Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/timer.c | |
3 | * | |
4a22f166 | 4 | * Kernel internal timers |
1da177e4 LT |
5 | * |
6 | * Copyright (C) 1991, 1992 Linus Torvalds | |
7 | * | |
8 | * 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better. | |
9 | * | |
10 | * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 | |
11 | * "A Kernel Model for Precision Timekeeping" by Dave Mills | |
12 | * 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to | |
13 | * serialize accesses to xtime/lost_ticks). | |
14 | * Copyright (C) 1998 Andrea Arcangeli | |
15 | * 1999-03-10 Improved NTP compatibility by Ulrich Windl | |
16 | * 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love | |
17 | * 2000-10-05 Implemented scalable SMP per-CPU timer handling. | |
18 | * Copyright (C) 2000, 2001, 2002 Ingo Molnar | |
19 | * Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar | |
20 | */ | |
21 | ||
22 | #include <linux/kernel_stat.h> | |
9984de1a | 23 | #include <linux/export.h> |
1da177e4 LT |
24 | #include <linux/interrupt.h> |
25 | #include <linux/percpu.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/mm.h> | |
28 | #include <linux/swap.h> | |
b488893a | 29 | #include <linux/pid_namespace.h> |
1da177e4 LT |
30 | #include <linux/notifier.h> |
31 | #include <linux/thread_info.h> | |
32 | #include <linux/time.h> | |
33 | #include <linux/jiffies.h> | |
34 | #include <linux/posix-timers.h> | |
35 | #include <linux/cpu.h> | |
36 | #include <linux/syscalls.h> | |
97a41e26 | 37 | #include <linux/delay.h> |
79bf2bb3 | 38 | #include <linux/tick.h> |
82f67cd9 | 39 | #include <linux/kallsyms.h> |
e360adbe | 40 | #include <linux/irq_work.h> |
174cd4b1 | 41 | #include <linux/sched/signal.h> |
cf4aebc2 | 42 | #include <linux/sched/sysctl.h> |
370c9135 | 43 | #include <linux/sched/nohz.h> |
b17b0153 | 44 | #include <linux/sched/debug.h> |
5a0e3ad6 | 45 | #include <linux/slab.h> |
1a0df594 | 46 | #include <linux/compat.h> |
1da177e4 | 47 | |
7c0f6ba6 | 48 | #include <linux/uaccess.h> |
1da177e4 LT |
49 | #include <asm/unistd.h> |
50 | #include <asm/div64.h> | |
51 | #include <asm/timex.h> | |
52 | #include <asm/io.h> | |
53 | ||
c1ad348b TG |
54 | #include "tick-internal.h" |
55 | ||
2b022e3d XG |
56 | #define CREATE_TRACE_POINTS |
57 | #include <trace/events/timer.h> | |
58 | ||
40747ffa | 59 | __visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; |
ecea8d19 TG |
60 | |
61 | EXPORT_SYMBOL(jiffies_64); | |
62 | ||
1da177e4 | 63 | /* |
500462a9 TG |
64 | * The timer wheel has LVL_DEPTH array levels. Each level provides an array of |
65 | * LVL_SIZE buckets. Each level is driven by its own clock and therefor each | |
66 | * level has a different granularity. | |
67 | * | |
68 | * The level granularity is: LVL_CLK_DIV ^ lvl | |
69 | * The level clock frequency is: HZ / (LVL_CLK_DIV ^ level) | |
70 | * | |
71 | * The array level of a newly armed timer depends on the relative expiry | |
72 | * time. The farther the expiry time is away the higher the array level and | |
73 | * therefor the granularity becomes. | |
74 | * | |
75 | * Contrary to the original timer wheel implementation, which aims for 'exact' | |
76 | * expiry of the timers, this implementation removes the need for recascading | |
77 | * the timers into the lower array levels. The previous 'classic' timer wheel | |
78 | * implementation of the kernel already violated the 'exact' expiry by adding | |
79 | * slack to the expiry time to provide batched expiration. The granularity | |
80 | * levels provide implicit batching. | |
81 | * | |
82 | * This is an optimization of the original timer wheel implementation for the | |
83 | * majority of the timer wheel use cases: timeouts. The vast majority of | |
84 | * timeout timers (networking, disk I/O ...) are canceled before expiry. If | |
85 | * the timeout expires it indicates that normal operation is disturbed, so it | |
86 | * does not matter much whether the timeout comes with a slight delay. | |
87 | * | |
88 | * The only exception to this are networking timers with a small expiry | |
89 | * time. They rely on the granularity. Those fit into the first wheel level, | |
90 | * which has HZ granularity. | |
91 | * | |
92 | * We don't have cascading anymore. timers with a expiry time above the | |
93 | * capacity of the last wheel level are force expired at the maximum timeout | |
94 | * value of the last wheel level. From data sampling we know that the maximum | |
95 | * value observed is 5 days (network connection tracking), so this should not | |
96 | * be an issue. | |
97 | * | |
98 | * The currently chosen array constants values are a good compromise between | |
99 | * array size and granularity. | |
100 | * | |
101 | * This results in the following granularity and range levels: | |
102 | * | |
103 | * HZ 1000 steps | |
104 | * Level Offset Granularity Range | |
105 | * 0 0 1 ms 0 ms - 63 ms | |
106 | * 1 64 8 ms 64 ms - 511 ms | |
107 | * 2 128 64 ms 512 ms - 4095 ms (512ms - ~4s) | |
108 | * 3 192 512 ms 4096 ms - 32767 ms (~4s - ~32s) | |
109 | * 4 256 4096 ms (~4s) 32768 ms - 262143 ms (~32s - ~4m) | |
110 | * 5 320 32768 ms (~32s) 262144 ms - 2097151 ms (~4m - ~34m) | |
111 | * 6 384 262144 ms (~4m) 2097152 ms - 16777215 ms (~34m - ~4h) | |
112 | * 7 448 2097152 ms (~34m) 16777216 ms - 134217727 ms (~4h - ~1d) | |
113 | * 8 512 16777216 ms (~4h) 134217728 ms - 1073741822 ms (~1d - ~12d) | |
114 | * | |
115 | * HZ 300 | |
116 | * Level Offset Granularity Range | |
117 | * 0 0 3 ms 0 ms - 210 ms | |
118 | * 1 64 26 ms 213 ms - 1703 ms (213ms - ~1s) | |
119 | * 2 128 213 ms 1706 ms - 13650 ms (~1s - ~13s) | |
120 | * 3 192 1706 ms (~1s) 13653 ms - 109223 ms (~13s - ~1m) | |
121 | * 4 256 13653 ms (~13s) 109226 ms - 873810 ms (~1m - ~14m) | |
122 | * 5 320 109226 ms (~1m) 873813 ms - 6990503 ms (~14m - ~1h) | |
123 | * 6 384 873813 ms (~14m) 6990506 ms - 55924050 ms (~1h - ~15h) | |
124 | * 7 448 6990506 ms (~1h) 55924053 ms - 447392423 ms (~15h - ~5d) | |
125 | * 8 512 55924053 ms (~15h) 447392426 ms - 3579139406 ms (~5d - ~41d) | |
126 | * | |
127 | * HZ 250 | |
128 | * Level Offset Granularity Range | |
129 | * 0 0 4 ms 0 ms - 255 ms | |
130 | * 1 64 32 ms 256 ms - 2047 ms (256ms - ~2s) | |
131 | * 2 128 256 ms 2048 ms - 16383 ms (~2s - ~16s) | |
132 | * 3 192 2048 ms (~2s) 16384 ms - 131071 ms (~16s - ~2m) | |
133 | * 4 256 16384 ms (~16s) 131072 ms - 1048575 ms (~2m - ~17m) | |
134 | * 5 320 131072 ms (~2m) 1048576 ms - 8388607 ms (~17m - ~2h) | |
135 | * 6 384 1048576 ms (~17m) 8388608 ms - 67108863 ms (~2h - ~18h) | |
136 | * 7 448 8388608 ms (~2h) 67108864 ms - 536870911 ms (~18h - ~6d) | |
137 | * 8 512 67108864 ms (~18h) 536870912 ms - 4294967288 ms (~6d - ~49d) | |
138 | * | |
139 | * HZ 100 | |
140 | * Level Offset Granularity Range | |
141 | * 0 0 10 ms 0 ms - 630 ms | |
142 | * 1 64 80 ms 640 ms - 5110 ms (640ms - ~5s) | |
143 | * 2 128 640 ms 5120 ms - 40950 ms (~5s - ~40s) | |
144 | * 3 192 5120 ms (~5s) 40960 ms - 327670 ms (~40s - ~5m) | |
145 | * 4 256 40960 ms (~40s) 327680 ms - 2621430 ms (~5m - ~43m) | |
146 | * 5 320 327680 ms (~5m) 2621440 ms - 20971510 ms (~43m - ~5h) | |
147 | * 6 384 2621440 ms (~43m) 20971520 ms - 167772150 ms (~5h - ~1d) | |
148 | * 7 448 20971520 ms (~5h) 167772160 ms - 1342177270 ms (~1d - ~15d) | |
1da177e4 | 149 | */ |
1da177e4 | 150 | |
500462a9 TG |
151 | /* Clock divisor for the next level */ |
152 | #define LVL_CLK_SHIFT 3 | |
153 | #define LVL_CLK_DIV (1UL << LVL_CLK_SHIFT) | |
154 | #define LVL_CLK_MASK (LVL_CLK_DIV - 1) | |
155 | #define LVL_SHIFT(n) ((n) * LVL_CLK_SHIFT) | |
156 | #define LVL_GRAN(n) (1UL << LVL_SHIFT(n)) | |
1da177e4 | 157 | |
500462a9 TG |
158 | /* |
159 | * The time start value for each level to select the bucket at enqueue | |
160 | * time. | |
161 | */ | |
162 | #define LVL_START(n) ((LVL_SIZE - 1) << (((n) - 1) * LVL_CLK_SHIFT)) | |
163 | ||
164 | /* Size of each clock level */ | |
165 | #define LVL_BITS 6 | |
166 | #define LVL_SIZE (1UL << LVL_BITS) | |
167 | #define LVL_MASK (LVL_SIZE - 1) | |
168 | #define LVL_OFFS(n) ((n) * LVL_SIZE) | |
169 | ||
170 | /* Level depth */ | |
171 | #if HZ > 100 | |
172 | # define LVL_DEPTH 9 | |
173 | # else | |
174 | # define LVL_DEPTH 8 | |
175 | #endif | |
176 | ||
177 | /* The cutoff (max. capacity of the wheel) */ | |
178 | #define WHEEL_TIMEOUT_CUTOFF (LVL_START(LVL_DEPTH)) | |
179 | #define WHEEL_TIMEOUT_MAX (WHEEL_TIMEOUT_CUTOFF - LVL_GRAN(LVL_DEPTH - 1)) | |
180 | ||
181 | /* | |
182 | * The resulting wheel size. If NOHZ is configured we allocate two | |
183 | * wheels so we have a separate storage for the deferrable timers. | |
184 | */ | |
185 | #define WHEEL_SIZE (LVL_SIZE * LVL_DEPTH) | |
186 | ||
187 | #ifdef CONFIG_NO_HZ_COMMON | |
188 | # define NR_BASES 2 | |
189 | # define BASE_STD 0 | |
190 | # define BASE_DEF 1 | |
191 | #else | |
192 | # define NR_BASES 1 | |
193 | # define BASE_STD 0 | |
194 | # define BASE_DEF 0 | |
195 | #endif | |
1da177e4 | 196 | |
494af3ed | 197 | struct timer_base { |
2287d866 | 198 | raw_spinlock_t lock; |
500462a9 TG |
199 | struct timer_list *running_timer; |
200 | unsigned long clk; | |
a683f390 | 201 | unsigned long next_expiry; |
500462a9 TG |
202 | unsigned int cpu; |
203 | bool migration_enabled; | |
204 | bool nohz_active; | |
a683f390 | 205 | bool is_idle; |
2fe59f50 | 206 | bool must_forward_clk; |
500462a9 TG |
207 | DECLARE_BITMAP(pending_map, WHEEL_SIZE); |
208 | struct hlist_head vectors[WHEEL_SIZE]; | |
6e453a67 | 209 | } ____cacheline_aligned; |
e52b1db3 | 210 | |
500462a9 | 211 | static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]); |
6e453a67 | 212 | |
bc7a34b8 TG |
213 | #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON) |
214 | unsigned int sysctl_timer_migration = 1; | |
215 | ||
683be13a | 216 | void timers_update_migration(bool update_nohz) |
bc7a34b8 TG |
217 | { |
218 | bool on = sysctl_timer_migration && tick_nohz_active; | |
219 | unsigned int cpu; | |
220 | ||
221 | /* Avoid the loop, if nothing to update */ | |
500462a9 | 222 | if (this_cpu_read(timer_bases[BASE_STD].migration_enabled) == on) |
bc7a34b8 TG |
223 | return; |
224 | ||
225 | for_each_possible_cpu(cpu) { | |
