2023-07-05 19:47:26

by Sidhartha Kumar

Subject: [PATCH v2 2/4] mm/memory: convert wp_page_shared() to use folios

Saves five implicit calls to compound_head().

Signed-off-by: Sidhartha Kumar <[email protected]>
---
v2:
- change function definition to pass in a folio

mm/memory.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index e73245b791a7a..fba33fb55a010 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3281,13 +3281,13 @@ static vm_fault_t wp_pfn_shared(struct vm_fault *vmf)
return 0;
}

-static vm_fault_t wp_page_shared(struct vm_fault *vmf)
+static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio)
__releases(vmf->ptl)
{
struct vm_area_struct *vma = vmf->vma;
vm_fault_t ret = 0;

- get_page(vmf->page);
+ folio_get(folio);

if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
vm_fault_t tmp;
@@ -3296,21 +3296,21 @@ static vm_fault_t wp_page_shared(struct vm_fault *vmf)
tmp = do_page_mkwrite(vmf);
if (unlikely(!tmp || (tmp &
(VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
- put_page(vmf->page);
+ folio_put(folio);
return tmp;
}
tmp = finish_mkwrite_fault(vmf);
if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
- unlock_page(vmf->page);
- put_page(vmf->page);
+ folio_unlock(folio);
+ folio_put(folio);
return tmp;
}
} else {
wp_page_reuse(vmf);
- lock_page(vmf->page);
+ folio_lock(folio);
}
ret |= fault_dirty_shared_page(vmf);
- put_page(vmf->page);
+ folio_put(folio);

return ret;
}
@@ -3375,7 +3375,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
*/
if (!vmf->page)
return wp_pfn_shared(vmf);
- return wp_page_shared(vmf);
+ return wp_page_shared(vmf, page_folio(vmf->page));
}

if (vmf->page)
--
2.41.0

2023-07-05 20:43:14

by Matthew Wilcox

Subject: Re: [PATCH v2 2/4] mm/memory: convert wp_page_shared() to use folios

On Wed, Jul 05, 2023 at 12:43:33PM -0700, Sidhartha Kumar wrote:
> @@ -3375,7 +3375,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
> */
> if (!vmf->page)
> return wp_pfn_shared(vmf);
> - return wp_page_shared(vmf);
> + return wp_page_shared(vmf, page_folio(vmf->page));
> }
>
> if (vmf->page)

I was actually hoping you'd move:

if (vmf->page)
folio = page_folio(vmf->page);

up to immediately after the call to vm_normal_page(), and avoid even
this call to page_folio().