kernel/linux.git/include/linux/delay.h, branch v6.19.11

time: Fix a few typos in time[r] related code comments

2025-11-14T19:34:50+00:00

Signed-off-by: Jianyun Gao Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20250927093411.1509275-1-jianyungao89@gmail.com

timers: Adjust flseep() to reflect reality

2024-10-15T22:36:47+00:00

fsleep() simply implements the recommendations of the outdated documentation in "Documentation/timers/timers-howto.rst". This should be a user friendly interface to choose always the best timeout function approach: - udelay() for very short sleep durations shorter than 10 microseconds - usleep_range() for sleep durations until 20 milliseconds - msleep() for the others The actual implementation has several problems: - It does not take into account that HZ resolution also has an impact on granularity of jiffies and has also an impact on the granularity of the buckets of timer wheel levels. This means that accuracy for the timeout does not have an upper limit. When executing fsleep(20000) on a HZ=100 system, the possible additional slack will be 50% as the granularity of the buckets in the lowest level is 10 milliseconds. - The upper limit of usleep_range() is twice the requested timeout. When no other interrupts occur in this range, the maximum value is used. This means that the requested sleep length has then an additional delay of 100%. Change the thresholds for the decisions in fsleep() to make sure the maximum slack which is added to the sleep duration is 25%. Note: Outdated documentation will be updated in a followup patch. Signed-off-by: Anna-Maria Behnsen Signed-off-by: Thomas Gleixner Reviewed-by: Frederic Weisbecker Link: https://lore.kernel.org/all/20241014-devel-anna-maria-b4-timers-flseep-v3-7-dc8b907cb62f@linutronix.de

timers: Update function descriptions of sleep/delay related functions

2024-10-15T22:36:47+00:00

A lot of commonly used functions for inserting a sleep or delay lack a proper function description. Add function descriptions to all of them to have important information in a central place close to the code. No functional change. Signed-off-by: Anna-Maria Behnsen Signed-off-by: Thomas Gleixner Reviewed-by: Frederic Weisbecker Link: https://lore.kernel.org/all/20241014-devel-anna-maria-b4-timers-flseep-v3-5-dc8b907cb62f@linutronix.de

timers: Rename usleep_idle_range() to usleep_range_idle()

2024-10-15T22:36:46+00:00

usleep_idle_range() is a variant of usleep_range(). Both are using usleep_range_state() as a base. To be able to find all the related functions in one go, rename it usleep_idle_range() to usleep_range_idle(). No functional change. Signed-off-by: Anna-Maria Behnsen Signed-off-by: Thomas Gleixner Reviewed-by: Frederic Weisbecker Reviewed-by: SeongJae Park Link: https://lore.kernel.org/all/20241014-devel-anna-maria-b4-timers-flseep-v3-4-dc8b907cb62f@linutronix.de

init: consolidate prototypes in linux/init.h

2023-06-10T00:44:16+00:00

The init/main.c file contains some extern declarations for functions defined in architecture code, and it defines some other functions that are called from architecture code with a custom prototype. Both of those result in warnings with 'make W=1': init/calibrate.c:261:37: error: no previous prototype for 'calibrate_delay_is_known' [-Werror=missing-prototypes] init/main.c:790:20: error: no previous prototype for 'mem_encrypt_init' [-Werror=missing-prototypes] init/main.c:792:20: error: no previous prototype for 'poking_init' [-Werror=missing-prototypes] arch/arm64/kernel/irq.c:122:13: error: no previous prototype for 'init_IRQ' [-Werror=missing-prototypes] arch/arm64/kernel/time.c:55:13: error: no previous prototype for 'time_init' [-Werror=missing-prototypes] arch/x86/kernel/process.c:935:13: error: no previous prototype for 'arch_post_acpi_subsys_init' [-Werror=missing-prototypes] init/calibrate.c:261:37: error: no previous prototype for 'calibrate_delay_is_known' [-Werror=missing-prototypes] kernel/fork.c:991:20: error: no previous prototype for 'arch_task_cache_init' [-Werror=missing-prototypes] Add prototypes for all of these in include/linux/init.h or another appropriate header, and remove the duplicate declarations from architecture specific code. [sfr@canb.auug.org.au: declare time_init_early()] Link: https://lkml.kernel.org/r/20230519124311.5167221c@canb.auug.org.au Link: https://lkml.kernel.org/r/20230517131102.934196-12-arnd@kernel.org Signed-off-by: Arnd Bergmann Signed-off-by: Stephen Rothwell Cc: Boqun Feng Cc: Catalin Marinas Cc: Christoph Lameter Cc: Dennis Zhou Cc: Eric Paris Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Michael Ellerman Cc: Michal Simek Cc: Palmer Dabbelt Cc: Paul Moore Cc: Pavel Machek Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Russell King Cc: Tejun Heo Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Waiman Long Cc: Will Deacon Signed-off-by: Andrew Morton

