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authorPeter Xu <peterx@redhat.com>2022-05-12 20:22:52 -0700
committerAndrew Morton <akpm@linux-foundation.org>2022-05-13 07:20:09 -0700
commit5c041f5d1f23d3a172dd0db3215634c484b4acd6 (patch)
tree07c9d48fc2e21f687e6a8b42bac589c387920051 /mm/filemap.c
parent679d103319101800567c8bb7e341b5eee39f6685 (diff)
downloadlwn-5c041f5d1f23d3a172dd0db3215634c484b4acd6.tar.gz
lwn-5c041f5d1f23d3a172dd0db3215634c484b4acd6.zip
mm: teach core mm about pte markers
This patch still does not use pte marker in any way, however it teaches the core mm about the pte marker idea. For example, handle_pte_marker() is introduced that will parse and handle all the pte marker faults. Many of the places are more about commenting it up - so that we know there's the possibility of pte marker showing up, and why we don't need special code for the cases. [peterx@redhat.com: userfaultfd.c needs swapops.h] Link: https://lkml.kernel.org/r/YmRlVj3cdizYJsr0@xz-m1.local Link: https://lkml.kernel.org/r/20220405014833.14015-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 9a1eef6c5d35..de34c6c10384 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3376,6 +3376,11 @@ again:
vmf->pte += xas.xa_index - last_pgoff;
last_pgoff = xas.xa_index;
+ /*
+ * NOTE: If there're PTE markers, we'll leave them to be
+ * handled in the specific fault path, and it'll prohibit the
+ * fault-around logic.
+ */
if (!pte_none(*vmf->pte))
goto unlock;