Commit f00f4843 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: convert unuse_pte() to use a folio throughout 

Saves about eight calls to compound_head().

Link: https://lkml.kernel.org/r/20231211162214.2146080-4-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 8d294a8c

mm/swapfile.c

+25 −22
Original line number Diff line number Diff line
@@ -1741,21 +1741,25 @@ static inline int pte_same_as_swp(pte_t pte, pte_t swp_pte) 
static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,

		unsigned long addr, swp_entry_t entry, struct folio *folio)

{

	struct page *page = folio_file_page(folio, swp_offset(entry));

	struct page *swapcache;

	struct page *page;

	struct folio *swapcache;

	spinlock_t *ptl;

	pte_t *pte, new_pte, old_pte;

	bool hwpoisoned = PageHWPoison(page);

	bool hwpoisoned = false;

	int ret = 1;



	swapcache = page;

	swapcache = folio;

	folio = ksm_might_need_to_copy(folio, vma, addr);

	if (unlikely(!folio))

		return -ENOMEM;

	else if (unlikely(folio == ERR_PTR(-EHWPOISON)))

	else if (unlikely(folio == ERR_PTR(-EHWPOISON))) {

		hwpoisoned = true;

	else

		folio = swapcache;

	}



	page = folio_file_page(folio, swp_offset(entry));

	if (PageHWPoison(page))

		hwpoisoned = true;



	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);

	if (unlikely(!pte || !pte_same_as_swp(ptep_get(pte),
@@ -1766,13 +1770,12 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, 


	old_pte = ptep_get(pte);



	if (unlikely(hwpoisoned || !PageUptodate(page))) {

	if (unlikely(hwpoisoned || !folio_test_uptodate(folio))) {

		swp_entry_t swp_entry;



		dec_mm_counter(vma->vm_mm, MM_SWAPENTS);

		if (hwpoisoned) {

			swp_entry = make_hwpoison_entry(swapcache);

			page = swapcache;

			swp_entry = make_hwpoison_entry(page);

		} else {

			swp_entry = make_poisoned_swp_entry();

		}
@@ -1786,27 +1789,27 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, 
	 * when reading from swap. This metadata may be indexed by swap entry

	 * so this must be called before swap_free().

	 */

	arch_swap_restore(entry, page_folio(page));

	arch_swap_restore(entry, folio);



	dec_mm_counter(vma->vm_mm, MM_SWAPENTS);

	inc_mm_counter(vma->vm_mm, MM_ANONPAGES);

	get_page(page);

	if (page == swapcache) {

	folio_get(folio);

	if (folio == swapcache) {

		rmap_t rmap_flags = RMAP_NONE;



		/*

		 * See do_swap_page(): PageWriteback() would be problematic.

		 * However, we do a wait_on_page_writeback() just before this

		 * call and have the page locked.

		 * See do_swap_page(): writeback would be problematic.

		 * However, we do a folio_wait_writeback() just before this

		 * call and have the folio locked.

		 */

		VM_BUG_ON_PAGE(PageWriteback(page), page);

		VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio);

		if (pte_swp_exclusive(old_pte))

			rmap_flags |= RMAP_EXCLUSIVE;



		page_add_anon_rmap(page, vma, addr, rmap_flags);

	} else { /* ksm created a completely new copy */

		page_add_new_anon_rmap(page, vma, addr);

		lru_cache_add_inactive_or_unevictable(page, vma);

		folio_add_new_anon_rmap(folio, vma, addr);

		folio_add_lru_vma(folio, vma);

	}

	new_pte = pte_mkold(mk_pte(page, vma->vm_page_prot));

	if (pte_swp_soft_dirty(old_pte))
@@ -1819,9 +1822,9 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, 
out:

	if (pte)

		pte_unmap_unlock(pte, ptl);

	if (page != swapcache) {

		unlock_page(page);

		put_page(page);

	if (folio != swapcache) {

		folio_unlock(folio);

		folio_put(folio);

	}

	return ret;

}