• Peter Xu's avatar
    khugepaged: skip collapse if uffd-wp detected · e1e267c7
    Peter Xu authored
    Don't collapse the huge PMD if there is any userfault write protected
    small PTEs.  The problem is that the write protection is in small page
    granularity and there's no way to keep all these write protection
    information if the small pages are going to be merged into a huge PMD.
    
    The same thing needs to be considered for swap entries and migration
    entries.  So do the check as well disregarding khugepaged_max_ptes_swap.
    Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Reviewed-by: default avatarJerome Glisse <jglisse@redhat.com>
    Reviewed-by: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Bobby Powers <bobbypowers@gmail.com>
    Cc: Brian Geffon <bgeffon@google.com>
    Cc: David Hildenbrand <david@redhat.com>
    Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
    Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
    Cc: Hugh Dickins <hughd@google.com>
    Cc: Johannes Weiner <hannes@cmpxchg.org>
    Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
    Cc: Martin Cracauer <cracauer@cons.org>
    Cc: Marty McFadden <mcfadden8@llnl.gov>
    Cc: Maya Gokhale <gokhale2@llnl.gov>
    Cc: Mel Gorman <mgorman@suse.de>
    Cc: Mike Kravetz <mike.kravetz@oracle.com>
    Cc: Pavel Emelyanov <xemul@openvz.org>
    Cc: Rik van Riel <riel@redhat.com>
    Cc: Shaohua Li <shli@fb.com>
    Link: http://lkml.kernel.org/r/20200220163112.11409-12-peterx@redhat.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    e1e267c7
khugepaged.c 55.5 KB