   pte_t *ptep, pte_t pte)
+static __always_inline void contpte_try_unfold(struct mm_struct *mm,
+   unsigned long addr, pte_t *ptep, pte_t pte)
 {
if (unlikely(pte_valid_cont(pte)))
__contpte_try_unfold(mm, addr, ptep, pte);
@@ -1279,7 +1279,7 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
 }
 
 #define set_ptes set_ptes
-static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
+static __always_inline void set_ptes(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte, unsigned int nr)
 {
pte = pte_mknoncont(pte);
@@ -1361,8 +1361,8 @@ static inline int ptep_clear_flush_young(struct 
vm_area_struct *vma,
 }
 
 #define wrprotect_ptes wrprotect_ptes
-static inline void wrprotect_ptes(struct mm_struct *mm, unsigned long addr,
-   pte_t *ptep, unsigned int nr)
+static __always_inline void wrprotect_ptes(struct mm_struct *mm,
+   unsigned long addr, pte_t *ptep, unsigned int 
nr)
 {
if (likely(nr == 1)) {
/*
-- 
2.25.1