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Alexei Starovoitov 8a6d047c8d Merge branch 'arena-spin-lock'
Kumar Kartikeya Dwivedi says:

====================
Arena Spin Lock

This set provides an implementation of queued spin lock for arena.
There is no support for resiliency and recovering from deadlocks yet.
We will wait for the rqspinlock patch set to land before incorporating
support.

One minor change compared to the qspinlock algorithm in the kernel is
that we don't have the trylock fallback when nesting count exceeds 4.
The maximum number of supported CPUs is 1024, but this can be increased
in the future if necessary.

The API supports returning an error, so resiliency support can be added
in the future. Callers are still expected to check for and handle any
potential errors.

Errors are returned when the spin loops time out, when the number of
CPUs is greater than 1024, or when the extreme edge case of NMI
interrupting NMI interrupting HardIRQ interrupting SoftIRQ interrupting
task, all of them simultaneously in slow path, occurs, which is
unsupported.

Changelog:
----------
v4 -> v5
v4: https://lore.kernel.org/bpf/20250305045136.2614132-1-memxor@gmail.com

 * Add better comment and document LLVM bug for __unqual_typeof.
 * Switch to precise counting in the selftest and simplify test.
 * Add comment about return value handling.
 * Reduce size for 100k to 50k to cap test runtime.

v3 -> v4
v3: https://lore.kernel.org/bpf/20250305011849.1168917-1-memxor@gmail.com

 * Drop extra corruption handling case in decode_tail.
 * Stick to 1, 1k, 100k critical section sizes.
 * Fix unqual_typeof to not cast away arena tag for pointers.
 * Remove hack to skip first qnode.
 * Choose 100 as repeat count, 1000 is too much for 100k size.
 * Use pthread_barrier in test.

v2 -> v3
v2: https://lore.kernel.org/bpf/20250118162238.2621311-1-memxor@gmail.com

 * Rename to arena_spin_lock
 * Introduce cond_break_label macro to jump to label from cond_break.
 * Drop trylock fallback when nesting count exceeds 4.
 * Fix bug in try_cmpxchg implementation.
 * Add tests with critical sections of varying lengths.
 * Add comments for _Generic trick to drop __arena tag.
 * Fix bug due to qnodes being placed on first page, leading to CPU 0's
   node being indistinguishable from NULL.

v1 -> v2
v1: https://lore.kernel.org/bpf/20250117223754.1020174-1-memxor@gmail.com

 * Fix definition of lock in selftest
====================

Link: https://patch.msgid.link/20250306035431.2186189-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-03-15 11:48:56 -07:00
arch bpf, x86: Support load-acquire and store-release instructions 2025-03-15 11:48:29 -07:00
block block-6.14-20250214 2025-02-14 11:40:59 -08:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
Documentation bpf, docs: Fix broken link to renamed bpf_iter_task_vmas.c 2025-03-15 11:48:56 -07:00
drivers Smaller than usual with no fixes from any subtree. 2025-02-20 10:19:54 -08:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf bpf-6.14-rc4 2025-02-20 18:13:57 -08:00
include bpf: simple DFA-based live registers analysis 2025-03-15 11:48:29 -07:00
init Kbuild updates for v6.14 2025-01-31 12:07:07 -08:00
io_uring io_uring-6.14-20250214 2025-02-14 11:30:53 -08:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel bpf: correct use/def for may_goto instruction 2025-03-15 11:48:30 -07:00
lib test_xarray: fix failure in check_pause when CONFIG_XARRAY_MULTI is not defined 2025-02-17 22:40:04 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf bpf-6.14-rc4 2025-02-20 18:13:57 -08:00
net net: filter: Avoid shadowing variable in bpf_convert_ctx_access() 2025-03-15 11:48:27 -07:00
rust Driver core api addition for 6.14-rc3 2025-02-16 12:54:42 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf bpf-6.14-rc4 2025-02-20 18:13:57 -08:00
scripts kbuild, bpf: Correct pahole version that supports distilled base btf feature 2025-02-24 14:14:52 -08:00
security Redo of pathname patternization and fix spelling errors. 2025-02-11 10:19:36 -08:00
sound ALSA: seq: Drop UMP events when no UMP-conversion is set 2025-02-17 18:02:02 +01:00
tools selftests/bpf: Add tests for arena spin lock 2025-03-15 11:48:56 -07:00
usr kbuild: Drop support for include/asm-<arch> in headers_check.pl 2024-12-21 11:43:17 +09:00
virt KVM: remove kvm_arch_post_init_vm 2025-02-04 11:27:45 -05:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-01-10 00:17:25 +01:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: use host dylib naming convention to support macOS 2025-01-10 01:01:24 +01:00
.mailmap mailmap: update Nick's entry 2025-02-17 22:40:03 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS MAINTAINERS: Move Pavel to kernel.org address 2025-02-07 09:12:33 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS Smaller than usual with no fixes from any subtree. 2025-02-20 10:19:54 -08:00
Makefile Linux 6.14-rc3 2025-02-16 14:02:44 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.