cregit-Linux how code gets into the kernel

Release 4.12 include/linux/delay.h

Directory: include/linux
#ifndef _LINUX_DELAY_H

#define _LINUX_DELAY_H

 * Copyright (C) 1993 Linus Torvalds
 * Delay routines, using a pre-computed "loops_per_jiffy" value.
 * Please note that ndelay(), udelay() and mdelay() may return early for
 * several reasons:
 *  1. computed loops_per_jiffy too low (due to the time taken to
 *     execute the timer interrupt.)
 *  2. cache behaviour affecting the time it takes to execute the
 *     loop function.
 *  3. CPU clock rate changes.
 * Please see this thread:

#include <linux/kernel.h>

extern unsigned long loops_per_jiffy;

#include <asm/delay.h>

 * Using udelay() for intervals greater than a few milliseconds can
 * risk overflow for high loops_per_jiffy (high bogomips) machines. The
 * mdelay() provides a wrapper to prevent this.  For delays greater
 * than MAX_UDELAY_MS milliseconds, the wrapper is used.  Architecture
 * specific values can be defined in asm-???/delay.h as an override.
 * The 2nd mdelay() definition ensures GCC will optimize away the 
 * while loop for the common cases where n <= MAX_UDELAY_MS  --  Paul G.


#define MAX_UDELAY_MS	5

#ifndef mdelay

#define mdelay(n) (\
        (__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
        ({unsigned long __ms=(n); while (__ms--) udelay(1000);}))

#ifndef ndelay

static inline void ndelay(unsigned long x) { udelay(DIV_ROUND_UP(x, 1000)); }


Andrew Morton21100.00%1100.00%

#define ndelay(x) ndelay(x) #endif extern unsigned long lpj_fine; void calibrate_delay(void); void msleep(unsigned int msecs); unsigned long msleep_interruptible(unsigned int msecs); void usleep_range(unsigned long min, unsigned long max);
static inline void ssleep(unsigned int seconds) { msleep(seconds * 1000); }


Jeff Garzik18100.00%1100.00%

#endif /* defined(_LINUX_DELAY_H) */

Overall Contributors

Linus Torvalds (pre-git)3626.87%529.41%
Andrew Morton2518.66%15.88%
Jeff Garzik1813.43%15.88%
Patrick Pannuto128.96%15.88%
Linus Torvalds118.21%15.88%
Maximilian Attems96.72%15.88%
Greg Kroah-Hartman85.97%15.88%
David Howells64.48%15.88%
Alok N Kataria53.73%211.76%
Anton Blanchard21.49%15.88%
Benjamin Herrenschmidt10.75%15.88%
Russell King10.75%15.88%
Directory: include/linux
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.