jiffies.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _LINUX_JIFFIES_H
  3#define _LINUX_JIFFIES_H
  4
  5#include <linux/cache.h>
  6#include <linux/limits.h>
  7#include <linux/math64.h>
  8#include <linux/minmax.h>
  9#include <linux/types.h>
 10#include <linux/time.h>
 11#include <linux/timex.h>
 12#include <vdso/jiffies.h>
 13#include <asm/param.h>			/* for HZ */
 14#include <generated/timeconst.h>
 15
 16/*
 17 * The following defines establish the engineering parameters of the PLL
 18 * model. The HZ variable establishes the timer interrupt frequency, 100 Hz
 19 * for the SunOS kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the
 20 * OSF/1 kernel. The SHIFT_HZ define expresses the same value as the
 21 * nearest power of two in order to avoid hardware multiply operations.
 22 */
 23#if HZ >= 12 && HZ < 24
 24# define SHIFT_HZ	4
 25#elif HZ >= 24 && HZ < 48
 26# define SHIFT_HZ	5
 27#elif HZ >= 48 && HZ < 96
 28# define SHIFT_HZ	6
 29#elif HZ >= 96 && HZ < 192
 30# define SHIFT_HZ	7
 31#elif HZ >= 192 && HZ < 384
 32# define SHIFT_HZ	8
 33#elif HZ >= 384 && HZ < 768
 34# define SHIFT_HZ	9
 35#elif HZ >= 768 && HZ < 1536
 36# define SHIFT_HZ	10
 37#elif HZ >= 1536 && HZ < 3072
 38# define SHIFT_HZ	11
 39#elif HZ >= 3072 && HZ < 6144
 40# define SHIFT_HZ	12
 41#elif HZ >= 6144 && HZ < 12288
 42# define SHIFT_HZ	13
 43#else
 44# error Invalid value of HZ.
 45#endif
 46
 47/* Suppose we want to divide two numbers NOM and DEN: NOM/DEN, then we can
 48 * improve accuracy by shifting LSH bits, hence calculating:
 49 *     (NOM << LSH) / DEN
 50 * This however means trouble for large NOM, because (NOM << LSH) may no
 51 * longer fit in 32 bits. The following way of calculating this gives us
 52 * some slack, under the following conditions:
 53 *   - (NOM / DEN) fits in (32 - LSH) bits.
 54 *   - (NOM % DEN) fits in (32 - LSH) bits.
 55 */
 56#define SH_DIV(NOM,DEN,LSH) (   (((NOM) / (DEN)) << (LSH))              \
 57                             + ((((NOM) % (DEN)) << (LSH)) + (DEN) / 2) / (DEN))
 58
 59/* LATCH is used in the interval timer and ftape setup. */
 60#define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ)	/* For divider */
 61
 62extern void register_refined_jiffies(long clock_tick_rate);
 63
 64/* TICK_USEC is the time between ticks in usec */
 65#define TICK_USEC ((USEC_PER_SEC + HZ/2) / HZ)
 66
 67/* USER_TICK_USEC is the time between ticks in usec assuming fake USER_HZ */
 68#define USER_TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ)
 69
 70#ifndef __jiffy_arch_data
 71#define __jiffy_arch_data
 72#endif
 73
 74/*
 75 * The 64-bit value is not atomic on 32-bit systems - you MUST NOT read it
 76 * without sampling the sequence number in jiffies_lock.
 77 * get_jiffies_64() will do this for you as appropriate.
 78 *
 79 * jiffies and jiffies_64 are at the same address for little-endian systems
 80 * and for 64-bit big-endian systems.
 81 * On 32-bit big-endian systems, jiffies is the lower 32 bits of jiffies_64
 82 * (i.e., at address @jiffies_64 + 4).
 83 * See arch/ARCH/kernel/vmlinux.lds.S
 84 */
 85extern u64 __cacheline_aligned_in_smp jiffies_64;
 86extern unsigned long volatile __cacheline_aligned_in_smp __jiffy_arch_data jiffies;
 87
 88#if (BITS_PER_LONG < 64)
 89u64 get_jiffies_64(void);
 90#else
 91/**
 92 * get_jiffies_64 - read the 64-bit non-atomic jiffies_64 value
 93 *
 94 * When BITS_PER_LONG < 64, this uses sequence number sampling using
 95 * jiffies_lock to protect the 64-bit read.
