linux 内核中各delay函数的区别

via: https://www.kernel.org/doc/html/latest/timers/timers-howto.html

ATOMIC CONTEXT:

You must use the *delay family of functions.

NON-ATOMIC CONTEXT:

You should use the *sleep[_range] family of functions.

– Backed by busy-wait loop（< ~10us）:

udelay(unsigned long usecs)

– Backed by hrtimers（10us - 20ms）:

usleep_range(unsigned long min, unsigned long max)

– Backed by jiffies / legacy_timers（10ms+ ）：

msleep(unsigned long msecs) msleep_interruptible(unsigned long msecs)

Linux内核中的高精度时钟（HRTIMER，High Resolution Timers）

CONFIG_HIGH_RES_TIMERS，在Kconfig的General setup/Timers subsystem/High Resolution Timer Support中。