Re: [PATCH V2] mm: Merge pte_mkhuge() call into arch_make_huge_pte()

2023-03-01 Thread Anshuman Khandual



On 3/1/23 12:26, Christophe Leroy wrote:
> Hi,
> 
> Le 03/02/2022 à 04:57, Anshuman Khandual a écrit :
>> Each call into pte_mkhuge() is invariably followed by arch_make_huge_pte().
>> Instead arch_make_huge_pte() can accommodate pte_mkhuge() at the beginning.
>> This updates generic fallback stub for arch_make_huge_pte() and available
>> platforms definitions. This makes huge pte creation much cleaner and easier
>> to follow.
> 
> I can't remember, what was the reason for not doing it in 
> remove_migration_pte() as well ?
> Looking at it, I have the feeling that we now have a redundant 
> pte_mkhuge() there.

I guess it just got missed out, but you are right, there seems to be a redundant
pte_mkhuge() in remove_migration_pte(), I will send out a patch dropping it off.

> 
> Also, could we get rid of the one in mm/debug_vm_pgtable.c ?

After this patch, arch_make_huge_pte() should be used instead in generic MM for
all cases. So you are suggesting arch_make_huge_pte() should be tested instead ?

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index c631ade3f1d2..15ee86034ddc 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -909,7 +909,7 @@ static void __init hugetlb_basic_tests(struct 
pgtable_debug_args *args)
 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
pte = pfn_pte(args->fixed_pmd_pfn, args->page_prot);
 
-   WARN_ON(!pte_huge(pte_mkhuge(pte)));
+   WARN_ON(!pte_huge(arch_make_huge_pte(pte)));
 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
 }
 #else  /* !CONFIG_HUGETLB_PAGE */

> 
> Also, shouldn't arch_make_huge_pte() be documented in 
> Documentation/vm/arch_pgtable_helpers.rst instead of pte_mkhuge() ?

diff --git a/Documentation/mm/arch_pgtable_helpers.rst 
b/Documentation/mm/arch_pgtable_helpers.rst
index fd2a19df884e..07a0618f84de 100644
--- a/Documentation/mm/arch_pgtable_helpers.rst
+++ b/Documentation/mm/arch_pgtable_helpers.rst
@@ -216,7 +216,7 @@ HugeTLB Page Table Helpers
 
+---+--+
 | pte_huge  | Tests a HugeTLB  
|
 
+---+--+
-| pte_mkhuge| Creates a HugeTLB
|
+| arch_make_huge_pte| Creates a HugeTLB
|
 
+---+--+
 | huge_pte_dirty| Tests a dirty HugeTLB
|
 
+---+--+

I will send out a patch implementing the above changes. I guess pte_mkhuge() now
will just be a platform helper, which can be folded into arch_make_huge_pte() if
and when required.