 96 *
 97 * Return: current 64-bit jiffies value
 98 */
 99static inline u64 get_jiffies_64(void)
100{
101	return (u64)jiffies;
102}
103#endif
104
105/**
106 * DOC: General information about time_* inlines
107 *
108 * These inlines deal with timer wrapping correctly. You are strongly encouraged
109 * to use them:
110 *
111 * #. Because people otherwise forget
112 * #. Because if the timer wrap changes in future you won't have to alter your
113 *    driver code.
114 */
115
116/**
117 * time_after - returns true if the time a is after time b.
118 * @a: first comparable as unsigned long
119 * @b: second comparable as unsigned long
120 *
121 * Do this with "<0" and ">=0" to only test the sign of the result. A
122 * good compiler would generate better code (and a really good compiler
123 * wouldn't care). Gcc is currently neither.
124 *
125 * Return: %true is time a is after time b, otherwise %false.
126 */
127#define time_after(a,b)		\
128	(typecheck(unsigned long, a) && \
129	 typecheck(unsigned long, b) && \
130	 ((long)((b) - (a)) < 0))
131/**
132 * time_before - returns true if the time a is before time b.
133 * @a: first comparable as unsigned long
134 * @b: second comparable as unsigned long
135 *
136 * Return: %true is time a is before time b, otherwise %false.
137 */
138#define time_before(a,b)	time_after(b,a)
139
140/**
141 * time_after_eq - returns true if the time a is after or the same as time b.
142 * @a: first comparable as unsigned long
143 * @b: second comparable as unsigned long
144 *
145 * Return: %true is time a is after or the same as time b, otherwise %false.
146 */
147#define time_after_eq(a,b)	\
148	(typecheck(unsigned long, a) && \
149	 typecheck(unsigned long, b) && \
150	 ((long)((a) - (b)) >= 0))
151/**
152 * time_before_eq - returns true if the time a is before or the same as time b.
153 * @a: first comparable as unsigned long
154 * @b: second comparable as unsigned long
155 *
156 * Return: %true is time a is before or the same as time b, otherwise %false.
157 */
158#define time_before_eq(a,b)	time_after_eq(b,a)
159
160/**
161 * time_in_range - Calculate whether a is in the range of [b, c].
162 * @a: time to test
163 * @b: beginning of the range
164 * @c: end of the range
165 *
166 * Return: %true is time a is in the range [b, c], otherwise %false.
167 */
168#define time_in_range(a,b,c) \
169	(time_after_eq(a,b) && \
170	 time_before_eq(a,c))
171
172/**
173 * time_in_range_open - Calculate whether a is in the range of [b, c).
174 * @a: time to test
175 * @b: beginning of the range
176 * @c: end of the range
177 *
178 * Return: %true is time a is in the range [b, c), otherwise %false.
179 */
180#define time_in_range_open(a,b,c) \
181	(time_after_eq(a,b) && \
182	 time_before(a,c))
183
184/* Same as above, but does so with platform independent 64bit types.
185 * These must be used when utilizing jiffies_64 (i.e. return value of
186 * get_jiffies_64()). */
187
188/**
189 * time_after64 - returns true if the time a is after time b.
190 * @a: first comparable as __u64
191 * @b: second comparable as __u64
192 *
193 * This must be used when utilizing jiffies_64 (i.e. return value of
194 * get_jiffies_64()).
195 *
196 * Return: %true is time a is after time b, otherwise %false.
197 */
198#define time_after64(a,b)	\
199	(typecheck(__u64, a) &&	\
200	 typecheck(__u64, b) && \
201	 ((__s64)((b) - (a)) < 0))
202/**
203 * time_before64 - returns true if the time a is before time b.
204 * @a: first comparable as __u64
205 * @b: second comparable as __u64
206 *
207 * This must be used when utilizing jiffies_64 (i.e. return value of
208 * get_jiffies_64()).
209 *
210 * Return: %true is time a is before time b, otherwise %false.
211 */
212#define time_before64(a,b)	time_after64(b,a)
213
214/**
215 * time_after_eq64 - returns true if the time a is after or the same as time b.