500462a9 TG |
226 | per_cpu(timer_bases[BASE_STD].migration_enabled, cpu) = on; |
227 | per_cpu(timer_bases[BASE_DEF].migration_enabled, cpu) = on; | |
bc7a34b8 | 228 | per_cpu(hrtimer_bases.migration_enabled, cpu) = on; |
683be13a TG |
229 | if (!update_nohz) |
230 | continue; | |
500462a9 TG |
231 | per_cpu(timer_bases[BASE_STD].nohz_active, cpu) = true; |
232 | per_cpu(timer_bases[BASE_DEF].nohz_active, cpu) = true; | |
683be13a | 233 | per_cpu(hrtimer_bases.nohz_active, cpu) = true; |
bc7a34b8 TG |
234 | } |
235 | } | |
236 | ||
237 | int timer_migration_handler(struct ctl_table *table, int write, | |
238 | void __user *buffer, size_t *lenp, | |
239 | loff_t *ppos) | |
240 | { | |
241 | static DEFINE_MUTEX(mutex); | |
242 | int ret; | |
243 | ||
244 | mutex_lock(&mutex); | |
b94bf594 | 245 | ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
bc7a34b8 | 246 | if (!ret && write) |
683be13a | 247 | timers_update_migration(false); |
bc7a34b8 TG |
248 | mutex_unlock(&mutex); |
249 | return ret; | |
250 | } | |
bc7a34b8 TG |
251 | #endif |
252 | ||
9c133c46 AS |
253 | static unsigned long round_jiffies_common(unsigned long j, int cpu, |
254 | bool force_up) | |
4c36a5de AV |
255 | { |
256 | int rem; | |
257 | unsigned long original = j; | |
258 | ||
259 | /* | |
260 | * We don't want all cpus firing their timers at once hitting the | |
261 | * same lock or cachelines, so we skew each extra cpu with an extra | |
262 | * 3 jiffies. This 3 jiffies came originally from the mm/ code which | |
263 | * already did this. | |
264 | * The skew is done by adding 3*cpunr, then round, then subtract this | |
265 | * extra offset again. | |
266 | */ | |
267 | j += cpu * 3; | |
268 | ||
269 | rem = j % HZ; | |
270 | ||
271 | /* | |
272 | * If the target jiffie is just after a whole second (which can happen | |
273 | * due to delays of the timer irq, long irq off times etc etc) then | |
274 | * we should round down to the whole second, not up. Use 1/4th second | |
275 | * as cutoff for this rounding as an extreme upper bound for this. | |
9c133c46 | 276 | * But never round down if @force_up is set. |
4c36a5de | 277 | */ |
9c133c46 | 278 | if (rem < HZ/4 && !force_up) /* round down */ |
4c36a5de AV |
279 | j = j - rem; |
280 | else /* round up */ | |
281 | j = j - rem + HZ; | |
282 | ||
283 | /* now that we have rounded, subtract the extra skew again */ | |
284 | j -= cpu * 3; | |
285 | ||
9e04d380 BVA |
286 | /* |
287 | * Make sure j is still in the future. Otherwise return the | |
288 | * unmodified value. | |
289 | */ | |
290 | return time_is_after_jiffies(j) ? j : original; | |
4c36a5de | 291 | } |
9c133c46 AS |
292 | |
293 | /** | |
294 | * __round_jiffies - function to round jiffies to a full second | |
295 | * @j: the time in (absolute) jiffies that should be rounded | |
296 | * @cpu: the processor number on which the timeout will happen | |
297 | * | |
298 | * __round_jiffies() rounds an absolute time in the future (in jiffies) | |
299 | * up or down to (approximately) full seconds. This is useful for timers | |
300 | * for which the exact time they fire does not matter too much, as long as | |
301 | * they fire approximately every X seconds. | |
302 | * | |
303 | * By rounding these timers to whole seconds, all such timers will fire | |
304 | * at the same time, rather than at various times spread out. The goal | |
305 | * of this is to have the CPU wake up less, which saves power. | |
306 | * | |
307 | * The exact rounding is skewed for each processor to avoid all | |
308 | * processors firing at the exact same time, which could lead | |
309 | * to lock contention or spurious cache line bouncing. | |
310 | * | |
311 | * The return value is the rounded version of the @j parameter. | |
312 | */ | |
313 | unsigned long __round_jiffies(unsigned long j, int cpu) | |
314 | { | |
315 | return round_jiffies_common(j, cpu, false); | |
316 | } | |
4c36a5de AV |
317 | EXPORT_SYMBOL_GPL(__round_jiffies); |
318 | ||
319 | /** | |
320 | * __round_jiffies_relative - function to round jiffies to a full second | |
321 | * @j: the time in (relative) jiffies that should be rounded | |
322 | * @cpu: the processor number on which the timeout will happen | |
323 | * | |
72fd4a35 | 324 | * __round_jiffies_relative() rounds a time delta in the future (in jiffies) |
4c36a5de AV |
325 | * up or down to (approximately) full seconds. This is useful for timers |
326 | * for which the exact time they fire does not matter too much, as long as | |
327 | * they fire approximately every X seconds. | |
328 | * | |
329 | * By rounding these timers to whole seconds, all such timers will fire | |
330 | * at the same time, rather than at various times spread out. The goal | |
331 | * of this is to have the CPU wake up less, which saves power. | |
332 | * | |
333 | * The exact rounding is skewed for each processor to avoid all | |
334 | * processors firing at the exact same time, which could lead | |
335 | * to lock contention or spurious cache line bouncing. | |
336 | * | |
72fd4a35 | 337 | * The return value is the rounded version of the @j parameter. |
4c36a5de AV |
338 | */ |
339 | unsigned long __round_jiffies_relative(unsigned long j, int cpu) | |
340 | { | |
9c133c46 AS |
341 | unsigned long j0 = jiffies; |
342 | ||
343 | /* Use j0 because jiffies might change while we run */ | |
344 | return round_jiffies_common(j + j0, cpu, false) - j0; | |
4c36a5de AV |
345 | } |
346 | EXPORT_SYMBOL_GPL(__round_jiffies_relative); | |
347 | ||
348 | /** | |
349 | * round_jiffies - function to round jiffies to a full second | |
350 | * @j: the time in (absolute) jiffies that should be rounded | |
351 | * | |
72fd4a35 | 352 | * round_jiffies() rounds an absolute time in the future (in jiffies) |
4c36a5de AV |
353 | * up or down to (approximately) full seconds. This is useful for timers |
354 | * for which the exact time they fire does not matter too much, as long as | |
355 | * they fire approximately every X seconds. | |
356 | * | |
357 | * By rounding these timers to whole seconds, all such timers will fire | |
358 | * at the same time, rather than at various times spread out. The goal | |
359 | * of this is to have the CPU wake up less, which saves power. | |
360 | * | |
72fd4a35 | 361 | * The return value is the rounded version of the @j parameter. |
4c36a5de AV |
362 | */ |
363 | unsigned long round_jiffies(unsigned long j) | |
364 | { | |
9c133c46 | 365 | return round_jiffies_common(j, raw_smp_processor_id(), false); |
4c36a5de AV |
366 | } |
367 | EXPORT_SYMBOL_GPL(round_jiffies); | |
368 | ||
369 | /** | |
370 | * round_jiffies_relative - function to round jiffies to a full second | |
371 | * @j: the time in (relative) jiffies that should be rounded | |
372 | * | |
72fd4a35 | 373 | * round_jiffies_relative() rounds a time delta in the future (in jiffies) |
4c36a5de AV |
374 | * up or down to (approximately) full seconds. This is useful for timers |
375 | * for which the exact time they fire does not matter too much, as long as | |
376 | * they fire approximately every X seconds. | |
377 | * | |
378 | * By rounding these timers to whole seconds, all such timers will fire | |
379 | * at the same time, rather than at various times spread out. The goal | |
380 | * of this is to have the CPU wake up less, which saves power. | |
381 | * | |
72fd4a35 | 382 | * The return value is the rounded version of the @j parameter. |
4c36a5de AV |
383 | */ |
384 | unsigned long round_jiffies_relative(unsigned long j) | |
385 | { | |
386 | return __round_jiffies_relative(j, raw_smp_processor_id()); | |
387 | } | |
388 | EXPORT_SYMBOL_GPL(round_jiffies_relative); | |
389 | ||
9c133c46 AS |
390 | /** |
391 | * __round_jiffies_up - function to round jiffies up to a full second | |
392 | * @j: the time in (absolute) jiffies that should be rounded | |
393 | * @cpu: the processor number on which the timeout will happen | |
394 | * | |
395 | * This is the same as __round_jiffies() except that it will never | |
396 | * round down. This is useful for timeouts for which the exact time | |
397 | * of firing does not matter too much, as long as they don't fire too | |
398 | * early. | |
399 | */ | |
400 | unsigned long __round_jiffies_up(unsigned long j, int cpu) | |
401 | { | |
402 | return round_jiffies_common(j, cpu, true); | |
403 | } | |
404 | EXPORT_SYMBOL_GPL(__round_jiffies_up); | |
405 | ||
406 | /** | |
407 | * __round_jiffies_up_relative - function to round jiffies up to a full second | |
408 | * @j: the time in (relative) jiffies that should be rounded | |
409 | * @cpu: the processor number on which the timeout will happen | |
410 | * | |
411 | * This is the same as __round_jiffies_relative() except that it will never | |
412 | * round down. This is useful for timeouts for which the exact time | |
413 | * of firing does not matter too much, as long as they don't fire too | |
414 | * early. | |
415 | */ | |
416 | unsigned long __round_jiffies_up_relative(unsigned long j, int cpu) | |
417 | { | |
418 | unsigned long j0 = jiffies; | |
419 | ||
420 | /* Use j0 because jiffies might change while we run */ | |
421 | return round_jiffies_common(j + j0, cpu, true) - j0; | |
422 | } | |
423 | EXPORT_SYMBOL_GPL(__round_jiffies_up_relative); | |
424 | ||
425 | /** | |
426 | * round_jiffies_up - function to round jiffies up to a full second | |
427 | * @j: the time in (absolute) jiffies that should be rounded | |
428 | * | |
429 | * This is the same as round_jiffies() except that it will never | |
430 | * round down. This is useful for timeouts for which the exact time | |
431 | * of firing does not matter too much, as long as they don't fire too | |
432 | * early. | |
433 | */ | |
434 | unsigned long round_jiffies_up(unsigned long j) | |
435 | { | |
436 | return round_jiffies_common(j, raw_smp_processor_id(), true); | |
437 | } | |
438 | EXPORT_SYMBOL_GPL(round_jiffies_up); | |
439 | ||
440 | /** | |
441 | * round_jiffies_up_relative - function to round jiffies up to a full second | |
442 | * @j: the time in (relative) jiffies that should be rounded | |
443 | * | |
444 | * This is the same as round_jiffies_relative() except that it will never | |
445 | * round down. This is useful for timeouts for which the exact time | |
446 | * of firing does not matter too much, as long as they don't fire too | |
447 | * early. | |
448 | */ | |
449 | unsigned long round_jiffies_up_relative(unsigned long j) | |
450 | { | |
451 | return __round_jiffies_up_relative(j, raw_smp_processor_id()); | |
452 | } | |
453 | EXPORT_SYMBOL_GPL(round_jiffies_up_relative); | |
454 | ||
3bbb9ec9 | 455 | |
500462a9 | 456 | static inline unsigned int timer_get_idx(struct timer_list *timer) |
3bbb9ec9 | 457 | { |
500462a9 | 458 | return (timer->flags & TIMER_ARRAYMASK) >> TIMER_ARRAYSHIFT; |
3bbb9ec9 | 459 | } |
3bbb9ec9 | 460 | |
500462a9 | 461 | static inline void timer_set_idx(struct timer_list *timer, unsigned int idx) |
1da177e4 | 462 | { |
500462a9 TG |
463 | timer->flags = (timer->flags & ~TIMER_ARRAYMASK) | |
464 | idx << TIMER_ARRAYSHIFT; | |
465 | } | |
1da177e4 | 466 | |
500462a9 TG |
467 | /* |
468 | * Helper function to calculate the array index for a given expiry | |
469 | * time. | |
470 | */ | |
471 | static inline unsigned calc_index(unsigned expires, unsigned lvl) | |
472 | { | |
473 | expires = (expires + LVL_GRAN(lvl)) >> LVL_SHIFT(lvl); | |
474 | return LVL_OFFS(lvl) + (expires & LVL_MASK); | |
475 | } | |
476 | ||
ffdf0477 | 477 | static int calc_wheel_index(unsigned long expires, unsigned long clk) |
1da177e4 | 478 | { |
ffdf0477 | 479 | unsigned long delta = expires - clk; |
500462a9 TG |
480 | unsigned int idx; |
481 | ||
482 | if (delta < LVL_START(1)) { | |
483 | idx = calc_index(expires, 0); | |
484 | } else if (delta < LVL_START(2)) { | |
485 | idx = calc_index(expires, 1); | |
486 | } else if (delta < LVL_START(3)) { | |
487 | idx = calc_index(expires, 2); | |
488 | } else if (delta < LVL_START(4)) { | |
489 | idx = calc_index(expires, 3); | |
490 | } else if (delta < LVL_START(5)) { | |
491 | idx = calc_index(expires, 4); | |
492 | } else if (delta < LVL_START(6)) { | |
493 | idx = calc_index(expires, 5); | |
494 | } else if (delta < LVL_START(7)) { | |
495 | idx = calc_index(expires, 6); | |
496 | } else if (LVL_DEPTH > 8 && delta < LVL_START(8)) { | |
497 | idx = calc_index(expires, 7); | |
498 | } else if ((long) delta < 0) { | |
ffdf0477 | 499 | idx = clk & LVL_MASK; |
1da177e4 | 500 | } else { |
500462a9 TG |
501 | /* |
502 | * Force expire obscene large timeouts to expire at the | |
503 | * capacity limit of the wheel. | |
1da177e4 | 504 | */ |
500462a9 TG |
505 | if (expires >= WHEEL_TIMEOUT_CUTOFF) |
506 | expires = WHEEL_TIMEOUT_MAX; | |
1bd04bf6 | 507 | |
500462a9 | 508 | idx = calc_index(expires, LVL_DEPTH - 1); |
1da177e4 | 509 | } |
ffdf0477 AMG |
510 | return idx; |
511 | } | |
1bd04bf6 | 512 | |
ffdf0477 AMG |
513 | /* |
514 | * Enqueue the timer into the hash bucket, mark it pending in | |
515 | * the bitmap and store the index in the timer flags. | |
516 | */ | |
517 | static void enqueue_timer(struct timer_base *base, struct timer_list *timer, | |
518 | unsigned int idx) | |
519 | { | |
520 | hlist_add_head(&timer->entry, base->vectors + idx); | |
500462a9 TG |
521 | __set_bit(idx, base->pending_map); |
522 | timer_set_idx(timer, idx); | |
1da177e4 LT |
523 | } |
524 | ||
ffdf0477 AMG |
525 | static void |
526 | __internal_add_timer(struct timer_base *base, struct timer_list *timer) | |
facbb4a7 | 527 | { |
ffdf0477 AMG |
528 | unsigned int idx; |
529 | ||
530 | idx = calc_wheel_index(timer->expires, base->clk); | |
531 | enqueue_timer(base, timer, idx); | |
532 | } | |
9f6d9baa | 533 | |
ffdf0477 AMG |
534 | static void |
535 | trigger_dyntick_cpu(struct timer_base *base, struct timer_list *timer) | |
536 | { | |
a683f390 TG |
537 | if (!IS_ENABLED(CONFIG_NO_HZ_COMMON) || !base->nohz_active) |
538 | return; | |
3bb475a3 | 539 | |
facbb4a7 | 540 | /* |
a683f390 TG |
541 | * TODO: This wants some optimizing similar to the code below, but we |
542 | * will do that when we switch from push to pull for deferrable timers. | |
facbb4a7 | 543 | */ |
a683f390 TG |
544 | if (timer->flags & TIMER_DEFERRABLE) { |
545 | if (tick_nohz_full_cpu(base->cpu)) | |
683be13a | 546 | wake_up_nohz_cpu(base->cpu); |
a683f390 | 547 | return; |
99d5f3aa | 548 | } |
9f6d9baa VK |
549 | |
550 | /* | |
a683f390 TG |
551 | * We might have to IPI the remote CPU if the base is idle and the |
552 | * timer is not deferrable. If the other CPU is on the way to idle | |
553 | * then it can't set base->is_idle as we hold the base lock: | |
9f6d9baa | 554 | */ |
a683f390 TG |
555 | if (!base->is_idle) |
556 | return; | |
557 | ||
558 | /* Check whether this is the new first expiring timer: */ | |
559 | if (time_after_eq(timer->expires, base->next_expiry)) | |
560 | return; | |
561 | ||
562 | /* | |
563 | * Set the next expiry time and kick the CPU so it can reevaluate the | |
564 | * wheel: | |
565 | */ | |
566 | base->next_expiry = timer->expires; | |
ffdf0477 AMG |
567 | wake_up_nohz_cpu(base->cpu); |
568 | } | |
569 | ||
570 | static void | |
571 | internal_add_timer(struct timer_base *base, struct timer_list *timer) | |
572 | { | |
573 | __internal_add_timer(base, timer); | |
574 | trigger_dyntick_cpu(base, timer); | |
facbb4a7 TG |
575 | } |
576 | ||
c6f3a97f TG |
577 | #ifdef CONFIG_DEBUG_OBJECTS_TIMERS |
578 | ||
579 | static struct debug_obj_descr timer_debug_descr; | |
580 | ||
99777288 SG |
581 | static void *timer_debug_hint(void *addr) |
582 | { | |
583 | return ((struct timer_list *) addr)->function; | |
584 | } | |
585 | ||
b9fdac7f DC |
586 | static bool timer_is_static_object(void *addr) |
587 | { | |
588 | struct timer_list *timer = addr; | |
589 | ||
590 | return (timer->entry.pprev == NULL && | |
591 | timer->entry.next == TIMER_ENTRY_STATIC); | |
592 | } | |
593 | ||
c6f3a97f TG |
594 | /* |
595 | * fixup_init is called when: | |
596 | * - an active object is initialized | |
55c888d6 | 597 | */ |
e3252464 | 598 | static bool timer_fixup_init(void *addr, enum debug_obj_state state) |
c6f3a97f TG |
599 | { |
600 | struct timer_list *timer = addr; | |
601 | ||
602 | switch (state) { | |
603 | case ODEBUG_STATE_ACTIVE: | |
604 | del_timer_sync(timer); | |
605 | debug_object_init(timer, &timer_debug_descr); | |
e3252464 | 606 | return true; |
c6f3a97f | 607 | default: |
e3252464 | 608 | return false; |
c6f3a97f TG |
609 | } |
610 | } | |
611 | ||
fb16b8cf | 612 | /* Stub timer callback for improperly used timers. */ |
ba16490e | 613 | static void stub_timer(struct timer_list *unused) |
fb16b8cf SB |
614 | { |
615 | WARN_ON(1); | |
616 | } | |
617 | ||
c6f3a97f TG |
618 | /* |
619 | * fixup_activate is called when: | |
620 | * - an active object is activated | |
b9fdac7f | 621 | * - an unknown non-static object is activated |
c6f3a97f | 622 | */ |
e3252464 | 623 | static bool timer_fixup_activate(void *addr, enum debug_obj_state state) |
c6f3a97f TG |
624 | { |
625 | struct timer_list *timer = addr; | |
626 | ||
627 | switch (state) { | |
c6f3a97f | 628 | case ODEBUG_STATE_NOTAVAILABLE: |
ba16490e | 629 | timer_setup(timer, stub_timer, 0); |
b9fdac7f | 630 | return true; |
c6f3a97f TG |
631 | |
632 | case ODEBUG_STATE_ACTIVE: | |
633 | WARN_ON(1); | |
634 | ||
635 | default: | |
e3252464 | 636 | return false; |
c6f3a97f TG |
637 | } |
638 | } | |
639 | ||
640 | /* | |
641 | * fixup_free is called when: | |
642 | * - an active object is freed | |
643 | */ | |
e3252464 | 644 | static bool timer_fixup_free(void *addr, enum debug_obj_state state) |
c6f3a97f TG |
645 | { |
646 | struct timer_list *timer = addr; | |
647 | ||
648 | switch (state) { | |
649 | case ODEBUG_STATE_ACTIVE: | |
650 | del_timer_sync(timer); | |
651 | debug_object_free(timer, &timer_debug_descr); | |
e3252464 | 652 | return true; |
c6f3a97f | 653 | default: |
e3252464 | 654 | return false; |
c6f3a97f TG |
655 | } |
656 | } | |
657 | ||
dc4218bd CC |
658 | /* |
659 | * fixup_assert_init is called when: | |
660 | * - an untracked/uninit-ed object is found | |
661 | */ | |
e3252464 | 662 | static bool timer_fixup_assert_init(void *addr, enum debug_obj_state state) |
dc4218bd CC |
663 | { |
664 | struct timer_list *timer = addr; | |
665 | ||
666 | switch (state) { | |
667 | case ODEBUG_STATE_NOTAVAILABLE: | |
ba16490e | 668 | timer_setup(timer, stub_timer, 0); |
b9fdac7f | 669 | return true; |
dc4218bd | 670 | default: |
e3252464 | 671 | return false; |
dc4218bd CC |
672 | } |
673 | } | |
674 | ||
c6f3a97f | 675 | static struct debug_obj_descr timer_debug_descr = { |
dc4218bd CC |
676 | .name = "timer_list", |
677 | .debug_hint = timer_debug_hint, | |
b9fdac7f | 678 | .is_static_object = timer_is_static_object, |
dc4218bd CC |
679 | .fixup_init = timer_fixup_init, |
680 | .fixup_activate = timer_fixup_activate, | |
681 | .fixup_free = timer_fixup_free, | |
682 | .fixup_assert_init = timer_fixup_assert_init, | |
c6f3a97f TG |
683 | }; |
684 | ||
685 | static inline void debug_timer_init(struct timer_list *timer) | |
686 | { | |
687 | debug_object_init(timer, &timer_debug_descr); | |
688 | } | |
689 | ||
690 | static inline void debug_timer_activate(struct timer_list *timer) | |
691 | { | |
692 | debug_object_activate(timer, &timer_debug_descr); | |
693 | } | |
694 | ||
695 | static inline void debug_timer_deactivate(struct timer_list *timer) | |
696 | { | |
697 | debug_object_deactivate(timer, &timer_debug_descr); | |
698 | } | |
699 | ||
700 | static inline void debug_timer_free(struct timer_list *timer) | |
701 | { | |
702 | debug_object_free(timer, &timer_debug_descr); | |
703 | } | |
704 | ||
dc4218bd CC |
705 | static inline void debug_timer_assert_init(struct timer_list *timer) |
706 | { | |
707 | debug_object_assert_init(timer, &timer_debug_descr); | |
708 | } | |
709 | ||
fc683995 TH |
710 | static void do_init_timer(struct timer_list *timer, unsigned int flags, |
711 | const char *name, struct lock_class_key *key); | |
c6f3a97f | 712 | |
fc683995 TH |
713 | void init_timer_on_stack_key(struct timer_list *timer, unsigned int flags, |
714 | const char *name, struct lock_class_key *key) | |
c6f3a97f TG |
715 | { |
716 | debug_object_init_on_stack(timer, &timer_debug_descr); | |
fc683995 | 717 | do_init_timer(timer, flags, name, key); |
c6f3a97f | 718 | } |
6f2b9b9a | 719 | EXPORT_SYMBOL_GPL(init_timer_on_stack_key); |
c6f3a97f TG |
720 | |
721 | void destroy_timer_on_stack(struct timer_list *timer) | |
722 | { | |
723 | debug_object_free(timer, &timer_debug_descr); | |
724 | } | |
725 | EXPORT_SYMBOL_GPL(destroy_timer_on_stack); | |
726 | ||
727 | #else | |
728 | static inline void debug_timer_init(struct timer_list *timer) { } | |
729 | static inline void debug_timer_activate(struct timer_list *timer) { } | |
730 | static inline void debug_timer_deactivate(struct timer_list *timer) { } | |
dc4218bd | 731 | static inline void debug_timer_assert_init(struct timer_list *timer) { } |
c6f3a97f TG |
732 | #endif |
733 | ||
2b022e3d XG |
734 | static inline void debug_init(struct timer_list *timer) |
735 | { | |
736 | debug_timer_init(timer); | |
737 | trace_timer_init(timer); | |
738 | } | |
739 | ||
740 | static inline void | |
741 | debug_activate(struct timer_list *timer, unsigned long expires) | |
742 | { | |
743 | debug_timer_activate(timer); | |
0eeda71b | 744 | trace_timer_start(timer, expires, timer->flags); |
2b022e3d XG |
745 | } |
746 | ||
747 | static inline void debug_deactivate(struct timer_list *timer) | |
748 | { | |
749 | debug_timer_deactivate(timer); | |
750 | trace_timer_cancel(timer); | |
751 | } | |
752 | ||
dc4218bd CC |
753 | static inline void debug_assert_init(struct timer_list *timer) |
754 | { | |
755 | debug_timer_assert_init(timer); | |
756 | } | |
757 | ||
fc683995 TH |
758 | static void do_init_timer(struct timer_list *timer, unsigned int flags, |
759 | const char *name, struct lock_class_key *key) | |
55c888d6 | 760 | { |
1dabbcec | 761 | timer->entry.pprev = NULL; |
0eeda71b | 762 | timer->flags = flags | raw_smp_processor_id(); |
6f2b9b9a | 763 | lockdep_init_map(&timer->lockdep_map, name, key, 0); |
55c888d6 | 764 | } |
c6f3a97f TG |
765 | |
766 | /** | |
633fe795 | 767 | * init_timer_key - initialize a timer |
c6f3a97f | 768 | * @timer: the timer to be initialized |
fc683995 | 769 | * @flags: timer flags |
633fe795 RD |
770 | * @name: name of the timer |
771 | * @key: lockdep class key of the fake lock used for tracking timer | |
772 | * sync lock dependencies | |
c6f3a97f | 773 | * |
633fe795 | 774 | * init_timer_key() must be done to a timer prior calling *any* of the |
c6f3a97f TG |
775 | * other timer functions. |
776 | */ | |
fc683995 TH |
777 | void init_timer_key(struct timer_list *timer, unsigned int flags, |
778 | const char *name, struct lock_class_key *key) | |
c6f3a97f | 779 | { |
2b022e3d | 780 | debug_init(timer); |
fc683995 | 781 | do_init_timer(timer, flags, name, key); |
c6f3a97f | 782 | } |
6f2b9b9a | 783 | EXPORT_SYMBOL(init_timer_key); |
55c888d6 | 784 | |
ec44bc7a | 785 | static inline void detach_timer(struct timer_list *timer, bool clear_pending) |
55c888d6 | 786 | { |
1dabbcec | 787 | struct hlist_node *entry = &timer->entry; |
55c888d6 | 788 | |
2b022e3d | 789 | debug_deactivate(timer); |
c6f3a97f | 790 | |
1dabbcec | 791 | __hlist_del(entry); |
55c888d6 | 792 | if (clear_pending) |
1dabbcec TG |
793 | entry->pprev = NULL; |
794 | entry->next = LIST_POISON2; | |
55c888d6 ON |
795 | } |
796 | ||
494af3ed | 797 | static int detach_if_pending(struct timer_list *timer, struct timer_base *base, |
ec44bc7a TG |
798 | bool clear_pending) |
799 | { | |
500462a9 TG |
800 | unsigned idx = timer_get_idx(timer); |
801 | ||
ec44bc7a TG |
802 | if (!timer_pending(timer)) |
803 | return 0; | |
804 | ||
500462a9 TG |
805 | if (hlist_is_singular_node(&timer->entry, base->vectors + idx)) |
806 | __clear_bit(idx, base->pending_map); | |
807 | ||
ec44bc7a | 808 | detach_timer(timer, clear_pending); |
ec44bc7a TG |
809 | return 1; |
810 | } | |
811 | ||
500462a9 TG |
812 | static inline struct timer_base *get_timer_cpu_base(u32 tflags, u32 cpu) |
813 | { | |
814 | struct timer_base *base = per_cpu_ptr(&timer_bases[BASE_STD], cpu); | |
815 | ||
816 | /* | |
817 | * If the timer is deferrable and nohz is active then we need to use | |
818 | * the deferrable base. | |
819 | */ | |
820 | if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active && | |
821 | (tflags & TIMER_DEFERRABLE)) | |
822 | base = per_cpu_ptr(&timer_bases[BASE_DEF], cpu); | |
823 | return base; | |
824 | } | |
825 | ||
826 | static inline struct timer_base *get_timer_this_cpu_base(u32 tflags) | |
827 | { | |
828 | struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); | |
829 | ||
830 | /* | |
831 | * If the timer is deferrable and nohz is active then we need to use | |
832 | * the deferrable base. | |
833 | */ | |
834 | if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active && | |
835 | (tflags & TIMER_DEFERRABLE)) | |
836 | base = this_cpu_ptr(&timer_bases[BASE_DEF]); | |
837 | return base; | |
838 | } | |
839 | ||
840 | static inline struct timer_base *get_timer_base(u32 tflags) | |
841 | { | |
842 | return get_timer_cpu_base(tflags, tflags & TIMER_CPUMASK); | |
843 | } | |
844 | ||
a683f390 TG |
845 | #ifdef CONFIG_NO_HZ_COMMON |
846 | static inline struct timer_base * | |
6bad6bcc | 847 | get_target_base(struct timer_base *base, unsigned tflags) |
500462a9 | 848 | { |
a683f390 | 849 | #ifdef CONFIG_SMP |
500462a9 TG |
850 | if ((tflags & TIMER_PINNED) || !base->migration_enabled) |
851 | return get_timer_this_cpu_base(tflags); | |
852 | return get_timer_cpu_base(tflags, get_nohz_timer_target()); | |
853 | #else | |
854 | return get_timer_this_cpu_base(tflags); | |
855 | #endif | |
856 | } | |
857 | ||
a683f390 TG |
858 | static inline void forward_timer_base(struct timer_base *base) |
859 | { | |
2fe59f50 | 860 | unsigned long jnow; |
6bad6bcc | 861 | |
a683f390 | 862 | /* |
2fe59f50 NP |
863 | * We only forward the base when we are idle or have just come out of |
864 | * idle (must_forward_clk logic), and have a delta between base clock | |
865 | * and jiffies. In the common case, run_timers will take care of it. | |
a683f390 | 866 | */ |
2fe59f50 NP |
867 | if (likely(!base->must_forward_clk)) |
868 | return; | |
869 | ||
870 | jnow = READ_ONCE(jiffies); | |
871 | base->must_forward_clk = base->is_idle; | |
872 | if ((long)(jnow - base->clk) < 2) | |
a683f390 TG |
873 | return; |
874 | ||
875 | /* | |
876 | * If the next expiry value is > jiffies, then we fast forward to | |
877 | * jiffies otherwise we forward to the next expiry value. | |
878 | */ | |
6bad6bcc TG |
879 | if (time_after(base->next_expiry, jnow)) |
880 | base->clk = jnow; | |
a683f390 TG |
881 | else |
882 | base->clk = base->next_expiry; | |
883 | } | |
884 | #else | |
885 | static inline struct timer_base * | |
6bad6bcc | 886 | get_target_base(struct timer_base *base, unsigned tflags) |
a683f390 TG |
887 | { |
888 | return get_timer_this_cpu_base(tflags); | |
889 | } | |
890 | ||
891 | static inline void forward_timer_base(struct timer_base *base) { } | |
892 | #endif | |
893 | ||
a683f390 | 894 | |
55c888d6 | 895 | /* |
500462a9 TG |
896 | * We are using hashed locking: Holding per_cpu(timer_bases[x]).lock means |
897 | * that all timers which are tied to this base are locked, and the base itself | |
898 | * is locked too. | |
55c888d6 ON |
899 | * |
900 | * So __run_timers/migrate_timers can safely modify all timers which could | |
500462a9 | 901 | * be found in the base->vectors array. |
55c888d6 | 902 | * |
500462a9 TG |
903 | * When a timer is migrating then the TIMER_MIGRATING flag is set and we need |
904 | * to wait until the migration is done. | |
55c888d6 | 905 | */ |
494af3ed | 906 | static struct timer_base *lock_timer_base(struct timer_list *timer, |
500462a9 | 907 | unsigned long *flags) |
89e7e374 | 908 | __acquires(timer->base->lock) |
55c888d6 | 909 | { |
55c888d6 | 910 | for (;;) { |
494af3ed | 911 | struct timer_base *base; |
b831275a TG |
912 | u32 tf; |
913 | ||
914 | /* | |
915 | * We need to use READ_ONCE() here, otherwise the compiler | |
916 | * might re-read @tf between the check for TIMER_MIGRATING | |
917 | * and spin_lock(). | |
918 | */ | |
919 | tf = READ_ONCE(timer->flags); | |
0eeda71b TG |
920 | |
921 | if (!(tf & TIMER_MIGRATING)) { | |
500462a9 | 922 | base = get_timer_base(tf); |
2287d866 | 923 | raw_spin_lock_irqsave(&base->lock, *flags); |
0eeda71b | 924 | if (timer->flags == tf) |
55c888d6 | 925 | return base; |
2287d866 | 926 | raw_spin_unlock_irqrestore(&base->lock, *flags); |
55c888d6 ON |
927 | } |
928 | cpu_relax(); | |
929 | } | |
930 | } | |
931 | ||
b24591e2 DH |
932 | #define MOD_TIMER_PENDING_ONLY 0x01 |
933 | #define MOD_TIMER_REDUCE 0x02 | |
934 | ||
74019224 | 935 | static inline int |
b24591e2 | 936 | __mod_timer(struct timer_list *timer, unsigned long expires, unsigned int options) |
1da177e4 | 937 | { |
494af3ed | 938 | struct timer_base *base, *new_base; |
f00c0afd AMG |
939 | unsigned int idx = UINT_MAX; |
940 | unsigned long clk = 0, flags; | |
bc7a34b8 | 941 | int ret = 0; |
1da177e4 | 942 | |
4da9152a TG |
943 | BUG_ON(!timer->function); |
944 | ||
500462a9 | 945 | /* |
f00c0afd AMG |
946 | * This is a common optimization triggered by the networking code - if |
947 | * the timer is re-modified to have the same timeout or ends up in the | |
948 | * same array bucket then just return: | |
500462a9 TG |
949 | */ |
950 | if (timer_pending(timer)) { | |
2fe59f50 NP |
951 | /* |
952 | * The downside of this optimization is that it can result in | |
953 | * larger granularity than you would get from adding a new | |
954 | * timer with this expiry. | |
955 | */ | |
b24591e2 DH |
956 | long diff = timer->expires - expires; |
957 | ||
958 | if (!diff) | |
959 | return 1; | |
960 | if (options & MOD_TIMER_REDUCE && diff <= 0) | |
500462a9 | 961 | return 1; |
4da9152a | 962 | |
f00c0afd | 963 | /* |
4da9152a TG |
964 | * We lock timer base and calculate the bucket index right |
965 | * here. If the timer ends up in the same bucket, then we | |
966 | * just update the expiry time and avoid the whole | |
967 | * dequeue/enqueue dance. | |
f00c0afd | 968 | */ |
4da9152a | 969 | base = lock_timer_base(timer, &flags); |
2fe59f50 | 970 | forward_timer_base(base); |
f00c0afd | 971 | |
b24591e2 DH |
972 | if (timer_pending(timer) && (options & MOD_TIMER_REDUCE) && |
973 | time_before_eq(timer->expires, expires)) { | |