timers: implement usleep_idle_range()

2021-12-11T01:10:55+00:00

Patch series "mm/damon: Fix fake /proc/loadavg reports", v3. This patchset fixes DAMON's fake load report issue. The first patch makes yet another variant of usleep_range() for this fix, and the second patch fixes the issue of DAMON by making it using the newly introduced function. This patch (of 2): Some kernel threads such as DAMON could need to repeatedly sleep in micro seconds level. Because usleep_range() sleeps in uninterruptible state, however, such threads would make /proc/loadavg reports fake load. To help such cases, this commit implements a variant of usleep_range() called usleep_idle_range(). It is same to usleep_range() but sets the state of the current task as TASK_IDLE while sleeping. Link: https://lkml.kernel.org/r/20211126145015.15862-1-sj@kernel.org Link: https://lkml.kernel.org/r/20211126145015.15862-2-sj@kernel.org Signed-off-by: SeongJae Park Suggested-by: Andrew Morton Reviewed-by: Thomas Gleixner Tested-by: Oleksandr Natalenko Cc: John Stultz Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

include/linux/delay.h: replace kernel.h with the necessary inclusions

2021-11-09T18:02:49+00:00

When kernel.h is used in the headers it adds a lot into dependency hell, especially when there are circular dependencies are involved. Replace kernel.h inclusion with the list of what is really being used. [akpm@linux-foundation.org: cxd2880_common.h needs bits.h for GENMASK()] [andriy.shevchenko@linux.intel.com: delay.h: fix for removed kernel.h] Link: https://lkml.kernel.org/r/20211028170143.56523-1-andriy.shevchenko@linux.intel.com [akpm@linux-foundation.org: include/linux/fwnode.h needs bits.h for BIT()] Link: https://lkml.kernel.org/r/20211027150324.79827-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

include/: replace HTTP links with HTTPS ones

2020-08-12T17:57:59+00:00

Rationale: Reduces attack surface on kernel devs opening the links for MITM as HTTPS traffic is much harder to manipulate. Signed-off-by: Alexander A. Klimov Signed-off-by: Andrew Morton Reviewed-by: Kees Cook Link: http://lkml.kernel.org/r/20200726110117.16346-1-grandmaster@al2klimov.de Signed-off-by: Linus Torvalds

timer: add fsleep for flexible sleeping

2020-05-07T00:03:34+00:00

Sleeping for a certain amount of time requires use of different functions, depending on the time period. Documentation/timers/timers-howto.rst explains when to use which function, and also checkpatch checks for some potentially problematic cases. So let's create a helper that automatically chooses the appropriate sleep function -> fsleep(), for flexible sleeping If the delay is a constant, then the compiler should be able to ensure that the new helper doesn't create overhead. If the delay is not constant, then the new helper can save some code. Signed-off-by: Heiner Kallweit Signed-off-by: David S. Miller

init/calibrate.c: provide proper prototype

2019-03-08T02:32:01+00:00

Sparse issues a warning: CHECK init/calibrate.c init/calibrate.c:271:28: warning: symbol 'calibration_delay_done' was not declared. Should it be static? The actual issue is that it's a __weak symbol that archs can override (in fact, ARM does so), but no prototype is provided. Let's provide one to prevent surprises. Link: http://lkml.kernel.org/r/18827.1548750938@turing-police.cc.vt.edu Signed-off-by: Valdis Kletnieks Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds