[5/6] arm64/mm: Call pgtable_page_dtor() for both PMD and PUD page table pages
diff mbox series

Message ID 1548307220-19756-6-git-send-email-anshuman.khandual@arm.com
State New
Headers show
Series
  • arm64/mm: Enable accounting for page table pages
Related show

Commit Message

Anshuman Khandual Jan. 24, 2019, 5:20 a.m. UTC
TLB flush during PMD and PUD level page table page tear down currently does
not call pgtable_page_dtor() like that for PTE page table pages. Now that
all the page table pages which are allocated from the buddy allocator must
have been initialized through pgtable_page_ctor() they must be freed back
only after being called into pgtable_page_dtor() destructor. Else these
pages might run into bad page state errors while getting freed into buddy
allocator.

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/arm64/include/asm/tlb.h | 2 ++
 1 file changed, 2 insertions(+)

Comments

Will Deacon Feb. 14, 2019, 5:11 p.m. UTC | #1
On Thu, Jan 24, 2019 at 10:50:19AM +0530, Anshuman Khandual wrote:
> TLB flush during PMD and PUD level page table page tear down currently does
> not call pgtable_page_dtor() like that for PTE page table pages. Now that
> all the page table pages which are allocated from the buddy allocator must
> have been initialized through pgtable_page_ctor() they must be freed back
> only after being called into pgtable_page_dtor() destructor. Else these
> pages might run into bad page state errors while getting freed into buddy
> allocator.
> 
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>  arch/arm64/include/asm/tlb.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h
> index 106fdc9..de46ba0 100644
> --- a/arch/arm64/include/asm/tlb.h
> +++ b/arch/arm64/include/asm/tlb.h
> @@ -62,6 +62,7 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
>  static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
>  				  unsigned long addr)
>  {
> +	pgtable_page_dtor(virt_to_page(pmdp));
>  	tlb_remove_table(tlb, virt_to_page(pmdp));
>  }
>  #endif
> @@ -70,6 +71,7 @@ static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
>  static inline void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pudp,
>  				  unsigned long addr)
>  {
> +	pgtable_page_dtor(virt_to_page(pudp));
>  	tlb_remove_table(tlb, virt_to_page(pudp));

This would be cleaner if you assigned to a temporary struct page * variable.
With that:

Acked-by: Will Deacon <will.deacon@arm.com>

Will
Anshuman Khandual Feb. 19, 2019, 4:34 a.m. UTC | #2
On 02/14/2019 10:41 PM, Will Deacon wrote:
> On Thu, Jan 24, 2019 at 10:50:19AM +0530, Anshuman Khandual wrote:
>> TLB flush during PMD and PUD level page table page tear down currently does
>> not call pgtable_page_dtor() like that for PTE page table pages. Now that
>> all the page table pages which are allocated from the buddy allocator must
>> have been initialized through pgtable_page_ctor() they must be freed back
>> only after being called into pgtable_page_dtor() destructor. Else these
>> pages might run into bad page state errors while getting freed into buddy
>> allocator.
>>
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>>  arch/arm64/include/asm/tlb.h | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h
>> index 106fdc9..de46ba0 100644
>> --- a/arch/arm64/include/asm/tlb.h
>> +++ b/arch/arm64/include/asm/tlb.h
>> @@ -62,6 +62,7 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
>>  static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
>>  				  unsigned long addr)
>>  {
>> +	pgtable_page_dtor(virt_to_page(pmdp));
>>  	tlb_remove_table(tlb, virt_to_page(pmdp));
>>  }
>>  #endif
>> @@ -70,6 +71,7 @@ static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
>>  static inline void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pudp,
>>  				  unsigned long addr)
>>  {
>> +	pgtable_page_dtor(virt_to_page(pudp));
>>  	tlb_remove_table(tlb, virt_to_page(pudp));
> 
> This would be cleaner if you assigned to a temporary struct page * variable.
> With that:

Sure will do.

> 
> Acked-by: Will Deacon <will.deacon@arm.com>
> 
> Will
>

Patch
diff mbox series

diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h
index 106fdc9..de46ba0 100644
--- a/arch/arm64/include/asm/tlb.h
+++ b/arch/arm64/include/asm/tlb.h
@@ -62,6 +62,7 @@  static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
 static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
 				  unsigned long addr)
 {
+	pgtable_page_dtor(virt_to_page(pmdp));
 	tlb_remove_table(tlb, virt_to_page(pmdp));
 }
 #endif
@@ -70,6 +71,7 @@  static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
 static inline void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pudp,
 				  unsigned long addr)
 {
+	pgtable_page_dtor(virt_to_page(pudp));
 	tlb_remove_table(tlb, virt_to_page(pudp));
 }
 #endif