[permalink] [raw]

Subject: Re: [PATCH v6 04/19] powerpc: mm: Add p?d_large() definitions

Le 26/03/2019 à 17:26, Steven Price a écrit :
> walk_page_range() is going to be allowed to walk page tables other than
> those of user space. For this it needs to know when it has reached a
> 'leaf' entry in the page tables. This information is provided by the
> p?d_large() functions/macros.
>
> For powerpc pmd_large() was already implemented, so hoist it out of the
> CONFIG_TRANSPARENT_HUGEPAGE condition and implement the other levels.
>
> Also since we now have a pmd_large always implemented we can drop the
> pmd_is_leaf() function.

Wouldn't it be better to drop the pmd_is_leaf() in a second patch ?

Christophe

>
> CC: Benjamin Herrenschmidt <[email protected]>
> CC: Paul Mackerras <[email protected]>
> CC: Michael Ellerman <[email protected]>
> CC: [email protected]
> CC: [email protected]
> Signed-off-by: Steven Price <[email protected]>
> ---
> arch/powerpc/include/asm/book3s/64/pgtable.h | 30 ++++++++++++++------
> arch/powerpc/kvm/book3s_64_mmu_radix.c | 12 ++------
> 2 files changed, 24 insertions(+), 18 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index 581f91be9dd4..f6d1ac8b832e 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -897,6 +897,12 @@ static inline int pud_present(pud_t pud)
> return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PRESENT));
> }
>
> +#define pud_large pud_large
> +static inline int pud_large(pud_t pud)
> +{
> + return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
> +}
> +
> extern struct page *pud_page(pud_t pud);
> extern struct page *pmd_page(pmd_t pmd);
> static inline pte_t pud_pte(pud_t pud)
> @@ -940,6 +946,12 @@ static inline int pgd_present(pgd_t pgd)
> return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PRESENT));
> }
>
> +#define pgd_large pgd_large
> +static inline int pgd_large(pgd_t pgd)
> +{
> + return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PTE));
> +}
> +
> static inline pte_t pgd_pte(pgd_t pgd)
> {
> return __pte_raw(pgd_raw(pgd));
> @@ -1093,6 +1105,15 @@ static inline bool pmd_access_permitted(pmd_t pmd, bool write)
> return pte_access_permitted(pmd_pte(pmd), write);
> }
>
> +#define pmd_large pmd_large
> +/*
> + * returns true for pmd migration entries, THP, devmap, hugetlb
> + */
> +static inline int pmd_large(pmd_t pmd)
> +{
> + return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
> +}
> +
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> extern pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot);
> extern pmd_t mk_pmd(struct page *page, pgprot_t pgprot);
> @@ -1119,15 +1140,6 @@ pmd_hugepage_update(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp,
> return hash__pmd_hugepage_update(mm, addr, pmdp, clr, set);
> }
>
> -/*
> - * returns true for pmd migration entries, THP, devmap, hugetlb
> - * But compile time dependent on THP config
> - */
> -static inline int pmd_large(pmd_t pmd)
> -{
> - return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
> -}
> -
> static inline pmd_t pmd_mknotpresent(pmd_t pmd)
> {
> return __pmd(pmd_val(pmd) & ~_PAGE_PRESENT);
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> index f55ef071883f..1b57b4e3f819 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> @@ -363,12 +363,6 @@ static void kvmppc_pte_free(pte_t *ptep)
> kmem_cache_free(kvm_pte_cache, ptep);
> }
>
> -/* Like pmd_huge() and pmd_large(), but works regardless of config options */
> -static inline int pmd_is_leaf(pmd_t pmd)
> -{
> - return !!(pmd_val(pmd) & _PAGE_PTE);
> -}
> -
> static pmd_t *kvmppc_pmd_alloc(void)
> {
> return kmem_cache_alloc(kvm_pmd_cache, GFP_KERNEL);
> @@ -460,7 +454,7 @@ static void kvmppc_unmap_free_pmd(struct kvm *kvm, pmd_t *pmd, bool full,
> for (im = 0; im < PTRS_PER_PMD; ++im, ++p) {
> if (!pmd_present(*p))
> continue;
> - if (pmd_is_leaf(*p)) {
> + if (pmd_large(*p)) {
> if (full) {
> pmd_clear(p);
> } else {
> @@ -593,7 +587,7 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, pte_t pte,
> else if (level <= 1)
> new_pmd = kvmppc_pmd_alloc();
>
> - if (level == 0 && !(pmd && pmd_present(*pmd) && !pmd_is_leaf(*pmd)))
> + if (level == 0 && !(pmd && pmd_present(*pmd) && !pmd_large(*pmd)))
> new_ptep = kvmppc_pte_alloc();
>
> /* Check if we might have been invalidated; let the guest retry if so */
> @@ -662,7 +656,7 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, pte_t pte,
> new_pmd = NULL;
> }
> pmd = pmd_offset(pud, gpa);
> - if (pmd_is_leaf(*pmd)) {
> + if (pmd_large(*pmd)) {
> unsigned long lgpa = gpa & PMD_MASK;
>
> /* Check if we raced and someone else has set the same thing */
>

2019-03-28 11:01:51

by Steven Price

[permalink] [raw]

Subject: Re: [PATCH v6 04/19] powerpc: mm: Add p?d_large() definitions

On 26/03/2019 16:58, Christophe Leroy wrote:
>
>
> Le 26/03/2019 à 17:26, Steven Price a écrit :
>> walk_page_range() is going to be allowed to walk page tables other than
>> those of user space. For this it needs to know when it has reached a
>> 'leaf' entry in the page tables. This information is provided by the
>> p?d_large() functions/macros.
>>
>> For powerpc pmd_large() was already implemented, so hoist it out of the
>> CONFIG_TRANSPARENT_HUGEPAGE condition and implement the other levels.
>>
>> Also since we now have a pmd_large always implemented we can drop the
>> pmd_is_leaf() function.
>
> Wouldn't it be better to drop the pmd_is_leaf() in a second patch ?

