[patch 0/6] improve memcg oom killer robustness

[Johannes Weiner <hannes@cmpxchg.org>]

The memcg code can trap tasks in the context of the failing allocation
until an OOM situation is resolved.  They can hold all kinds of locks
(fs, mm) at this point, which makes it prone to deadlocking.

This series converts memcg OOM handling into a two step process that
is started in the charge context, but any waiting is done after the
fault stack is fully unwound.

Patches 1-4 prepare architecture handlers to support the new memcg
requirements, but in doing so they also remove old cruft and unify
out-of-memory behavior across architectures.

Patch 5 disables the memcg OOM handling for syscalls, readahead,
kernel faults, because they can gracefully unwind the stack with
-ENOMEM.  OOM handling is restricted to user triggered faults that
have no other option.

Patch 6 implements the two-part OOM handling such that tasks are never
trapped with the full charge stack in an OOM situation.

 arch/alpha/mm/fault.c      |   7 ++++---
 arch/arc/mm/fault.c        |  11 ++++-------
 arch/arm/mm/fault.c        |  23 +++++++++++++----------
 arch/arm64/mm/fault.c      |  23 +++++++++++++----------
 arch/avr32/mm/fault.c      |   4 +++-
 arch/cris/mm/fault.c       |   6 ++++--
 arch/frv/mm/fault.c        |  10 ++++++----
 arch/hexagon/mm/vm_fault.c |   6 ++++--
 arch/ia64/mm/fault.c       |   6 ++++--
 arch/m32r/mm/fault.c       |  10 ++++++----
 arch/m68k/mm/fault.c       |   2 ++
 arch/metag/mm/fault.c      |   6 ++++--
 arch/microblaze/mm/fault.c |   7 +++++--
 arch/mips/mm/fault.c       |   8 ++++++--
 arch/mn10300/mm/fault.c    |   2 ++
 arch/openrisc/mm/fault.c   |   1 +
 arch/parisc/mm/fault.c     |   7 +++++--
 arch/powerpc/mm/fault.c    |   7 ++++---
 arch/s390/mm/fault.c       |   2 ++
 arch/score/mm/fault.c      |  13 ++++++-------
 arch/sh/mm/fault.c         |   9 ++++++---
 arch/sparc/mm/fault_32.c   |  12 +++++++++---
 arch/sparc/mm/fault_64.c   |   8 +++++---
 arch/tile/mm/fault.c       |  13 +++++--------
 arch/um/kernel/trap.c      |  22 ++++++++++++++--------
 arch/unicore32/mm/fault.c  |  22 +++++++++++++---------
 arch/x86/mm/fault.c        |  43 ++++++++++++++++++++++---------------------
 arch/xtensa/mm/fault.c     |   2 ++
 include/linux/memcontrol.h |  40 ++++++++++++++++++++++++++++++++++++++++
 include/linux/mm.h         |   1 +
 include/linux/sched.h      |   6 ++++++
 mm/filemap.c               |  11 ++++++++++-
 mm/memcontrol.c            | 156 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------------------------------
 mm/memory.c                |  43 +++++++++++++++++++++++++++++++++----------
 mm/oom_kill.c              |   7 +++++--
 35 files changed, 373 insertions(+), 183 deletions(-)

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