974 | ret = 1; | |
975 | goto out_unlock; | |
976 | } | |
977 | ||
4da9152a | 978 | clk = base->clk; |
f00c0afd AMG |
979 | idx = calc_wheel_index(expires, clk); |
980 | ||
981 | /* | |
982 | * Retrieve and compare the array index of the pending | |
983 | * timer. If it matches set the expiry to the new value so a | |
984 | * subsequent call will exit in the expires check above. | |
985 | */ | |
986 | if (idx == timer_get_idx(timer)) { | |
b24591e2 DH |
987 | if (!(options & MOD_TIMER_REDUCE)) |
988 | timer->expires = expires; | |
989 | else if (time_after(timer->expires, expires)) | |
990 | timer->expires = expires; | |
4da9152a TG |
991 | ret = 1; |
992 | goto out_unlock; | |
f00c0afd | 993 | } |
4da9152a TG |
994 | } else { |
995 | base = lock_timer_base(timer, &flags); | |
2fe59f50 | 996 | forward_timer_base(base); |
500462a9 TG |
997 | } |
998 | ||
ec44bc7a | 999 | ret = detach_if_pending(timer, base, false); |
b24591e2 | 1000 | if (!ret && (options & MOD_TIMER_PENDING_ONLY)) |
ec44bc7a | 1001 | goto out_unlock; |
55c888d6 | 1002 | |
2b022e3d | 1003 | debug_activate(timer, expires); |
c6f3a97f | 1004 | |
500462a9 | 1005 | new_base = get_target_base(base, timer->flags); |
eea08f32 | 1006 | |
3691c519 | 1007 | if (base != new_base) { |
1da177e4 | 1008 | /* |
500462a9 | 1009 | * We are trying to schedule the timer on the new base. |
55c888d6 ON |
1010 | * However we can't change timer's base while it is running, |
1011 | * otherwise del_timer_sync() can't detect that the timer's | |
500462a9 TG |
1012 | * handler yet has not finished. This also guarantees that the |
1013 | * timer is serialized wrt itself. | |
1da177e4 | 1014 | */ |
a2c348fe | 1015 | if (likely(base->running_timer != timer)) { |
55c888d6 | 1016 | /* See the comment in lock_timer_base() */ |
0eeda71b TG |
1017 | timer->flags |= TIMER_MIGRATING; |
1018 | ||
2287d866 | 1019 | raw_spin_unlock(&base->lock); |
a2c348fe | 1020 | base = new_base; |
2287d866 | 1021 | raw_spin_lock(&base->lock); |
d0023a14 ED |
1022 | WRITE_ONCE(timer->flags, |
1023 | (timer->flags & ~TIMER_BASEMASK) | base->cpu); | |
2fe59f50 | 1024 | forward_timer_base(base); |
1da177e4 LT |
1025 | } |
1026 | } | |
1027 | ||
1da177e4 | 1028 | timer->expires = expires; |
f00c0afd AMG |
1029 | /* |
1030 | * If 'idx' was calculated above and the base time did not advance | |
4da9152a TG |
1031 | * between calculating 'idx' and possibly switching the base, only |
1032 | * enqueue_timer() and trigger_dyntick_cpu() is required. Otherwise | |
1033 | * we need to (re)calculate the wheel index via | |
1034 | * internal_add_timer(). | |
f00c0afd AMG |
1035 | */ |
1036 | if (idx != UINT_MAX && clk == base->clk) { | |
1037 | enqueue_timer(base, timer, idx); | |
1038 | trigger_dyntick_cpu(base, timer); | |
1039 | } else { | |
1040 | internal_add_timer(base, timer); | |
1041 | } | |
74019224 IM |
1042 | |
1043 | out_unlock: | |
2287d866 | 1044 | raw_spin_unlock_irqrestore(&base->lock, flags); |
1da177e4 LT |
1045 | |
1046 | return ret; | |
1047 | } | |
1048 | ||
2aae4a10 | 1049 | /** |
74019224 IM |
1050 | * mod_timer_pending - modify a pending timer's timeout |
1051 | * @timer: the pending timer to be modified | |
1052 | * @expires: new timeout in jiffies | |
1da177e4 | 1053 | * |
74019224 IM |
1054 | * mod_timer_pending() is the same for pending timers as mod_timer(), |
1055 | * but will not re-activate and modify already deleted timers. | |
1056 | * | |
1057 | * It is useful for unserialized use of timers. | |
1da177e4 | 1058 | */ |
74019224 | 1059 | int mod_timer_pending(struct timer_list *timer, unsigned long expires) |
1da177e4 | 1060 | { |
b24591e2 | 1061 | return __mod_timer(timer, expires, MOD_TIMER_PENDING_ONLY); |
1da177e4 | 1062 | } |
74019224 | 1063 | EXPORT_SYMBOL(mod_timer_pending); |
1da177e4 | 1064 | |
2aae4a10 | 1065 | /** |
1da177e4 LT |
1066 | * mod_timer - modify a timer's timeout |
1067 | * @timer: the timer to be modified | |
2aae4a10 | 1068 | * @expires: new timeout in jiffies |
1da177e4 | 1069 | * |
72fd4a35 | 1070 | * mod_timer() is a more efficient way to update the expire field of an |
1da177e4 LT |
1071 | * active timer (if the timer is inactive it will be activated) |
1072 | * | |
1073 | * mod_timer(timer, expires) is equivalent to: | |
1074 | * | |
1075 | * del_timer(timer); timer->expires = expires; add_timer(timer); | |
1076 | * | |
1077 | * Note that if there are multiple unserialized concurrent users of the | |
1078 | * same timer, then mod_timer() is the only safe way to modify the timeout, | |
1079 | * since add_timer() cannot modify an already running timer. | |
1080 | * | |
1081 | * The function returns whether it has modified a pending timer or not. | |
1082 | * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an | |
1083 | * active timer returns 1.) | |
1084 | */ | |
1085 | int mod_timer(struct timer_list *timer, unsigned long expires) | |
1086 | { | |
b24591e2 | 1087 | return __mod_timer(timer, expires, 0); |
1da177e4 | 1088 | } |
1da177e4 LT |
1089 | EXPORT_SYMBOL(mod_timer); |
1090 | ||
b24591e2 DH |
1091 | /** |
1092 | * timer_reduce - Modify a timer's timeout if it would reduce the timeout | |
1093 | * @timer: The timer to be modified | |
1094 | * @expires: New timeout in jiffies | |
1095 | * | |
1096 | * timer_reduce() is very similar to mod_timer(), except that it will only | |
1097 | * modify a running timer if that would reduce the expiration time (it will | |
1098 | * start a timer that isn't running). | |
1099 | */ | |
1100 | int timer_reduce(struct timer_list *timer, unsigned long expires) | |
1101 | { | |
1102 | return __mod_timer(timer, expires, MOD_TIMER_REDUCE); | |
1103 | } | |
1104 | EXPORT_SYMBOL(timer_reduce); | |
1105 | ||
74019224 IM |
1106 | /** |
1107 | * add_timer - start a timer | |
1108 | * @timer: the timer to be added | |
1109 | * | |
1110 | * The kernel will do a ->function(->data) callback from the | |
1111 | * timer interrupt at the ->expires point in the future. The | |
1112 | * current time is 'jiffies'. | |
1113 | * | |
1114 | * The timer's ->expires, ->function (and if the handler uses it, ->data) | |
1115 | * fields must be set prior calling this function. | |
1116 | * | |
1117 | * Timers with an ->expires field in the past will be executed in the next | |
1118 | * timer tick. | |
1119 | */ | |
1120 | void add_timer(struct timer_list *timer) | |
1121 | { | |
1122 | BUG_ON(timer_pending(timer)); | |
1123 | mod_timer(timer, timer->expires); | |
1124 | } | |
1125 | EXPORT_SYMBOL(add_timer); | |
1126 | ||
1127 | /** | |
1128 | * add_timer_on - start a timer on a particular CPU | |
1129 | * @timer: the timer to be added | |
1130 | * @cpu: the CPU to start it on | |
1131 | * | |
1132 | * This is not very scalable on SMP. Double adds are not possible. | |
1133 | */ | |
1134 | void add_timer_on(struct timer_list *timer, int cpu) | |
1135 | { | |
500462a9 | 1136 | struct timer_base *new_base, *base; |
74019224 IM |
1137 | unsigned long flags; |
1138 | ||
74019224 | 1139 | BUG_ON(timer_pending(timer) || !timer->function); |
22b886dd | 1140 | |
500462a9 TG |
1141 | new_base = get_timer_cpu_base(timer->flags, cpu); |
1142 | ||
22b886dd TH |
1143 | /* |
1144 | * If @timer was on a different CPU, it should be migrated with the | |
1145 | * old base locked to prevent other operations proceeding with the | |
1146 | * wrong base locked. See lock_timer_base(). | |
1147 | */ | |
1148 | base = lock_timer_base(timer, &flags); | |
1149 | if (base != new_base) { | |
1150 | timer->flags |= TIMER_MIGRATING; | |
1151 | ||
2287d866 | 1152 | raw_spin_unlock(&base->lock); |
22b886dd | 1153 | base = new_base; |
2287d866 | 1154 | raw_spin_lock(&base->lock); |
22b886dd TH |
1155 | WRITE_ONCE(timer->flags, |
1156 | (timer->flags & ~TIMER_BASEMASK) | cpu); | |
1157 | } | |
2fe59f50 | 1158 | forward_timer_base(base); |
22b886dd | 1159 | |
2b022e3d | 1160 | debug_activate(timer, timer->expires); |
74019224 | 1161 | internal_add_timer(base, timer); |
2287d866 | 1162 | raw_spin_unlock_irqrestore(&base->lock, flags); |
74019224 | 1163 | } |
a9862e05 | 1164 | EXPORT_SYMBOL_GPL(add_timer_on); |
74019224 | 1165 | |
2aae4a10 | 1166 | /** |
0ba42a59 | 1167 | * del_timer - deactivate a timer. |
1da177e4 LT |
1168 | * @timer: the timer to be deactivated |
1169 | * | |
1170 | * del_timer() deactivates a timer - this works on both active and inactive | |
1171 | * timers. | |
1172 | * | |
1173 | * The function returns whether it has deactivated a pending timer or not. | |
1174 | * (ie. del_timer() of an inactive timer returns 0, del_timer() of an | |
1175 | * active timer returns 1.) | |
1176 | */ | |
1177 | int del_timer(struct timer_list *timer) | |
1178 | { | |
494af3ed | 1179 | struct timer_base *base; |
1da177e4 | 1180 | unsigned long flags; |
55c888d6 | 1181 | int ret = 0; |
1da177e4 | 1182 | |
dc4218bd CC |
1183 | debug_assert_init(timer); |
1184 | ||
55c888d6 ON |
1185 | if (timer_pending(timer)) { |
1186 | base = lock_timer_base(timer, &flags); | |
ec44bc7a | 1187 | ret = detach_if_pending(timer, base, true); |
2287d866 | 1188 | raw_spin_unlock_irqrestore(&base->lock, flags); |
1da177e4 | 1189 | } |
1da177e4 | 1190 | |
55c888d6 | 1191 | return ret; |
1da177e4 | 1192 | } |
1da177e4 LT |
1193 | EXPORT_SYMBOL(del_timer); |
1194 | ||
2aae4a10 REB |
1195 | /** |
1196 | * try_to_del_timer_sync - Try to deactivate a timer | |
d15bc69a | 1197 | * @timer: timer to delete |
2aae4a10 | 1198 | * |
fd450b73 ON |
1199 | * This function tries to deactivate a timer. Upon successful (ret >= 0) |
1200 | * exit the timer is not queued and the handler is not running on any CPU. | |
fd450b73 ON |
1201 | */ |
1202 | int try_to_del_timer_sync(struct timer_list *timer) | |
1203 | { | |
494af3ed | 1204 | struct timer_base *base; |
fd450b73 ON |
1205 | unsigned long flags; |
1206 | int ret = -1; | |
1207 | ||
dc4218bd CC |
1208 | debug_assert_init(timer); |
1209 | ||
fd450b73 ON |
1210 | base = lock_timer_base(timer, &flags); |
1211 | ||
dfb4357d | 1212 | if (base->running_timer != timer) |
ec44bc7a | 1213 | ret = detach_if_pending(timer, base, true); |
dfb4357d | 1214 | |
2287d866 | 1215 | raw_spin_unlock_irqrestore(&base->lock, flags); |
