[RFC v1 0/4] Two alternatives for mm async teardown

[Claudio Imbrenda]

This RFC series proposes two possible ways for enabling asynchronous mm
teardown.

The first approach, in patch 1, is simply to provide an arch hook in
exit_mm. This has no functional change for archs that don't explicitly
use the hook, and leaves the hard part to arch code (including
accounting, if any).

The second approach, in patches 2 to 4, adds a new syscall to allow an
mm to be asynchronously torn down in the context of another process
(similarly to how process_mrelease works). It also adds an OOM notifier
to prevent the OOM killer from killing processes while the teardown is
in progress.


Claudio Imbrenda (4):
  exit: add arch mmput hook in exit_mm
  kernel/fork.c: implement new process_mmput_async syscall
  mm: wire up the process_mmput_async syscall
  kernel/fork.c: process_mmput_async: stop OOM while freeing memory

 arch/alpha/kernel/syscalls/syscall.tbl      |   2 +
 arch/arm/tools/syscall.tbl                  |   1 +
 arch/arm64/include/asm/unistd.h             |   2 +-
 arch/arm64/include/asm/unistd32.h           |   2 +
 arch/ia64/kernel/syscalls/syscall.tbl       |   2 +
 arch/m68k/kernel/syscalls/syscall.tbl       |   2 +
 arch/microblaze/kernel/syscalls/syscall.tbl |   2 +
 arch/mips/kernel/syscalls/syscall_n32.tbl   |   2 +
 arch/mips/kernel/syscalls/syscall_n64.tbl   |   2 +
 arch/mips/kernel/syscalls/syscall_o32.tbl   |   2 +
 arch/parisc/kernel/syscalls/syscall.tbl     |   2 +
 arch/powerpc/kernel/syscalls/syscall.tbl    |   2 +
 arch/s390/kernel/syscalls/syscall.tbl       |   2 +
 arch/sh/kernel/syscalls/syscall.tbl         |   2 +
 arch/sparc/kernel/syscalls/syscall.tbl      |   2 +
 arch/x86/entry/syscalls/syscall_32.tbl      |   1 +
 arch/x86/entry/syscalls/syscall_64.tbl      |   1 +
 arch/xtensa/kernel/syscalls/syscall.tbl     |   2 +
 include/asm-generic/mmu_context.h           |   4 +
 include/linux/mm_types.h                    |   1 +
 include/linux/syscalls.h                    |   1 +
 include/uapi/asm-generic/unistd.h           |   5 +-
 kernel/exit.c                               |   2 +-
 kernel/fork.c                               | 131 +++++++++++++++++++-
 kernel/sys_ni.c                             |   1 +
 25 files changed, 173 insertions(+), 5 deletions(-)

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2.31.1