[PATCH v0.7 0/5] sched,mm,x86/uaccess: implement User Managed Concurrency Groups

[Peter Oskolkov <posk@posk.io>]

User Managed Concurrency Groups (UMCG) is an M:N threading
subsystem/toolkit that lets user space application developers implement
in-process user space schedulers.

Key changes from the previous patchset
https://lore.kernel.org/all/20210917180323.278250-1-posk@google.com/ :

- userspace atomic helpers moved into mm/
- UMCG task states are now tagged with timestamps
- cross-mm interactions (wakeups) are not permitted
- several smaller fixes and refactorings

These big things remain to be addressed (in no particular order):
- support tracing/debugging
- make context switches faster (see umcg_do_context_switch in umcg.c)
- support other architectures
- cleanup and post userspace support in tools/lib/umcg/
- cleanup and post selftests in tools/testing/selftests/umcg/
- allow cross-mm wakeups (securely)

I'm working on finalizing libumcg and kselftests.

Signed-off-by: Peter Oskolkov <posk@google.com>

Peter Oskolkov (5):
  sched/umcg: add WF_CURRENT_CPU and externise ttwu
  mm, x86/uaccess: add userspace atomic helpers
  sched/umcg: implement UMCG syscalls
  sched/umcg: add Documentation/userspace-api/umcg.rst
  sched/umcg: add Documentation/userspace-api/umcg.txt

 Documentation/userspace-api/umcg.rst   | 611 ++++++++++++++++
 Documentation/userspace-api/umcg.txt   | 594 ++++++++++++++++
 arch/x86/entry/syscalls/syscall_64.tbl |   2 +
 arch/x86/include/asm/uaccess_64.h      |  93 +++
 fs/exec.c                              |   1 +
 include/linux/sched.h                  |  71 ++
 include/linux/syscalls.h               |   3 +
 include/linux/uaccess.h                |  46 ++
 include/uapi/asm-generic/unistd.h      |   6 +-
 include/uapi/linux/umcg.h              | 137 ++++
 init/Kconfig                           |  10 +
 kernel/entry/common.c                  |   4 +-
 kernel/exit.c                          |   5 +
 kernel/sched/Makefile                  |   1 +
 kernel/sched/core.c                    |  12 +-
 kernel/sched/fair.c                    |   4 +
 kernel/sched/sched.h                   |  15 +-
 kernel/sched/umcg.c                    | 926 +++++++++++++++++++++++++
 kernel/sys_ni.c                        |   4 +
 mm/maccess.c                           | 264 +++++++
 20 files changed, 2797 insertions(+), 12 deletions(-)
 create mode 100644 Documentation/userspace-api/umcg.rst
 create mode 100644 Documentation/userspace-api/umcg.txt
 create mode 100644 include/uapi/linux/umcg.h
 create mode 100644 kernel/sched/umcg.c

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2.25.1