+ mm-non-pmd-mappable-large-folios-for-folio_add_new_anon_rmap.patch added to mm-unstable branch

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The patch titled
     Subject: mm: non-pmd-mappable, large folios for folio_add_new_anon_rmap()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-non-pmd-mappable-large-folios-for-folio_add_new_anon_rmap.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-non-pmd-mappable-large-folios-for-folio_add_new_anon_rmap.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Ryan Roberts <ryan.roberts@xxxxxxx>
Subject: mm: non-pmd-mappable, large folios for folio_add_new_anon_rmap()
Date: Thu, 10 Aug 2023 15:29:39 +0100

In preparation for LARGE_ANON_FOLIO support, improve
folio_add_new_anon_rmap() to allow a non-pmd-mappable, large folio to be
passed to it.  In this case, all contained pages are accounted using the
order-0 folio (or base page) scheme.

Link: https://lkml.kernel.org/r/20230810142942.3169679-3-ryan.roberts@xxxxxxx
Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx>
Reviewed-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Reviewed-by: Yin Fengwei <fengwei.yin@xxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Huang, Ying <ying.huang@xxxxxxxxx>
Cc: Itaru Kitayama <itaru.kitayama@xxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/rmap.c |   27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

--- a/mm/rmap.c~mm-non-pmd-mappable-large-folios-for-folio_add_new_anon_rmap
+++ a/mm/rmap.c
@@ -1266,31 +1266,44 @@ void page_add_anon_rmap(struct page *pag
  * This means the inc-and-test can be bypassed.
  * The folio does not have to be locked.
  *
- * If the folio is large, it is accounted as a THP.  As the folio
+ * If the folio is pmd-mappable, it is accounted as a THP.  As the folio
  * is new, it's assumed to be mapped exclusively by a single process.
  */
 void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
 		unsigned long address)
 {
-	int nr;
+	int nr = folio_nr_pages(folio);
 
-	VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
+	VM_BUG_ON_VMA(address < vma->vm_start ||
+			address + (nr << PAGE_SHIFT) > vma->vm_end, vma);
 	__folio_set_swapbacked(folio);
 
-	if (likely(!folio_test_pmd_mappable(folio))) {
+	if (likely(!folio_test_large(folio))) {
 		/* increment count (starts at -1) */
 		atomic_set(&folio->_mapcount, 0);
-		nr = 1;
+		__page_set_anon_rmap(folio, &folio->page, vma, address, 1);
+	} else if (!folio_test_pmd_mappable(folio)) {
+		int i;
+
+		for (i = 0; i < nr; i++) {
+			struct page *page = folio_page(folio, i);
+
+			/* increment count (starts at -1) */
+			atomic_set(&page->_mapcount, 0);
+			__page_set_anon_rmap(folio, page, vma,
+					address + (i << PAGE_SHIFT), 1);
+		}
+
+		atomic_set(&folio->_nr_pages_mapped, nr);
 	} else {
 		/* increment count (starts at -1) */
 		atomic_set(&folio->_entire_mapcount, 0);
 		atomic_set(&folio->_nr_pages_mapped, COMPOUND_MAPPED);
-		nr = folio_nr_pages(folio);
+		__page_set_anon_rmap(folio, &folio->page, vma, address, 1);
 		__lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr);
 	}
 
 	__lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr);
-	__page_set_anon_rmap(folio, &folio->page, vma, address, 1);
 }
 
 /**
_

Patches currently in -mm which might be from ryan.roberts@xxxxxxx are

selftests-line-buffer-test-programs-stdout.patch
selftests-line-buffer-test-programs-stdout-fix.patch
selftests-mm-skip-soft-dirty-tests-on-arm64.patch
selftests-mm-enable-mrelease_test-for-arm64.patch
selftests-mm-fix-thuge-gen-test-bugs.patch
selftests-mm-va_high_addr_switch-should-skip-unsupported-arm64-configs.patch
selftests-mm-make-migration-test-robust-to-failure.patch
selftests-mm-optionally-pass-duration-to-transhuge-stress.patch
selftests-mm-run-all-tests-from-run_vmtestssh.patch
mm-allow-deferred-splitting-of-arbitrary-large-anon-folios.patch
mm-non-pmd-mappable-large-folios-for-folio_add_new_anon_rmap.patch
mm-large_anon_folio-for-improved-performance.patch
selftests-mm-cow-generalize-do_run_with_thp-helper.patch
selftests-mm-cow-add-large-anon-folio-tests.patch




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