Fair point, I'll split this patch.

Thanks for the review,

Steve

> Christophe
>
>>
>> CC: Benjamin Herrenschmidt <[email protected]>
>> CC: Paul Mackerras <[email protected]>
>> CC: Michael Ellerman <[email protected]>
>> CC: [email protected]
>> CC: [email protected]
>> Signed-off-by: Steven Price <[email protected]>
>> ---
>> arch/powerpc/include/asm/book3s/64/pgtable.h | 30 ++++++++++++++------
>> arch/powerpc/kvm/book3s_64_mmu_radix.c       | 12 ++------
>> 2 files changed, 24 insertions(+), 18 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h
>> b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> index 581f91be9dd4..f6d1ac8b832e 100644
>> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
>> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> @@ -897,6 +897,12 @@ static inline int pud_present(pud_t pud)
>>       return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PRESENT));
>> }
>> +#define pud_large    pud_large
>> +static inline int pud_large(pud_t pud)
>> +{
>> +    return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
>> +}
>> +
>> extern struct page *pud_page(pud_t pud);
>> extern struct page *pmd_page(pmd_t pmd);
>> static inline pte_t pud_pte(pud_t pud)
>> @@ -940,6 +946,12 @@ static inline int pgd_present(pgd_t pgd)
>>       return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PRESENT));
>> }
>> +#define pgd_large    pgd_large
>> +static inline int pgd_large(pgd_t pgd)
>> +{
>> +    return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PTE));
>> +}
>> +
>> static inline pte_t pgd_pte(pgd_t pgd)
>> {
>>       return __pte_raw(pgd_raw(pgd));
>> @@ -1093,6 +1105,15 @@ static inline bool pmd_access_permitted(pmd_t
>> pmd, bool write)
>>       return pte_access_permitted(pmd_pte(pmd), write);
>> }
>> +#define pmd_large    pmd_large
>> +/*
>> + * returns true for pmd migration entries, THP, devmap, hugetlb
>> + */
>> +static inline int pmd_large(pmd_t pmd)
>> +{
>> +    return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
>> +}
>> +
>> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>> extern pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot);
>> extern pmd_t mk_pmd(struct page *page, pgprot_t pgprot);
>> @@ -1119,15 +1140,6 @@ pmd_hugepage_update(struct mm_struct *mm,
>> unsigned long addr, pmd_t *pmdp,
>>       return hash__pmd_hugepage_update(mm, addr, pmdp, clr, set);
>> }
>> -/*
>> - * returns true for pmd migration entries, THP, devmap, hugetlb
>> - * But compile time dependent on THP config
>> - */
>> -static inline int pmd_large(pmd_t pmd)
>> -{
>> -    return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
>> -}
>> -
>> static inline pmd_t pmd_mknotpresent(pmd_t pmd)
>> {
>>       return __pmd(pmd_val(pmd) & ~_PAGE_PRESENT);
>> diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c
>> b/arch/powerpc/kvm/book3s_64_mmu_radix.c
>> index f55ef071883f..1b57b4e3f819 100644
>> --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
>> +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
>> @@ -363,12 +363,6 @@ static void kvmppc_pte_free(pte_t *ptep)
>>       kmem_cache_free(kvm_pte_cache, ptep);
>> }
>> -/* Like pmd_huge() and pmd_large(), but works regardless of config
>> options */
>> -static inline int pmd_is_leaf(pmd_t pmd)
>> -{
>> -    return !!(pmd_val(pmd) & _PAGE_PTE);
>> -}
>> -
>> static pmd_t *kvmppc_pmd_alloc(void)
>> {
>>       return kmem_cache_alloc(kvm_pmd_cache, GFP_KERNEL);
>> @@ -460,7 +454,7 @@ static void kvmppc_unmap_free_pmd(struct kvm *kvm,
>> pmd_t *pmd, bool full,
>>       for (im = 0; im < PTRS_PER_PMD; ++im, ++p) {
>>           if (!pmd_present(*p))
>>               continue;
>> -        if (pmd_is_leaf(*p)) {
>> +        if (pmd_large(*p)) {
>>               if (full) {
>>                   pmd_clear(p);
>>               } else {
>> @@ -593,7 +587,7 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t
>> *pgtable, pte_t pte,
>>       else if (level <= 1)
>>           new_pmd = kvmppc_pmd_alloc();
>> -    if (level == 0 && !(pmd && pmd_present(*pmd) &&
>> !pmd_is_leaf(*pmd)))
>> +    if (level == 0 && !(pmd && pmd_present(*pmd) && !pmd_large(*pmd)))
>>           new_ptep = kvmppc_pte_alloc();
>>       /* Check if we might have been invalidated; let the guest
>> retry if so */
>> @@ -662,7 +656,7 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t
>> *pgtable, pte_t pte,
>>           new_pmd = NULL;
>>       }
>>       pmd = pmd_offset(pud, gpa);
>> -    if (pmd_is_leaf(*pmd)) {
>> +    if (pmd_large(*pmd)) {
>>           unsigned long lgpa = gpa & PMD_MASK;
>>           /* Check if we raced and someone else has set the same
>> thing */
>>
>
> _______________________________________________
> linux-arm-kernel mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel