[v1] mm: rewrite pfnmap tracking and remove VM_PAT

[PATCH v1 11/11] mm/io-mapping: track_pfn() -> "pfnmap tracking"

Posted by David Hildenbrand 9 months, 2 weeks ago

track_pfn() does not exist, let's simply refer to it as "pfnmap
tracking".

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/io-mapping.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/io-mapping.c b/mm/io-mapping.c
index 01b3627999304..7266441ad0834 100644
--- a/mm/io-mapping.c
+++ b/mm/io-mapping.c
@@ -21,7 +21,7 @@ int io_mapping_map_user(struct io_mapping *iomap, struct vm_area_struct *vma,
 	if (WARN_ON_ONCE((vma->vm_flags & expected_flags) != expected_flags))
 		return -EINVAL;
 
-	/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
+	/* We rely on prevalidation of the io-mapping to skip pfnmap tracking. */
 	return remap_pfn_range_notrack(vma, addr, pfn, size,
 		__pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
 			 (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)));
-- 
2.49.0

Re: [PATCH v1 11/11] mm/io-mapping: track_pfn() -> "pfnmap tracking"

Posted by Lorenzo Stoakes 9 months, 2 weeks ago

On Fri, Apr 25, 2025 at 10:17:15AM +0200, David Hildenbrand wrote:
> track_pfn() does not exist, let's simply refer to it as "pfnmap
> tracking".
>
> Signed-off-by: David Hildenbrand <david@redhat.com>

LGTM, so:

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

> ---
>  mm/io-mapping.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/io-mapping.c b/mm/io-mapping.c
> index 01b3627999304..7266441ad0834 100644
> --- a/mm/io-mapping.c
> +++ b/mm/io-mapping.c
> @@ -21,7 +21,7 @@ int io_mapping_map_user(struct io_mapping *iomap, struct vm_area_struct *vma,
>  	if (WARN_ON_ONCE((vma->vm_flags & expected_flags) != expected_flags))
>  		return -EINVAL;
>
> -	/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
> +	/* We rely on prevalidation of the io-mapping to skip pfnmap tracking. */
>  	return remap_pfn_range_notrack(vma, addr, pfn, size,
>  		__pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
>  			 (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)));
> --
> 2.49.0
>

However this doesn't apply after commit b8d8f1830bab ("mm/io-mapping:
precompute remap protection flags for clarity"), so will need a rebase :)
seems this was cleaned up to separate the __pgprot() bit from the
remap_pfn_range_notrack().

Note of course this commit hash is from mm-new so quite changeable... :)

Re: [PATCH v1 11/11] mm/io-mapping: track_pfn() -> "pfnmap tracking"

Posted by David Hildenbrand 9 months, 2 weeks ago

On 28.04.25 18:06, Lorenzo Stoakes wrote:
> On Fri, Apr 25, 2025 at 10:17:15AM +0200, David Hildenbrand wrote:
>> track_pfn() does not exist, let's simply refer to it as "pfnmap
>> tracking".
>>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
> 
> LGTM, so:
> 
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> 
>> ---
>>   mm/io-mapping.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/io-mapping.c b/mm/io-mapping.c
>> index 01b3627999304..7266441ad0834 100644
>> --- a/mm/io-mapping.c
>> +++ b/mm/io-mapping.c
>> @@ -21,7 +21,7 @@ int io_mapping_map_user(struct io_mapping *iomap, struct vm_area_struct *vma,
>>   	if (WARN_ON_ONCE((vma->vm_flags & expected_flags) != expected_flags))
>>   		return -EINVAL;
>>
>> -	/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
>> +	/* We rely on prevalidation of the io-mapping to skip pfnmap tracking. */
>>   	return remap_pfn_range_notrack(vma, addr, pfn, size,
>>   		__pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
>>   			 (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)));
>> --
>> 2.49.0
>>
> 
> However this doesn't apply after commit b8d8f1830bab ("mm/io-mapping:
> precompute remap protection flags for clarity"), so will need a rebase :)
> seems this was cleaned up to separate the __pgprot() bit from the
> remap_pfn_range_notrack().

Yeah, I reviewed that just today. Trivial conflict :)

Thanks!

-- 
Cheers,

David / dhildenb