Re: [PATCH 7/9] mm: Convert migrate_vma_insert_page() to use a folio

[Alistair Popple <apopple@nvidia.com>]

Thanks. I've been working on converting most of the code in
migrate_device.c to use folios to add support for device-private THP
migration and had this exact change so feel free to add:

Reviewed-by: Alistair Popple <apopple@nvidia.com>

"Matthew Wilcox (Oracle)" <willy@infradead.org> writes:

> Replaces five calls to compound_head() with one.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  mm/migrate_device.c | 23 ++++++++++++-----------
>  1 file changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/mm/migrate_device.c b/mm/migrate_device.c
> index 8ac1f79f754a..81193363f8cd 100644
> --- a/mm/migrate_device.c
> +++ b/mm/migrate_device.c
> @@ -564,6 +564,7 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
>  				    struct page *page,
>  				    unsigned long *src)
>  {
> +	struct folio *folio = page_folio(page);
>  	struct vm_area_struct *vma = migrate->vma;
>  	struct mm_struct *mm = vma->vm_mm;
>  	bool flush = false;
> @@ -596,17 +597,17 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
>  		goto abort;
>  	if (unlikely(anon_vma_prepare(vma)))
>  		goto abort;
> -	if (mem_cgroup_charge(page_folio(page), vma->vm_mm, GFP_KERNEL))
> +	if (mem_cgroup_charge(folio, vma->vm_mm, GFP_KERNEL))
>  		goto abort;
>  
>  	/*
> -	 * The memory barrier inside __SetPageUptodate makes sure that
> -	 * preceding stores to the page contents become visible before
> +	 * The memory barrier inside __folio_mark_uptodate makes sure that
> +	 * preceding stores to the folio contents become visible before
>  	 * the set_pte_at() write.
>  	 */
> -	__SetPageUptodate(page);
> +	__folio_mark_uptodate(folio);
>  
> -	if (is_device_private_page(page)) {
> +	if (folio_is_device_private(folio)) {
>  		swp_entry_t swp_entry;
>  
>  		if (vma->vm_flags & VM_WRITE)
> @@ -617,8 +618,8 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
>  						page_to_pfn(page));
>  		entry = swp_entry_to_pte(swp_entry);
>  	} else {
> -		if (is_zone_device_page(page) &&
> -		    !is_device_coherent_page(page)) {
> +		if (folio_is_zone_device(folio) &&
> +		    !folio_is_device_coherent(folio)) {
>  			pr_warn_once("Unsupported ZONE_DEVICE page type.\n");
>  			goto abort;
>  		}
> @@ -652,10 +653,10 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
>  		goto unlock_abort;
>  
>  	inc_mm_counter(mm, MM_ANONPAGES);
> -	page_add_new_anon_rmap(page, vma, addr);
> -	if (!is_zone_device_page(page))
> -		lru_cache_add_inactive_or_unevictable(page, vma);
> -	get_page(page);
> +	folio_add_new_anon_rmap(folio, vma, addr);
> +	if (!folio_is_zone_device(folio))
> +		folio_add_lru_vma(folio, vma);
> +	folio_get(folio);
>  
>  	if (flush) {
>  		flush_cache_page(vma, addr, pte_pfn(orig_pte));