diff mbox series

[v1,4/5] mm: ptdump: Support hugepd table entries

Message ID f41a177a0fd5a71db616e586a9ec5c51102c6656.1618506910.git.christophe.leroy@csgroup.eu (mailing list archive)
State New
Headers show
Series Convert powerpc to GENERIC_PTDUMP | expand

Commit Message

Christophe Leroy April 15, 2021, 5:18 p.m. UTC
Which hugepd, page table entries can be at any level
and can be of any size.

Add support for them.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 mm/ptdump.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

Comments

Daniel Axtens April 15, 2021, 11:29 p.m. UTC | #1
Hi Christophe,

> Which hugepd, page table entries can be at any level
> and can be of any size.
>
> Add support for them.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
>  mm/ptdump.c | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/mm/ptdump.c b/mm/ptdump.c
> index 61cd16afb1c8..6efdb8c15a7d 100644
> --- a/mm/ptdump.c
> +++ b/mm/ptdump.c
> @@ -112,11 +112,24 @@ static int ptdump_pte_entry(pte_t *pte, unsigned long addr,
>  {
>  	struct ptdump_state *st = walk->private;
>  	pte_t val = ptep_get(pte);
> +	unsigned long page_size = next - addr;
> +	int level;
> +
> +	if (page_size >= PGDIR_SIZE)
> +		level = 0;
> +	else if (page_size >= P4D_SIZE)
> +		level = 1;
> +	else if (page_size >= PUD_SIZE)
> +		level = 2;
> +	else if (page_size >= PMD_SIZE)
> +		level = 3;
> +	else
> +		level = 4;
>  
>  	if (st->effective_prot)
> -		st->effective_prot(st, 4, pte_val(val));
> +		st->effective_prot(st, level, pte_val(val));
>  
> -	st->note_page(st, addr, 4, pte_val(val), PAGE_SIZE);
> +	st->note_page(st, addr, level, pte_val(val), page_size);

It seems to me that passing both level and page_size is a bit redundant,
but I guess it does reduce the impact on each arch's code?

Kind regards,
Daniel

>  
>  	return 0;
>  }
> -- 
> 2.25.0
Christophe Leroy April 16, 2021, 5:25 a.m. UTC | #2
Hi Daniel,

Le 16/04/2021 à 01:29, Daniel Axtens a écrit :
> Hi Christophe,
> 
>> Which hugepd, page table entries can be at any level
>> and can be of any size.
>>
>> Add support for them.
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>> ---
>>   mm/ptdump.c | 17 +++++++++++++++--
>>   1 file changed, 15 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/ptdump.c b/mm/ptdump.c
>> index 61cd16afb1c8..6efdb8c15a7d 100644
>> --- a/mm/ptdump.c
>> +++ b/mm/ptdump.c
>> @@ -112,11 +112,24 @@ static int ptdump_pte_entry(pte_t *pte, unsigned long addr,
>>   {
>>   	struct ptdump_state *st = walk->private;
>>   	pte_t val = ptep_get(pte);
>> +	unsigned long page_size = next - addr;
>> +	int level;
>> +
>> +	if (page_size >= PGDIR_SIZE)
>> +		level = 0;
>> +	else if (page_size >= P4D_SIZE)
>> +		level = 1;
>> +	else if (page_size >= PUD_SIZE)
>> +		level = 2;
>> +	else if (page_size >= PMD_SIZE)
>> +		level = 3;
>> +	else
>> +		level = 4;
>>   
>>   	if (st->effective_prot)
>> -		st->effective_prot(st, 4, pte_val(val));
>> +		st->effective_prot(st, level, pte_val(val));
>>   
>> -	st->note_page(st, addr, 4, pte_val(val), PAGE_SIZE);
>> +	st->note_page(st, addr, level, pte_val(val), page_size);
> 
> It seems to me that passing both level and page_size is a bit redundant,
> but I guess it does reduce the impact on each arch's code?

Exactly, as shown above, the level can be re-calculated based on the page size, but it would be a 
unnecessary impact on all architectures and would duplicate the re-calculation of the level whereas 
in most cases we get it for free from the caller.

> 
> Kind regards,
> Daniel
> 
>>   
>>   	return 0;
>>   }
>> -- 
>> 2.25.0
diff mbox series

Patch

diff --git a/mm/ptdump.c b/mm/ptdump.c
index 61cd16afb1c8..6efdb8c15a7d 100644
--- a/mm/ptdump.c
+++ b/mm/ptdump.c
@@ -112,11 +112,24 @@  static int ptdump_pte_entry(pte_t *pte, unsigned long addr,
 {
 	struct ptdump_state *st = walk->private;
 	pte_t val = ptep_get(pte);
+	unsigned long page_size = next - addr;
+	int level;
+
+	if (page_size >= PGDIR_SIZE)
+		level = 0;
+	else if (page_size >= P4D_SIZE)
+		level = 1;
+	else if (page_size >= PUD_SIZE)
+		level = 2;
+	else if (page_size >= PMD_SIZE)
+		level = 3;
+	else
+		level = 4;
 
 	if (st->effective_prot)
-		st->effective_prot(st, 4, pte_val(val));
+		st->effective_prot(st, level, pte_val(val));
 
-	st->note_page(st, addr, 4, pte_val(val), PAGE_SIZE);
+	st->note_page(st, addr, level, pte_val(val), page_size);
 
 	return 0;
 }