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Frederic Weisbecker 19b344a91f timers: Assert no next dyntick timer look-up while CPU is offline
The next timer (re-)evaluation, with the purpose of entering/updating
the dyntick mode, can happen from 3 sites and none of them are relevant
while the CPU is offline:

1) The idle loop:
	a) From the quick check helping the cpuidle governor to heuristically
	   predict the best C-state.
	b) While stopping the tick.

   But if the CPU is offline, the tick has been cancelled and there is
   consequently no need to further stop the tick.

2) Remote expiry: when a CPU remotely expires global timers on behalf of
   another CPU, the latter target's next timer is re-evaluated
   afterwards. However remote expîry doesn't happen on offline CPUs.

3) IRQ exit: on nohz_full mode, the tick is (re-)evaluated on IRQ exit.
   But full dynticks is disabled on offline CPUs.

Therefore it is safe to assume that no next dyntick timer lookup can
be performed on offline CPUs.

Assert this expectation to report any surprise.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240225225508.11587-17-frederic@kernel.org
2024-02-26 11:37:32 +01:00
arch csky/vdso: Use generic union vdso_data_store 2024-02-20 20:56:01 +01:00
block blk-iocost: Fix an UBSAN shift-out-of-bounds warning 2024-02-08 10:11:39 -07:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto crypto: algif_hash - Remove bogus SGL free on zero-length error path 2024-02-02 18:08:12 +08:00
Documentation clocksource: Scale the watchdog read retries automatically 2024-02-21 12:00:42 +01:00
drivers - Fix GICv4.1 affinity update 2024-02-18 09:14:12 -08:00
fs bcachefs fixes for v6.8-rc5 2024-02-17 13:17:32 -08:00
include tick: Assume timekeeping is correctly handed over upon last offline idle call 2024-02-26 11:37:32 +01:00
init update workarounds for gcc "asm goto" issue 2024-02-15 11:14:33 -08:00
io_uring io_uring/net: fix multishot accept overflow handling 2024-02-14 18:30:19 -07:00
ipc shm: Slim down dependencies 2023-12-20 19:26:31 -05:00
kernel timers: Assert no next dyntick timer look-up while CPU is offline 2024-02-26 11:37:32 +01:00
lib Driver core fixes for 6.8-rc5 2024-02-17 08:56:41 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/memory: Use exception ip to search exception tables 2024-02-12 23:04:42 +01:00
net Including fixes from can, wireless and netfilter. 2024-02-15 11:39:27 -08:00
rust Rust changes for v6.8 2024-01-11 13:05:41 -08:00
samples work around gcc bugs with 'asm goto' with outputs 2024-02-09 15:57:48 -08:00
scripts kallsyms: ignore ARMv4 thunks along with others 2024-02-15 22:44:56 +09:00
security lsm/stable-6.8 PR 20240215 2024-02-16 07:58:43 -08:00
sound ALSA: usb-audio: More relaxed check of MIDI jack names 2024-02-15 16:56:05 +01:00
tools clocksource: Scale the watchdog read retries automatically 2024-02-21 12:00:42 +01:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt Generic: 2024-01-17 13:03:37 -08:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.mailmap Including fixes from can, wireless and netfilter. 2024-02-15 11:39:27 -08:00
.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: supplement of zswap maintainers update 2024-01-25 23:52:21 -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 timer_migration: Add tracepoints 2024-02-22 17:52:32 +01:00
Makefile Linux 6.8-rc5 2024-02-18 12:56:25 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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 Restructured Text 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.