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

Peter Oskolkov
2021-11-22T21:13:39Z

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