216 * @a: first comparable as __u64
217 * @b: second comparable as __u64
218 *
219 * This must be used when utilizing jiffies_64 (i.e. return value of
220 * get_jiffies_64()).
221 *
222 * Return: %true is time a is after or the same as time b, otherwise %false.
223 */
224#define time_after_eq64(a,b)	\
225	(typecheck(__u64, a) && \
226	 typecheck(__u64, b) && \
227	 ((__s64)((a) - (b)) >= 0))
228/**
229 * time_before_eq64 - returns true if the time a is before or the same as time b.
230 * @a: first comparable as __u64
231 * @b: second comparable as __u64
232 *
233 * This must be used when utilizing jiffies_64 (i.e. return value of
234 * get_jiffies_64()).
235 *
236 * Return: %true is time a is before or the same as time b, otherwise %false.
237 */
238#define time_before_eq64(a,b)	time_after_eq64(b,a)
239
240/**
241 * time_in_range64 - Calculate whether a is in the range of [b, c].
242 * @a: time to test
243 * @b: beginning of the range
244 * @c: end of the range
245 *
246 * Return: %true is time a is in the range [b, c], otherwise %false.
247 */
248#define time_in_range64(a, b, c) \
249	(time_after_eq64(a, b) && \
250	 time_before_eq64(a, c))
251
252/*
253 * These eight macros compare jiffies[_64] and 'a' for convenience.
254 */
255
256/**
257 * time_is_before_jiffies - return true if a is before jiffies
258 * @a: time (unsigned long) to compare to jiffies
259 *
260 * Return: %true is time a is before jiffies, otherwise %false.
261 */
262#define time_is_before_jiffies(a) time_after(jiffies, a)
263/**
264 * time_is_before_jiffies64 - return true if a is before jiffies_64
265 * @a: time (__u64) to compare to jiffies_64
266 *
267 * Return: %true is time a is before jiffies_64, otherwise %false.
268 */
269#define time_is_before_jiffies64(a) time_after64(get_jiffies_64(), a)
270
271/**
272 * time_is_after_jiffies - return true if a is after jiffies
273 * @a: time (unsigned long) to compare to jiffies
274 *
275 * Return: %true is time a is after jiffies, otherwise %false.
276 */
277#define time_is_after_jiffies(a) time_before(jiffies, a)
278/**
279 * time_is_after_jiffies64 - return true if a is after jiffies_64
280 * @a: time (__u64) to compare to jiffies_64
281 *
282 * Return: %true is time a is after jiffies_64, otherwise %false.
283 */
284#define time_is_after_jiffies64(a) time_before64(get_jiffies_64(), a)
285
286/**
287 * time_is_before_eq_jiffies - return true if a is before or equal to jiffies
288 * @a: time (unsigned long) to compare to jiffies
289 *
290 * Return: %true is time a is before or the same as jiffies, otherwise %false.
291 */
292#define time_is_before_eq_jiffies(a) time_after_eq(jiffies, a)
293/**
294 * time_is_before_eq_jiffies64 - return true if a is before or equal to jiffies_64
295 * @a: time (__u64) to compare to jiffies_64
296 *
297 * Return: %true is time a is before or the same jiffies_64, otherwise %false.
298 */
299#define time_is_before_eq_jiffies64(a) time_after_eq64(get_jiffies_64(), a)
300
301/**
302 * time_is_after_eq_jiffies - return true if a is after or equal to jiffies
303 * @a: time (unsigned long) to compare to jiffies
304 *
305 * Return: %true is time a is after or the same as jiffies, otherwise %false.
306 */
307#define time_is_after_eq_jiffies(a) time_before_eq(jiffies, a)
308/**
309 * time_is_after_eq_jiffies64 - return true if a is after or equal to jiffies_64
310 * @a: time (__u64) to compare to jiffies_64
311 *
312 * Return: %true is time a is after or the same as jiffies_64, otherwise %false.
313 */
314#define time_is_after_eq_jiffies64(a) time_before_eq64(get_jiffies_64(), a)
315
316/*
317 * Have the 32-bit jiffies value wrap 5 minutes after boot
318 * so jiffies wrap bugs show up earlier.
319 */
320#define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ))
321
322/*
323 * Change timeval to jiffies, trying to avoid the
324 * most obvious overflows..