- Anshuman

> 
> Christophe
> 
>>
>> Cc: Catalin Marinas 
>> Cc: Will Deacon 
>> Cc: Michael Ellerman 
>> Cc: Paul Mackerras 
>> Cc: "David S. Miller" 
>> Cc: Mike Kravetz 
>> Cc: Andrew Morton 
>> Cc: linux-arm-ker...@lists.infradead.org
>> Cc: linuxppc-dev@lists.ozlabs.org
>> Cc: sparcli...@vger.kernel.org
>> Cc: linux...@kvack.org
>> Cc: linux-ker...@vger.kernel.org
>> Reviewed-by: Christophe Leroy 
>> Acked-by: Mike Kravetz 
>> Signed-off-by: Anshuman Khandual 
>> ---
>> This applies on v5.17-rc2
>>
>> Changes in V2:
>>
>> - Direct PTE encode in arch_make_huge_pte() on powerpc platform per 
>> Christophe
>>
>> Changes in V1:
>>
>> https://lore.kernel.org/all/1643780286-18798-1-git-send-email-anshuman.khand...@arm.com/
>>
>>   arch/arm64/mm/hugetlbpage.c  | 1 +
>>   arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h | 4 ++--
>>   arch/sparc/mm/hugetlbpage.c  | 1 +
>>   include/linux/hugetlb.h  | 2 +-
>>   mm/hugetlb.c | 3 +--
>>   mm/vmalloc.c | 1 -
>>   6 files changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
>> index ffb9c229610a..228226c5fa80 100644
>> --- a/arch/arm64/mm/hugetlbpage.c
>> +++ b/arch/arm64/mm/hugetlbpage.c
>> @@ -347,6 +347,7 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int 
>> shift, vm_flags_t flags)
>>   {
>>  size_t pagesize = 1UL << shift;
>>   
>> +entry = pte_mkhuge(entry);
>>  if (pagesize == CONT_PTE_SIZE) {
>>  entry = pte_mkcont(entry);
>>  } else if (pagesize == CONT_PMD_SIZE) {
>> diff --git a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h 
>> b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
>> index 64b6c608eca4..de092b04ee1a 100644
>> --- a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
>> +++ b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
>> @@ -71,9 +71,9 @@ static inline pte_t arch_make_huge_pte(pte_t entry, 
>> unsigned int shift, vm_flags
>>  size_t size = 1UL << shift;
>>   
>>  if (size == SZ_16K)
>> -return __pte(pte_val(entry) & ~_PAGE_HUGE);

Re: [PATCH V2] mm: Merge pte_mkhuge() call into arch_make_huge_pte()

2023-02-28 Thread Christophe Leroy
Hi,

Le 03/02/2022 à 04:57, Anshuman Khandual a écrit :
> Each call into pte_mkhuge() is invariably followed by arch_make_huge_pte().
> Instead arch_make_huge_pte() can accommodate pte_mkhuge() at the beginning.
> This updates generic fallback stub for arch_make_huge_pte() and available
> platforms definitions. This makes huge pte creation much cleaner and easier
> to follow.

I can't remember, what was the reason for not doing it in 
remove_migration_pte() as well ?
Looking at it, I have the feeling that we now have a redundant 
pte_mkhuge() there.

Also, could we get rid of the one in mm/debug_vm_pgtable.c ?

Also, shouldn't arch_make_huge_pte() be documented in 
Documentation/vm/arch_pgtable_helpers.rst instead of pte_mkhuge() ?

