On 12.12.19 16:21, Li Xinhai wrote:
> When vm_ops->page_mkwrite is defined, and called from wp_page_shared and
> do_shared_fault, the set_page_dirty must already called by page_mkwrite.
> Then in fault_dirty_shared_page, avoid this repeated call.
>
> Signed-off-by: Li Xinhai <lixinhai.lxh@xxxxxxxxx>
> Cc: Jan Kara <jack@xxxxxxx>
> ---
> mm/memory.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 606da18..34a83d7 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -2300,10 +2300,11 @@ static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf)
> struct vm_area_struct *vma = vmf->vma;
> struct address_space *mapping;
> struct page *page = vmf->page;
> - bool dirtied;
> + bool dirtied = false;
> bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite;
>
> - dirtied = set_page_dirty(page);
> + if(!page_mkwrite)
> + dirtied = set_page_dirty(page);
> VM_BUG_ON_PAGE(PageAnon(page), page);
> /*
> * Take a local copy of the address_space - page.mapping may be zeroed
> @@ -3645,7 +3646,7 @@ static vm_fault_t do_shared_fault(struct vm_fault *vmf)
> * Check if the backing address space wants to know that the page is
> * about to become writable
> */
> - if (vma->vm_ops->page_mkwrite) {
> + if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
> unlock_page(vmf->page);
> tmp = do_page_mkwrite(vmf);
> if (unlikely(!tmp ||
>
This hunk looks like an unrelated change to me.
--
Thanks,
David / dhildenb
