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Kumar Kartikeya Dwivedi 14c48ee814 rqspinlock: Add support for timeouts
Introduce policy macro RES_CHECK_TIMEOUT which can be used to detect
when the timeout has expired for the slow path to return an error. It
depends on being passed two variables initialized to 0: ts, ret. The
'ts' parameter is of type rqspinlock_timeout.

This macro resolves to the (ret) expression so that it can be used in
statements like smp_cond_load_acquire to break the waiting loop
condition.

The 'spin' member is used to amortize the cost of checking time by
dispatching to the implementation every 64k iterations. The
'timeout_end' member is used to keep track of the timestamp that denotes
the end of the waiting period. The 'ret' parameter denotes the status of
the timeout, and can be checked in the slow path to detect timeouts
after waiting loops.

The 'duration' member is used to store the timeout duration for each
waiting loop. The default timeout value defined in the header
(RES_DEF_TIMEOUT) is 0.25 seconds.

This macro will be used as a condition for waiting loops in the slow
path.  Since each waiting loop applies a fresh timeout using the same
rqspinlock_timeout, we add a new RES_RESET_TIMEOUT as well to ensure the
values can be easily reinitialized to the default state.

Reviewed-by: Barret Rhoden <brho@google.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250316040541.108729-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-03-19 08:03:04 -07:00
arch bpf, x86: Fix objtool warning for timed may_goto 2025-03-15 15:55:14 -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 rqspinlock: Add support for timeouts 2025-03-19 08:03:04 -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 rqspinlock: Add support for timeouts 2025-03-19 08:03:04 -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 security: Propagate caller information in bpf hooks 2025-03-15 11:48:58 -07:00
sound ALSA: seq: Drop UMP events when no UMP-conversion is set 2025-02-17 18:02:02 +01:00
tools bpftool: Using the right format specifiers 2025-03-17 13:50:56 -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 kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
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.