[PATCH v0.9.1 0/6] sched,mm,x86/uaccess: implement User Managed Concurrency Groups

From: Peter Oskolkov <posk@posk.io>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	linux-api@vger.kernel.org
Cc: Paul Turner <pjt@google.com>, Ben Segall <bsegall@google.com>,
	Peter Oskolkov <posk@google.com>, Peter Oskolkov <posk@posk.io>,
	Andrei Vagin <avagin@google.com>, Jann Horn <jannh@google.com>,
	Thierry Delisle <tdelisle@uwaterloo.ca>
Subject: [PATCH v0.9.1 0/6] sched,mm,x86/uaccess: implement User Managed Concurrency Groups
Date: Mon, 22 Nov 2021 13:13:21 -0800	[thread overview]
Message-ID: <20211122211327.5931-1-posk@google.com> (raw)

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

This v0.9.1 patchset is the same as v0.9, where u32/u64 in
uapi/linux/umcg.h are replaced with __u32/__u64, as test robot/lkp
does not recognize u32/u64 for some reason.

v0.9 is v0.8 rebased on top of the current tip/sched/core,
with a fix in umcg_update_state of an issue reported by Tao Zhou.

Key changes from patchset v0.7:
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

 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      |    7 +-
 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               | 1202 ++++++++++++++++++++++++
 tools/lib/umcg/libumcg.h               |  299 ++++++
 tools/lib/umcg/libumcg.txt             |  438 +++++++++
 24 files changed, 4168 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: cb0e52b7748737b2cf6481fdd9b920ce7e1ebbdf
--
2.25.1