• Hugh Dickins's avatar
    mm/munlock: delete munlock_vma_pages_all(), allow oomreap · a213e5cf
    Hugh Dickins authored
    munlock_vma_pages_range() will still be required, when munlocking but
    not munmapping a set of pages; but when unmapping a pte, the mlock count
    will be maintained in much the same way as it will be maintained when
    mapping in the pte.  Which removes the need for munlock_vma_pages_all()
    on mlocked vmas when munmapping or exiting: eliminating the catastrophic
    contention on i_mmap_rwsem, and the need for page lock on the pages.
    
    There is still a need to update locked_vm accounting according to the
    munmapped vmas when munmapping: do that in detach_vmas_to_be_unmapped().
    exit_mmap() does not need locked_vm updates, so delete unlock_range().
    
    And wasn't I the one who forbade the OOM reaper to attack mlocked vmas,
    because of the uncertainty in blocking on all those page locks?
    No fear of that now, so permit the OOM reaper on mlocked vmas.
    Signed-off-by: default avatarHugh Dickins <hughd@google.com>
    Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
    Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
    a213e5cf
internal.h 22.2 KB