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Shakeel Butt 36df6e3dbd cgroup: make css_rstat_updated nmi safe
To make css_rstat_updated() able to safely run in nmi context, let's
move the rstat update tree creation at the flush side and use per-cpu
lockless lists in struct cgroup_subsys to track the css whose stats are
updated on that cpu.

The struct cgroup_subsys_state now has per-cpu lnode which needs to be
inserted into the corresponding per-cpu lhead of struct cgroup_subsys.
Since we want the insertion to be nmi safe, there can be multiple
inserters on the same cpu for the same lnode. Here multiple inserters
are from stacked contexts like softirq, hardirq and nmi.

The current llist does not provide function to protect against the
scenario where multiple inserters can use the same lnode. So, using
llist_node() out of the box is not safe for this scenario.

However we can protect against multiple inserters using the same lnode
by using the fact llist node points to itself when not on the llist and
atomically reset it and select the winner as the single inserter.

Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Tested-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-06-17 10:01:00 -10:00
arch Xtensa updates for v6.16 2025-06-03 09:05:01 -07:00
block cgroup: Changes for v6.16 2025-05-27 20:59:53 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto EFI updates for v6.16 2025-05-30 12:42:57 -07:00
Documentation Documentation: cgroup: add section explaining controller availability 2025-06-09 08:05:13 -10:00
drivers hid-for-linus-2025060301 2025-06-03 10:34:36 -07:00
fs - The 2 patch series "zram: support algorithm-specific parameters" from 2025-06-02 16:00:26 -07:00
include cgroup: support to enable nmi-safe css_rstat_updated 2025-06-17 09:58:45 -10:00
init - The 2 patch series "zram: support algorithm-specific parameters" from 2025-06-02 16:00:26 -07:00
io_uring Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
ipc - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
kernel cgroup: make css_rstat_updated nmi safe 2025-06-17 10:01:00 -10:00
lib bitmap-for-6.16 2025-06-03 07:39:23 -07:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm - The 2 patch series "zram: support algorithm-specific parameters" from 2025-06-02 16:00:26 -07:00
net vfs-6.16-rc1.netfs 2025-06-02 15:04:06 -07:00
rust - The 2 patch series "zram: support algorithm-specific parameters" from 2025-06-02 16:00:26 -07:00
samples - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
scripts - The 2 patch series "zram: support algorithm-specific parameters" from 2025-06-02 16:00:26 -07:00
security require gcc-8 and binutils-2.30 2025-05-31 08:16:52 -07:00
sound sound updates for 6.16-rc1 2025-05-27 15:05:18 -07:00
tools selftests: cgroup: Fix compilation on pre-cgroupns kernels 2025-06-17 08:13:25 -10:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge branch 'kvm-lockdep-common' into HEAD 2025-05-28 06:29:17 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.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 .gitignore: ignore Python compiled bytecode 2025-04-24 10:12:46 -06:00
.mailmap - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS Update Christoph's Email address and make it consistent 2025-05-12 23:50:31 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS hwmon updates for v6.16 2025-06-03 09:11:26 -07:00
Makefile A moderately busy cycle for documentation this time around: 2025-05-27 11:22:19 -07:00
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.