325 *
326 * And some not so obvious.
327 *
328 * Note that we don't want to return LONG_MAX, because
329 * for various timeout reasons we often end up having
330 * to wait "jiffies+1" in order to guarantee that we wait
331 * at _least_ "jiffies" - so "jiffies+1" had better still
332 * be positive.
333 */
334#define MAX_JIFFY_OFFSET ((LONG_MAX >> 1)-1)
335
336extern unsigned long preset_lpj;
337
338/*
339 * We want to do realistic conversions of time so we need to use the same
340 * values the update wall clock code uses as the jiffies size.  This value
341 * is: TICK_NSEC (which is defined in timex.h).  This
342 * is a constant and is in nanoseconds.  We will use scaled math
343 * with a set of scales defined here as SEC_JIFFIE_SC,  USEC_JIFFIE_SC and
344 * NSEC_JIFFIE_SC.  Note that these defines contain nothing but
345 * constants and so are computed at compile time.  SHIFT_HZ (computed in
346 * timex.h) adjusts the scaling for different HZ values.
347
348 * Scaled math???  What is that?
349 *
350 * Scaled math is a way to do integer math on values that would,
351 * otherwise, either overflow, underflow, or cause undesired div
352 * instructions to appear in the execution path.  In short, we "scale"
353 * up the operands so they take more bits (more precision, less
354 * underflow), do the desired operation and then "scale" the result back
355 * by the same amount.  If we do the scaling by shifting we avoid the
356 * costly mpy and the dastardly div instructions.
357
358 * Suppose, for example, we want to convert from seconds to jiffies
359 * where jiffies is defined in nanoseconds as NSEC_PER_JIFFIE.  The
360 * simple math is: jiff = (sec * NSEC_PER_SEC) / NSEC_PER_JIFFIE; We
361 * observe that (NSEC_PER_SEC / NSEC_PER_JIFFIE) is a constant which we
362 * might calculate at compile time, however, the result will only have
363 * about 3-4 bits of precision (less for smaller values of HZ).
364 *
365 * So, we scale as follows:
366 * jiff = (sec) * (NSEC_PER_SEC / NSEC_PER_JIFFIE);
367 * jiff = ((sec) * ((NSEC_PER_SEC * SCALE)/ NSEC_PER_JIFFIE)) / SCALE;
368 * Then we make SCALE a power of two so:
369 * jiff = ((sec) * ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) >> SCALE;
370 * Now we define:
371 * #define SEC_CONV = ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE))
372 * jiff = (sec * SEC_CONV) >> SCALE;
373 *
374 * Often the math we use will expand beyond 32-bits so we tell C how to
375 * do this and pass the 64-bit result of the mpy through the ">> SCALE"
376 * which should take the result back to 32-bits.  We want this expansion
377 * to capture as much precision as possible.  At the same time we don't
378 * want to overflow so we pick the SCALE to avoid this.  In this file,
379 * that means using a different scale for each range of HZ values (as
380 * defined in timex.h).
381 *
382 * For those who want to know, gcc will give a 64-bit result from a "*"
383 * operator if the result is a long long AND at least one of the
384 * operands is cast to long long (usually just prior to the "*" so as
385 * not to confuse it into thinking it really has a 64-bit operand,
386 * which, buy the way, it can do, but it takes more code and at least 2
387 * mpys).
388
389 * We also need to be aware that one second in nanoseconds is only a
390 * couple of bits away from overflowing a 32-bit word, so we MUST use
391 * 64-bits to get the full range time in nanoseconds.
392
393 */
394
395/*
396 * Here are the scales we will use.  One for seconds, nanoseconds and
397 * microseconds.
398 *
399 * Within the limits of cpp we do a rough cut at the SEC_JIFFIE_SC and
400 * check if the sign bit is set.  If not, we bump the shift count by 1.
401 * (Gets an extra bit of precision where we can use it.)
402 * We know it is set for HZ = 1024 and HZ = 100 not for 1000.
403 * Haven't tested others.
404
405 * Limits of cpp (for #if expressions) only long (no long long), but
406 * then we only need the most signicant bit.
