diff mbox series

[v2,08/40] mm/memory: page_add_file_rmap() -> folio_add_file_rmap_[pte|pmd]()

Message ID 20231220224504.646757-9-david@redhat.com (mailing list archive)
State New
Headers show
Series mm/rmap: interface overhaul | expand

Commit Message

David Hildenbrand Dec. 20, 2023, 10:44 p.m. UTC 
Let's convert insert_page_into_pte_locked() and do_set_pmd(). While at it,
perform some folio conversion.

Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/memory.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

Comments

Vincent Donnefort Aug. 9, 2024, 5:13 p.m. UTC | #1 
Hi,

Sorry, reviving this thread as I have ran into something weird:

On Wed, Dec 20, 2023 at 11:44:32PM +0100, David Hildenbrand wrote:
> Let's convert insert_page_into_pte_locked() and do_set_pmd(). While at it,
> perform some folio conversion.
> 
> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  mm/memory.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/mm/memory.c b/mm/memory.c
> index 7f957e5a84311..c77d3952d261f 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c

[...]

>  vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
>  {
> +	struct folio *folio = page_folio(page);
>  	struct vm_area_struct *vma = vmf->vma;
>  	bool write = vmf->flags & FAULT_FLAG_WRITE;
>  	unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
> @@ -4418,8 +4421,7 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
>  	if (!thp_vma_suitable_order(vma, haddr, PMD_ORDER))
>  		return ret;
>  
> -	page = compound_head(page);
> -	if (compound_order(page) != HPAGE_PMD_ORDER)
> +	if (page != &folio->page || folio_order(folio) != HPAGE_PMD_ORDER)
>  		return ret;

Is this `page != &folio->page` expected? I believe this check wasn't there
before as we had `page = compound_head()`.

It breaks the installation of a PMD level mapping for shmem when the fault
address is in the middle of this block. In its fault path, shmem sets

  vmf->page = folio_file_page(folio, vmf->pgoff)

which fails this test above.

>  
>  	/*
> @@ -4428,7 +4430,7 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
>  	 * check.  This kind of THP just can be PTE mapped.  Access to
>  	 * the corrupted subpage should trigger SIGBUS as expected.
>  	 */
> -	if (unlikely(PageHasHWPoisoned(page)))
> +	if (unlikely(folio_test_has_hwpoisoned(folio)))
>  		return ret;
>  
>  	/*
> @@ -4452,7 +4454,7 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
>  		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
>  
>  	add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR);
> -	page_add_file_rmap(page, vma, true);
> +	folio_add_file_rmap_pmd(folio, page, vma);
>  
>  	/*
>  	 * deposit and withdraw with pmd lock held
> -- 
> 2.43.0
>
David Hildenbrand Aug. 9, 2024, 5:27 p.m. UTC | #2 
On 09.08.24 19:13, Vincent Donnefort wrote:
> Hi,
> 
> Sorry, reviving this thread as I have ran into something weird:
> 
> On Wed, Dec 20, 2023 at 11:44:32PM +0100, David Hildenbrand wrote:
>> Let's convert insert_page_into_pte_locked() and do_set_pmd(). While at it,
>> perform some folio conversion.
>>
>> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
>> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
>> ---
>>   mm/memory.c | 14 ++++++++------
>>   1 file changed, 8 insertions(+), 6 deletions(-)
>>
>> diff --git a/mm/memory.c b/mm/memory.c
>> index 7f957e5a84311..c77d3952d261f 100644
>> --- a/mm/memory.c
>> +++ b/mm/memory.c
> 
> [...]
> 
>>   vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
>>   {
>> +	struct folio *folio = page_folio(page);
>>   	struct vm_area_struct *vma = vmf->vma;
>>   	bool write = vmf->flags & FAULT_FLAG_WRITE;
>>   	unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
>> @@ -4418,8 +4421,7 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
>>   	if (!thp_vma_suitable_order(vma, haddr, PMD_ORDER))
>>   		return ret;
>>   
>> -	page = compound_head(page);
>> -	if (compound_order(page) != HPAGE_PMD_ORDER)
>> +	if (page != &folio->page || folio_order(folio) != HPAGE_PMD_ORDER)
>>   		return ret;
> 
> Is this `page != &folio->page` expected? I believe this check wasn't there
> before as we had `page = compound_head()`.
> 
> It breaks the installation of a PMD level mapping for shmem when the fault
> address is in the middle of this block. In its fault path, shmem sets
> 
>    vmf->page = folio_file_page(folio, vmf->pgoff)
> 
> which fails this test above.

