linux-kernel - [PATCH RFC 29/39] mm/migrate_device: page_remove_rmap() -> folio_remove_rmap

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Message-ID: <20231204142146.91437-30-david@redhat.com>
Date:   Mon,  4 Dec 2023 15:21:36 +0100
From:   David Hildenbrand <david@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-mm@...ck.org, David Hildenbrand <david@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        Hugh Dickins <hughd@...gle.com>,
        Ryan Roberts <ryan.roberts@....com>,
        Yin Fengwei <fengwei.yin@...el.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Muchun Song <muchun.song@...ux.dev>,
        Peter Xu <peterx@...hat.com>
Subject: [PATCH RFC 29/39] mm/migrate_device: page_remove_rmap() -> folio_remove_rmap_pte()

Let's convert migrate_vma_collect_pmd(). While at it, perform more
folio conversion.

Signed-off-by: David Hildenbrand <david@...hat.com>
---
 mm/migrate_device.c | 39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 8ac1f79f754a2..c51c99151ebb5 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -107,6 +107,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 
 	for (; addr < end; addr += PAGE_SIZE, ptep++) {
 		unsigned long mpfn = 0, pfn;
+		struct folio *folio;
 		struct page *page;
 		swp_entry_t entry;
 		pte_t pte;
@@ -168,41 +169,43 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 		}
 
 		/*
-		 * By getting a reference on the page we pin it and that blocks
+		 * By getting a reference on the folio we pin it and that blocks
 		 * any kind of migration. Side effect is that it "freezes" the
 		 * pte.
 		 *
-		 * We drop this reference after isolating the page from the lru
-		 * for non device page (device page are not on the lru and thus
+		 * We drop this reference after isolating the folio from the lru
+		 * for non device folio (device folio are not on the lru and thus
 		 * can't be dropped from it).
 		 */
-		get_page(page);
+		folio = page_folio(page);
+		folio_get(folio);
 
 		/*
-		 * We rely on trylock_page() to avoid deadlock between
+		 * We rely on folio_trylock() to avoid deadlock between
 		 * concurrent migrations where each is waiting on the others
-		 * page lock. If we can't immediately lock the page we fail this
+		 * folio lock. If we can't immediately lock the folio we fail this
 		 * migration as it is only best effort anyway.
 		 *
-		 * If we can lock the page it's safe to set up a migration entry
-		 * now. In the common case where the page is mapped once in a
+		 * If we can lock the folio it's safe to set up a migration entry
+		 * now. In the common case where the folio is mapped once in a
 		 * single process setting up the migration entry now is an
 		 * optimisation to avoid walking the rmap later with
 		 * try_to_migrate().
 		 */
-		if (trylock_page(page)) {
+		if (folio_trylock(folio)) {
 			bool anon_exclusive;
 			pte_t swp_pte;
 
 			flush_cache_page(vma, addr, pte_pfn(pte));
-			anon_exclusive = PageAnon(page) && PageAnonExclusive(page);
+			anon_exclusive = folio_test_anon(folio) &&
+					  PageAnonExclusive(page);
 			if (anon_exclusive) {
 				pte = ptep_clear_flush(vma, addr, ptep);
 
 				if (page_try_share_anon_rmap(page)) {
 					set_pte_at(mm, addr, ptep, pte);
-					unlock_page(page);
-					put_page(page);
+					folio_unlock(folio);
+					folio_put(folio);
 					mpfn = 0;
 					goto next;
 				}
@@ -214,7 +217,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 
 			/* Set the dirty flag on the folio now the pte is gone. */
 			if (pte_dirty(pte))
-				folio_mark_dirty(page_folio(page));
+				folio_mark_dirty(folio);
 
 			/* Setup special migration page table entry */
 			if (mpfn & MIGRATE_PFN_WRITE)
@@ -248,16 +251,16 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 
 			/*
 			 * This is like regular unmap: we remove the rmap and
-			 * drop page refcount. Page won't be freed, as we took
-			 * a reference just above.
+			 * drop the folio refcount. The folio won't be freed, as
+			 * we took a reference just above.
 			 */
-			page_remove_rmap(page, vma, false);
-			put_page(page);
+			folio_remove_rmap_pte(folio, page, vma);
+			folio_put(folio);
 
 			if (pte_present(pte))
 				unmapped++;
 		} else {
-			put_page(page);
+			folio_put(folio);
 			mpfn = 0;
 		}
 
-- 
2.41.0