Commit 7ce5f7e1 authored Nov 23, 2022 by Anshuman Khandual Committed by Andrew Morton Nov 30, 2022

documentation/mm: update pmd_present() in arch_pgtable_helpers.rst

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/

Link: https://lkml.kernel.org/r/20221123051319.1312582-1-anshuman.khandual@arm.com


Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent be21b32a

Documentation/mm/arch_pgtable_helpers.rst

+1 −1

Original line number	Diff line number	Diff line
		@@ -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 \|
		+---------------------------+--------------------------------------------------+