Re: [PATCH] paravirt: remove paravirt ops pmd_update[_defer] and pte_update_defer

[Juergen Gross]

Ping?

On 17/11/15 15:51, Juergen Gross wrote:
> pte_update_defer can be removed as it is always set to the same
> function as pte_update. So any usage of pte_update_defer() can be
> replaced by pte_update().
> 
> pmd_update and pmd_update_defer are always set to paravirt_nop, so they
> can just be nuked.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> ---
>  arch/x86/include/asm/paravirt.h       | 17 -----------------
>  arch/x86/include/asm/paravirt_types.h |  6 ------
>  arch/x86/include/asm/pgtable.h        | 15 ++-------------
>  arch/x86/kernel/paravirt.c            |  3 ---
>  arch/x86/lguest/boot.c                |  1 -
>  arch/x86/mm/pgtable.c                 |  7 +------
>  arch/x86/xen/mmu.c                    |  1 -
>  7 files changed, 3 insertions(+), 47 deletions(-)
> 
> diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
> index 10d0596..398f068 100644
> --- a/arch/x86/include/asm/paravirt.h
> +++ b/arch/x86/include/asm/paravirt.h
> @@ -375,23 +375,6 @@ static inline void pte_update(struct mm_struct *mm, unsigned long addr,
>  {
>  	PVOP_VCALL3(pv_mmu_ops.pte_update, mm, addr, ptep);
>  }
> -static inline void pmd_update(struct mm_struct *mm, unsigned long addr,
> -			      pmd_t *pmdp)
> -{
> -	PVOP_VCALL3(pv_mmu_ops.pmd_update, mm, addr, pmdp);
> -}
> -
> -static inline void pte_update_defer(struct mm_struct *mm, unsigned long addr,
> -				    pte_t *ptep)
> -{
> -	PVOP_VCALL3(pv_mmu_ops.pte_update_defer, mm, addr, ptep);
> -}
> -
> -static inline void pmd_update_defer(struct mm_struct *mm, unsigned long addr,
> -				    pmd_t *pmdp)
> -{
> -	PVOP_VCALL3(pv_mmu_ops.pmd_update_defer, mm, addr, pmdp);
> -}
>  
>  static inline pte_t __pte(pteval_t val)
>  {
> diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
> index 31247b5..6418541 100644
> --- a/arch/x86/include/asm/paravirt_types.h
> +++ b/arch/x86/include/asm/paravirt_types.h
> @@ -274,12 +274,6 @@ struct pv_mmu_ops {
>  			   pmd_t *pmdp, pmd_t pmdval);
>  	void (*pte_update)(struct mm_struct *mm, unsigned long addr,
>  			   pte_t *ptep);
> -	void (*pte_update_defer)(struct mm_struct *mm,
> -				 unsigned long addr, pte_t *ptep);
> -	void (*pmd_update)(struct mm_struct *mm, unsigned long addr,
> -			   pmd_t *pmdp);
> -	void (*pmd_update_defer)(struct mm_struct *mm,
> -				 unsigned long addr, pmd_t *pmdp);
>  
>  	pte_t (*ptep_modify_prot_start)(struct mm_struct *mm, unsigned long addr,
>  					pte_t *ptep);
> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> index 6ec0c8b..d3eee66 100644
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -69,9 +69,6 @@ extern struct mm_struct *pgd_page_get_mm(struct page *page);
>  #define pmd_clear(pmd)			native_pmd_clear(pmd)
>  
>  #define pte_update(mm, addr, ptep)              do { } while (0)
> -#define pte_update_defer(mm, addr, ptep)        do { } while (0)
> -#define pmd_update(mm, addr, ptep)              do { } while (0)
> -#define pmd_update_defer(mm, addr, ptep)        do { } while (0)
>  
>  #define pgd_val(x)	native_pgd_val(x)
>  #define __pgd(x)	native_make_pgd(x)
> @@ -731,14 +728,9 @@ static inline void native_set_pmd_at(struct mm_struct *mm, unsigned long addr,
>   * updates should either be sets, clears, or set_pte_atomic for P->P
>   * transitions, which means this hook should only be called for user PTEs.
>   * This hook implies a P->P protection or access change has taken place, which
> - * requires a subsequent TLB flush.  The notification can optionally be delayed
> - * until the TLB flush event by using the pte_update_defer form of the
> - * interface, but care must be taken to assure that the flush happens while
