huge pagecache: extend mremap pmd rmap lockout to files
authorHugh Dickins <hughd@google.com>
Fri, 20 May 2016 00:12:57 +0000 (17:12 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 20 May 2016 02:12:14 +0000 (19:12 -0700)
commit1d069b7dd56728a0eb6acb138dce0d37600dee00
tree29a891a8640bbf0356037d39a115e6ca7a995a75
parentbf8616d5fa179d6c755f06726567c6d63c6fbbc7
huge pagecache: extend mremap pmd rmap lockout to files

Whatever huge pagecache implementation we go with, file rmap locking
must be added to anon rmap locking, when mremap's move_page_tables()
finds a pmd_trans_huge pmd entry: a simple change, let's do it now.

Factor out take_rmap_locks() and drop_rmap_locks() to handle the locking
for make move_ptes() and move_page_tables(), and delete the
VM_BUG_ON_VMA which rejected vm_file and required anon_vma.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Yang Shi <yang.shi@linaro.org>
Cc: Ning Qu <quning@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/mremap.c