kernel/linux.git/Documentation/kernel-hacking, branch v7.0-rc7

Documentation: kernel-hacking: Remove :c:func: annotations

2026-01-06T22:15:15+00:00

Remove the useless :c:func: annotations. Suggested-by: Jonathan Corbet Signed-off-by: Thorsten Blum Signed-off-by: Jonathan Corbet Message-ID: <20251222232506.2615-2-thorsten.blum@linux.dev>

Documentation: kernel-hacking: Convert internal links

2026-01-06T22:08:43+00:00

Convert internal cross-references in "Putting Your Stuff in the kernel" section from inline code to internal links. Signed-off-by: Bagas Sanjaya Signed-off-by: Jonathan Corbet Message-ID: <20251223035254.22894-4-bagasdotme@gmail.com>

Documentation: kernel-hacking: Do not italicize EXPORT_SYMBOL{,_GPL}() references

2026-01-06T22:08:43+00:00

Do not italicize EXPORT_SYMBOL() and EXPORT_SYMBOL_GPL() references in EXPORT_SYMBOL_NS() and EXPORT_SYMBOL_NS_GPL() subsections. Signed-off-by: Bagas Sanjaya Signed-off-by: Jonathan Corbet Message-ID: <20251223035254.22894-3-bagasdotme@gmail.com>

Documentation: kernel-hacking: Remove current macro annotation

2026-01-06T22:08:43+00:00

Remove unneeded :c:macro: annotation of current macro. Signed-off-by: Bagas Sanjaya Signed-off-by: Jonathan Corbet Message-ID: <20251223035254.22894-2-bagasdotme@gmail.com>

Documentation: kernel-hacking: Remove comma

2025-12-22T21:40:24+00:00

The comma is wrong, remove it. Signed-off-by: Thorsten Blum Acked-by: Randy Dunlap Signed-off-by: Jonathan Corbet Message-ID: <20251219171827.44015-2-thorsten.blum@linux.dev>

docs/licensing: Clarify wording about "GPL" and "Proprietary"

2024-11-22T17:44:25+00:00

There are currently some doubts about out-of-tree kernel modules licensed under GPLv3 and if they are supposed to be able to use symbols exported using EXPORT_SYMBOL_GPL. Clarify that "Proprietary" means anything non-GPL2 even though the license might be an open source license. Also disambiguate "GPL compatible" to "GPLv2 compatible". Signed-off-by: Uwe Kleine-König Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20241115103842.585207-2-ukleinek@kernel.org

fix grammar on false-sharing.rst

2024-10-14T19:22:17+00:00

Fix slight grammar mistake on kernel-hacking/false-sharing.rst Signed-off-by: Vishnu Sanal T Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20241007191253.112697-2-t.v.s10123@gmail.com

Documentation: Add document for false sharing

2023-04-10T22:46:11+00:00

When doing performance tuning or debugging performance regressions, more and more cases are found to be related to false sharing [1][2][3], and the situation can be worse for newer platforms with hundreds of CPUs. There are already many commits in current kernel specially for mitigating the performance degradation due to false sharing. False sharing could harm the performance silently without being noticed, due to reasons like: * data members of a big data structure randomly sitting together in one cache line * global data of small size are linked compactly together So it's better to make a simple document about the normal pattern of false sharing, basic ways to mitigate it and call out to developers to pay attention during code-writing. [ Many thanks to Dave Hansen, Ying Huang, Tim Chen, Julie Du and Yu Chen for their contributions ] [1]. https://lore.kernel.org/lkml/20220619150456.GB34471@xsang-OptiPlex-9020/ [2]. https://lore.kernel.org/lkml/20201102091543.GM31092@shao2-debian/ [3]. https://lore.kernel.org/lkml/20230307125538.818862491@linutronix.de/ Signed-off-by: Feng Tang Reviewed-by: Randy Dunlap Reviewed-by: Shakeel Butt Link: https://lore.kernel.org/r/20230407041235.37886-1-feng.tang@intel.com Signed-off-by: Jonathan Corbet

docs: locking: Discourage from calling disable_irq() in atomic

2023-01-11T18:45:26+00:00

Correct the example in the documentation so that disable_irq() is not being called in atomic context. disable_irq() calls sleeping synchronize_irq(), it's not allowed to call them in atomic context. Signed-off-by: Alexander Sverdlin Signed-off-by: Thomas Gleixner Reviewed-by: Manfred Spraul Cc: linux-doc@vger.kernel.org Link: https://lore.kernel.org/lkml/87k02wbs2n.ffs@tglx/ Link: https://lore.kernel.org/r/20221212163715.830315-1-alexander.sverdlin@siemens.com

Merge tag 'timers-core-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-12-12T20:52:02+00:00

Pull timer updates from Thomas Gleixner: "Updates for timers, timekeeping and drivers: Core: - The timer_shutdown[_sync]() infrastructure: Tearing down timers can be tedious when there are circular dependencies to other things which need to be torn down. A prime example is timer and workqueue where the timer schedules work and the work arms the timer. What needs to prevented is that pending work which is drained via destroy_workqueue() does not rearm the previously shutdown timer. Nothing in that shutdown sequence relies on the timer being functional. The conclusion was that the semantics of timer_shutdown_sync() should be: - timer is not enqueued - timer callback is not running - timer cannot be rearmed Preventing the rearming of shutdown timers is done by discarding rearm attempts silently. A warning for the case that a rearm attempt of a shutdown timer is detected would not be really helpful because it's entirely unclear how it should be acted upon. The only way to address such a case is to add 'if (in_shutdown)' conditionals all over the place. This is error prone and in most cases of teardown not required all. - The real fix for the bluetooth HCI teardown based on timer_shutdown_sync(). A larger scale conversion to timer_shutdown_sync() is work in progress. - Consolidation of VDSO time namespace helper functions - Small fixes for timer and timerqueue Drivers: - Prevent integer overflow on the XGene-1 TVAL register which causes an never ending interrupt storm. - The usual set of new device tree bindings - Small fixes and improvements all over the place" * tag 'timers-core-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits) dt-bindings: timer: renesas,cmt: Add r8a779g0 CMT support dt-bindings: timer: renesas,tmu: Add r8a779g0 support clocksource/drivers/arm_arch_timer: Use kstrtobool() instead of strtobool() clocksource/drivers/timer-ti-dm: Fix missing clk_disable_unprepare in dmtimer_systimer_init_clock() clocksource/drivers/timer-ti-dm: Clear settings on probe and free clocksource/drivers/timer-ti-dm: Make timer_get_irq static clocksource/drivers/timer-ti-dm: Fix warning for omap_timer_match clocksource/drivers/arm_arch_timer: Fix XGene-1 TVAL register math error clocksource/drivers/timer-npcm7xx: Enable timer 1 clock before use dt-bindings: timer: nuvoton,npcm7xx-timer: Allow specifying all clocks dt-bindings: timer: rockchip: Add rockchip,rk3128-timer clockevents: Repair kernel-doc for clockevent_delta2ns() clocksource/drivers/ingenic-ost: Define pm functions properly in platform_driver struct clocksource/drivers/sh_cmt: Access registers according to spec vdso/timens: Refactor copy-pasted find_timens_vvar_page() helper into one copy Bluetooth: hci_qca: Fix the teardown problem for real timers: Update the documentation to reflect on the new timer_shutdown() API timers: Provide timer_shutdown[_sync]() timers: Add shutdown mechanism to the internal functions timers: Split [try_to_]del_timer[_sync]() to prepare for shutdown mode ...