Re: [PATCH v0.8 0/6] sched,mm,x86/uaccess: implement User Managed Concurrency Groups

[Barry Song <21cnbao@gmail.com>]

On Fri, Nov 5, 2021 at 8:58 AM Peter Oskolkov <posk@posk.io> wrote:
>
> 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/20211012232522.714898-1-posk@google.com/:
>
> - added libumcg tools/lib/umcg;
> - worker "wakeup" is reworked so that it is now purely a userspace op,
>   instead of waking the thread in order for it to block on return
>   to the userspace immediately;
> - a couple of minor 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 selftests in tools/testing/selftests/umcg/
> - allow cross-mm wakeups (securely)
>
>
> Peter Oskolkov (6):
>   sched/umcg: add WF_CURRENT_CPU and externise ttwu
>   mm, x86/uaccess: add userspace atomic helpers
>   sched/umcg: implement UMCG syscalls
>   sched/umcg, lib/umcg: implement libumcg
>   sched/umcg: add Documentation/userspace-api/umcg.txt
>   sched/umcg, lib/umcg: add tools/lib/umcg/libumcg.txt

Hi Peter,
Do you have a real workload or an example application using UMCG?

>
>  Documentation/userspace-api/umcg.txt   |  598 ++++++++++++
>  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                    |  949 +++++++++++++++++++
>  kernel/sys_ni.c                        |    4 +
>  mm/maccess.c                           |  264 ++++++
>  tools/lib/umcg/.gitignore              |    4 +
>  tools/lib/umcg/Makefile                |   11 +
>  tools/lib/umcg/libumcg.c               | 1201 ++++++++++++++++++++++++
>  tools/lib/umcg/libumcg.h               |  299 ++++++
>  tools/lib/umcg/libumcg.txt             |  438 +++++++++
>  24 files changed, 4166 insertions(+), 12 deletions(-)
>  create mode 100644 Documentation/userspace-api/umcg.txt
>  create mode 100644 include/uapi/linux/umcg.h
>  create mode 100644 kernel/sched/umcg.c
>  create mode 100644 tools/lib/umcg/.gitignore
>  create mode 100644 tools/lib/umcg/Makefile
>  create mode 100644 tools/lib/umcg/libumcg.c
>  create mode 100644 tools/lib/umcg/libumcg.h
>  create mode 100644 tools/lib/umcg/libumcg.txt
>
>
> base-commit: 8ea9183db4ad8afbcb7089a77c23eaf965b0cacd
> --
> 2.25.1
>

Thanks
Barry