mm/khugepaged: collapse_shmem() stop if punched or truncated
authorHugh Dickins <hughd@google.com>
Fri, 30 Nov 2018 22:10:25 +0000 (14:10 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 30 Nov 2018 22:56:15 +0000 (14:56 -0800)
commit701270fa193aadf00bdcf607738f64997275d4c7
tree6f9a0bd6ab13d9213050c0ff4e739953dd5c7570
parent006d3ff27e884f80bd7d306b041afc415f63598f
mm/khugepaged: collapse_shmem() stop if punched or truncated

Huge tmpfs testing showed that although collapse_shmem() recognizes a
concurrently truncated or hole-punched page correctly, its handling of
holes was liable to refill an emptied extent.  Add check to stop that.

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261522040.2275@eggly.anvils
Fixes: f3f0e1d2150b2 ("khugepaged: add support of collapse for tmpfs/shmem pages")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: <stable@vger.kernel.org> [4.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/khugepaged.c