linux-kernel - [PATCH RFC 33/39] mm/rmap: convert page_dup_file_rmap() to folio_dup_file_rmap

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Message-ID: <20231204142146.91437-34-david@redhat.com>
Date:   Mon,  4 Dec 2023 15:21:40 +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 33/39] mm/rmap: convert page_dup_file_rmap() to folio_dup_file_rmap_[pte|ptes|pmd]()

Let's convert page_dup_file_rmap() like the other rmap functions. As there
is only a single caller, convert that single caller right away and remove
page_dup_file_rmap().

Add folio_dup_file_rmap_ptes() right away, we want to perform rmap
baching during fork() soon.

Signed-off-by: David Hildenbrand <david@...hat.com>
---
 include/linux/rmap.h | 56 ++++++++++++++++++++++++++++++++++++++++----
 mm/memory.c          |  2 +-
 2 files changed, 52 insertions(+), 6 deletions(-)

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index bdbfb11638e4f..21d72cc602adc 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -303,6 +303,57 @@ static inline void hugetlb_remove_rmap(struct folio *folio)
 	atomic_dec(&folio->_entire_mapcount);
 }
 
+static inline void __folio_dup_rmap(struct folio *folio, struct page *page,
+		unsigned int nr_pages, enum rmap_mode mode)
+{
+	__folio_rmap_sanity_checks(folio, page, nr_pages, mode);
+
+	if (likely(mode == RMAP_MODE_PTE)) {
+		do {
+			atomic_inc(&page->_mapcount);
+		} while (page++, --nr_pages > 0);
+	} else if (mode == RMAP_MODE_PMD) {
+		atomic_inc(&folio->_entire_mapcount);
+	}
+}
+
+/**
+ * folio_dup_file_rmap_ptes - duplicate PTE mappings of a page range of a folio
+ * @folio:	The folio to duplicate the mappings of
+ * @page:	The first page to duplicate the mappings of
+ * @nr_pages:	The number of pages of which the mapping will be duplicated
+ *
+ * The page range of the folio is defined by [page, page + nr_pages)
+ *
+ * The caller needs to hold the page table lock.
+ */
+static inline void folio_dup_file_rmap_ptes(struct folio *folio,
+		struct page *page, unsigned int nr_pages)
+{
+	__folio_dup_rmap(folio, page, nr_pages, RMAP_MODE_PTE);
+}
+#define folio_dup_file_rmap_pte(folio, page) \
+	folio_dup_file_rmap_ptes(folio, page, 1)
+
+/**
+ * folio_dup_file_rmap_pmd - duplicate a PMD mapping of a page range of a folio
+ * @folio:	The folio to duplicate the mapping of
+ * @page:	The first page to duplicate the mapping of
+ *
+ * The page range of the folio is defined by [page, page + HPAGE_PMD_NR)
+ *
+ * The caller needs to hold the page table lock.
+ */
+static inline void folio_dup_file_rmap_pmd(struct folio *folio,
+		struct page *page)
+{
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	__folio_dup_rmap(folio, page, HPAGE_PMD_NR, RMAP_MODE_PTE);
+#else
+	WARN_ON_ONCE(true);
+#endif
+}
+
 static inline void __page_dup_rmap(struct page *page, bool compound)
 {
 	VM_WARN_ON(folio_test_hugetlb(page_folio(page)));
@@ -317,11 +368,6 @@ static inline void __page_dup_rmap(struct page *page, bool compound)
 	}
 }
 
-static inline void page_dup_file_rmap(struct page *page, bool compound)
-{
-	__page_dup_rmap(page, compound);
-}
-
 /**
  * page_try_dup_anon_rmap - try duplicating a mapping of an already mapped
  *			    anonymous page
diff --git a/mm/memory.c b/mm/memory.c
index 8c4f98bb617fa..eaab6a2e14eba 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -961,7 +961,7 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
 		rss[MM_ANONPAGES]++;
 	} else if (page) {
 		folio_get(folio);
-		page_dup_file_rmap(page, false);
+		folio_dup_file_rmap_pte(folio, page);
 		rss[mm_counter_file(page)]++;
 	}
 
-- 
2.41.0