Commit dd21bfa4 authored by Yun Zhou's avatar Yun Zhou Committed by Linus Torvalds
Browse files

proc: fix documentation and description of pagemap 

Since bit 57 was exported for uffd-wp write-protected (commit
fb8e37f3: "mm/pagemap: export uffd-wp protection information"),
fixing it can reduce some unnecessary confusion.

Link: https://lkml.kernel.org/r/20220301044538.3042713-1-yun.zhou@windriver.com


Fixes: fb8e37f3 ("mm/pagemap: export uffd-wp protection information")
Signed-off-by: default avatarYun Zhou <yun.zhou@windriver.com>
Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Tiberiu A Georgescu <tiberiu.georgescu@nutanix.com>
Cc: Florian Schmidt <florian.schmidt@nutanix.com>
Cc: Ivan Teterevkov <ivan.teterevkov@nutanix.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Colin Cross <ccross@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b773827e

Documentation/admin-guide/mm/pagemap.rst

+1 −1
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ There are four components to pagemap: 
    * Bit  56    page exclusively mapped (since 4.2)

    * Bit  57    pte is uffd-wp write-protected (since 5.13) (see

      :ref:`Documentation/admin-guide/mm/userfaultfd.rst <userfaultfd>`)

    * Bits 57-60 zero

    * Bits 58-60 zero

    * Bit  61    page is file-page or shared-anon (since 3.5)

    * Bit  62    page swapped

    * Bit  63    page present

fs/proc/task_mmu.c

+2 −1
Original line number Diff line number Diff line
@@ -1597,7 +1597,8 @@ static const struct mm_walk_ops pagemap_ops = { 
 * Bits 5-54  swap offset if swapped

 * Bit  55    pte is soft-dirty (see Documentation/admin-guide/mm/soft-dirty.rst)

 * Bit  56    page exclusively mapped

 * Bits 57-60 zero

 * Bit  57    pte is uffd-wp write-protected

 * Bits 58-60 zero

 * Bit  61    page is file-page or shared-anon

 * Bit  62    page swapped

 * Bit  63    page present