407 */
408
409#define SEC_JIFFIE_SC (31 - SHIFT_HZ)
410#if !((((NSEC_PER_SEC << 2) / TICK_NSEC) << (SEC_JIFFIE_SC - 2)) & 0x80000000)
411#undef SEC_JIFFIE_SC
412#define SEC_JIFFIE_SC (32 - SHIFT_HZ)
413#endif
414#define NSEC_JIFFIE_SC (SEC_JIFFIE_SC + 29)
415#define SEC_CONVERSION ((unsigned long)((((u64)NSEC_PER_SEC << SEC_JIFFIE_SC) +\
416                                TICK_NSEC -1) / (u64)TICK_NSEC))
417
418#define NSEC_CONVERSION ((unsigned long)((((u64)1 << NSEC_JIFFIE_SC) +\
419                                        TICK_NSEC -1) / (u64)TICK_NSEC))
420/*
421 * The maximum jiffy value is (MAX_INT >> 1).  Here we translate that
422 * into seconds.  The 64-bit case will overflow if we are not careful,
423 * so use the messy SH_DIV macro to do it.  Still all constants.
424 */
425#if BITS_PER_LONG < 64
426# define MAX_SEC_IN_JIFFIES \
427	(long)((u64)((u64)MAX_JIFFY_OFFSET * TICK_NSEC) / NSEC_PER_SEC)
428#else	/* take care of overflow on 64-bit machines */
429# define MAX_SEC_IN_JIFFIES \
430	(SH_DIV((MAX_JIFFY_OFFSET >> SEC_JIFFIE_SC) * TICK_NSEC, NSEC_PER_SEC, 1) - 1)
431
432#endif
433
434/*
435 * Convert various time units to each other:
436 */
437extern unsigned int jiffies_to_msecs(const unsigned long j);
438extern unsigned int jiffies_to_usecs(const unsigned long j);
439
440/**
441 * jiffies_to_nsecs - Convert jiffies to nanoseconds
442 * @j: jiffies value
443 *
444 * Return: nanoseconds value
445 */
446static inline u64 jiffies_to_nsecs(const unsigned long j)
447{
448	return (u64)jiffies_to_usecs(j) * NSEC_PER_USEC;
449}
450
451extern u64 jiffies64_to_nsecs(u64 j);
452extern u64 jiffies64_to_msecs(u64 j);
453
454extern unsigned long __msecs_to_jiffies(const unsigned int m);
455#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
456/*
457 * HZ is equal to or smaller than 1000, and 1000 is a nice round
458 * multiple of HZ, divide with the factor between them, but round
459 * upwards:
460 */
461static inline unsigned long _msecs_to_jiffies(const unsigned int m)
462{
463	return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ);
464}
465#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
466/*
467 * HZ is larger than 1000, and HZ is a nice round multiple of 1000 -
468 * simply multiply with the factor between them.
469 *
470 * But first make sure the multiplication result cannot overflow:
471 */
472static inline unsigned long _msecs_to_jiffies(const unsigned int m)
473{
474	if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
475		return MAX_JIFFY_OFFSET;
476	return m * (HZ / MSEC_PER_SEC);
477}
478#else
479/*
480 * Generic case - multiply, round and divide. But first check that if
481 * we are doing a net multiplication, that we wouldn't overflow:
482 */
483static inline unsigned long _msecs_to_jiffies(const unsigned int m)
484{
485	if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
486		return MAX_JIFFY_OFFSET;
487
488	return (MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32) >> MSEC_TO_HZ_SHR32;
489}
490#endif
491/**
492 * msecs_to_jiffies: - convert milliseconds to jiffies
493 * @m:	time in milliseconds
494 *
495 * conversion is done as follows:
496 *
497 * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)
498 *
499 * - 'too large' values [that would result in larger than
500 *   MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
501 *
502 * - all other values are converted to jiffies by either multiplying
503 *   the input value by a factor or dividing it with a factor and
504 *   handling any 32-bit overflows.
505 *   for the details see _msecs_to_jiffies()
506 *
507 * msecs_to_jiffies() checks for the passed in value being a constant
508 * via __builtin_constant_p() allowing gcc to eliminate most of the
509 * code. __msecs_to_jiffies() is called if the value passed does not
510 * allow constant folding and the actual conversion must be done at
511 * runtime.
512 * The HZ range specific helpers _msecs_to_jiffies() are called both
513 * directly here and from __msecs_to_jiffies() in the case where
514 * constant folding is not possible.
