Messages in this thread Patch in this message | | | From | Anshuman Khandual <> | Subject | [PATCH] documentation/mm: Update pmd_present() in arch_pgtable_helpers.rst | Date | Wed, 23 Nov 2022 10:43:19 +0530 |
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Although pmd_present() might seem to indicate a valid and mapped pmd entry, in reality it returns true when pmd_page() points to a valid page in memory , regardless whether the pmd entry is mapped or not. Andrea Arcangeli had earlier explained [1] the required semantics for pmd_present(). This just updates the documentation for pmd_present() as required.
[1] https://lore.kernel.org/lkml/20181017020930.GN30832@redhat.com/
Cc: Jonathan Corbet <corbet@lwn.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: linux-mm@kvack.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> --- This applies on v6.1-rc6
The latest trigger was from an earlier discussion here.
https://lore.kernel.org/all/53c0c955-7afe-905b-468a-cd7ac81238c5@arm.com/
Documentation/mm/arch_pgtable_helpers.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/mm/arch_pgtable_helpers.rst b/Documentation/mm/arch_pgtable_helpers.rst index cbaee9e59241..fd2a19df884e 100644 --- a/Documentation/mm/arch_pgtable_helpers.rst +++ b/Documentation/mm/arch_pgtable_helpers.rst @@ -94,7 +94,7 @@ PMD Page Table Helpers +---------------------------+--------------------------------------------------+ | pmd_trans_huge | Tests a Transparent Huge Page (THP) at PMD | +---------------------------+--------------------------------------------------+ -| pmd_present | Tests a valid mapped PMD | +| pmd_present | Tests whether pmd_page() points to valid memory | +---------------------------+--------------------------------------------------+ | pmd_young | Tests a young PMD | +---------------------------+--------------------------------------------------+ -- 2.25.1
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