08 Apr, 2020
2 commits
-
Adding these missing helpers for uffd-wp operations with pmd
swap/migration entries.Signed-off-by: Peter Xu
Signed-off-by: Andrew Morton
Reviewed-by: Jerome Glisse
Reviewed-by: Mike Rapoport
Cc: Andrea Arcangeli
Cc: Bobby Powers
Cc: Brian Geffon
Cc: David Hildenbrand
Cc: Denis Plotnikov
Cc: "Dr . David Alan Gilbert"
Cc: Hugh Dickins
Cc: Johannes Weiner
Cc: "Kirill A . Shutemov"
Cc: Martin Cracauer
Cc: Marty McFadden
Cc: Maya Gokhale
Cc: Mel Gorman
Cc: Mike Kravetz
Cc: Pavel Emelyanov
Cc: Rik van Riel
Cc: Shaohua Li
Link: http://lkml.kernel.org/r/20200220163112.11409-10-peterx@redhat.com
Signed-off-by: Linus Torvalds -
Accurate userfaultfd WP tracking is possible by tracking exactly which
virtual memory ranges were writeprotected by userland. We can't relay
only on the RW bit of the mapped pagetable because that information is
destroyed by fork() or KSM or swap. If we were to relay on that, we'd
need to stay on the safe side and generate false positive wp faults for
every swapped out page.[peterx@redhat.com: append _PAGE_UFD_WP to _PAGE_CHG_MASK]
Signed-off-by: Andrea Arcangeli
Signed-off-by: Peter Xu
Signed-off-by: Andrew Morton
Reviewed-by: Jerome Glisse
Reviewed-by: Mike Rapoport
Cc: Bobby Powers
Cc: Brian Geffon
Cc: David Hildenbrand
Cc: Denis Plotnikov
Cc: "Dr . David Alan Gilbert"
Cc: Hugh Dickins
Cc: Johannes Weiner
Cc: "Kirill A . Shutemov"
Cc: Martin Cracauer
Cc: Marty McFadden
Cc: Maya Gokhale
Cc: Mel Gorman
Cc: Mike Kravetz
Cc: Pavel Emelyanov
Cc: Rik van Riel
Cc: Shaohua Li
Link: http://lkml.kernel.org/r/20200220163112.11409-4-peterx@redhat.com
Signed-off-by: Linus Torvalds