515 *
516 * Return: jiffies value
517 */
518static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)
519{
520	if (__builtin_constant_p(m)) {
521		if ((int)m < 0)
522			return MAX_JIFFY_OFFSET;
523		return _msecs_to_jiffies(m);
524	} else {
525		return __msecs_to_jiffies(m);
526	}
527}
528
529/**
530 * secs_to_jiffies: - convert seconds to jiffies
531 * @_secs: time in seconds
532 *
533 * Conversion is done by simple multiplication with HZ
534 *
535 * secs_to_jiffies() is defined as a macro rather than a static inline
536 * function so it can be used in static initializers.
537 *
538 * Return: jiffies value
539 */
540#define secs_to_jiffies(_secs) (unsigned long)((_secs) * HZ)
541
542extern unsigned long __usecs_to_jiffies(const unsigned int u);
543#if !(USEC_PER_SEC % HZ)
544static inline unsigned long _usecs_to_jiffies(const unsigned int u)
545{
546	return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ);
547}
548#else
549static inline unsigned long _usecs_to_jiffies(const unsigned int u)
550{
551	return (USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32)
552		>> USEC_TO_HZ_SHR32;
553}
554#endif
555
556/**
557 * usecs_to_jiffies: - convert microseconds to jiffies
558 * @u:	time in microseconds
559 *
560 * conversion is done as follows:
561 *
562 * - 'too large' values [that would result in larger than
563 *   MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
564 *
565 * - all other values are converted to jiffies by either multiplying
566 *   the input value by a factor or dividing it with a factor and
567 *   handling any 32-bit overflows as for msecs_to_jiffies.
568 *
569 * usecs_to_jiffies() checks for the passed in value being a constant
570 * via __builtin_constant_p() allowing gcc to eliminate most of the
571 * code. __usecs_to_jiffies() is called if the value passed does not
572 * allow constant folding and the actual conversion must be done at
573 * runtime.
574 * The HZ range specific helpers _usecs_to_jiffies() are called both
575 * directly here and from __msecs_to_jiffies() in the case where
576 * constant folding is not possible.
577 *
578 * Return: jiffies value
579 */
580static __always_inline unsigned long usecs_to_jiffies(const unsigned int u)
581{
582	if (__builtin_constant_p(u)) {
583		if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
584			return MAX_JIFFY_OFFSET;
585		return _usecs_to_jiffies(u);
586	} else {
587		return __usecs_to_jiffies(u);
588	}
589}
590
591extern unsigned long timespec64_to_jiffies(const struct timespec64 *value);
592extern void jiffies_to_timespec64(const unsigned long jiffies,
593				  struct timespec64 *value);
594extern clock_t jiffies_to_clock_t(unsigned long x);
595
596static inline clock_t jiffies_delta_to_clock_t(long delta)
597{
598	return jiffies_to_clock_t(max(0L, delta));
599}
600
601static inline unsigned int jiffies_delta_to_msecs(long delta)
602{
603	return jiffies_to_msecs(max(0L, delta));
604}
605
606extern unsigned long clock_t_to_jiffies(unsigned long x);
607extern u64 jiffies_64_to_clock_t(u64 x);
608extern u64 nsec_to_clock_t(u64 x);
609extern u64 nsecs_to_jiffies64(u64 n);
610extern unsigned long nsecs_to_jiffies(u64 n);
611
612#define TIMESTAMP_SIZE	30
613
614struct ctl_table;
615int proc_dointvec_jiffies(const struct ctl_table *table, int dir, void *buffer,
616			  size_t *lenp, loff_t *ppos);
617int proc_dointvec_ms_jiffies_minmax(const struct ctl_table *table, int dir,
618				    void *buffer, size_t *lenp, loff_t *ppos);
619int proc_dointvec_userhz_jiffies(const struct ctl_table *table, int dir,
620				 void *buffer, size_t *lenp, loff_t *ppos);
621int proc_dointvec_ms_jiffies(const struct ctl_table *table, int dir, void *buffer,
622			     size_t *lenp, loff_t *ppos);
623int proc_doulongvec_ms_jiffies_minmax(const struct ctl_table *table, int dir,
624				      void *buffer, size_t *lenp, loff_t *ppos);
625
626#endif