Christophe

> 
> Cc: Catalin Marinas 
> Cc: Will Deacon 
> Cc: Michael Ellerman 
> Cc: Paul Mackerras 
> Cc: "David S. Miller" 
> Cc: Mike Kravetz 
> Cc: Andrew Morton 
> Cc: linux-arm-ker...@lists.infradead.org
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: sparcli...@vger.kernel.org
> Cc: linux...@kvack.org
> Cc: linux-ker...@vger.kernel.org
> Reviewed-by: Christophe Leroy 
> Acked-by: Mike Kravetz 
> Signed-off-by: Anshuman Khandual 
> ---
> This applies on v5.17-rc2
> 
> Changes in V2:
> 
> - Direct PTE encode in arch_make_huge_pte() on powerpc platform per Christophe
> 
> Changes in V1:
> 
> https://lore.kernel.org/all/1643780286-18798-1-git-send-email-anshuman.khand...@arm.com/
> 
>   arch/arm64/mm/hugetlbpage.c  | 1 +
>   arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h | 4 ++--
>   arch/sparc/mm/hugetlbpage.c  | 1 +
>   include/linux/hugetlb.h  | 2 +-
>   mm/hugetlb.c | 3 +--
>   mm/vmalloc.c | 1 -
>   6 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
> index ffb9c229610a..228226c5fa80 100644
> --- a/arch/arm64/mm/hugetlbpage.c
> +++ b/arch/arm64/mm/hugetlbpage.c
> @@ -347,6 +347,7 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, 
> vm_flags_t flags)
>   {
>   size_t pagesize = 1UL << shift;
>   
> + entry = pte_mkhuge(entry);
>   if (pagesize == CONT_PTE_SIZE) {
>   entry = pte_mkcont(entry);
>   } else if (pagesize == CONT_PMD_SIZE) {
> diff --git a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h 
> b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
> index 64b6c608eca4..de092b04ee1a 100644
> --- a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
> +++ b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
> @@ -71,9 +71,9 @@ static inline pte_t arch_make_huge_pte(pte_t entry, 
> unsigned int shift, vm_flags
>   size_t size = 1UL << shift;
>   
>   if (size == SZ_16K)
> - return __pte(pte_val(entry) & ~_PAGE_HUGE);
> + return __pte(pte_val(entry) | _PAGE_SPS);
>   else
> - return entry;
> + return __pte(pte_val(entry) | _PAGE_SPS | _PAGE_HUGE);
>   }
>   #define arch_make_huge_pte arch_make_huge_pte
>   #endif
> diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c
> index 0f49fada2093..d8e0e3c7038d 100644
> --- a/arch/sparc/mm/hugetlbpage.c
> +++ b/arch/sparc/mm/hugetlbpage.c
> @@ -181,6 +181,7 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, 
> vm_flags_t flags)
>   {
>   pte_t pte;
>   
> + entry = pte_mkhuge(entry);
>   pte = hugepage_shift_to_tte(entry, shift);
>   
>   #ifdef CONFIG_SPARC64
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index d1897a69c540..52c462390aee 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -754,7 +754,7 @@ static inline void arch_clear_hugepage_flags(struct page 
> *page) { }
>   static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift,
>  vm_flags_t flags)
>   {
> - return entry;
> + return pte_mkhuge(entry);
>   }
>   #endif
>   
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 61895cc01d09..5ca253c1b4e4 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -4637,7 +4637,6 @@ static pte_t make_huge_pte(struct vm_area_struct *vma, 
> struct page *page,
>  vma->vm_page_prot));
>   }
>   entry = pte_mkyoung(entry);
> - entry = pte_mkhuge(entry);
>   entry = arch_make_huge_pte(entry, shift, vma->vm_flags);
>   
>   return entry;
> @@ -6172,7 +6171,7 @@ unsigned long hugetlb_change_protection(struct 
> vm_area_struct *vma,
>   unsigned int shift = huge_page_shift(hstate_vma(vma));
>   
>   old_pte = huge_ptep_modify_prot_start(vma, address, 
> ptep);
> - pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
> + pte = huge_pte_modify(old_pte, newprot);
>   pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
>   

Re: [PATCH V2] mm: Merge pte_mkhuge() call into arch_make_huge_pte()

2022-02-03 Thread Catalin Marinas
On Thu, Feb 03, 2022 at 09:27:49AM +0530, Anshuman Khandual wrote:
> Each call into pte_mkhuge() is invariably followed by arch_make_huge_pte().
> Instead arch_make_huge_pte() can accommodate pte_mkhuge() at the beginning.
> This updates generic fallback stub for arch_make_huge_pte() and available
> platforms definitions. This makes huge pte creation much cleaner and easier
> to follow.
> 
> Cc: Catalin Marinas 
> Cc: Will Deacon 
> Cc: Michael Ellerman 
> Cc: Paul Mackerras 
> Cc: "David S. Miller" 
> Cc: Mike Kravetz 
> Cc: Andrew Morton 
> Cc: linux-arm-ker...@lists.infradead.org
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: sparcli...@vger.kernel.org
> Cc: linux...@kvack.org
> Cc: linux-ker...@vger.kernel.org
> Reviewed-by: Christophe Leroy 
> Acked-by: Mike Kravetz 
> Signed-off-by: Anshuman Khandual 

Acking v2 as well:

Acked-by: Catalin Marinas 


[PATCH V2] mm: Merge pte_mkhuge() call into arch_make_huge_pte()

2022-02-02 Thread Anshuman Khandual
Each call into pte_mkhuge() is invariably followed by arch_make_huge_pte().
Instead arch_make_huge_pte() can accommodate pte_mkhuge() at the beginning.
This updates generic fallback stub for arch_make_huge_pte() and available
platforms definitions. This makes huge pte creation much cleaner and easier
to follow.

Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Michael Ellerman 
Cc: Paul Mackerras 
Cc: "David S. Miller" 
Cc: Mike Kravetz 
Cc: Andrew Morton 
Cc: linux-arm-ker...@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparcli...@vger.kernel.org
Cc: linux...@kvack.org
Cc: linux-ker...@vger.kernel.org
Reviewed-by: Christophe Leroy 
Acked-by: Mike Kravetz 
Signed-off-by: Anshuman Khandual 
---
This applies on v5.17-rc2

Changes in V2:

- Direct PTE encode in arch_make_huge_pte() on powerpc platform per Christophe

Changes in V1:

https://lore.kernel.org/all/1643780286-18798-1-git-send-email-anshuman.khand...@arm.com/

 arch/arm64/mm/hugetlbpage.c  | 1 +
 arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h | 4 ++--
 arch/sparc/mm/hugetlbpage.c  | 1 +
 include/linux/hugetlb.h  | 2 +-
 mm/hugetlb.c | 3 +--
 mm/vmalloc.c | 1 -
 6 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index ffb9c229610a..228226c5fa80 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -347,6 +347,7 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, 
vm_flags_t flags)
 {
size_t pagesize = 1UL << shift;
 
+   entry = pte_mkhuge(entry);
if (pagesize == CONT_PTE_SIZE) {
entry = pte_mkcont(entry);
} else if (pagesize == CONT_PMD_SIZE) {
diff --git a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h 
b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
index 64b6c608eca4..de092b04ee1a 100644
--- a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
@@ -71,9 +71,9 @@ static inline pte_t arch_make_huge_pte(pte_t entry, unsigned 
int shift, vm_flags
size_t size = 1UL << shift;
 
if (size == SZ_16K)
-   return __pte(pte_val(entry) & ~_PAGE_HUGE);
+   return __pte(pte_val(entry) | _PAGE_SPS);
else
-   return entry;
+   return __pte(pte_val(entry) | _PAGE_SPS | _PAGE_HUGE);
 }
 #define arch_make_huge_pte arch_make_huge_pte
 #endif
diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c
index 0f49fada2093..d8e0e3c7038d 100644
--- a/arch/sparc/mm/hugetlbpage.c
+++ b/arch/sparc/mm/hugetlbpage.c
@@ -181,6 +181,7 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, 
vm_flags_t flags)
 {
pte_t pte;
 
+   entry = pte_mkhuge(entry);
pte = hugepage_shift_to_tte(entry, shift);
 
 #ifdef CONFIG_SPARC64
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index d1897a69c540..52c462390aee 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -754,7 +754,7 @@ static inline void arch_clear_hugepage_flags(struct page 
*page) { }
 static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift,
   vm_flags_t flags)
 {
-   return entry;
+   return pte_mkhuge(entry);
 }
 #endif
 
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 61895cc01d09..5ca253c1b4e4 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4637,7 +4637,6 @@ static pte_t make_huge_pte(struct vm_area_struct *vma, 
struct page *page,
   vma->vm_page_prot));
}
entry = pte_mkyoung(entry);
-   entry = pte_mkhuge(entry);
entry = arch_make_huge_pte(entry, shift, vma->vm_flags);
 
return entry;
@@ -6172,7 +6171,7 @@ unsigned long hugetlb_change_protection(struct 
vm_area_struct *vma,
unsigned int shift = huge_page_shift(hstate_vma(vma));
 
old_pte = huge_ptep_modify_prot_start(vma, address, 
ptep);
-   pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
+   pte = huge_pte_modify(old_pte, newprot);
pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
huge_ptep_modify_prot_commit(vma, address, ptep, 
old_pte, pte);
pages++;
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 4165304d3547..d0b14dd73adc 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -118,7 +118,6 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, 
unsigned long end,
if (size != PAGE_SIZE) {
pte_t entry = pfn_pte(pfn, prot);
 
-   entry = pte_mkhuge(entry);
entry = arch_make_huge_pte(entry, ilog2(size), 0);
set_huge_pte_at(_mm, addr, pte, entry);
pfn +=