fd450b73 ON |
1216 | |
1217 | return ret; | |
1218 | } | |
e19dff1f DH |
1219 | EXPORT_SYMBOL(try_to_del_timer_sync); |
1220 | ||
6f1bc451 | 1221 | #ifdef CONFIG_SMP |
2aae4a10 | 1222 | /** |
1da177e4 LT |
1223 | * del_timer_sync - deactivate a timer and wait for the handler to finish. |
1224 | * @timer: the timer to be deactivated | |
1225 | * | |
1226 | * This function only differs from del_timer() on SMP: besides deactivating | |
1227 | * the timer it also makes sure the handler has finished executing on other | |
1228 | * CPUs. | |
1229 | * | |
72fd4a35 | 1230 | * Synchronization rules: Callers must prevent restarting of the timer, |
1da177e4 | 1231 | * otherwise this function is meaningless. It must not be called from |
c5f66e99 TH |
1232 | * interrupt contexts unless the timer is an irqsafe one. The caller must |
1233 | * not hold locks which would prevent completion of the timer's | |
1234 | * handler. The timer's handler must not call add_timer_on(). Upon exit the | |
1235 | * timer is not queued and the handler is not running on any CPU. | |
1da177e4 | 1236 | * |
c5f66e99 TH |
1237 | * Note: For !irqsafe timers, you must not hold locks that are held in |
1238 | * interrupt context while calling this function. Even if the lock has | |
1239 | * nothing to do with the timer in question. Here's why: | |
48228f7b SR |
1240 | * |
1241 | * CPU0 CPU1 | |
1242 | * ---- ---- | |
1243 | * <SOFTIRQ> | |
1244 | * call_timer_fn(); | |
1245 | * base->running_timer = mytimer; | |
1246 | * spin_lock_irq(somelock); | |
1247 | * <IRQ> | |
1248 | * spin_lock(somelock); | |
1249 | * del_timer_sync(mytimer); | |
1250 | * while (base->running_timer == mytimer); | |
1251 | * | |
1252 | * Now del_timer_sync() will never return and never release somelock. | |
1253 | * The interrupt on the other CPU is waiting to grab somelock but | |
1254 | * it has interrupted the softirq that CPU0 is waiting to finish. | |
1255 | * | |
1da177e4 | 1256 | * The function returns whether it has deactivated a pending timer or not. |
1da177e4 LT |
1257 | */ |
1258 | int del_timer_sync(struct timer_list *timer) | |
1259 | { | |
6f2b9b9a | 1260 | #ifdef CONFIG_LOCKDEP |
f266a511 PZ |
1261 | unsigned long flags; |
1262 | ||
48228f7b SR |
1263 | /* |
1264 | * If lockdep gives a backtrace here, please reference | |
1265 | * the synchronization rules above. | |
1266 | */ | |
7ff20792 | 1267 | local_irq_save(flags); |
6f2b9b9a JB |
1268 | lock_map_acquire(&timer->lockdep_map); |
1269 | lock_map_release(&timer->lockdep_map); | |
7ff20792 | 1270 | local_irq_restore(flags); |
6f2b9b9a | 1271 | #endif |
466bd303 YZ |
1272 | /* |
1273 | * don't use it in hardirq context, because it | |
1274 | * could lead to deadlock. | |
1275 | */ | |
0eeda71b | 1276 | WARN_ON(in_irq() && !(timer->flags & TIMER_IRQSAFE)); |
fd450b73 ON |
1277 | for (;;) { |
1278 | int ret = try_to_del_timer_sync(timer); | |
1279 | if (ret >= 0) | |
1280 | return ret; | |
a0009652 | 1281 | cpu_relax(); |
fd450b73 | 1282 | } |
1da177e4 | 1283 | } |
55c888d6 | 1284 | EXPORT_SYMBOL(del_timer_sync); |
1da177e4 LT |
1285 | #endif |
1286 | ||
576da126 TG |
1287 | static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long), |
1288 | unsigned long data) | |
1289 | { | |
4a2b4b22 | 1290 | int count = preempt_count(); |
576da126 TG |
1291 | |
1292 | #ifdef CONFIG_LOCKDEP | |
1293 | /* | |
1294 | * It is permissible to free the timer from inside the | |
1295 | * function that is called from it, this we need to take into | |
1296 | * account for lockdep too. To avoid bogus "held lock freed" | |
1297 | * warnings as well as problems when looking into | |
1298 | * timer->lockdep_map, make a copy and use that here. | |
1299 | */ | |
4d82a1de PZ |
1300 | struct lockdep_map lockdep_map; |
1301 | ||
1302 | lockdep_copy_map(&lockdep_map, &timer->lockdep_map); | |
576da126 TG |
1303 | #endif |
1304 | /* | |
1305 | * Couple the lock chain with the lock chain at | |
1306 | * del_timer_sync() by acquiring the lock_map around the fn() | |
1307 | * call here and in del_timer_sync(). | |
1308 | */ | |
1309 | lock_map_acquire(&lockdep_map); | |
1310 | ||
1311 | trace_timer_expire_entry(timer); | |
1312 | fn(data); | |
1313 | trace_timer_expire_exit(timer); | |
1314 | ||
1315 | lock_map_release(&lockdep_map); | |
1316 | ||
4a2b4b22 | 1317 | if (count != preempt_count()) { |
802702e0 | 1318 | WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n", |
4a2b4b22 | 1319 | fn, count, preempt_count()); |
802702e0 TG |
1320 | /* |
1321 | * Restore the preempt count. That gives us a decent | |
1322 | * chance to survive and extract information. If the | |
1323 | * callback kept a lock held, bad luck, but not worse | |
1324 | * than the BUG() we had. | |
1325 | */ | |
4a2b4b22 | 1326 | preempt_count_set(count); |
576da126 TG |
1327 | } |
1328 | } | |
1329 | ||
500462a9 | 1330 | static void expire_timers(struct timer_base *base, struct hlist_head *head) |
1da177e4 | 1331 | { |
500462a9 TG |
1332 | while (!hlist_empty(head)) { |
1333 | struct timer_list *timer; | |
1334 | void (*fn)(unsigned long); | |
1335 | unsigned long data; | |
1da177e4 | 1336 | |
500462a9 | 1337 | timer = hlist_entry(head->first, struct timer_list, entry); |
3bb475a3 | 1338 | |
500462a9 TG |
1339 | base->running_timer = timer; |
1340 | detach_timer(timer, true); | |
3bb475a3 | 1341 | |
500462a9 TG |
1342 | fn = timer->function; |
1343 | data = timer->data; | |
1344 | ||
1345 | if (timer->flags & TIMER_IRQSAFE) { | |
2287d866 | 1346 | raw_spin_unlock(&base->lock); |
500462a9 | 1347 | call_timer_fn(timer, fn, data); |
2287d866 | 1348 | raw_spin_lock(&base->lock); |
500462a9 | 1349 | } else { |
2287d866 | 1350 | raw_spin_unlock_irq(&base->lock); |
500462a9 | 1351 | call_timer_fn(timer, fn, data); |
2287d866 | 1352 | raw_spin_lock_irq(&base->lock); |
3bb475a3 | 1353 | } |
500462a9 TG |
1354 | } |
1355 | } | |
3bb475a3 | 1356 | |
23696838 AMG |
1357 | static int __collect_expired_timers(struct timer_base *base, |
1358 | struct hlist_head *heads) | |
500462a9 TG |
1359 | { |
1360 | unsigned long clk = base->clk; | |
1361 | struct hlist_head *vec; | |
1362 | int i, levels = 0; | |
1363 | unsigned int idx; | |
626ab0e6 | 1364 | |
500462a9 TG |
1365 | for (i = 0; i < LVL_DEPTH; i++) { |
1366 | idx = (clk & LVL_MASK) + i * LVL_SIZE; | |
1367 | ||
1368 | if (__test_and_clear_bit(idx, base->pending_map)) { | |
1369 | vec = base->vectors + idx; | |
1370 | hlist_move_list(vec, heads++); | |
1371 | levels++; | |
1da177e4 | 1372 | } |
500462a9 TG |
1373 | /* Is it time to look at the next level? */ |
1374 | if (clk & LVL_CLK_MASK) | |
1375 | break; | |
1376 | /* Shift clock for the next level granularity */ | |
1377 | clk >>= LVL_CLK_SHIFT; | |
1da177e4 | 1378 | } |
500462a9 | 1379 | return levels; |
1da177e4 LT |
1380 | } |
1381 | ||
3451d024 | 1382 | #ifdef CONFIG_NO_HZ_COMMON |
1da177e4 | 1383 | /* |
23696838 AMG |
1384 | * Find the next pending bucket of a level. Search from level start (@offset) |
1385 | * + @clk upwards and if nothing there, search from start of the level | |
1386 | * (@offset) up to @offset + clk. | |
1da177e4 | 1387 | */ |
500462a9 TG |
1388 | static int next_pending_bucket(struct timer_base *base, unsigned offset, |
1389 | unsigned clk) | |
1390 | { | |
1391 | unsigned pos, start = offset + clk; | |
1392 | unsigned end = offset + LVL_SIZE; | |
1393 | ||
1394 | pos = find_next_bit(base->pending_map, end, start); | |
1395 | if (pos < end) | |
1396 | return pos - start; | |
1397 | ||
1398 | pos = find_next_bit(base->pending_map, start, offset); | |
1399 | return pos < start ? pos + LVL_SIZE - start : -1; | |
1400 | } | |
1401 | ||
1402 | /* | |
23696838 AMG |
1403 | * Search the first expiring timer in the various clock levels. Caller must |
1404 | * hold base->lock. | |
1da177e4 | 1405 | */ |
494af3ed | 1406 | static unsigned long __next_timer_interrupt(struct timer_base *base) |
1da177e4 | 1407 | { |
500462a9 TG |
1408 | unsigned long clk, next, adj; |
1409 | unsigned lvl, offset = 0; | |
1410 | ||
500462a9 TG |
1411 | next = base->clk + NEXT_TIMER_MAX_DELTA; |
1412 | clk = base->clk; | |
1413 | for (lvl = 0; lvl < LVL_DEPTH; lvl++, offset += LVL_SIZE) { | |
1414 | int pos = next_pending_bucket(base, offset, clk & LVL_MASK); | |
1415 | ||
1416 | if (pos >= 0) { | |
1417 | unsigned long tmp = clk + (unsigned long) pos; | |
1418 | ||
1419 | tmp <<= LVL_SHIFT(lvl); | |
1420 | if (time_before(tmp, next)) | |
1421 | next = tmp; | |
1da177e4 | 1422 | } |
500462a9 TG |
1423 | /* |
1424 | * Clock for the next level. If the current level clock lower | |
1425 | * bits are zero, we look at the next level as is. If not we | |
1426 | * need to advance it by one because that's going to be the | |
1427 | * next expiring bucket in that level. base->clk is the next | |
1428 | * expiring jiffie. So in case of: | |
1429 | * | |
1430 | * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0 | |
1431 | * 0 0 0 0 0 0 | |
1432 | * | |
1433 | * we have to look at all levels @index 0. With | |
1434 | * | |
1435 | * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0 | |
1436 | * 0 0 0 0 0 2 | |
1437 | * | |
1438 | * LVL0 has the next expiring bucket @index 2. The upper | |
1439 | * levels have the next expiring bucket @index 1. | |
1440 | * | |
1441 | * In case that the propagation wraps the next level the same | |
1442 | * rules apply: | |
1443 | * | |
1444 | * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0 | |
1445 | * 0 0 0 0 F 2 | |
1446 | * | |
1447 | * So after looking at LVL0 we get: | |
1448 | * | |
1449 | * LVL5 LVL4 LVL3 LVL2 LVL1 | |
1450 | * 0 0 0 1 0 | |
1451 | * | |
1452 | * So no propagation from LVL1 to LVL2 because that happened | |
1453 | * with the add already, but then we need to propagate further | |
1454 | * from LVL2 to LVL3. | |
1455 | * | |
1456 | * So the simple check whether the lower bits of the current | |
1457 | * level are 0 or not is sufficient for all cases. | |
1458 | */ | |
1459 | adj = clk & LVL_CLK_MASK ? 1 : 0; | |
1460 | clk >>= LVL_CLK_SHIFT; | |
1461 | clk += adj; | |
1da177e4 | 1462 | } |
500462a9 | 1463 | return next; |
1cfd6849 | 1464 | } |
69239749 | 1465 | |
1cfd6849 TG |
1466 | /* |
