tree 5095c6e9fd2527a8636188059e35f7f45b9648a2
parent 7267ec008b5cd8b3579e188b1ff238815643e372
author Kirill A. Shutemov <kirill.shutemov@linux.intel.com> 1469571926 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1469575159 -0700

rmap: support file thp

Naive approach: on mapping/unmapping the page as compound we update
->_mapcount on each 4k page.  That's not efficient, but it's not obvious
how we can optimize this.  We can look into optimization later.

PG_double_map optimization doesn't work for file pages since lifecycle
of file pages is different comparing to anon pages: file page can be
mapped again at any time.

Link: http://lkml.kernel.org/r/1466021202-61880-11-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>