Already fixed? :)

commit ab1ffc86cb5bec1c92387b9811d9036512f8f4eb (tag: 
mm-hotfixes-stable-2024-06-26-17-28)
Author: Andrew Bresticker <abrestic@rivosinc.com>
Date:   Tue Jun 11 08:32:16 2024 -0700

     mm/memory: don't require head page for do_set_pmd()
Vincent Donnefort Aug. 9, 2024, 5:32 p.m. UTC | #3 
On Fri, Aug 09, 2024 at 07:27:27PM +0200, David Hildenbrand wrote:
> On 09.08.24 19:13, Vincent Donnefort wrote:
> > Hi,
> > 
> > Sorry, reviving this thread as I have ran into something weird:
> > 
> > On Wed, Dec 20, 2023 at 11:44:32PM +0100, David Hildenbrand wrote:
> > > Let's convert insert_page_into_pte_locked() and do_set_pmd(). While at it,
> > > perform some folio conversion.
> > > 
> > > Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
> > > Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
> > > Signed-off-by: David Hildenbrand <david@redhat.com>
> > > ---
> > >   mm/memory.c | 14 ++++++++------
> > >   1 file changed, 8 insertions(+), 6 deletions(-)
> > > 
> > > diff --git a/mm/memory.c b/mm/memory.c
> > > index 7f957e5a84311..c77d3952d261f 100644
> > > --- a/mm/memory.c
> > > +++ b/mm/memory.c
> > 
> > [...]
> > 
> > >   vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
> > >   {
> > > +	struct folio *folio = page_folio(page);
> > >   	struct vm_area_struct *vma = vmf->vma;
> > >   	bool write = vmf->flags & FAULT_FLAG_WRITE;
> > >   	unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
> > > @@ -4418,8 +4421,7 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
> > >   	if (!thp_vma_suitable_order(vma, haddr, PMD_ORDER))
> > >   		return ret;
> > > -	page = compound_head(page);
> > > -	if (compound_order(page) != HPAGE_PMD_ORDER)
> > > +	if (page != &folio->page || folio_order(folio) != HPAGE_PMD_ORDER)
> > >   		return ret;
> > 
> > Is this `page != &folio->page` expected? I believe this check wasn't there
> > before as we had `page = compound_head()`.
> > 
> > It breaks the installation of a PMD level mapping for shmem when the fault
> > address is in the middle of this block. In its fault path, shmem sets
> > 
> >    vmf->page = folio_file_page(folio, vmf->pgoff)
> > 
> > which fails this test above.
> 
> Already fixed? :)
> 
> commit ab1ffc86cb5bec1c92387b9811d9036512f8f4eb (tag:
> mm-hotfixes-stable-2024-06-26-17-28)
> Author: Andrew Bresticker <abrestic@rivosinc.com>
> Date:   Tue Jun 11 08:32:16 2024 -0700
> 
>     mm/memory: don't require head page for do_set_pmd()
> 

Duh of course I haven't looked anything recent enough, my bad!

Thanks for your quick answer!

> 
> -- 
> Cheers,
> 
> David / dhildenb
>
diff mbox series

Patch

diff --git a/mm/memory.c b/mm/memory.c
index 7f957e5a84311..c77d3952d261f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1859,12 +1859,14 @@  static int validate_page_before_insert(struct page *page)
 static int insert_page_into_pte_locked(struct vm_area_struct *vma, pte_t *pte,
 			unsigned long addr, struct page *page, pgprot_t prot)
 {
+	struct folio *folio = page_folio(page);
+
 	if (!pte_none(ptep_get(pte)))
 		return -EBUSY;
 	/* Ok, finally just insert the thing.. */
-	get_page(page);
+	folio_get(folio);
 	inc_mm_counter(vma->vm_mm, mm_counter_file(page));
-	page_add_file_rmap(page, vma, false);
+	folio_add_file_rmap_pte(folio, page, vma);
 	set_pte_at(vma->vm_mm, addr, pte, mk_pte(page, prot));
 	return 0;
 }
@@ -4409,6 +4411,7 @@  static void deposit_prealloc_pte(struct vm_fault *vmf)
 
 vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
 {
+	struct folio *folio = page_folio(page);
 	struct vm_area_struct *vma = vmf->vma;
 	bool write = vmf->flags & FAULT_FLAG_WRITE;
 	unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
@@ -4418,8 +4421,7 @@  vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
 	if (!thp_vma_suitable_order(vma, haddr, PMD_ORDER))
 		return ret;
 
-	page = compound_head(page);
-	if (compound_order(page) != HPAGE_PMD_ORDER)
+	if (page != &folio->page || folio_order(folio) != HPAGE_PMD_ORDER)
 		return ret;
 
 	/*
@@ -4428,7 +4430,7 @@  vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
 	 * check.  This kind of THP just can be PTE mapped.  Access to
 	 * the corrupted subpage should trigger SIGBUS as expected.
 	 */
-	if (unlikely(PageHasHWPoisoned(page)))
+	if (unlikely(folio_test_has_hwpoisoned(folio)))
 		return ret;
 
 	/*
@@ -4452,7 +4454,7 @@  vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
 		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
 
 	add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR);
-	page_add_file_rmap(page, vma, true);
+	folio_add_file_rmap_pmd(folio, page, vma);
 
 	/*
 	 * deposit and withdraw with pmd lock held