Commit 98b211d6 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

madvise: convert madvise_free_pte_range() to use a folio 

Saves a lot of calls to compound_head().

Link: https://lkml.kernel.org/r/20220902194653.1739778-44-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 2fad3d14

mm/madvise.c

+25 −24
Original line number Diff line number Diff line
@@ -601,6 +601,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, 
	struct vm_area_struct *vma = walk->vma;

	spinlock_t *ptl;

	pte_t *orig_pte, *pte, ptent;

	struct folio *folio;

	struct page *page;

	int nr_swap = 0;

	unsigned long next;
@@ -645,56 +646,56 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, 
		page = vm_normal_page(vma, addr, ptent);

		if (!page || is_zone_device_page(page))

			continue;

		folio = page_folio(page);



		/*

		 * If pmd isn't transhuge but the page is THP and

		 * If pmd isn't transhuge but the folio is large and

		 * is owned by only this process, split it and

		 * deactivate all pages.

		 */

		if (PageTransCompound(page)) {

			if (page_mapcount(page) != 1)

		if (folio_test_large(folio)) {

			if (folio_mapcount(folio) != 1)

				goto out;

			get_page(page);

			if (!trylock_page(page)) {

				put_page(page);

			folio_get(folio);

			if (!folio_trylock(folio)) {

				folio_put(folio);

				goto out;

			}

			pte_unmap_unlock(orig_pte, ptl);

			if (split_huge_page(page)) {

				unlock_page(page);

				put_page(page);

			if (split_folio(folio)) {

				folio_unlock(folio);

				folio_put(folio);

				orig_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);

				goto out;

			}

			unlock_page(page);

			put_page(page);

			folio_unlock(folio);

			folio_put(folio);

			orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);

			pte--;

			addr -= PAGE_SIZE;

			continue;

		}



		VM_BUG_ON_PAGE(PageTransCompound(page), page);



		if (PageSwapCache(page) || PageDirty(page)) {

			if (!trylock_page(page))

		if (folio_test_swapcache(folio) || folio_test_dirty(folio)) {

			if (!folio_trylock(folio))

				continue;

			/*

			 * If page is shared with others, we couldn't clear

			 * PG_dirty of the page.

			 * If folio is shared with others, we mustn't clear

			 * the folio's dirty flag.

			 */

			if (page_mapcount(page) != 1) {

				unlock_page(page);

			if (folio_mapcount(folio) != 1) {

				folio_unlock(folio);

				continue;

			}



			if (PageSwapCache(page) && !try_to_free_swap(page)) {

				unlock_page(page);

			if (folio_test_swapcache(folio) &&

			    !folio_free_swap(folio)) {

				folio_unlock(folio);

				continue;

			}



			ClearPageDirty(page);

			unlock_page(page);

			folio_clear_dirty(folio);

			folio_unlock(folio);

		}



		if (pte_young(ptent) || pte_dirty(ptent)) {
@@ -712,7 +713,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, 
			set_pte_at(mm, addr, pte, ptent);

			tlb_remove_tlb_entry(tlb, pte, addr);

		}

		mark_page_lazyfree(page);

		mark_page_lazyfree(&folio->page);

	}

out:

	if (nr_swap) {