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Frederic Weisbecker f400565faa perf: Remove too early and redundant CPU hotplug handling
The CPU hotplug handlers are called twice: at prepare and online stage.

Their role is to:

1) Enable/disable a CPU context. This is irrelevant and even buggy at
   the prepare stage because the CPU is still offline. On early
   secondary CPU up, creating an event attached to that CPU might
   silently fail because the CPU context is observed as online but the
   context installation's IPI failure is ignored.

2) Update the scope cpumasks and re-migrate the events accordingly in
   the CPU down case. This is irrelevant at the prepare stage.

3) Remove the events attached to the context of the offlining CPU. It
   even uses an (unnecessary) IPI for it. This is also irrelevant at the
   prepare stage.

Also none of the *_PREPARE and *_STARTING architecture perf related CPU
hotplug callbacks rely on CPUHP_PERF_PREPARE.

CPUHP_AP_PERF_ONLINE is enough and the right place to perform the work.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20250424161128.29176-4-frederic@kernel.org
2025-05-08 21:50:19 +02:00
arch perf/x86: Optimize the is_x86_event 2025-04-25 14:55:22 +02:00
block vfs-6.15-rc3.fixes.2 2025-04-19 14:31:08 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: ahash - Disable request chaining 2025-04-12 09:33:09 +08:00
Documentation 16 hotfixes. 2 are cc:stable and the remainder address post-6.14 issues 2025-04-19 21:46:58 -07:00
drivers gcc-15: disable '-Wunterminated-string-initialization' entirely for now 2025-04-20 15:30:53 -07:00
fs for-6.15-rc3-tag 2025-04-22 10:22:38 -07:00
include perf: Remove too early and redundant CPU hotplug handling 2025-05-08 21:50:19 +02:00
init Kconfig: switch CONFIG_SYSFS_SYCALL default to n 2025-04-15 10:28:35 +02:00
io_uring io_uring/zcrx: fix late dma unmap for a dead dev 2025-04-18 06:12:10 -06:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel perf: Remove too early and redundant CPU hotplug handling 2025-05-08 21:50:19 +02:00
lib hardening fixes for v6.15-rc3 2025-04-18 13:20:20 -07:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm 16 hotfixes. 2 are cc:stable and the remainder address post-6.14 issues 2025-04-19 21:46:58 -07:00
net Including fixes from Bluetooth, CAN and Netfilter. 2025-04-17 11:45:30 -07:00
rust rust: helpers: Add dma_alloc_attrs() and dma_free_attrs() 2025-04-15 23:06:03 +02:00
samples samples/livepatch: add module descriptions 2025-04-11 17:32:38 -07:00
scripts Rust fixes for v6.15 2025-04-19 10:02:43 -07:00
security ima: process_measurement() needlessly takes inode_lock() on MAY_READ 2025-04-22 16:39:32 +02:00
sound ASoC: Fixes for v6.15 2025-04-11 15:51:19 +02:00
tools Merge branch 'perf/urgent' 2025-04-25 14:55:20 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-05 04:06:45 +09:00
virt ARM: 2025-04-08 13:47:55 -07:00
.clang-format clang-format: Update the ForEachMacros list for v6.15-rc1 2025-04-13 11:03:59 +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 kbuild: Create intermediate vmlinux build with relocations preserved 2025-03-17 00:29:50 +09:00
.mailmap sound fixes for 6.15-rc3 2025-04-17 10:14:51 -07:00
.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 MAINTAINERS: update SLAB ALLOCATOR maintainers 2025-04-17 20:10:06 -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 16 hotfixes. 2 are cc:stable and the remainder address post-6.14 issues 2025-04-19 21:46:58 -07:00
Makefile gcc-15: disable '-Wunterminated-string-initialization' entirely for now 2025-04-20 15:30:53 -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.