[CRIU] [PATCH v3 0/6] lazy-pages: fix pre- and post-copy combination.

[Mike Rapoport]

Hi,

These patches fix the pre- and post-copy combination when khugepaged is
enabled [1].

When we combine pre-dump with lazy pages, we populate a part of a memory region
with data that was saved during the pre-dump. Afterwards, the region is
registered with userfaultfd and we expect to get page faults for the parts of
the region that were not yet populated. However, khugepaged collapses the pages
and the page faults we would expect do not occur.
    
To mitigate this problem we temporarily disable THP for the restored process,
up to the point when we register all the memory regions with userfaultfd.
    
Note, that currently disabling THP has a side effect that all VMAs of the
restored process will have VM_NOHUGEPAGE flag set. This will be resolved
when the appropriate patch [2] will be merged into the kernel.

v3:
* drop unrelated patches
* save current state of the THP disable prctl in mm*img
* add comment as per Pavel's request

v2:
* fix build on arm
* massage lazy-thp test a bit

[1] https://lists.openvz.org/pipermail/criu/2017-May/037728.html
[2] http://git.cmpxchg.org/cgit.cgi/linux-mmotm.git/commit/kernel/sys.c?id=252662e4127f52022d675081762e7882ebd9d496

Mike Rapoport (6):
  mem: kill trailing whitespace
  proc_parse: make smaps parsing helpers globally available
  kerndat: add test for availability of PR_SET_THP_DISABLE prctl
  mem: add dump state of THP_DISABLED prctl
  lazy-pages: fix memory corruption when combining pre-dump with lazy pages
  test: add test that verifies proper intraction between lazy-pages and THP

 criu/cr-dump.c                  |  3 ++
 criu/cr-restore.c               |  3 ++
 criu/include/kerndat.h          |  1 +
 criu/include/pagemap.h          |  5 +++
 criu/include/parasite.h         |  1 +
 criu/include/prctl.h            |  8 +++++
 criu/include/proc_parse.h       |  3 ++
 criu/include/restorer.h         |  1 +
 criu/include/rst_info.h         |  2 ++
 criu/kerndat.c                  | 74 ++++++++++++++++++++++++++++++++++++++++
 criu/mem.c                      | 44 +++++++++++++++++++++---
 criu/pie/parasite.c             |  1 +
 criu/pie/restorer.c             |  8 +++++
 criu/proc_parse.c               | 75 ++++++++++++++++++++++++-----------------
 images/mm.proto                 |  1 +
 test/zdtm/transition/Makefile   |  1 +
 test/zdtm/transition/lazy-thp.c | 61 +++++++++++++++++++++++++++++++++
 17 files changed, 258 insertions(+), 34 deletions(-)
 create mode 100644 test/zdtm/transition/lazy-thp.c

-- 
2.7.4