Messages in this thread Patch in this message | | | Subject | [PATCH net-next 1/2] timer: add fsleep for flexible sleeping | From | Heiner Kallweit <> | Date | Fri, 1 May 2020 23:27:21 +0200 |
| |
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 <hkallweit1@gmail.com> --- Documentation/timers/timers-howto.rst | 3 +++ include/linux/delay.h | 11 +++++++++++ 2 files changed, 14 insertions(+)
diff --git a/Documentation/timers/timers-howto.rst b/Documentation/timers/timers-howto.rst index 7e3167bec..afb0a43b8 100644 --- a/Documentation/timers/timers-howto.rst +++ b/Documentation/timers/timers-howto.rst @@ -110,3 +110,6 @@ NON-ATOMIC CONTEXT: short, the difference is whether the sleep can be ended early by a signal. In general, just use msleep unless you know you have a need for the interruptible variant. + + FLEXIBLE SLEEPING (any delay, uninterruptible) + * Use fsleep diff --git a/include/linux/delay.h b/include/linux/delay.h index 8e6828094..cb1d508ca 100644 --- a/include/linux/delay.h +++ b/include/linux/delay.h @@ -65,4 +65,15 @@ static inline void ssleep(unsigned int seconds) msleep(seconds * 1000); } +/* see Documentation/timers/timers-howto.rst for the thresholds */ +static inline void fsleep(unsigned long usecs) +{ + if (usecs <= 10) + udelay(usecs); + else if (usecs <= 20000) + usleep_range(usecs, 2 * usecs); + else + msleep(DIV_ROUND_UP(usecs, 1000)); +} + #endif /* defined(_LINUX_DELAY_H) */ -- 2.26.2
| |