> - * still holding the same page table lock so that the shadow and primary pages
> - * do not become out of sync on SMP.
> + * requires a subsequent TLB flush.
>   */
>  #define pte_update(mm, addr, ptep)		do { } while (0)
> -#define pte_update_defer(mm, addr, ptep)	do { } while (0)
>  #endif
>  
>  /*
> @@ -830,9 +822,7 @@ static inline int pmd_write(pmd_t pmd)
>  static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, unsigned long addr,
>  				       pmd_t *pmdp)
>  {
> -	pmd_t pmd = native_pmdp_get_and_clear(pmdp);
> -	pmd_update(mm, addr, pmdp);
> -	return pmd;
> +	return native_pmdp_get_and_clear(pmdp);
>  }
>  
>  #define __HAVE_ARCH_PMDP_SET_WRPROTECT
> @@ -840,7 +830,6 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
>  				      unsigned long addr, pmd_t *pmdp)
>  {
>  	clear_bit(_PAGE_BIT_RW, (unsigned long *)pmdp);
> -	pmd_update(mm, addr, pmdp);
>  }
>  
>  /*
> diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
> index c2130ae..f601250 100644
> --- a/arch/x86/kernel/paravirt.c
> +++ b/arch/x86/kernel/paravirt.c
> @@ -444,9 +444,6 @@ struct pv_mmu_ops pv_mmu_ops = {
>  	.set_pmd = native_set_pmd,
>  	.set_pmd_at = native_set_pmd_at,
>  	.pte_update = paravirt_nop,
> -	.pte_update_defer = paravirt_nop,
> -	.pmd_update = paravirt_nop,
> -	.pmd_update_defer = paravirt_nop,
>  
>  	.ptep_modify_prot_start = __ptep_modify_prot_start,
>  	.ptep_modify_prot_commit = __ptep_modify_prot_commit,
> diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
> index a0d09f6..a1900d4 100644
> --- a/arch/x86/lguest/boot.c
> +++ b/arch/x86/lguest/boot.c
> @@ -1472,7 +1472,6 @@ __init void lguest_init(void)
>  	pv_mmu_ops.lazy_mode.leave = lguest_leave_lazy_mmu_mode;
>  	pv_mmu_ops.lazy_mode.flush = paravirt_flush_lazy_mmu;
>  	pv_mmu_ops.pte_update = lguest_pte_update;
> -	pv_mmu_ops.pte_update_defer = lguest_pte_update;
>  
>  #ifdef CONFIG_X86_LOCAL_APIC
>  	/* APIC read/write intercepts */
> diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
> index fb0a9dd..ee9c2e3 100644
> --- a/arch/x86/mm/pgtable.c
> +++ b/arch/x86/mm/pgtable.c
> @@ -414,7 +414,7 @@ int ptep_set_access_flags(struct vm_area_struct *vma,
>  
>  	if (changed && dirty) {
>  		*ptep = entry;
> -		pte_update_defer(vma->vm_mm, address, ptep);
> +		pte_update(vma->vm_mm, address, ptep);
>  	}
>  
>  	return changed;
> @@ -431,7 +431,6 @@ int pmdp_set_access_flags(struct vm_area_struct *vma,
>  
>  	if (changed && dirty) {
>  		*pmdp = entry;
> -		pmd_update_defer(vma->vm_mm, address, pmdp);
>  		/*
>  		 * We had a write-protection fault here and changed the pmd
>  		 * to to more permissive. No need to flush the TLB for that,
> @@ -469,9 +468,6 @@ int pmdp_test_and_clear_young(struct vm_area_struct *vma,
>  		ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
>  					 (unsigned long *)pmdp);
>  
> -	if (ret)
> -		pmd_update(vma->vm_mm, addr, pmdp);
> -
>  	return ret;
>  }
>  #endif
> @@ -518,7 +514,6 @@ void pmdp_splitting_flush(struct vm_area_struct *vma,
>  	set = !test_and_set_bit(_PAGE_BIT_SPLITTING,
>  				(unsigned long *)pmdp);
>  	if (set) {
> -		pmd_update(vma->vm_mm, address, pmdp);
>  		/* need tlb flush only to serialize against gup-fast */
>  		flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
>  	}
> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> index ac161db..896dc14 100644
> --- a/arch/x86/xen/mmu.c
> +++ b/arch/x86/xen/mmu.c
> @@ -2436,7 +2436,6 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
>  	.flush_tlb_others = xen_flush_tlb_others,
>  
>  	.pte_update = paravirt_nop,
> -	.pte_update_defer = paravirt_nop,
>  
>  	.pgd_alloc = xen_pgd_alloc,
>  	.pgd_free = xen_pgd_free,
> 

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