1467 | * Check, if the next hrtimer event is before the next timer wheel | |
1468 | * event: | |
1469 | */ | |
c1ad348b | 1470 | static u64 cmp_next_hrtimer_event(u64 basem, u64 expires) |
1cfd6849 | 1471 | { |
c1ad348b | 1472 | u64 nextevt = hrtimer_get_next_event(); |
0662b713 | 1473 | |
9501b6cf | 1474 | /* |
c1ad348b TG |
1475 | * If high resolution timers are enabled |
1476 | * hrtimer_get_next_event() returns KTIME_MAX. | |
9501b6cf | 1477 | */ |
c1ad348b TG |
1478 | if (expires <= nextevt) |
1479 | return expires; | |
eaad084b TG |
1480 | |
1481 | /* | |
c1ad348b TG |
1482 | * If the next timer is already expired, return the tick base |
1483 | * time so the tick is fired immediately. | |
eaad084b | 1484 | */ |
c1ad348b TG |
1485 | if (nextevt <= basem) |
1486 | return basem; | |
eaad084b | 1487 | |
9501b6cf | 1488 | /* |
c1ad348b TG |
1489 | * Round up to the next jiffie. High resolution timers are |
1490 | * off, so the hrtimers are expired in the tick and we need to | |
1491 | * make sure that this tick really expires the timer to avoid | |
1492 | * a ping pong of the nohz stop code. | |
1493 | * | |
1494 | * Use DIV_ROUND_UP_ULL to prevent gcc calling __divdi3 | |
9501b6cf | 1495 | */ |
c1ad348b | 1496 | return DIV_ROUND_UP_ULL(nextevt, TICK_NSEC) * TICK_NSEC; |
1da177e4 | 1497 | } |
1cfd6849 TG |
1498 | |
1499 | /** | |
c1ad348b TG |
1500 | * get_next_timer_interrupt - return the time (clock mono) of the next timer |
1501 | * @basej: base time jiffies | |
1502 | * @basem: base time clock monotonic | |
1503 | * | |
1504 | * Returns the tick aligned clock monotonic time of the next pending | |
1505 | * timer or KTIME_MAX if no timer is pending. | |
1cfd6849 | 1506 | */ |
c1ad348b | 1507 | u64 get_next_timer_interrupt(unsigned long basej, u64 basem) |
1cfd6849 | 1508 | { |
500462a9 | 1509 | struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); |
c1ad348b TG |
1510 | u64 expires = KTIME_MAX; |
1511 | unsigned long nextevt; | |
46c8f0b0 | 1512 | bool is_max_delta; |
1cfd6849 | 1513 | |
dbd87b5a HC |
1514 | /* |
1515 | * Pretend that there is no timer pending if the cpu is offline. | |
1516 | * Possible pending timers will be migrated later to an active cpu. | |
1517 | */ | |
1518 | if (cpu_is_offline(smp_processor_id())) | |
e40468a5 TG |
1519 | return expires; |
1520 | ||
2287d866 | 1521 | raw_spin_lock(&base->lock); |
500462a9 | 1522 | nextevt = __next_timer_interrupt(base); |
46c8f0b0 | 1523 | is_max_delta = (nextevt == base->clk + NEXT_TIMER_MAX_DELTA); |
a683f390 TG |
1524 | base->next_expiry = nextevt; |
1525 | /* | |
041ad7bc TG |
1526 | * We have a fresh next event. Check whether we can forward the |
1527 | * base. We can only do that when @basej is past base->clk | |
1528 | * otherwise we might rewind base->clk. | |
a683f390 | 1529 | */ |
041ad7bc TG |
1530 | if (time_after(basej, base->clk)) { |
1531 | if (time_after(nextevt, basej)) | |
1532 | base->clk = basej; | |
1533 | else if (time_after(nextevt, base->clk)) | |
1534 | base->clk = nextevt; | |
1535 | } | |
23696838 | 1536 | |
a683f390 | 1537 | if (time_before_eq(nextevt, basej)) { |
500462a9 | 1538 | expires = basem; |
a683f390 TG |
1539 | base->is_idle = false; |
1540 | } else { | |
46c8f0b0 | 1541 | if (!is_max_delta) |
34f41c03 | 1542 | expires = basem + (u64)(nextevt - basej) * TICK_NSEC; |
a683f390 | 1543 | /* |
2fe59f50 NP |
1544 | * If we expect to sleep more than a tick, mark the base idle. |
1545 | * Also the tick is stopped so any added timer must forward | |
1546 | * the base clk itself to keep granularity small. This idle | |
1547 | * logic is only maintained for the BASE_STD base, deferrable | |
1548 | * timers may still see large granularity skew (by design). | |
a683f390 | 1549 | */ |
2fe59f50 NP |
1550 | if ((expires - basem) > TICK_NSEC) { |
1551 | base->must_forward_clk = true; | |
a683f390 | 1552 | base->is_idle = true; |
2fe59f50 | 1553 | } |
e40468a5 | 1554 | } |
2287d866 | 1555 | raw_spin_unlock(&base->lock); |
1cfd6849 | 1556 | |
c1ad348b | 1557 | return cmp_next_hrtimer_event(basem, expires); |
1cfd6849 | 1558 | } |
23696838 | 1559 | |
a683f390 TG |
1560 | /** |
1561 | * timer_clear_idle - Clear the idle state of the timer base | |
1562 | * | |
1563 | * Called with interrupts disabled | |
1564 | */ | |
1565 | void timer_clear_idle(void) | |
1566 | { | |
1567 | struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); | |
1568 | ||
1569 | /* | |
1570 | * We do this unlocked. The worst outcome is a remote enqueue sending | |
1571 | * a pointless IPI, but taking the lock would just make the window for | |
1572 | * sending the IPI a few instructions smaller for the cost of taking | |
1573 | * the lock in the exit from idle path. | |
1574 | */ | |
1575 | base->is_idle = false; | |
1576 | } | |
1577 | ||
23696838 AMG |
1578 | static int collect_expired_timers(struct timer_base *base, |
1579 | struct hlist_head *heads) | |
1580 | { | |
1581 | /* | |
1582 | * NOHZ optimization. After a long idle sleep we need to forward the | |
1583 | * base to current jiffies. Avoid a loop by searching the bitfield for | |
1584 | * the next expiring timer. | |
1585 | */ | |
1586 | if ((long)(jiffies - base->clk) > 2) { | |
1587 | unsigned long next = __next_timer_interrupt(base); | |
1588 | ||
1589 | /* | |
1590 | * If the next timer is ahead of time forward to current | |
a683f390 | 1591 | * jiffies, otherwise forward to the next expiry time: |
23696838 AMG |
1592 | */ |
1593 | if (time_after(next, jiffies)) { | |
c310ce4d ZD |
1594 | /* |
1595 | * The call site will increment base->clk and then | |
1596 | * terminate the expiry loop immediately. | |
1597 | */ | |
1598 | base->clk = jiffies; | |
23696838 AMG |
1599 | return 0; |
1600 | } | |
1601 | base->clk = next; | |
1602 | } | |
1603 | return __collect_expired_timers(base, heads); | |
1604 | } | |
1605 | #else | |
1606 | static inline int collect_expired_timers(struct timer_base *base, | |
1607 | struct hlist_head *heads) | |
1608 | { | |
1609 | return __collect_expired_timers(base, heads); | |
1610 | } | |
1da177e4 LT |
1611 | #endif |
1612 | ||
1da177e4 | 1613 | /* |
5b4db0c2 | 1614 | * Called from the timer interrupt handler to charge one tick to the current |
1da177e4 LT |
1615 | * process. user_tick is 1 if the tick is user time, 0 for system. |
1616 | */ | |
1617 | void update_process_times(int user_tick) | |
1618 | { | |
1619 | struct task_struct *p = current; | |
1da177e4 LT |
1620 | |
1621 | /* Note: this timer irq context must be accounted for as well. */ | |
fa13a5a1 | 1622 | account_process_tick(p, user_tick); |
1da177e4 | 1623 | run_local_timers(); |
c3377c2d | 1624 | rcu_check_callbacks(user_tick); |
e360adbe PZ |
1625 | #ifdef CONFIG_IRQ_WORK |
1626 | if (in_irq()) | |
76a33061 | 1627 | irq_work_tick(); |
e360adbe | 1628 | #endif |
1da177e4 | 1629 | scheduler_tick(); |
baa73d9e NP |
1630 | if (IS_ENABLED(CONFIG_POSIX_TIMERS)) |
1631 | run_posix_cpu_timers(p); | |
1da177e4 LT |
1632 | } |
1633 | ||
73420fea AMG |
1634 | /** |
1635 | * __run_timers - run all expired timers (if any) on this CPU. | |
1636 | * @base: the timer vector to be processed. | |
1637 | */ | |
1638 | static inline void __run_timers(struct timer_base *base) | |
1639 | { | |
1640 | struct hlist_head heads[LVL_DEPTH]; | |
1641 | int levels; | |
1642 | ||
1643 | if (!time_after_eq(jiffies, base->clk)) | |
1644 | return; | |
1645 | ||
2287d866 | 1646 | raw_spin_lock_irq(&base->lock); |
73420fea AMG |
1647 | |
1648 | while (time_after_eq(jiffies, base->clk)) { | |
1649 | ||
1650 | levels = collect_expired_timers(base, heads); | |
1651 | base->clk++; | |
1652 | ||
1653 | while (levels--) | |
1654 | expire_timers(base, heads + levels); | |
1655 | } | |
1656 | base->running_timer = NULL; | |
2287d866 | 1657 | raw_spin_unlock_irq(&base->lock); |
73420fea AMG |
1658 | } |
1659 | ||
1da177e4 LT |
1660 | /* |
1661 | * This function runs timers and the timer-tq in bottom half context. | |
1662 | */ | |
0766f788 | 1663 | static __latent_entropy void run_timer_softirq(struct softirq_action *h) |
1da177e4 | 1664 | { |
500462a9 | 1665 | struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); |
1da177e4 | 1666 | |
2fe59f50 NP |
1667 | /* |
1668 | * must_forward_clk must be cleared before running timers so that any | |
1669 | * timer functions that call mod_timer will not try to forward the | |
1670 | * base. idle trcking / clock forwarding logic is only used with | |
1671 | * BASE_STD timers. | |
1672 | * | |
1673 | * The deferrable base does not do idle tracking at all, so we do | |
1674 | * not forward it. This can result in very large variations in | |
1675 | * granularity for deferrable timers, but they can be deferred for | |
1676 | * long periods due to idle. | |
1677 | */ | |
1678 | base->must_forward_clk = false; | |
1679 | ||
500462a9 TG |
1680 | __run_timers(base); |
1681 | if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active) | |
1682 | __run_timers(this_cpu_ptr(&timer_bases[BASE_DEF])); | |
1da177e4 LT |
1683 | } |
1684 | ||
1685 | /* | |
1686 | * Called by the local, per-CPU timer interrupt on SMP. | |
1687 | */ | |
1688 | void run_local_timers(void) | |
1689 | { | |
4e85876a TG |
1690 | struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); |
1691 | ||
d3d74453 | 1692 | hrtimer_run_queues(); |
4e85876a TG |
1693 | /* Raise the softirq only if required. */ |
1694 | if (time_before(jiffies, base->clk)) { | |
1695 | if (!IS_ENABLED(CONFIG_NO_HZ_COMMON) || !base->nohz_active) | |
1696 | return; | |
1697 | /* CPU is awake, so check the deferrable base. */ | |
1698 | base++; | |
1699 | if (time_before(jiffies, base->clk)) | |
1700 | return; | |
1701 | } | |
1da177e4 LT |
1702 | raise_softirq(TIMER_SOFTIRQ); |
1703 | } | |
1704 | ||
58e1177b KC |
1705 | /* |
1706 | * Since schedule_timeout()'s timer is defined on the stack, it must store | |
1707 | * the target task on the stack as well. | |
1708 | */ | |
1709 | struct process_timer { | |
1710 | struct timer_list timer; | |
1711 | struct task_struct *task; | |
1712 | }; | |
1713 | ||
1714 | static void process_timeout(struct timer_list *t) | |
1da177e4 | 1715 | { |
58e1177b KC |
1716 | struct process_timer *timeout = from_timer(timeout, t, timer); |
1717 | ||
1718 | wake_up_process(timeout->task); | |
1da177e4 LT |
1719 | } |
1720 | ||
1721 | /** | |
1722 | * schedule_timeout - sleep until timeout | |
1723 | * @timeout: timeout value in jiffies | |
1724 | * | |
1725 | * Make the current task sleep until @timeout jiffies have | |
1726 | * elapsed. The routine will return immediately unless | |
1727 | * the current task state has been set (see set_current_state()). | |
1728 | * | |
1729 | * You can set the task state as follows - | |
1730 | * | |
1731 | * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to | |
4b7e9cf9 DA |
1732 | * pass before the routine returns unless the current task is explicitly |
1733 | * woken up, (e.g. by wake_up_process())". | |
1da177e4 LT |
1734 | * |
1735 | * %TASK_INTERRUPTIBLE - the routine may return early if a signal is | |
4b7e9cf9 DA |
1736 | * delivered to the current task or the current task is explicitly woken |
1737 | * up. | |
1da177e4 LT |
1738 | * |
1739 | * The current task state is guaranteed to be TASK_RUNNING when this | |
1740 | * routine returns. | |
1741 | * | |
1742 | * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule | |
1743 | * the CPU away without a bound on the timeout. In this case the return | |
1744 | * value will be %MAX_SCHEDULE_TIMEOUT. | |
1745 | * | |
4b7e9cf9 DA |
1746 | * Returns 0 when the timer has expired otherwise the remaining time in |
1747 | * jiffies will be returned. In all cases the return value is guaranteed | |
1748 | * to be non-negative. | |
1da177e4 | 1749 | */ |
7ad5b3a5 | 1750 | signed long __sched schedule_timeout(signed long timeout) |
1da177e4 | 1751 | { |
58e1177b | 1752 | struct process_timer timer; |
1da177e4 LT |
1753 | unsigned long expire; |
1754 | ||
1755 | switch (timeout) | |
1756 | { | |
1757 | case MAX_SCHEDULE_TIMEOUT: | |
1758 | /* | |
1759 | * These two special cases are useful to be comfortable | |
1760 | * in the caller. Nothing more. We could take | |
1761 | * MAX_SCHEDULE_TIMEOUT from one of the negative value | |
1762 | * but I' d like to return a valid offset (>=0) to allow | |
1763 | * the caller to do everything it want with the retval. | |
1764 | */ | |
1765 | schedule(); | |
1766 | goto out; | |
1767 | default: | |
1768 | /* | |
1769 | * Another bit of PARANOID. Note that the retval will be | |
1770 | * 0 since no piece of kernel is supposed to do a check | |
1771 | * for a negative retval of schedule_timeout() (since it | |
1772 | * should never happens anyway). You just have the printk() | |
1773 | * that will tell you if something is gone wrong and where. | |
1774 | */ | |
5b149bcc | 1775 | if (timeout < 0) { |
1da177e4 | 1776 | printk(KERN_ERR "schedule_timeout: wrong timeout " |
5b149bcc AM |
1777 | "value %lx\n", timeout); |
1778 | dump_stack(); | |
1da177e4 LT |
1779 | current->state = TASK_RUNNING; |
1780 | goto out; | |
1781 | } | |
1782 | } | |
1783 | ||
1784 | expire = timeout + jiffies; | |
1785 | ||
58e1177b KC |
1786 | timer.task = current; |
1787 | timer_setup_on_stack(&timer.timer, process_timeout, 0); | |
b24591e2 | 1788 | __mod_timer(&timer.timer, expire, 0); |
1da177e4 | 1789 | schedule(); |
58e1177b | 1790 | del_singleshot_timer_sync(&timer.timer); |
1da177e4 | 1791 | |
c6f3a97f | 1792 | /* Remove the timer from the object tracker */ |
58e1177b | 1793 | destroy_timer_on_stack(&timer.timer); |
c6f3a97f | 1794 | |
1da177e4 LT |
1795 | timeout = expire - jiffies; |
1796 | ||
1797 | out: | |
1798 | return timeout < 0 ? 0 : timeout; | |
1799 | } | |
1da177e4 LT |
1800 | EXPORT_SYMBOL(schedule_timeout); |
1801 | ||
8a1c1757 AM |
1802 | /* |
1803 | * We can use __set_current_state() here because schedule_timeout() calls | |
1804 | * schedule() unconditionally. | |
1805 | */ | |
64ed93a2 NA |
1806 | signed long __sched schedule_timeout_interruptible(signed long timeout) |
1807 | { | |
a5a0d52c AM |
1808 | __set_current_state(TASK_INTERRUPTIBLE); |
1809 | return schedule_timeout(timeout); | |
64ed93a2 NA |
1810 | } |
1811 | EXPORT_SYMBOL(schedule_timeout_interruptible); | |
1812 | ||
294d5cc2 MW |
1813 | signed long __sched schedule_timeout_killable(signed long timeout) |
1814 | { | |
1815 | __set_current_state(TASK_KILLABLE); | |
1816 | return schedule_timeout(timeout); | |
1817 | } | |
1818 | EXPORT_SYMBOL(schedule_timeout_killable); | |
1819 | ||
64ed93a2 NA |
1820 | signed long __sched schedule_timeout_uninterruptible(signed long timeout) |
1821 | { | |
a5a0d52c AM |
1822 | __set_current_state(TASK_UNINTERRUPTIBLE); |
1823 | return schedule_timeout(timeout); | |
64ed93a2 NA |
1824 | } |
1825 | EXPORT_SYMBOL(schedule_timeout_uninterruptible); | |
1826 | ||
69b27baf AM |
1827 | /* |
1828 | * Like schedule_timeout_uninterruptible(), except this task will not contribute | |
1829 | * to load average. | |
1830 | */ | |
1831 | signed long __sched schedule_timeout_idle(signed long timeout) | |
1832 | { | |
1833 | __set_current_state(TASK_IDLE); | |
1834 | return schedule_timeout(timeout); | |
1835 | } | |
1836 | EXPORT_SYMBOL(schedule_timeout_idle); | |
1837 | ||
1da177e4 | 1838 | #ifdef CONFIG_HOTPLUG_CPU |
494af3ed | 1839 | static void migrate_timer_list(struct timer_base *new_base, struct hlist_head *head) |
1da177e4 LT |
1840 | { |
1841 | struct timer_list *timer; | |
0eeda71b | 1842 | int cpu = new_base->cpu; |
1da177e4 | 1843 | |
1dabbcec TG |
1844 | while (!hlist_empty(head)) { |
1845 | timer = hlist_entry(head->first, struct timer_list, entry); | |
ec44bc7a | 1846 | detach_timer(timer, false); |
0eeda71b | 1847 | timer->flags = (timer->flags & ~TIMER_BASEMASK) | cpu; |
1da177e4 | 1848 | internal_add_timer(new_base, timer); |
1da177e4 | 1849 | } |
1da177e4 LT |
1850 | } |
1851 | ||
24f73b99 | 1852 | int timers_dead_cpu(unsigned int cpu) |
1da177e4 | 1853 | { |
494af3ed TG |
1854 | struct timer_base *old_base; |
1855 | struct timer_base *new_base; | |
500462a9 | 1856 | int b, i; |
1da177e4 LT |
1857 | |
1858 | BUG_ON(cpu_online(cpu)); | |
55c888d6 | 1859 | |
500462a9 TG |
1860 | for (b = 0; b < NR_BASES; b++) { |
1861 | old_base = per_cpu_ptr(&timer_bases[b], cpu); | |
1862 | new_base = get_cpu_ptr(&timer_bases[b]); | |
1863 | /* | |
1864 | * The caller is globally serialized and nobody else | |
1865 | * takes two locks at once, deadlock is not possible. | |
1866 | */ | |
2287d866 SAS |
1867 | raw_spin_lock_irq(&new_base->lock); |
1868 | raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); | |
500462a9 TG |
1869 | |
1870 | BUG_ON(old_base->running_timer); | |
1871 | ||
1872 | for (i = 0; i < WHEEL_SIZE; i++) | |
1873 | migrate_timer_list(new_base, old_base->vectors + i); | |
8def9060 | 1874 | |
2287d866 SAS |
1875 | raw_spin_unlock(&old_base->lock); |
1876 | raw_spin_unlock_irq(&new_base->lock); | |
500462a9 TG |
1877 | put_cpu_ptr(&timer_bases); |
1878 | } | |
24f73b99 | 1879 | return 0; |
1da177e4 | 1880 | } |
1da177e4 | 1881 | |
3650b57f | 1882 | #endif /* CONFIG_HOTPLUG_CPU */ |
1da177e4 | 1883 | |
0eeda71b | 1884 | static void __init init_timer_cpu(int cpu) |
8def9060 | 1885 | { |
500462a9 TG |
1886 | struct timer_base *base; |
1887 | int i; | |
8def9060 | 1888 | |
500462a9 TG |
1889 | for (i = 0; i < NR_BASES; i++) { |
1890 | base = per_cpu_ptr(&timer_bases[i], cpu); | |
1891 | base->cpu = cpu; | |
2287d866 | 1892 | raw_spin_lock_init(&base->lock); |
500462a9 TG |
1893 | base->clk = jiffies; |
1894 | } | |
8def9060 VK |
1895 | } |
1896 | ||
1897 | static void __init init_timer_cpus(void) | |
1da177e4 | 1898 | { |
8def9060 VK |
1899 | int cpu; |
1900 | ||
0eeda71b TG |
1901 | for_each_possible_cpu(cpu) |
1902 | init_timer_cpu(cpu); | |
8def9060 | 1903 | } |
e52b1db3 | 1904 | |
8def9060 VK |
1905 | void __init init_timers(void) |
1906 | { | |
8def9060 | 1907 | init_timer_cpus(); |
962cf36c | 1908 | open_softirq(TIMER_SOFTIRQ, run_timer_softirq); |
1da177e4 LT |
1909 | } |
1910 | ||
1da177e4 LT |
1911 | /** |
1912 | * msleep - sleep safely even with waitqueue interruptions | |
1913 | * @msecs: Time in milliseconds to sleep for | |
1914 | */ | |
1915 | void msleep(unsigned int msecs) | |
1916 | { | |
1917 | unsigned long timeout = msecs_to_jiffies(msecs) + 1; | |
1918 | ||
75bcc8c5 NA |
1919 | while (timeout) |
1920 | timeout = schedule_timeout_uninterruptible(timeout); | |
1da177e4 LT |
1921 | } |
1922 | ||
1923 | EXPORT_SYMBOL(msleep); | |
1924 | ||
1925 | /** | |
96ec3efd | 1926 | * msleep_interruptible - sleep waiting for signals |
1da177e4 LT |
1927 | * @msecs: Time in milliseconds to sleep for |
1928 | */ | |
1929 | unsigned long msleep_interruptible(unsigned int msecs) | |
1930 | { | |
1931 | unsigned long timeout = msecs_to_jiffies(msecs) + 1; | |
1932 | ||
75bcc8c5 NA |
1933 | while (timeout && !signal_pending(current)) |
1934 | timeout = schedule_timeout_interruptible(timeout); | |
1da177e4 LT |
1935 | return jiffies_to_msecs(timeout); |
1936 | } | |
1937 | ||
1938 | EXPORT_SYMBOL(msleep_interruptible); | |
5e7f5a17 | 1939 | |
5e7f5a17 | 1940 | /** |
b5227d03 | 1941 | * usleep_range - Sleep for an approximate time |
5e7f5a17 PP |
1942 | * @min: Minimum time in usecs to sleep |
1943 | * @max: Maximum time in usecs to sleep | |
b5227d03 BH |
1944 | * |
1945 | * In non-atomic context where the exact wakeup time is flexible, use | |
1946 | * usleep_range() instead of udelay(). The sleep improves responsiveness | |
1947 | * by avoiding the CPU-hogging busy-wait of udelay(), and the range reduces | |
1948 | * power usage by allowing hrtimers to take advantage of an already- | |
1949 | * scheduled interrupt instead of scheduling a new one just for this sleep. | |
5e7f5a17 | 1950 | */ |
2ad5d327 | 1951 | void __sched usleep_range(unsigned long min, unsigned long max) |
5e7f5a17 | 1952 | { |
6c5e9059 DA |
1953 | ktime_t exp = ktime_add_us(ktime_get(), min); |
1954 | u64 delta = (u64)(max - min) * NSEC_PER_USEC; | |
1955 | ||
1956 | for (;;) { | |
1957 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
1958 | /* Do not return before the requested sleep time has elapsed */ | |
1959 | if (!schedule_hrtimeout_range(&exp, delta, HRTIMER_MODE_ABS)) | |
1960 | break; | |
1961 | } | |
5e7f5a17 PP |
1962 | } |
1963 | EXPORT_SYMBOL(usleep_range); |