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35728b82 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
4a22f166 | 3 | * Kernel internal timers |
1da177e4 LT |
4 | * |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | * | |
7 | * 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better. | |
8 | * | |
9 | * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 | |
10 | * "A Kernel Model for Precision Timekeeping" by Dave Mills | |
11 | * 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to | |
12 | * serialize accesses to xtime/lost_ticks). | |
13 | * Copyright (C) 1998 Andrea Arcangeli | |
14 | * 1999-03-10 Improved NTP compatibility by Ulrich Windl | |
15 | * 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love | |
16 | * 2000-10-05 Implemented scalable SMP per-CPU timer handling. | |
17 | * Copyright (C) 2000, 2001, 2002 Ingo Molnar | |
18 | * Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar | |
19 | */ | |
20 | ||
21 | #include <linux/kernel_stat.h> | |
9984de1a | 22 | #include <linux/export.h> |
1da177e4 LT |
23 | #include <linux/interrupt.h> |
24 | #include <linux/percpu.h> | |
25 | #include <linux/init.h> | |
26 | #include <linux/mm.h> | |
27 | #include <linux/swap.h> | |
b488893a | 28 | #include <linux/pid_namespace.h> |
1da177e4 LT |
29 | #include <linux/notifier.h> |
30 | #include <linux/thread_info.h> | |
31 | #include <linux/time.h> | |
32 | #include <linux/jiffies.h> | |
33 | #include <linux/posix-timers.h> | |
34 | #include <linux/cpu.h> | |
35 | #include <linux/syscalls.h> | |
97a41e26 | 36 | #include <linux/delay.h> |
79bf2bb3 | 37 | #include <linux/tick.h> |
82f67cd9 | 38 | #include <linux/kallsyms.h> |
e360adbe | 39 | #include <linux/irq_work.h> |
174cd4b1 | 40 | #include <linux/sched/signal.h> |
cf4aebc2 | 41 | #include <linux/sched/sysctl.h> |
370c9135 | 42 | #include <linux/sched/nohz.h> |
b17b0153 | 43 | #include <linux/sched/debug.h> |
5a0e3ad6 | 44 | #include <linux/slab.h> |
1a0df594 | 45 | #include <linux/compat.h> |
1da177e4 | 46 | |
7c0f6ba6 | 47 | #include <linux/uaccess.h> |
1da177e4 LT |
48 | #include <asm/unistd.h> |
49 | #include <asm/div64.h> | |
50 | #include <asm/timex.h> | |
51 | #include <asm/io.h> | |
52 | ||
c1ad348b TG |
53 | #include "tick-internal.h" |
54 | ||
2b022e3d XG |
55 | #define CREATE_TRACE_POINTS |
56 | #include <trace/events/timer.h> | |
57 | ||
40747ffa | 58 | __visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; |
ecea8d19 TG |
59 | |
60 | EXPORT_SYMBOL(jiffies_64); | |
61 | ||
1da177e4 | 62 | /* |
500462a9 TG |
63 | * The timer wheel has LVL_DEPTH array levels. Each level provides an array of |
64 | * LVL_SIZE buckets. Each level is driven by its own clock and therefor each | |
65 | * level has a different granularity. | |
66 | * | |
67 | * The level granularity is: LVL_CLK_DIV ^ lvl | |
68 | * The level clock frequency is: HZ / (LVL_CLK_DIV ^ level) | |
69 | * | |
70 | * The array level of a newly armed timer depends on the relative expiry | |
71 | * time. The farther the expiry time is away the higher the array level and | |
72 | * therefor the granularity becomes. | |
73 | * | |
74 | * Contrary to the original timer wheel implementation, which aims for 'exact' | |
75 | * expiry of the timers, this implementation removes the need for recascading | |
76 | * the timers into the lower array levels. The previous 'classic' timer wheel | |
77 | * implementation of the kernel already violated the 'exact' expiry by adding | |
78 | * slack to the expiry time to provide batched expiration. The granularity | |
79 | * levels provide implicit batching. | |
80 | * | |
81 | * This is an optimization of the original timer wheel implementation for the | |
82 | * majority of the timer wheel use cases: timeouts. The vast majority of | |
83 | * timeout timers (networking, disk I/O ...) are canceled before expiry. If | |
84 | * the timeout expires it indicates that normal operation is disturbed, so it | |
85 | * does not matter much whether the timeout comes with a slight delay. | |
86 | * | |
87 | * The only exception to this are networking timers with a small expiry | |
88 | * time. They rely on the granularity. Those fit into the first wheel level, | |
89 | * which has HZ granularity. | |
90 | * | |
91 | * We don't have cascading anymore. timers with a expiry time above the | |
92 | * capacity of the last wheel level are force expired at the maximum timeout | |
93 | * value of the last wheel level. From data sampling we know that the maximum | |
94 | * value observed is 5 days (network connection tracking), so this should not | |
95 | * be an issue. | |
96 | * | |
97 | * The currently chosen array constants values are a good compromise between | |
98 | * array size and granularity. | |
99 | * | |
100 | * This results in the following granularity and range levels: | |
101 | * | |
102 | * HZ 1000 steps | |
103 | * Level Offset Granularity Range | |
104 | * 0 0 1 ms 0 ms - 63 ms | |
105 | * 1 64 8 ms 64 ms - 511 ms | |
106 | * 2 128 64 ms 512 ms - 4095 ms (512ms - ~4s) | |
107 | * 3 192 512 ms 4096 ms - 32767 ms (~4s - ~32s) | |
108 | * 4 256 4096 ms (~4s) 32768 ms - 262143 ms (~32s - ~4m) | |
109 | * 5 320 32768 ms (~32s) 262144 ms - 2097151 ms (~4m - ~34m) | |
110 | * 6 384 262144 ms (~4m) 2097152 ms - 16777215 ms (~34m - ~4h) | |
111 | * 7 448 2097152 ms (~34m) 16777216 ms - 134217727 ms (~4h - ~1d) | |
112 | * 8 512 16777216 ms (~4h) 134217728 ms - 1073741822 ms (~1d - ~12d) | |
113 | * | |
114 | * HZ 300 | |
115 | * Level Offset Granularity Range | |
116 | * 0 0 3 ms 0 ms - 210 ms | |
117 | * 1 64 26 ms 213 ms - 1703 ms (213ms - ~1s) | |
118 | * 2 128 213 ms 1706 ms - 13650 ms (~1s - ~13s) | |
119 | * 3 192 1706 ms (~1s) 13653 ms - 109223 ms (~13s - ~1m) | |
120 | * 4 256 13653 ms (~13s) 109226 ms - 873810 ms (~1m - ~14m) | |
121 | * 5 320 109226 ms (~1m) 873813 ms - 6990503 ms (~14m - ~1h) | |
122 | * 6 384 873813 ms (~14m) 6990506 ms - 55924050 ms (~1h - ~15h) | |
123 | * 7 448 6990506 ms (~1h) 55924053 ms - 447392423 ms (~15h - ~5d) | |
124 | * 8 512 55924053 ms (~15h) 447392426 ms - 3579139406 ms (~5d - ~41d) | |
125 | * | |
126 | * HZ 250 | |
127 | * Level Offset Granularity Range | |
128 | * 0 0 4 ms 0 ms - 255 ms | |
129 | * 1 64 32 ms 256 ms - 2047 ms (256ms - ~2s) | |
130 | * 2 128 256 ms 2048 ms - 16383 ms (~2s - ~16s) | |
131 | * 3 192 2048 ms (~2s) 16384 ms - 131071 ms (~16s - ~2m) | |
132 | * 4 256 16384 ms (~16s) 131072 ms - 1048575 ms (~2m - ~17m) | |
133 | * 5 320 131072 ms (~2m) 1048576 ms - 8388607 ms (~17m - ~2h) | |
134 | * 6 384 1048576 ms (~17m) 8388608 ms - 67108863 ms (~2h - ~18h) | |
135 | * 7 448 8388608 ms (~2h) 67108864 ms - 536870911 ms (~18h - ~6d) | |
136 | * 8 512 67108864 ms (~18h) 536870912 ms - 4294967288 ms (~6d - ~49d) | |
137 | * | |
138 | * HZ 100 | |
139 | * Level Offset Granularity Range | |
140 | * 0 0 10 ms 0 ms - 630 ms | |
141 | * 1 64 80 ms 640 ms - 5110 ms (640ms - ~5s) | |
142 | * 2 128 640 ms 5120 ms - 40950 ms (~5s - ~40s) | |
143 | * 3 192 5120 ms (~5s) 40960 ms - 327670 ms (~40s - ~5m) | |
144 | * 4 256 40960 ms (~40s) 327680 ms - 2621430 ms (~5m - ~43m) | |
145 | * 5 320 327680 ms (~5m) 2621440 ms - 20971510 ms (~43m - ~5h) | |
146 | * 6 384 2621440 ms (~43m) 20971520 ms - 167772150 ms (~5h - ~1d) | |
147 | * 7 448 20971520 ms (~5h) 167772160 ms - 1342177270 ms (~1d - ~15d) | |
1da177e4 | 148 | */ |
1da177e4 | 149 | |
500462a9 TG |
150 | /* Clock divisor for the next level */ |
151 | #define LVL_CLK_SHIFT 3 | |
152 | #define LVL_CLK_DIV (1UL << LVL_CLK_SHIFT) | |
153 | #define LVL_CLK_MASK (LVL_CLK_DIV - 1) | |
154 | #define LVL_SHIFT(n) ((n) * LVL_CLK_SHIFT) | |
155 | #define LVL_GRAN(n) (1UL << LVL_SHIFT(n)) | |
1da177e4 | 156 | |
500462a9 TG |
157 | /* |
158 | * The time start value for each level to select the bucket at enqueue | |
159 | * time. | |
160 | */ | |
161 | #define LVL_START(n) ((LVL_SIZE - 1) << (((n) - 1) * LVL_CLK_SHIFT)) | |
162 | ||
163 | /* Size of each clock level */ | |
164 | #define LVL_BITS 6 | |
165 | #define LVL_SIZE (1UL << LVL_BITS) | |
166 | #define LVL_MASK (LVL_SIZE - 1) | |
167 | #define LVL_OFFS(n) ((n) * LVL_SIZE) | |
168 | ||
169 | /* Level depth */ | |
170 | #if HZ > 100 | |
171 | # define LVL_DEPTH 9 | |
172 | # else | |
173 | # define LVL_DEPTH 8 | |
174 | #endif | |
175 | ||
176 | /* The cutoff (max. capacity of the wheel) */ | |
177 | #define WHEEL_TIMEOUT_CUTOFF (LVL_START(LVL_DEPTH)) | |
178 | #define WHEEL_TIMEOUT_MAX (WHEEL_TIMEOUT_CUTOFF - LVL_GRAN(LVL_DEPTH - 1)) | |
179 | ||
180 | /* | |
181 | * The resulting wheel size. If NOHZ is configured we allocate two | |
182 | * wheels so we have a separate storage for the deferrable timers. | |
183 | */ | |
184 | #define WHEEL_SIZE (LVL_SIZE * LVL_DEPTH) | |
185 | ||
186 | #ifdef CONFIG_NO_HZ_COMMON | |
187 | # define NR_BASES 2 | |
188 | # define BASE_STD 0 | |
189 | # define BASE_DEF 1 | |
190 | #else | |
191 | # define NR_BASES 1 | |
192 | # define BASE_STD 0 | |
193 | # define BASE_DEF 0 | |
194 | #endif | |
1da177e4 | 195 | |
494af3ed | 196 | struct timer_base { |
2287d866 | 197 | raw_spinlock_t lock; |
500462a9 TG |
198 | struct timer_list *running_timer; |
199 | unsigned long clk; | |
a683f390 | 200 | unsigned long next_expiry; |
500462a9 | 201 | unsigned int cpu; |
a683f390 | 202 | bool is_idle; |
2fe59f50 | 203 | bool must_forward_clk; |
500462a9 TG |
204 | DECLARE_BITMAP(pending_map, WHEEL_SIZE); |
205 | struct hlist_head vectors[WHEEL_SIZE]; | |
6e453a67 | 206 | } ____cacheline_aligned; |
e52b1db3 | 207 | |
500462a9 | 208 | static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]); |
6e453a67 | 209 | |
ae67bada TG |
210 | #ifdef CONFIG_NO_HZ_COMMON |
211 | ||
14c80341 | 212 | static DEFINE_STATIC_KEY_FALSE(timers_nohz_active); |
ae67bada TG |
213 | static DEFINE_MUTEX(timer_keys_mutex); |
214 | ||
215 | static void timer_update_keys(struct work_struct *work); | |
216 | static DECLARE_WORK(timer_update_work, timer_update_keys); | |
217 | ||
218 | #ifdef CONFIG_SMP | |
bc7a34b8 TG |
219 | unsigned int sysctl_timer_migration = 1; |
220 | ||
ae67bada TG |
221 | DEFINE_STATIC_KEY_FALSE(timers_migration_enabled); |
222 | ||
223 | static void timers_update_migration(void) | |
bc7a34b8 | 224 | { |
ae67bada TG |
225 | if (sysctl_timer_migration && tick_nohz_active) |
226 | static_branch_enable(&timers_migration_enabled); | |
227 | else | |
228 | static_branch_disable(&timers_migration_enabled); | |
229 | } | |
230 | #else | |
231 | static inline void timers_update_migration(void) { } | |
232 | #endif /* !CONFIG_SMP */ | |
bc7a34b8 | 233 | |
ae67bada TG |
234 | static void timer_update_keys(struct work_struct *work) |
235 | { | |
236 | mutex_lock(&timer_keys_mutex); | |
237 | timers_update_migration(); | |
238 | static_branch_enable(&timers_nohz_active); | |
239 | mutex_unlock(&timer_keys_mutex); | |
240 | } | |
bc7a34b8 | 241 | |
ae67bada TG |
242 | void timers_update_nohz(void) |
243 | { | |
244 | schedule_work(&timer_update_work); | |
bc7a34b8 TG |
245 | } |
246 | ||
247 | int timer_migration_handler(struct ctl_table *table, int write, | |
248 | void __user *buffer, size_t *lenp, | |
249 | loff_t *ppos) | |
250 | { | |
bc7a34b8 TG |
251 | int ret; |
252 | ||
ae67bada | 253 | mutex_lock(&timer_keys_mutex); |
b94bf594 | 254 | ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
bc7a34b8 | 255 | if (!ret && write) |
ae67bada TG |
256 | timers_update_migration(); |
257 | mutex_unlock(&timer_keys_mutex); | |
bc7a34b8 TG |
258 | return ret; |
259 | } | |
14c80341 AMG |
260 | |
261 | static inline bool is_timers_nohz_active(void) | |
262 | { | |
263 | return static_branch_unlikely(&timers_nohz_active); | |
264 | } | |
265 | #else | |
266 | static inline bool is_timers_nohz_active(void) { return false; } | |
ae67bada | 267 | #endif /* NO_HZ_COMMON */ |
bc7a34b8 | 268 | |
9c133c46 AS |
269 | static unsigned long round_jiffies_common(unsigned long j, int cpu, |
270 | bool force_up) | |
4c36a5de AV |
271 | { |
272 | int rem; | |
273 | unsigned long original = j; | |
274 | ||
275 | /* | |
276 | * We don't want all cpus firing their timers at once hitting the | |
277 | * same lock or cachelines, so we skew each extra cpu with an extra | |
278 | * 3 jiffies. This 3 jiffies came originally from the mm/ code which | |
279 | * already did this. | |
280 | * The skew is done by adding 3*cpunr, then round, then subtract this | |
281 | * extra offset again. | |
282 | */ | |
283 | j += cpu * 3; | |
284 | ||
285 | rem = j % HZ; | |
286 | ||
287 | /* | |
288 | * If the target jiffie is just after a whole second (which can happen | |
289 | * due to delays of the timer irq, long irq off times etc etc) then | |
290 | * we should round down to the whole second, not up. Use 1/4th second | |
291 | * as cutoff for this rounding as an extreme upper bound for this. | |
9c133c46 | 292 | * But never round down if @force_up is set. |
4c36a5de | 293 | */ |
9c133c46 | 294 | if (rem < HZ/4 && !force_up) /* round down */ |
4c36a5de AV |
295 | j = j - rem; |
296 | else /* round up */ | |
297 | j = j - rem + HZ; | |
298 | ||
299 | /* now that we have rounded, subtract the extra skew again */ | |
300 | j -= cpu * 3; | |
301 | ||
9e04d380 BVA |
302 | /* |
303 | * Make sure j is still in the future. Otherwise return the | |
304 | * unmodified value. | |
305 | */ | |
306 | return time_is_after_jiffies(j) ? j : original; | |
4c36a5de | 307 | } |
9c133c46 AS |
308 | |
309 | /** | |
310 | * __round_jiffies - function to round jiffies to a full second | |
311 | * @j: the time in (absolute) jiffies that should be rounded | |
312 | * @cpu: the processor number on which the timeout will happen | |
313 | * | |
314 | * __round_jiffies() rounds an absolute time in the future (in jiffies) | |
315 | * up or down to (approximately) full seconds. This is useful for timers | |
316 | * for which the exact time they fire does not matter too much, as long as | |
317 | * they fire approximately every X seconds. | |
318 | * | |
319 | * By rounding these timers to whole seconds, all such timers will fire | |
320 | * at the same time, rather than at various times spread out. The goal | |
321 | * of this is to have the CPU wake up less, which saves power. | |
322 | * | |
323 | * The exact rounding is skewed for each processor to avoid all | |
324 | * processors firing at the exact same time, which could lead | |
325 | * to lock contention or spurious cache line bouncing. | |
326 | * | |
327 | * The return value is the rounded version of the @j parameter. | |
328 | */ | |
329 | unsigned long __round_jiffies(unsigned long j, int cpu) | |
330 | { | |
331 | return round_jiffies_common(j, cpu, false); | |
332 | } | |
4c36a5de AV |
333 | EXPORT_SYMBOL_GPL(__round_jiffies); |
334 | ||
335 | /** | |
336 | * __round_jiffies_relative - function to round jiffies to a full second | |
337 | * @j: the time in (relative) jiffies that should be rounded | |
338 | * @cpu: the processor number on which the timeout will happen | |
339 | * | |
72fd4a35 | 340 | * __round_jiffies_relative() rounds a time delta in the future (in jiffies) |
4c36a5de AV |
341 | * up or down to (approximately) full seconds. This is useful for timers |
342 | * for which the exact time they fire does not matter too much, as long as | |
343 | * they fire approximately every X seconds. | |
344 | * | |
345 | * By rounding these timers to whole seconds, all such timers will fire | |
346 | * at the same time, rather than at various times spread out. The goal | |
347 | * of this is to have the CPU wake up less, which saves power. | |
348 | * | |
349 | * The exact rounding is skewed for each processor to avoid all | |
350 | * processors firing at the exact same time, which could lead | |
351 | * to lock contention or spurious cache line bouncing. | |
352 | * | |
72fd4a35 | 353 | * The return value is the rounded version of the @j parameter. |
4c36a5de AV |
354 | */ |
355 | unsigned long __round_jiffies_relative(unsigned long j, int cpu) | |
356 | { | |
9c133c46 AS |
357 | unsigned long j0 = jiffies; |
358 | ||
359 | /* Use j0 because jiffies might change while we run */ | |
360 | return round_jiffies_common(j + j0, cpu, false) - j0; | |
4c36a5de AV |
361 | } |
362 | EXPORT_SYMBOL_GPL(__round_jiffies_relative); | |
363 | ||
364 | /** | |
365 | * round_jiffies - function to round jiffies to a full second | |
366 | * @j: the time in (absolute) jiffies that should be rounded | |
367 | * | |
72fd4a35 | 368 | * round_jiffies() rounds an absolute time in the future (in jiffies) |
4c36a5de AV |
369 | * up or down to (approximately) full seconds. This is useful for timers |
370 | * for which the exact time they fire does not matter too much, as long as | |
371 | * they fire approximately every X seconds. | |
372 | * | |
373 | * By rounding these timers to whole seconds, all such timers will fire | |
374 | * at the same time, rather than at various times spread out. The goal | |
375 | * of this is to have the CPU wake up less, which saves power. | |
376 | * | |
72fd4a35 | 377 | * The return value is the rounded version of the @j parameter. |
4c36a5de AV |
378 | */ |
379 | unsigned long round_jiffies(unsigned long j) | |
380 | { | |
9c133c46 | 381 | return round_jiffies_common(j, raw_smp_processor_id(), false); |
4c36a5de AV |
382 | } |
383 | EXPORT_SYMBOL_GPL(round_jiffies); | |
384 | ||
385 | /** | |
386 | * round_jiffies_relative - function to round jiffies to a full second | |
387 | * @j: the time in (relative) jiffies that should be rounded | |
388 | * | |
72fd4a35 | 389 | * round_jiffies_relative() rounds a time delta in the future (in jiffies) |
4c36a5de AV |
390 | * up or down to (approximately) full seconds. This is useful for timers |
391 | * for which the exact time they fire does not matter too much, as long as | |
392 | * they fire approximately every X seconds. | |
393 | * | |
394 | * By rounding these timers to whole seconds, all such timers will fire | |
395 | * at the same time, rather than at various times spread out. The goal | |
396 | * of this is to have the CPU wake up less, which saves power. | |
397 | * | |
72fd4a35 | 398 | * The return value is the rounded version of the @j parameter. |
4c36a5de AV |
399 | */ |
400 | unsigned long round_jiffies_relative(unsigned long j) | |
401 | { | |
402 | return __round_jiffies_relative(j, raw_smp_processor_id()); | |
403 | } | |
404 | EXPORT_SYMBOL_GPL(round_jiffies_relative); | |
405 | ||
9c133c46 AS |
406 | /** |
407 | * __round_jiffies_up - function to round jiffies up to a full second | |
408 | * @j: the time in (absolute) 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() 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(unsigned long j, int cpu) | |
417 | { | |
418 | return round_jiffies_common(j, cpu, true); | |
419 | } | |
420 | EXPORT_SYMBOL_GPL(__round_jiffies_up); | |
421 | ||
422 | /** | |
423 | * __round_jiffies_up_relative - function to round jiffies up to a full second | |
424 | * @j: the time in (relative) jiffies that should be rounded | |
425 | * @cpu: the processor number on which the timeout will happen | |
426 | * | |
427 | * This is the same as __round_jiffies_relative() except that it will never | |
428 | * round down. This is useful for timeouts for which the exact time | |
429 | * of firing does not matter too much, as long as they don't fire too | |
430 | * early. | |
431 | */ | |
432 | unsigned long __round_jiffies_up_relative(unsigned long j, int cpu) | |
433 | { | |
434 | unsigned long j0 = jiffies; | |
435 | ||
436 | /* Use j0 because jiffies might change while we run */ | |
437 | return round_jiffies_common(j + j0, cpu, true) - j0; | |
438 | } | |
439 | EXPORT_SYMBOL_GPL(__round_jiffies_up_relative); | |
440 | ||
441 | /** | |
442 | * round_jiffies_up - function to round jiffies up to a full second | |
443 | * @j: the time in (absolute) jiffies that should be rounded | |
444 | * | |
445 | * This is the same as round_jiffies() except that it will never | |
446 | * round down. This is useful for timeouts for which the exact time | |
447 | * of firing does not matter too much, as long as they don't fire too | |
448 | * early. | |
449 | */ | |
450 | unsigned long round_jiffies_up(unsigned long j) | |
451 | { | |
452 | return round_jiffies_common(j, raw_smp_processor_id(), true); | |
453 | } | |
454 | EXPORT_SYMBOL_GPL(round_jiffies_up); | |
455 | ||
456 | /** | |
457 | * round_jiffies_up_relative - function to round jiffies up to a full second | |
458 | * @j: the time in (relative) jiffies that should be rounded | |
459 | * | |
460 | * This is the same as round_jiffies_relative() except that it will never | |
461 | * round down. This is useful for timeouts for which the exact time | |
462 | * of firing does not matter too much, as long as they don't fire too | |
463 | * early. | |
464 | */ | |
465 | unsigned long round_jiffies_up_relative(unsigned long j) | |
466 | { | |
467 | return __round_jiffies_up_relative(j, raw_smp_processor_id()); | |
468 | } | |
469 | EXPORT_SYMBOL_GPL(round_jiffies_up_relative); | |
470 | ||
3bbb9ec9 | 471 | |
500462a9 | 472 | static inline unsigned int timer_get_idx(struct timer_list *timer) |
3bbb9ec9 | 473 | { |
500462a9 | 474 | return (timer->flags & TIMER_ARRAYMASK) >> TIMER_ARRAYSHIFT; |
3bbb9ec9 | 475 | } |
3bbb9ec9 | 476 | |
500462a9 | 477 | static inline void timer_set_idx(struct timer_list *timer, unsigned int idx) |
1da177e4 | 478 | { |
500462a9 TG |
479 | timer->flags = (timer->flags & ~TIMER_ARRAYMASK) | |
480 | idx << TIMER_ARRAYSHIFT; | |
481 | } | |
1da177e4 | 482 | |
500462a9 TG |
483 | /* |
484 | * Helper function to calculate the array index for a given expiry | |
485 | * time. | |
486 | */ | |
487 | static inline unsigned calc_index(unsigned expires, unsigned lvl) | |
488 | { | |
489 | expires = (expires + LVL_GRAN(lvl)) >> LVL_SHIFT(lvl); | |
490 | return LVL_OFFS(lvl) + (expires & LVL_MASK); | |
491 | } | |
492 | ||
ffdf0477 | 493 | static int calc_wheel_index(unsigned long expires, unsigned long clk) |
1da177e4 | 494 | { |
ffdf0477 | 495 | unsigned long delta = expires - clk; |
500462a9 TG |
496 | unsigned int idx; |
497 | ||
498 | if (delta < LVL_START(1)) { | |
499 | idx = calc_index(expires, 0); | |
500 | } else if (delta < LVL_START(2)) { | |
501 | idx = calc_index(expires, 1); | |
502 | } else if (delta < LVL_START(3)) { | |
503 | idx = calc_index(expires, 2); | |
504 | } else if (delta < LVL_START(4)) { | |
505 | idx = calc_index(expires, 3); | |
506 | } else if (delta < LVL_START(5)) { | |
507 | idx = calc_index(expires, 4); | |
508 | } else if (delta < LVL_START(6)) { | |
509 | idx = calc_index(expires, 5); | |
510 | } else if (delta < LVL_START(7)) { | |
511 | idx = calc_index(expires, 6); | |
512 | } else if (LVL_DEPTH > 8 && delta < LVL_START(8)) { | |
513 | idx = calc_index(expires, 7); | |
514 | } else if ((long) delta < 0) { | |
ffdf0477 | 515 | idx = clk & LVL_MASK; |
1da177e4 | 516 | } else { |
500462a9 TG |
517 | /* |
518 | * Force expire obscene large timeouts to expire at the | |
519 | * capacity limit of the wheel. | |
1da177e4 | 520 | */ |
500462a9 TG |
521 | if (expires >= WHEEL_TIMEOUT_CUTOFF) |
522 | expires = WHEEL_TIMEOUT_MAX; | |
1bd04bf6 | 523 | |
500462a9 | 524 | idx = calc_index(expires, LVL_DEPTH - 1); |
1da177e4 | 525 | } |
ffdf0477 AMG |
526 | return idx; |
527 | } | |
1bd04bf6 | 528 | |
ffdf0477 AMG |
529 | /* |
530 | * Enqueue the timer into the hash bucket, mark it pending in | |
531 | * the bitmap and store the index in the timer flags. | |
532 | */ | |
533 | static void enqueue_timer(struct timer_base *base, struct timer_list *timer, | |
534 | unsigned int idx) | |
535 | { | |
536 | hlist_add_head(&timer->entry, base->vectors + idx); | |
500462a9 TG |
537 | __set_bit(idx, base->pending_map); |
538 | timer_set_idx(timer, idx); | |
1da177e4 LT |
539 | } |
540 | ||
ffdf0477 AMG |
541 | static void |
542 | __internal_add_timer(struct timer_base *base, struct timer_list *timer) | |
facbb4a7 | 543 | { |
ffdf0477 AMG |
544 | unsigned int idx; |
545 | ||
546 | idx = calc_wheel_index(timer->expires, base->clk); | |
547 | enqueue_timer(base, timer, idx); | |
548 | } | |
9f6d9baa | 549 | |
ffdf0477 AMG |
550 | static void |
551 | trigger_dyntick_cpu(struct timer_base *base, struct timer_list *timer) | |
552 | { | |
ae67bada | 553 | if (!is_timers_nohz_active()) |
a683f390 | 554 | return; |
3bb475a3 | 555 | |
facbb4a7 | 556 | /* |
a683f390 TG |
557 | * TODO: This wants some optimizing similar to the code below, but we |
558 | * will do that when we switch from push to pull for deferrable timers. | |
facbb4a7 | 559 | */ |
a683f390 TG |
560 | if (timer->flags & TIMER_DEFERRABLE) { |
561 | if (tick_nohz_full_cpu(base->cpu)) | |
683be13a | 562 | wake_up_nohz_cpu(base->cpu); |
a683f390 | 563 | return; |
99d5f3aa | 564 | } |
9f6d9baa VK |
565 | |
566 | /* | |
a683f390 TG |
567 | * We might have to IPI the remote CPU if the base is idle and the |
568 | * timer is not deferrable. If the other CPU is on the way to idle | |
569 | * then it can't set base->is_idle as we hold the base lock: | |
9f6d9baa | 570 | */ |
a683f390 TG |
571 | if (!base->is_idle) |
572 | return; | |
573 | ||
574 | /* Check whether this is the new first expiring timer: */ | |
575 | if (time_after_eq(timer->expires, base->next_expiry)) | |
576 | return; | |
577 | ||
578 | /* | |
579 | * Set the next expiry time and kick the CPU so it can reevaluate the | |
580 | * wheel: | |
581 | */ | |
582 | base->next_expiry = timer->expires; | |
30587589 | 583 | wake_up_nohz_cpu(base->cpu); |
ffdf0477 AMG |
584 | } |
585 | ||
586 | static void | |
587 | internal_add_timer(struct timer_base *base, struct timer_list *timer) | |
588 | { | |
589 | __internal_add_timer(base, timer); | |
590 | trigger_dyntick_cpu(base, timer); | |
facbb4a7 TG |
591 | } |
592 | ||
c6f3a97f TG |
593 | #ifdef CONFIG_DEBUG_OBJECTS_TIMERS |
594 | ||
595 | static struct debug_obj_descr timer_debug_descr; | |
596 | ||
99777288 SG |
597 | static void *timer_debug_hint(void *addr) |
598 | { | |
599 | return ((struct timer_list *) addr)->function; | |
600 | } | |
601 | ||
b9fdac7f DC |
602 | static bool timer_is_static_object(void *addr) |
603 | { | |
604 | struct timer_list *timer = addr; | |
605 | ||
606 | return (timer->entry.pprev == NULL && | |
607 | timer->entry.next == TIMER_ENTRY_STATIC); | |
608 | } | |
609 | ||
c6f3a97f TG |
610 | /* |
611 | * fixup_init is called when: | |
612 | * - an active object is initialized | |
55c888d6 | 613 | */ |
e3252464 | 614 | static bool timer_fixup_init(void *addr, enum debug_obj_state state) |
c6f3a97f TG |
615 | { |
616 | struct timer_list *timer = addr; | |
617 | ||
618 | switch (state) { | |
619 | case ODEBUG_STATE_ACTIVE: | |
620 | del_timer_sync(timer); | |
621 | debug_object_init(timer, &timer_debug_descr); | |
e3252464 | 622 | return true; |
c6f3a97f | 623 | default: |
e3252464 | 624 | return false; |
c6f3a97f TG |
625 | } |
626 | } | |
627 | ||
fb16b8cf | 628 | /* Stub timer callback for improperly used timers. */ |
ba16490e | 629 | static void stub_timer(struct timer_list *unused) |
fb16b8cf SB |
630 | { |
631 | WARN_ON(1); | |
632 | } | |
633 | ||
c6f3a97f TG |
634 | /* |
635 | * fixup_activate is called when: | |
636 | * - an active object is activated | |
b9fdac7f | 637 | * - an unknown non-static object is activated |
c6f3a97f | 638 | */ |
e3252464 | 639 | static bool timer_fixup_activate(void *addr, enum debug_obj_state state) |
c6f3a97f TG |
640 | { |
641 | struct timer_list *timer = addr; | |
642 | ||
643 | switch (state) { | |
c6f3a97f | 644 | case ODEBUG_STATE_NOTAVAILABLE: |
ba16490e | 645 | timer_setup(timer, stub_timer, 0); |
b9fdac7f | 646 | return true; |
c6f3a97f TG |
647 | |
648 | case ODEBUG_STATE_ACTIVE: | |
649 | WARN_ON(1); | |
75b710af | 650 | /* fall through */ |
c6f3a97f | 651 | default: |
e3252464 | 652 | return false; |
c6f3a97f TG |
653 | } |
654 | } | |
655 | ||
656 | /* | |
657 | * fixup_free is called when: | |
658 | * - an active object is freed | |
659 | */ | |
e3252464 | 660 | static bool timer_fixup_free(void *addr, enum debug_obj_state state) |
c6f3a97f TG |
661 | { |
662 | struct timer_list *timer = addr; | |
663 | ||
664 | switch (state) { | |
665 | case ODEBUG_STATE_ACTIVE: | |
666 | del_timer_sync(timer); | |
667 | debug_object_free(timer, &timer_debug_descr); | |
e3252464 | 668 | return true; |
c6f3a97f | 669 | default: |
e3252464 | 670 | return false; |
c6f3a97f TG |
671 | } |
672 | } | |
673 | ||
dc4218bd CC |
674 | /* |
675 | * fixup_assert_init is called when: | |
676 | * - an untracked/uninit-ed object is found | |
677 | */ | |
e3252464 | 678 | static bool timer_fixup_assert_init(void *addr, enum debug_obj_state state) |
dc4218bd CC |
679 | { |
680 | struct timer_list *timer = addr; | |
681 | ||
682 | switch (state) { | |
683 | case ODEBUG_STATE_NOTAVAILABLE: | |
ba16490e | 684 | timer_setup(timer, stub_timer, 0); |
b9fdac7f | 685 | return true; |
dc4218bd | 686 | default: |
e3252464 | 687 | return false; |
dc4218bd CC |
688 | } |
689 | } | |
690 | ||
c6f3a97f | 691 | static struct debug_obj_descr timer_debug_descr = { |
dc4218bd CC |
692 | .name = "timer_list", |
693 | .debug_hint = timer_debug_hint, | |
b9fdac7f | 694 | .is_static_object = timer_is_static_object, |
dc4218bd CC |
695 | .fixup_init = timer_fixup_init, |
696 | .fixup_activate = timer_fixup_activate, | |
697 | .fixup_free = timer_fixup_free, | |
698 | .fixup_assert_init = timer_fixup_assert_init, | |
c6f3a97f TG |
699 | }; |
700 | ||
701 | static inline void debug_timer_init(struct timer_list *timer) | |
702 | { | |
703 | debug_object_init(timer, &timer_debug_descr); | |
704 | } | |
705 | ||
706 | static inline void debug_timer_activate(struct timer_list *timer) | |
707 | { | |
708 | debug_object_activate(timer, &timer_debug_descr); | |
709 | } | |
710 | ||
711 | static inline void debug_timer_deactivate(struct timer_list *timer) | |
712 | { | |
713 | debug_object_deactivate(timer, &timer_debug_descr); | |
714 | } | |
715 | ||
716 | static inline void debug_timer_free(struct timer_list *timer) | |
717 | { | |
718 | debug_object_free(timer, &timer_debug_descr); | |
719 | } | |
720 | ||
dc4218bd CC |
721 | static inline void debug_timer_assert_init(struct timer_list *timer) |
722 | { | |
723 | debug_object_assert_init(timer, &timer_debug_descr); | |
724 | } | |
725 | ||
188665b2 KC |
726 | static void do_init_timer(struct timer_list *timer, |
727 | void (*func)(struct timer_list *), | |
728 | unsigned int flags, | |
fc683995 | 729 | const char *name, struct lock_class_key *key); |
c6f3a97f | 730 | |
188665b2 KC |
731 | void init_timer_on_stack_key(struct timer_list *timer, |
732 | void (*func)(struct timer_list *), | |
733 | unsigned int flags, | |
fc683995 | 734 | const char *name, struct lock_class_key *key) |
c6f3a97f TG |
735 | { |
736 | debug_object_init_on_stack(timer, &timer_debug_descr); | |
188665b2 | 737 | do_init_timer(timer, func, flags, name, key); |
c6f3a97f | 738 | } |
6f2b9b9a | 739 | EXPORT_SYMBOL_GPL(init_timer_on_stack_key); |
c6f3a97f TG |
740 | |
741 | void destroy_timer_on_stack(struct timer_list *timer) | |
742 | { | |
743 | debug_object_free(timer, &timer_debug_descr); | |
744 | } | |
745 | EXPORT_SYMBOL_GPL(destroy_timer_on_stack); | |
746 | ||
747 | #else | |
748 | static inline void debug_timer_init(struct timer_list *timer) { } | |
749 | static inline void debug_timer_activate(struct timer_list *timer) { } | |
750 | static inline void debug_timer_deactivate(struct timer_list *timer) { } | |
dc4218bd | 751 | static inline void debug_timer_assert_init(struct timer_list *timer) { } |
c6f3a97f TG |
752 | #endif |
753 | ||
2b022e3d XG |
754 | static inline void debug_init(struct timer_list *timer) |
755 | { | |
756 | debug_timer_init(timer); | |
757 | trace_timer_init(timer); | |
758 | } | |
759 | ||
760 | static inline void | |
761 | debug_activate(struct timer_list *timer, unsigned long expires) | |
762 | { | |
763 | debug_timer_activate(timer); | |
0eeda71b | 764 | trace_timer_start(timer, expires, timer->flags); |
2b022e3d XG |
765 | } |
766 | ||
767 | static inline void debug_deactivate(struct timer_list *timer) | |
768 | { | |
769 | debug_timer_deactivate(timer); | |
770 | trace_timer_cancel(timer); | |
771 | } | |
772 | ||
dc4218bd CC |
773 | static inline void debug_assert_init(struct timer_list *timer) |
774 | { | |
775 | debug_timer_assert_init(timer); | |
776 | } | |
777 | ||
188665b2 KC |
778 | static void do_init_timer(struct timer_list *timer, |
779 | void (*func)(struct timer_list *), | |
780 | unsigned int flags, | |
fc683995 | 781 | const char *name, struct lock_class_key *key) |
55c888d6 | 782 | { |
1dabbcec | 783 | timer->entry.pprev = NULL; |
188665b2 | 784 | timer->function = func; |
0eeda71b | 785 | timer->flags = flags | raw_smp_processor_id(); |
6f2b9b9a | 786 | lockdep_init_map(&timer->lockdep_map, name, key, 0); |
55c888d6 | 787 | } |
c6f3a97f TG |
788 | |
789 | /** | |
633fe795 | 790 | * init_timer_key - initialize a timer |
c6f3a97f | 791 | * @timer: the timer to be initialized |
188665b2 | 792 | * @func: timer callback function |
fc683995 | 793 | * @flags: timer flags |
633fe795 RD |
794 | * @name: name of the timer |
795 | * @key: lockdep class key of the fake lock used for tracking timer | |
796 | * sync lock dependencies | |
c6f3a97f | 797 | * |
633fe795 | 798 | * init_timer_key() must be done to a timer prior calling *any* of the |
c6f3a97f TG |
799 | * other timer functions. |
800 | */ | |
188665b2 KC |
801 | void init_timer_key(struct timer_list *timer, |
802 | void (*func)(struct timer_list *), unsigned int flags, | |
fc683995 | 803 | const char *name, struct lock_class_key *key) |
c6f3a97f | 804 | { |
2b022e3d | 805 | debug_init(timer); |
188665b2 | 806 | do_init_timer(timer, func, flags, name, key); |
c6f3a97f | 807 | } |
6f2b9b9a | 808 | EXPORT_SYMBOL(init_timer_key); |
55c888d6 | 809 | |
ec44bc7a | 810 | static inline void detach_timer(struct timer_list *timer, bool clear_pending) |
55c888d6 | 811 | { |
1dabbcec | 812 | struct hlist_node *entry = &timer->entry; |
55c888d6 | 813 | |
2b022e3d | 814 | debug_deactivate(timer); |
c6f3a97f | 815 | |
1dabbcec | 816 | __hlist_del(entry); |
55c888d6 | 817 | if (clear_pending) |
1dabbcec TG |
818 | entry->pprev = NULL; |
819 | entry->next = LIST_POISON2; | |
55c888d6 ON |
820 | } |
821 | ||
494af3ed | 822 | static int detach_if_pending(struct timer_list *timer, struct timer_base *base, |
ec44bc7a TG |
823 | bool clear_pending) |
824 | { | |
500462a9 TG |
825 | unsigned idx = timer_get_idx(timer); |
826 | ||
ec44bc7a TG |
827 | if (!timer_pending(timer)) |
828 | return 0; | |
829 | ||
500462a9 TG |
830 | if (hlist_is_singular_node(&timer->entry, base->vectors + idx)) |
831 | __clear_bit(idx, base->pending_map); | |
832 | ||
ec44bc7a | 833 | detach_timer(timer, clear_pending); |
ec44bc7a TG |
834 | return 1; |
835 | } | |
836 | ||
500462a9 TG |
837 | static inline struct timer_base *get_timer_cpu_base(u32 tflags, u32 cpu) |
838 | { | |
839 | struct timer_base *base = per_cpu_ptr(&timer_bases[BASE_STD], cpu); | |
840 | ||
841 | /* | |
ced6d5c1 AMG |
842 | * If the timer is deferrable and NO_HZ_COMMON is set then we need |
843 | * to use the deferrable base. | |
500462a9 | 844 | */ |
ced6d5c1 | 845 | if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && (tflags & TIMER_DEFERRABLE)) |
500462a9 TG |
846 | base = per_cpu_ptr(&timer_bases[BASE_DEF], cpu); |
847 | return base; | |
848 | } | |
849 | ||
850 | static inline struct timer_base *get_timer_this_cpu_base(u32 tflags) | |
851 | { | |
852 | struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); | |
853 | ||
854 | /* | |
ced6d5c1 AMG |
855 | * If the timer is deferrable and NO_HZ_COMMON is set then we need |
856 | * to use the deferrable base. | |
500462a9 | 857 | */ |
ced6d5c1 | 858 | if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && (tflags & TIMER_DEFERRABLE)) |
500462a9 TG |
859 | base = this_cpu_ptr(&timer_bases[BASE_DEF]); |
860 | return base; | |
861 | } | |
862 | ||
863 | static inline struct timer_base *get_timer_base(u32 tflags) | |
864 | { | |
865 | return get_timer_cpu_base(tflags, tflags & TIMER_CPUMASK); | |
866 | } | |
867 | ||
a683f390 | 868 | static inline struct timer_base * |
6bad6bcc | 869 | get_target_base(struct timer_base *base, unsigned tflags) |
500462a9 | 870 | { |
ae67bada TG |
871 | #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON) |
872 | if (static_branch_likely(&timers_migration_enabled) && | |
873 | !(tflags & TIMER_PINNED)) | |
874 | return get_timer_cpu_base(tflags, get_nohz_timer_target()); | |
500462a9 | 875 | #endif |
ae67bada | 876 | return get_timer_this_cpu_base(tflags); |
500462a9 TG |
877 | } |
878 | ||
a683f390 TG |
879 | static inline void forward_timer_base(struct timer_base *base) |
880 | { | |
ae67bada | 881 | #ifdef CONFIG_NO_HZ_COMMON |
2fe59f50 | 882 | unsigned long jnow; |
6bad6bcc | 883 | |
a683f390 | 884 | /* |
2fe59f50 NP |
885 | * We only forward the base when we are idle or have just come out of |
886 | * idle (must_forward_clk logic), and have a delta between base clock | |
887 | * and jiffies. In the common case, run_timers will take care of it. | |
a683f390 | 888 | */ |
2fe59f50 NP |
889 | if (likely(!base->must_forward_clk)) |
890 | return; | |
891 | ||
892 | jnow = READ_ONCE(jiffies); | |
893 | base->must_forward_clk = base->is_idle; | |
894 | if ((long)(jnow - base->clk) < 2) | |
a683f390 TG |
895 | return; |
896 | ||
897 | /* | |
898 | * If the next expiry value is > jiffies, then we fast forward to | |
899 | * jiffies otherwise we forward to the next expiry value. | |
900 | */ | |
6bad6bcc TG |
901 | if (time_after(base->next_expiry, jnow)) |
902 | base->clk = jnow; | |
a683f390 TG |
903 | else |
904 | base->clk = base->next_expiry; | |
a683f390 | 905 | #endif |
ae67bada | 906 | } |
a683f390 | 907 | |
a683f390 | 908 | |
55c888d6 | 909 | /* |
500462a9 TG |
910 | * We are using hashed locking: Holding per_cpu(timer_bases[x]).lock means |
911 | * that all timers which are tied to this base are locked, and the base itself | |
912 | * is locked too. | |
55c888d6 ON |
913 | * |
914 | * So __run_timers/migrate_timers can safely modify all timers which could | |
500462a9 | 915 | * be found in the base->vectors array. |
55c888d6 | 916 | * |
500462a9 TG |
917 | * When a timer is migrating then the TIMER_MIGRATING flag is set and we need |
918 | * to wait until the migration is done. | |
55c888d6 | 919 | */ |
494af3ed | 920 | static struct timer_base *lock_timer_base(struct timer_list *timer, |
500462a9 | 921 | unsigned long *flags) |
89e7e374 | 922 | __acquires(timer->base->lock) |
55c888d6 | 923 | { |
55c888d6 | 924 | for (;;) { |
494af3ed | 925 | struct timer_base *base; |
b831275a TG |
926 | u32 tf; |
927 | ||
928 | /* | |
929 | * We need to use READ_ONCE() here, otherwise the compiler | |
930 | * might re-read @tf between the check for TIMER_MIGRATING | |
931 | * and spin_lock(). | |
932 | */ | |
933 | tf = READ_ONCE(timer->flags); | |
0eeda71b TG |
934 | |
935 | if (!(tf & TIMER_MIGRATING)) { | |
500462a9 | 936 | base = get_timer_base(tf); |
2287d866 | 937 | raw_spin_lock_irqsave(&base->lock, *flags); |
0eeda71b | 938 | if (timer->flags == tf) |
55c888d6 | 939 | return base; |
2287d866 | 940 | raw_spin_unlock_irqrestore(&base->lock, *flags); |
55c888d6 ON |
941 | } |
942 | cpu_relax(); | |
943 | } | |
944 | } | |
945 | ||
b24591e2 DH |
946 | #define MOD_TIMER_PENDING_ONLY 0x01 |
947 | #define MOD_TIMER_REDUCE 0x02 | |
948 | ||
74019224 | 949 | static inline int |
b24591e2 | 950 | __mod_timer(struct timer_list *timer, unsigned long expires, unsigned int options) |
1da177e4 | 951 | { |
494af3ed | 952 | struct timer_base *base, *new_base; |
f00c0afd AMG |
953 | unsigned int idx = UINT_MAX; |
954 | unsigned long clk = 0, flags; | |
bc7a34b8 | 955 | int ret = 0; |
1da177e4 | 956 | |
4da9152a TG |
957 | BUG_ON(!timer->function); |
958 | ||
500462a9 | 959 | /* |
f00c0afd AMG |
960 | * This is a common optimization triggered by the networking code - if |
961 | * the timer is re-modified to have the same timeout or ends up in the | |
962 | * same array bucket then just return: | |
500462a9 TG |
963 | */ |
964 | if (timer_pending(timer)) { | |
2fe59f50 NP |
965 | /* |
966 | * The downside of this optimization is that it can result in | |
967 | * larger granularity than you would get from adding a new | |
968 | * timer with this expiry. | |
969 | */ | |
b24591e2 DH |
970 | long diff = timer->expires - expires; |
971 | ||
972 | if (!diff) | |
973 | return 1; | |
974 | if (options & MOD_TIMER_REDUCE && diff <= 0) | |
500462a9 | 975 | return 1; |
4da9152a | 976 | |
f00c0afd | 977 | /* |
4da9152a TG |
978 | * We lock timer base and calculate the bucket index right |
979 | * here. If the timer ends up in the same bucket, then we | |
980 | * just update the expiry time and avoid the whole | |
981 | * dequeue/enqueue dance. | |
f00c0afd | 982 | */ |
4da9152a | 983 | base = lock_timer_base(timer, &flags); |
2fe59f50 | 984 | forward_timer_base(base); |
f00c0afd | 985 | |
b24591e2 DH |
986 | if (timer_pending(timer) && (options & MOD_TIMER_REDUCE) && |
987 | time_before_eq(timer->expires, expires)) { | |
988 | ret = 1; | |
989 | goto out_unlock; | |
990 | } | |
991 | ||
4da9152a | 992 | clk = base->clk; |
f00c0afd AMG |
993 | idx = calc_wheel_index(expires, clk); |
994 | ||
995 | /* | |
996 | * Retrieve and compare the array index of the pending | |
997 | * timer. If it matches set the expiry to the new value so a | |
998 | * subsequent call will exit in the expires check above. | |
999 | */ | |
1000 | if (idx == timer_get_idx(timer)) { | |
b24591e2 DH |
1001 | if (!(options & MOD_TIMER_REDUCE)) |
1002 | timer->expires = expires; | |
1003 | else if (time_after(timer->expires, expires)) | |
1004 | timer->expires = expires; | |
4da9152a TG |
1005 | ret = 1; |
1006 | goto out_unlock; | |
f00c0afd | 1007 | } |
4da9152a TG |
1008 | } else { |
1009 | base = lock_timer_base(timer, &flags); | |
2fe59f50 | 1010 | forward_timer_base(base); |
500462a9 TG |
1011 | } |
1012 | ||
ec44bc7a | 1013 | ret = detach_if_pending(timer, base, false); |
b24591e2 | 1014 | if (!ret && (options & MOD_TIMER_PENDING_ONLY)) |
ec44bc7a | 1015 | goto out_unlock; |
55c888d6 | 1016 | |
500462a9 | 1017 | new_base = get_target_base(base, timer->flags); |
eea08f32 | 1018 | |
3691c519 | 1019 | if (base != new_base) { |
1da177e4 | 1020 | /* |
500462a9 | 1021 | * We are trying to schedule the timer on the new base. |
55c888d6 ON |
1022 | * However we can't change timer's base while it is running, |
1023 | * otherwise del_timer_sync() can't detect that the timer's | |
500462a9 TG |
1024 | * handler yet has not finished. This also guarantees that the |
1025 | * timer is serialized wrt itself. | |
1da177e4 | 1026 | */ |
a2c348fe | 1027 | if (likely(base->running_timer != timer)) { |
55c888d6 | 1028 | /* See the comment in lock_timer_base() */ |
0eeda71b TG |
1029 | timer->flags |= TIMER_MIGRATING; |
1030 | ||
2287d866 | 1031 | raw_spin_unlock(&base->lock); |
a2c348fe | 1032 | base = new_base; |
2287d866 | 1033 | raw_spin_lock(&base->lock); |
d0023a14 ED |
1034 | WRITE_ONCE(timer->flags, |
1035 | (timer->flags & ~TIMER_BASEMASK) | base->cpu); | |
2fe59f50 | 1036 | forward_timer_base(base); |
1da177e4 LT |
1037 | } |
1038 | } | |
1039 | ||
fd45bb77 TG |
1040 | debug_activate(timer, expires); |
1041 | ||
1da177e4 | 1042 | timer->expires = expires; |
f00c0afd AMG |
1043 | /* |
1044 | * If 'idx' was calculated above and the base time did not advance | |
4da9152a TG |
1045 | * between calculating 'idx' and possibly switching the base, only |
1046 | * enqueue_timer() and trigger_dyntick_cpu() is required. Otherwise | |
1047 | * we need to (re)calculate the wheel index via | |
1048 | * internal_add_timer(). | |
f00c0afd AMG |
1049 | */ |
1050 | if (idx != UINT_MAX && clk == base->clk) { | |
1051 | enqueue_timer(base, timer, idx); | |
1052 | trigger_dyntick_cpu(base, timer); | |
1053 | } else { | |
1054 | internal_add_timer(base, timer); | |
1055 | } | |
74019224 IM |
1056 | |
1057 | out_unlock: | |
2287d866 | 1058 | raw_spin_unlock_irqrestore(&base->lock, flags); |
1da177e4 LT |
1059 | |
1060 | return ret; | |
1061 | } | |
1062 | ||
2aae4a10 | 1063 | /** |
74019224 IM |
1064 | * mod_timer_pending - modify a pending timer's timeout |
1065 | * @timer: the pending timer to be modified | |
1066 | * @expires: new timeout in jiffies | |
1da177e4 | 1067 | * |
74019224 IM |
1068 | * mod_timer_pending() is the same for pending timers as mod_timer(), |
1069 | * but will not re-activate and modify already deleted timers. | |
1070 | * | |
1071 | * It is useful for unserialized use of timers. | |
1da177e4 | 1072 | */ |
74019224 | 1073 | int mod_timer_pending(struct timer_list *timer, unsigned long expires) |
1da177e4 | 1074 | { |
b24591e2 | 1075 | return __mod_timer(timer, expires, MOD_TIMER_PENDING_ONLY); |
1da177e4 | 1076 | } |
74019224 | 1077 | EXPORT_SYMBOL(mod_timer_pending); |
1da177e4 | 1078 | |
2aae4a10 | 1079 | /** |
1da177e4 LT |
1080 | * mod_timer - modify a timer's timeout |
1081 | * @timer: the timer to be modified | |
2aae4a10 | 1082 | * @expires: new timeout in jiffies |
1da177e4 | 1083 | * |
72fd4a35 | 1084 | * mod_timer() is a more efficient way to update the expire field of an |
1da177e4 LT |
1085 | * active timer (if the timer is inactive it will be activated) |
1086 | * | |
1087 | * mod_timer(timer, expires) is equivalent to: | |
1088 | * | |
1089 | * del_timer(timer); timer->expires = expires; add_timer(timer); | |
1090 | * | |
1091 | * Note that if there are multiple unserialized concurrent users of the | |
1092 | * same timer, then mod_timer() is the only safe way to modify the timeout, | |
1093 | * since add_timer() cannot modify an already running timer. | |
1094 | * | |
1095 | * The function returns whether it has modified a pending timer or not. | |
1096 | * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an | |
1097 | * active timer returns 1.) | |
1098 | */ | |
1099 | int mod_timer(struct timer_list *timer, unsigned long expires) | |
1100 | { | |
b24591e2 | 1101 | return __mod_timer(timer, expires, 0); |
1da177e4 | 1102 | } |
1da177e4 LT |
1103 | EXPORT_SYMBOL(mod_timer); |
1104 | ||
b24591e2 DH |
1105 | /** |
1106 | * timer_reduce - Modify a timer's timeout if it would reduce the timeout | |
1107 | * @timer: The timer to be modified | |
1108 | * @expires: New timeout in jiffies | |
1109 | * | |
1110 | * timer_reduce() is very similar to mod_timer(), except that it will only | |
1111 | * modify a running timer if that would reduce the expiration time (it will | |
1112 | * start a timer that isn't running). | |
1113 | */ | |
1114 | int timer_reduce(struct timer_list *timer, unsigned long expires) | |
1115 | { | |
1116 | return __mod_timer(timer, expires, MOD_TIMER_REDUCE); | |
1117 | } | |
1118 | EXPORT_SYMBOL(timer_reduce); | |
1119 | ||
74019224 IM |
1120 | /** |
1121 | * add_timer - start a timer | |
1122 | * @timer: the timer to be added | |
1123 | * | |
c1eba5bc | 1124 | * The kernel will do a ->function(@timer) callback from the |
74019224 IM |
1125 | * timer interrupt at the ->expires point in the future. The |
1126 | * current time is 'jiffies'. | |
1127 | * | |
c1eba5bc KC |
1128 | * The timer's ->expires, ->function fields must be set prior calling this |
1129 | * function. | |
74019224 IM |
1130 | * |
1131 | * Timers with an ->expires field in the past will be executed in the next | |
1132 | * timer tick. | |
1133 | */ | |
1134 | void add_timer(struct timer_list *timer) | |
1135 | { | |
1136 | BUG_ON(timer_pending(timer)); | |
1137 | mod_timer(timer, timer->expires); | |
1138 | } | |
1139 | EXPORT_SYMBOL(add_timer); | |
1140 | ||
1141 | /** | |
1142 | * add_timer_on - start a timer on a particular CPU | |
1143 | * @timer: the timer to be added | |
1144 | * @cpu: the CPU to start it on | |
1145 | * | |
1146 | * This is not very scalable on SMP. Double adds are not possible. | |
1147 | */ | |
1148 | void add_timer_on(struct timer_list *timer, int cpu) | |
1149 | { | |
500462a9 | 1150 | struct timer_base *new_base, *base; |
74019224 IM |
1151 | unsigned long flags; |
1152 | ||
74019224 | 1153 | BUG_ON(timer_pending(timer) || !timer->function); |
22b886dd | 1154 | |
500462a9 TG |
1155 | new_base = get_timer_cpu_base(timer->flags, cpu); |
1156 | ||
22b886dd TH |
1157 | /* |
1158 | * If @timer was on a different CPU, it should be migrated with the | |
1159 | * old base locked to prevent other operations proceeding with the | |
1160 | * wrong base locked. See lock_timer_base(). | |
1161 | */ | |
1162 | base = lock_timer_base(timer, &flags); | |
1163 | if (base != new_base) { | |
1164 | timer->flags |= TIMER_MIGRATING; | |
1165 | ||
2287d866 | 1166 | raw_spin_unlock(&base->lock); |
22b886dd | 1167 | base = new_base; |
2287d866 | 1168 | raw_spin_lock(&base->lock); |
22b886dd TH |
1169 | WRITE_ONCE(timer->flags, |
1170 | (timer->flags & ~TIMER_BASEMASK) | cpu); | |
1171 | } | |
2fe59f50 | 1172 | forward_timer_base(base); |
22b886dd | 1173 | |
2b022e3d | 1174 | debug_activate(timer, timer->expires); |
74019224 | 1175 | internal_add_timer(base, timer); |
2287d866 | 1176 | raw_spin_unlock_irqrestore(&base->lock, flags); |
74019224 | 1177 | } |
a9862e05 | 1178 | EXPORT_SYMBOL_GPL(add_timer_on); |
74019224 | 1179 | |
2aae4a10 | 1180 | /** |
0ba42a59 | 1181 | * del_timer - deactivate a timer. |
1da177e4 LT |
1182 | * @timer: the timer to be deactivated |
1183 | * | |
1184 | * del_timer() deactivates a timer - this works on both active and inactive | |
1185 | * timers. | |
1186 | * | |
1187 | * The function returns whether it has deactivated a pending timer or not. | |
1188 | * (ie. del_timer() of an inactive timer returns 0, del_timer() of an | |
1189 | * active timer returns 1.) | |
1190 | */ | |
1191 | int del_timer(struct timer_list *timer) | |
1192 | { | |
494af3ed | 1193 | struct timer_base *base; |
1da177e4 | 1194 | unsigned long flags; |
55c888d6 | 1195 | int ret = 0; |
1da177e4 | 1196 | |
dc4218bd CC |
1197 | debug_assert_init(timer); |
1198 | ||
55c888d6 ON |
1199 | if (timer_pending(timer)) { |
1200 | base = lock_timer_base(timer, &flags); | |
ec44bc7a | 1201 | ret = detach_if_pending(timer, base, true); |
2287d866 | 1202 | raw_spin_unlock_irqrestore(&base->lock, flags); |
1da177e4 | 1203 | } |
1da177e4 | 1204 | |
55c888d6 | 1205 | return ret; |
1da177e4 | 1206 | } |
1da177e4 LT |
1207 | EXPORT_SYMBOL(del_timer); |
1208 | ||
2aae4a10 REB |
1209 | /** |
1210 | * try_to_del_timer_sync - Try to deactivate a timer | |
d15bc69a | 1211 | * @timer: timer to delete |
2aae4a10 | 1212 | * |
fd450b73 ON |
1213 | * This function tries to deactivate a timer. Upon successful (ret >= 0) |
1214 | * exit the timer is not queued and the handler is not running on any CPU. | |
fd450b73 ON |
1215 | */ |
1216 | int try_to_del_timer_sync(struct timer_list *timer) | |
1217 | { | |
494af3ed | 1218 | struct timer_base *base; |
fd450b73 ON |
1219 | unsigned long flags; |
1220 | int ret = -1; | |
1221 | ||
dc4218bd CC |
1222 | debug_assert_init(timer); |
1223 | ||
fd450b73 ON |
1224 | base = lock_timer_base(timer, &flags); |
1225 | ||
dfb4357d | 1226 | if (base->running_timer != timer) |
ec44bc7a | 1227 | ret = detach_if_pending(timer, base, true); |
dfb4357d | 1228 | |
2287d866 | 1229 | raw_spin_unlock_irqrestore(&base->lock, flags); |
fd450b73 ON |
1230 | |
1231 | return ret; | |
1232 | } | |
e19dff1f DH |
1233 | EXPORT_SYMBOL(try_to_del_timer_sync); |
1234 | ||
6f1bc451 | 1235 | #ifdef CONFIG_SMP |
2aae4a10 | 1236 | /** |
1da177e4 LT |
1237 | * del_timer_sync - deactivate a timer and wait for the handler to finish. |
1238 | * @timer: the timer to be deactivated | |
1239 | * | |
1240 | * This function only differs from del_timer() on SMP: besides deactivating | |
1241 | * the timer it also makes sure the handler has finished executing on other | |
1242 | * CPUs. | |
1243 | * | |
72fd4a35 | 1244 | * Synchronization rules: Callers must prevent restarting of the timer, |
1da177e4 | 1245 | * otherwise this function is meaningless. It must not be called from |
c5f66e99 TH |
1246 | * interrupt contexts unless the timer is an irqsafe one. The caller must |
1247 | * not hold locks which would prevent completion of the timer's | |
1248 | * handler. The timer's handler must not call add_timer_on(). Upon exit the | |
1249 | * timer is not queued and the handler is not running on any CPU. | |
1da177e4 | 1250 | * |
c5f66e99 TH |
1251 | * Note: For !irqsafe timers, you must not hold locks that are held in |
1252 | * interrupt context while calling this function. Even if the lock has | |
bf9c96be | 1253 | * nothing to do with the timer in question. Here's why:: |
48228f7b SR |
1254 | * |
1255 | * CPU0 CPU1 | |
1256 | * ---- ---- | |
bf9c96be MCC |
1257 | * <SOFTIRQ> |
1258 | * call_timer_fn(); | |
1259 | * base->running_timer = mytimer; | |
1260 | * spin_lock_irq(somelock); | |
48228f7b SR |
1261 | * <IRQ> |
1262 | * spin_lock(somelock); | |
bf9c96be MCC |
1263 | * del_timer_sync(mytimer); |
1264 | * while (base->running_timer == mytimer); | |
48228f7b SR |
1265 | * |
1266 | * Now del_timer_sync() will never return and never release somelock. | |
1267 | * The interrupt on the other CPU is waiting to grab somelock but | |
1268 | * it has interrupted the softirq that CPU0 is waiting to finish. | |
1269 | * | |
1da177e4 | 1270 | * The function returns whether it has deactivated a pending timer or not. |
1da177e4 LT |
1271 | */ |
1272 | int del_timer_sync(struct timer_list *timer) | |
1273 | { | |
6f2b9b9a | 1274 | #ifdef CONFIG_LOCKDEP |
f266a511 PZ |
1275 | unsigned long flags; |
1276 | ||
48228f7b SR |
1277 | /* |
1278 | * If lockdep gives a backtrace here, please reference | |
1279 | * the synchronization rules above. | |
1280 | */ | |
7ff20792 | 1281 | local_irq_save(flags); |
6f2b9b9a JB |
1282 | lock_map_acquire(&timer->lockdep_map); |
1283 | lock_map_release(&timer->lockdep_map); | |
7ff20792 | 1284 | local_irq_restore(flags); |
6f2b9b9a | 1285 | #endif |
466bd303 YZ |
1286 | /* |
1287 | * don't use it in hardirq context, because it | |
1288 | * could lead to deadlock. | |
1289 | */ | |
0eeda71b | 1290 | WARN_ON(in_irq() && !(timer->flags & TIMER_IRQSAFE)); |
fd450b73 ON |
1291 | for (;;) { |
1292 | int ret = try_to_del_timer_sync(timer); | |
1293 | if (ret >= 0) | |
1294 | return ret; | |
a0009652 | 1295 | cpu_relax(); |
fd450b73 | 1296 | } |
1da177e4 | 1297 | } |
55c888d6 | 1298 | EXPORT_SYMBOL(del_timer_sync); |
1da177e4 LT |
1299 | #endif |
1300 | ||
354b46b1 | 1301 | static void call_timer_fn(struct timer_list *timer, void (*fn)(struct timer_list *)) |
576da126 | 1302 | { |
4a2b4b22 | 1303 | int count = preempt_count(); |
576da126 TG |
1304 | |
1305 | #ifdef CONFIG_LOCKDEP | |
1306 | /* | |
1307 | * It is permissible to free the timer from inside the | |
1308 | * function that is called from it, this we need to take into | |
1309 | * account for lockdep too. To avoid bogus "held lock freed" | |
1310 | * warnings as well as problems when looking into | |
1311 | * timer->lockdep_map, make a copy and use that here. | |
1312 | */ | |
4d82a1de PZ |
1313 | struct lockdep_map lockdep_map; |
1314 | ||
1315 | lockdep_copy_map(&lockdep_map, &timer->lockdep_map); | |
576da126 TG |
1316 | #endif |
1317 | /* | |
1318 | * Couple the lock chain with the lock chain at | |
1319 | * del_timer_sync() by acquiring the lock_map around the fn() | |
1320 | * call here and in del_timer_sync(). | |
1321 | */ | |
1322 | lock_map_acquire(&lockdep_map); | |
1323 | ||
1324 | trace_timer_expire_entry(timer); | |
354b46b1 | 1325 | fn(timer); |
576da126 TG |
1326 | trace_timer_expire_exit(timer); |
1327 | ||
1328 | lock_map_release(&lockdep_map); | |
1329 | ||
4a2b4b22 | 1330 | if (count != preempt_count()) { |
802702e0 | 1331 | WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n", |
4a2b4b22 | 1332 | fn, count, preempt_count()); |
802702e0 TG |
1333 | /* |
1334 | * Restore the preempt count. That gives us a decent | |
1335 | * chance to survive and extract information. If the | |
1336 | * callback kept a lock held, bad luck, but not worse | |
1337 | * than the BUG() we had. | |
1338 | */ | |
4a2b4b22 | 1339 | preempt_count_set(count); |
576da126 TG |
1340 | } |
1341 | } | |
1342 | ||
500462a9 | 1343 | static void expire_timers(struct timer_base *base, struct hlist_head *head) |
1da177e4 | 1344 | { |
500462a9 TG |
1345 | while (!hlist_empty(head)) { |
1346 | struct timer_list *timer; | |
354b46b1 | 1347 | void (*fn)(struct timer_list *); |
1da177e4 | 1348 | |
500462a9 | 1349 | timer = hlist_entry(head->first, struct timer_list, entry); |
3bb475a3 | 1350 | |
500462a9 TG |
1351 | base->running_timer = timer; |
1352 | detach_timer(timer, true); | |
3bb475a3 | 1353 | |
500462a9 | 1354 | fn = timer->function; |
500462a9 TG |
1355 | |
1356 | if (timer->flags & TIMER_IRQSAFE) { | |
2287d866 | 1357 | raw_spin_unlock(&base->lock); |
c1eba5bc | 1358 | call_timer_fn(timer, fn); |
2287d866 | 1359 | raw_spin_lock(&base->lock); |
500462a9 | 1360 | } else { |
2287d866 | 1361 | raw_spin_unlock_irq(&base->lock); |
c1eba5bc | 1362 | call_timer_fn(timer, fn); |
2287d866 | 1363 | raw_spin_lock_irq(&base->lock); |
3bb475a3 | 1364 | } |
500462a9 TG |
1365 | } |
1366 | } | |
3bb475a3 | 1367 | |
23696838 AMG |
1368 | static int __collect_expired_timers(struct timer_base *base, |
1369 | struct hlist_head *heads) | |
500462a9 TG |
1370 | { |
1371 | unsigned long clk = base->clk; | |
1372 | struct hlist_head *vec; | |
1373 | int i, levels = 0; | |
1374 | unsigned int idx; | |
626ab0e6 | 1375 | |
500462a9 TG |
1376 | for (i = 0; i < LVL_DEPTH; i++) { |
1377 | idx = (clk & LVL_MASK) + i * LVL_SIZE; | |
1378 | ||
1379 | if (__test_and_clear_bit(idx, base->pending_map)) { | |
1380 | vec = base->vectors + idx; | |
1381 | hlist_move_list(vec, heads++); | |
1382 | levels++; | |
1da177e4 | 1383 | } |
500462a9 TG |
1384 | /* Is it time to look at the next level? */ |
1385 | if (clk & LVL_CLK_MASK) | |
1386 | break; | |
1387 | /* Shift clock for the next level granularity */ | |
1388 | clk >>= LVL_CLK_SHIFT; | |
1da177e4 | 1389 | } |
500462a9 | 1390 | return levels; |
1da177e4 LT |
1391 | } |
1392 | ||
3451d024 | 1393 | #ifdef CONFIG_NO_HZ_COMMON |
1da177e4 | 1394 | /* |
23696838 AMG |
1395 | * Find the next pending bucket of a level. Search from level start (@offset) |
1396 | * + @clk upwards and if nothing there, search from start of the level | |
1397 | * (@offset) up to @offset + clk. | |
1da177e4 | 1398 | */ |
500462a9 TG |
1399 | static int next_pending_bucket(struct timer_base *base, unsigned offset, |
1400 | unsigned clk) | |
1401 | { | |
1402 | unsigned pos, start = offset + clk; | |
1403 | unsigned end = offset + LVL_SIZE; | |
1404 | ||
1405 | pos = find_next_bit(base->pending_map, end, start); | |
1406 | if (pos < end) | |
1407 | return pos - start; | |
1408 | ||
1409 | pos = find_next_bit(base->pending_map, start, offset); | |
1410 | return pos < start ? pos + LVL_SIZE - start : -1; | |
1411 | } | |
1412 | ||
1413 | /* | |
23696838 AMG |
1414 | * Search the first expiring timer in the various clock levels. Caller must |
1415 | * hold base->lock. | |
1da177e4 | 1416 | */ |
494af3ed | 1417 | static unsigned long __next_timer_interrupt(struct timer_base *base) |
1da177e4 | 1418 | { |
500462a9 TG |
1419 | unsigned long clk, next, adj; |
1420 | unsigned lvl, offset = 0; | |
1421 | ||
500462a9 TG |
1422 | next = base->clk + NEXT_TIMER_MAX_DELTA; |
1423 | clk = base->clk; | |
1424 | for (lvl = 0; lvl < LVL_DEPTH; lvl++, offset += LVL_SIZE) { | |
1425 | int pos = next_pending_bucket(base, offset, clk & LVL_MASK); | |
1426 | ||
1427 | if (pos >= 0) { | |
1428 | unsigned long tmp = clk + (unsigned long) pos; | |
1429 | ||
1430 | tmp <<= LVL_SHIFT(lvl); | |
1431 | if (time_before(tmp, next)) | |
1432 | next = tmp; | |
1da177e4 | 1433 | } |
500462a9 TG |
1434 | /* |
1435 | * Clock for the next level. If the current level clock lower | |
1436 | * bits are zero, we look at the next level as is. If not we | |
1437 | * need to advance it by one because that's going to be the | |
1438 | * next expiring bucket in that level. base->clk is the next | |
1439 | * expiring jiffie. So in case of: | |
1440 | * | |
1441 | * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0 | |
1442 | * 0 0 0 0 0 0 | |
1443 | * | |
1444 | * we have to look at all levels @index 0. With | |
1445 | * | |
1446 | * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0 | |
1447 | * 0 0 0 0 0 2 | |
1448 | * | |
1449 | * LVL0 has the next expiring bucket @index 2. The upper | |
1450 | * levels have the next expiring bucket @index 1. | |
1451 | * | |
1452 | * In case that the propagation wraps the next level the same | |
1453 | * rules apply: | |
1454 | * | |
1455 | * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0 | |
1456 | * 0 0 0 0 F 2 | |
1457 | * | |
1458 | * So after looking at LVL0 we get: | |
1459 | * | |
1460 | * LVL5 LVL4 LVL3 LVL2 LVL1 | |
1461 | * 0 0 0 1 0 | |
1462 | * | |
1463 | * So no propagation from LVL1 to LVL2 because that happened | |
1464 | * with the add already, but then we need to propagate further | |
1465 | * from LVL2 to LVL3. | |
1466 | * | |
1467 | * So the simple check whether the lower bits of the current | |
1468 | * level are 0 or not is sufficient for all cases. | |
1469 | */ | |
1470 | adj = clk & LVL_CLK_MASK ? 1 : 0; | |
1471 | clk >>= LVL_CLK_SHIFT; | |
1472 | clk += adj; | |
1da177e4 | 1473 | } |
500462a9 | 1474 | return next; |
1cfd6849 | 1475 | } |
69239749 | 1476 | |
1cfd6849 TG |
1477 | /* |
1478 | * Check, if the next hrtimer event is before the next timer wheel | |
1479 | * event: | |
1480 | */ | |
c1ad348b | 1481 | static u64 cmp_next_hrtimer_event(u64 basem, u64 expires) |
1cfd6849 | 1482 | { |
c1ad348b | 1483 | u64 nextevt = hrtimer_get_next_event(); |
0662b713 | 1484 | |
9501b6cf | 1485 | /* |
c1ad348b TG |
1486 | * If high resolution timers are enabled |
1487 | * hrtimer_get_next_event() returns KTIME_MAX. | |
9501b6cf | 1488 | */ |
c1ad348b TG |
1489 | if (expires <= nextevt) |
1490 | return expires; | |
eaad084b TG |
1491 | |
1492 | /* | |
c1ad348b TG |
1493 | * If the next timer is already expired, return the tick base |
1494 | * time so the tick is fired immediately. | |
eaad084b | 1495 | */ |
c1ad348b TG |
1496 | if (nextevt <= basem) |
1497 | return basem; | |
eaad084b | 1498 | |
9501b6cf | 1499 | /* |
c1ad348b TG |
1500 | * Round up to the next jiffie. High resolution timers are |
1501 | * off, so the hrtimers are expired in the tick and we need to | |
1502 | * make sure that this tick really expires the timer to avoid | |
1503 | * a ping pong of the nohz stop code. | |
1504 | * | |
1505 | * Use DIV_ROUND_UP_ULL to prevent gcc calling __divdi3 | |
9501b6cf | 1506 | */ |
c1ad348b | 1507 | return DIV_ROUND_UP_ULL(nextevt, TICK_NSEC) * TICK_NSEC; |
1da177e4 | 1508 | } |
1cfd6849 TG |
1509 | |
1510 | /** | |
c1ad348b TG |
1511 | * get_next_timer_interrupt - return the time (clock mono) of the next timer |
1512 | * @basej: base time jiffies | |
1513 | * @basem: base time clock monotonic | |
1514 | * | |
1515 | * Returns the tick aligned clock monotonic time of the next pending | |
1516 | * timer or KTIME_MAX if no timer is pending. | |
1cfd6849 | 1517 | */ |
c1ad348b | 1518 | u64 get_next_timer_interrupt(unsigned long basej, u64 basem) |
1cfd6849 | 1519 | { |
500462a9 | 1520 | struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); |
c1ad348b TG |
1521 | u64 expires = KTIME_MAX; |
1522 | unsigned long nextevt; | |
46c8f0b0 | 1523 | bool is_max_delta; |
1cfd6849 | 1524 | |
dbd87b5a HC |
1525 | /* |
1526 | * Pretend that there is no timer pending if the cpu is offline. | |
1527 | * Possible pending timers will be migrated later to an active cpu. | |
1528 | */ | |
1529 | if (cpu_is_offline(smp_processor_id())) | |
e40468a5 TG |
1530 | return expires; |
1531 | ||
2287d866 | 1532 | raw_spin_lock(&base->lock); |
500462a9 | 1533 | nextevt = __next_timer_interrupt(base); |
46c8f0b0 | 1534 | is_max_delta = (nextevt == base->clk + NEXT_TIMER_MAX_DELTA); |
a683f390 TG |
1535 | base->next_expiry = nextevt; |
1536 | /* | |
041ad7bc TG |
1537 | * We have a fresh next event. Check whether we can forward the |
1538 | * base. We can only do that when @basej is past base->clk | |
1539 | * otherwise we might rewind base->clk. | |
a683f390 | 1540 | */ |
041ad7bc TG |
1541 | if (time_after(basej, base->clk)) { |
1542 | if (time_after(nextevt, basej)) | |
1543 | base->clk = basej; | |
1544 | else if (time_after(nextevt, base->clk)) | |
1545 | base->clk = nextevt; | |
1546 | } | |
23696838 | 1547 | |
a683f390 | 1548 | if (time_before_eq(nextevt, basej)) { |
500462a9 | 1549 | expires = basem; |
a683f390 TG |
1550 | base->is_idle = false; |
1551 | } else { | |
46c8f0b0 | 1552 | if (!is_max_delta) |
34f41c03 | 1553 | expires = basem + (u64)(nextevt - basej) * TICK_NSEC; |
a683f390 | 1554 | /* |
2fe59f50 NP |
1555 | * If we expect to sleep more than a tick, mark the base idle. |
1556 | * Also the tick is stopped so any added timer must forward | |
1557 | * the base clk itself to keep granularity small. This idle | |
1558 | * logic is only maintained for the BASE_STD base, deferrable | |
1559 | * timers may still see large granularity skew (by design). | |
a683f390 | 1560 | */ |
2fe59f50 NP |
1561 | if ((expires - basem) > TICK_NSEC) { |
1562 | base->must_forward_clk = true; | |
a683f390 | 1563 | base->is_idle = true; |
2fe59f50 | 1564 | } |
e40468a5 | 1565 | } |
2287d866 | 1566 | raw_spin_unlock(&base->lock); |
1cfd6849 | 1567 | |
c1ad348b | 1568 | return cmp_next_hrtimer_event(basem, expires); |
1cfd6849 | 1569 | } |
23696838 | 1570 | |
a683f390 TG |
1571 | /** |
1572 | * timer_clear_idle - Clear the idle state of the timer base | |
1573 | * | |
1574 | * Called with interrupts disabled | |
1575 | */ | |
1576 | void timer_clear_idle(void) | |
1577 | { | |
1578 | struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); | |
1579 | ||
1580 | /* | |
1581 | * We do this unlocked. The worst outcome is a remote enqueue sending | |
1582 | * a pointless IPI, but taking the lock would just make the window for | |
1583 | * sending the IPI a few instructions smaller for the cost of taking | |
1584 | * the lock in the exit from idle path. | |
1585 | */ | |
1586 | base->is_idle = false; | |
1587 | } | |
1588 | ||
23696838 AMG |
1589 | static int collect_expired_timers(struct timer_base *base, |
1590 | struct hlist_head *heads) | |
1591 | { | |
1592 | /* | |
1593 | * NOHZ optimization. After a long idle sleep we need to forward the | |
1594 | * base to current jiffies. Avoid a loop by searching the bitfield for | |
1595 | * the next expiring timer. | |
1596 | */ | |
1597 | if ((long)(jiffies - base->clk) > 2) { | |
1598 | unsigned long next = __next_timer_interrupt(base); | |
1599 | ||
1600 | /* | |
1601 | * If the next timer is ahead of time forward to current | |
a683f390 | 1602 | * jiffies, otherwise forward to the next expiry time: |
23696838 AMG |
1603 | */ |
1604 | if (time_after(next, jiffies)) { | |
c310ce4d ZD |
1605 | /* |
1606 | * The call site will increment base->clk and then | |
1607 | * terminate the expiry loop immediately. | |
1608 | */ | |
1609 | base->clk = jiffies; | |
23696838 AMG |
1610 | return 0; |
1611 | } | |
1612 | base->clk = next; | |
1613 | } | |
1614 | return __collect_expired_timers(base, heads); | |
1615 | } | |
1616 | #else | |
1617 | static inline int collect_expired_timers(struct timer_base *base, | |
1618 | struct hlist_head *heads) | |
1619 | { | |
1620 | return __collect_expired_timers(base, heads); | |
1621 | } | |
1da177e4 LT |
1622 | #endif |
1623 | ||
1da177e4 | 1624 | /* |
5b4db0c2 | 1625 | * Called from the timer interrupt handler to charge one tick to the current |
1da177e4 LT |
1626 | * process. user_tick is 1 if the tick is user time, 0 for system. |
1627 | */ | |
1628 | void update_process_times(int user_tick) | |
1629 | { | |
1630 | struct task_struct *p = current; | |
1da177e4 LT |
1631 | |
1632 | /* Note: this timer irq context must be accounted for as well. */ | |
fa13a5a1 | 1633 | account_process_tick(p, user_tick); |
1da177e4 | 1634 | run_local_timers(); |
c98cac60 | 1635 | rcu_sched_clock_irq(user_tick); |
e360adbe PZ |
1636 | #ifdef CONFIG_IRQ_WORK |
1637 | if (in_irq()) | |
76a33061 | 1638 | irq_work_tick(); |
e360adbe | 1639 | #endif |
1da177e4 | 1640 | scheduler_tick(); |
baa73d9e NP |
1641 | if (IS_ENABLED(CONFIG_POSIX_TIMERS)) |
1642 | run_posix_cpu_timers(p); | |
1da177e4 LT |
1643 | } |
1644 | ||
73420fea AMG |
1645 | /** |
1646 | * __run_timers - run all expired timers (if any) on this CPU. | |
1647 | * @base: the timer vector to be processed. | |
1648 | */ | |
1649 | static inline void __run_timers(struct timer_base *base) | |
1650 | { | |
1651 | struct hlist_head heads[LVL_DEPTH]; | |
1652 | int levels; | |
1653 | ||
1654 | if (!time_after_eq(jiffies, base->clk)) | |
1655 | return; | |
1656 | ||
2287d866 | 1657 | raw_spin_lock_irq(&base->lock); |
73420fea | 1658 | |
363e934d GK |
1659 | /* |
1660 | * timer_base::must_forward_clk must be cleared before running | |
1661 | * timers so that any timer functions that call mod_timer() will | |
1662 | * not try to forward the base. Idle tracking / clock forwarding | |
1663 | * logic is only used with BASE_STD timers. | |
1664 | * | |
1665 | * The must_forward_clk flag is cleared unconditionally also for | |
1666 | * the deferrable base. The deferrable base is not affected by idle | |
1667 | * tracking and never forwarded, so clearing the flag is a NOOP. | |
1668 | * | |
1669 | * The fact that the deferrable base is never forwarded can cause | |
1670 | * large variations in granularity for deferrable timers, but they | |
1671 | * can be deferred for long periods due to idle anyway. | |
1672 | */ | |
1673 | base->must_forward_clk = false; | |
1674 | ||
73420fea AMG |
1675 | while (time_after_eq(jiffies, base->clk)) { |
1676 | ||
1677 | levels = collect_expired_timers(base, heads); | |
1678 | base->clk++; | |
1679 | ||
1680 | while (levels--) | |
1681 | expire_timers(base, heads + levels); | |
1682 | } | |
1683 | base->running_timer = NULL; | |
2287d866 | 1684 | raw_spin_unlock_irq(&base->lock); |
73420fea AMG |
1685 | } |
1686 | ||
1da177e4 LT |
1687 | /* |
1688 | * This function runs timers and the timer-tq in bottom half context. | |
1689 | */ | |
0766f788 | 1690 | static __latent_entropy void run_timer_softirq(struct softirq_action *h) |
1da177e4 | 1691 | { |
500462a9 | 1692 | struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); |
1da177e4 | 1693 | |
500462a9 | 1694 | __run_timers(base); |
ced6d5c1 | 1695 | if (IS_ENABLED(CONFIG_NO_HZ_COMMON)) |
500462a9 | 1696 | __run_timers(this_cpu_ptr(&timer_bases[BASE_DEF])); |
1da177e4 LT |
1697 | } |
1698 | ||
1699 | /* | |
1700 | * Called by the local, per-CPU timer interrupt on SMP. | |
1701 | */ | |
1702 | void run_local_timers(void) | |
1703 | { | |
4e85876a TG |
1704 | struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); |
1705 | ||
d3d74453 | 1706 | hrtimer_run_queues(); |
4e85876a TG |
1707 | /* Raise the softirq only if required. */ |
1708 | if (time_before(jiffies, base->clk)) { | |
ed4bbf79 | 1709 | if (!IS_ENABLED(CONFIG_NO_HZ_COMMON)) |
4e85876a TG |
1710 | return; |
1711 | /* CPU is awake, so check the deferrable base. */ | |
1712 | base++; | |
1713 | if (time_before(jiffies, base->clk)) | |
1714 | return; | |
1715 | } | |
1da177e4 LT |
1716 | raise_softirq(TIMER_SOFTIRQ); |
1717 | } | |
1718 | ||
58e1177b KC |
1719 | /* |
1720 | * Since schedule_timeout()'s timer is defined on the stack, it must store | |
1721 | * the target task on the stack as well. | |
1722 | */ | |
1723 | struct process_timer { | |
1724 | struct timer_list timer; | |
1725 | struct task_struct *task; | |
1726 | }; | |
1727 | ||
1728 | static void process_timeout(struct timer_list *t) | |
1da177e4 | 1729 | { |
58e1177b KC |
1730 | struct process_timer *timeout = from_timer(timeout, t, timer); |
1731 | ||
1732 | wake_up_process(timeout->task); | |
1da177e4 LT |
1733 | } |
1734 | ||
1735 | /** | |
1736 | * schedule_timeout - sleep until timeout | |
1737 | * @timeout: timeout value in jiffies | |
1738 | * | |
1739 | * Make the current task sleep until @timeout jiffies have | |
1740 | * elapsed. The routine will return immediately unless | |
1741 | * the current task state has been set (see set_current_state()). | |
1742 | * | |
1743 | * You can set the task state as follows - | |
1744 | * | |
1745 | * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to | |
4b7e9cf9 DA |
1746 | * pass before the routine returns unless the current task is explicitly |
1747 | * woken up, (e.g. by wake_up_process())". | |
1da177e4 LT |
1748 | * |
1749 | * %TASK_INTERRUPTIBLE - the routine may return early if a signal is | |
4b7e9cf9 DA |
1750 | * delivered to the current task or the current task is explicitly woken |
1751 | * up. | |
1da177e4 LT |
1752 | * |
1753 | * The current task state is guaranteed to be TASK_RUNNING when this | |
1754 | * routine returns. | |
1755 | * | |
1756 | * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule | |
1757 | * the CPU away without a bound on the timeout. In this case the return | |
1758 | * value will be %MAX_SCHEDULE_TIMEOUT. | |
1759 | * | |
4b7e9cf9 DA |
1760 | * Returns 0 when the timer has expired otherwise the remaining time in |
1761 | * jiffies will be returned. In all cases the return value is guaranteed | |
1762 | * to be non-negative. | |
1da177e4 | 1763 | */ |
7ad5b3a5 | 1764 | signed long __sched schedule_timeout(signed long timeout) |
1da177e4 | 1765 | { |
58e1177b | 1766 | struct process_timer timer; |
1da177e4 LT |
1767 | unsigned long expire; |
1768 | ||
1769 | switch (timeout) | |
1770 | { | |
1771 | case MAX_SCHEDULE_TIMEOUT: | |
1772 | /* | |
1773 | * These two special cases are useful to be comfortable | |
1774 | * in the caller. Nothing more. We could take | |
1775 | * MAX_SCHEDULE_TIMEOUT from one of the negative value | |
1776 | * but I' d like to return a valid offset (>=0) to allow | |
1777 | * the caller to do everything it want with the retval. | |
1778 | */ | |
1779 | schedule(); | |
1780 | goto out; | |
1781 | default: | |
1782 | /* | |
1783 | * Another bit of PARANOID. Note that the retval will be | |
1784 | * 0 since no piece of kernel is supposed to do a check | |
1785 | * for a negative retval of schedule_timeout() (since it | |
1786 | * should never happens anyway). You just have the printk() | |
1787 | * that will tell you if something is gone wrong and where. | |
1788 | */ | |
5b149bcc | 1789 | if (timeout < 0) { |
1da177e4 | 1790 | printk(KERN_ERR "schedule_timeout: wrong timeout " |
5b149bcc AM |
1791 | "value %lx\n", timeout); |
1792 | dump_stack(); | |
1da177e4 LT |
1793 | current->state = TASK_RUNNING; |
1794 | goto out; | |
1795 | } | |
1796 | } | |
1797 | ||
1798 | expire = timeout + jiffies; | |
1799 | ||
58e1177b KC |
1800 | timer.task = current; |
1801 | timer_setup_on_stack(&timer.timer, process_timeout, 0); | |
b24591e2 | 1802 | __mod_timer(&timer.timer, expire, 0); |
1da177e4 | 1803 | schedule(); |
58e1177b | 1804 | del_singleshot_timer_sync(&timer.timer); |
1da177e4 | 1805 | |
c6f3a97f | 1806 | /* Remove the timer from the object tracker */ |
58e1177b | 1807 | destroy_timer_on_stack(&timer.timer); |
c6f3a97f | 1808 | |
1da177e4 LT |
1809 | timeout = expire - jiffies; |
1810 | ||
1811 | out: | |
1812 | return timeout < 0 ? 0 : timeout; | |
1813 | } | |
1da177e4 LT |
1814 | EXPORT_SYMBOL(schedule_timeout); |
1815 | ||
8a1c1757 AM |
1816 | /* |
1817 | * We can use __set_current_state() here because schedule_timeout() calls | |
1818 | * schedule() unconditionally. | |
1819 | */ | |
64ed93a2 NA |
1820 | signed long __sched schedule_timeout_interruptible(signed long timeout) |
1821 | { | |
a5a0d52c AM |
1822 | __set_current_state(TASK_INTERRUPTIBLE); |
1823 | return schedule_timeout(timeout); | |
64ed93a2 NA |
1824 | } |
1825 | EXPORT_SYMBOL(schedule_timeout_interruptible); | |
1826 | ||
294d5cc2 MW |
1827 | signed long __sched schedule_timeout_killable(signed long timeout) |
1828 | { | |
1829 | __set_current_state(TASK_KILLABLE); | |
1830 | return schedule_timeout(timeout); | |
1831 | } | |
1832 | EXPORT_SYMBOL(schedule_timeout_killable); | |
1833 | ||
64ed93a2 NA |
1834 | signed long __sched schedule_timeout_uninterruptible(signed long timeout) |
1835 | { | |
a5a0d52c AM |
1836 | __set_current_state(TASK_UNINTERRUPTIBLE); |
1837 | return schedule_timeout(timeout); | |
64ed93a2 NA |
1838 | } |
1839 | EXPORT_SYMBOL(schedule_timeout_uninterruptible); | |
1840 | ||
69b27baf AM |
1841 | /* |
1842 | * Like schedule_timeout_uninterruptible(), except this task will not contribute | |
1843 | * to load average. | |
1844 | */ | |
1845 | signed long __sched schedule_timeout_idle(signed long timeout) | |
1846 | { | |
1847 | __set_current_state(TASK_IDLE); | |
1848 | return schedule_timeout(timeout); | |
1849 | } | |
1850 | EXPORT_SYMBOL(schedule_timeout_idle); | |
1851 | ||
1da177e4 | 1852 | #ifdef CONFIG_HOTPLUG_CPU |
494af3ed | 1853 | static void migrate_timer_list(struct timer_base *new_base, struct hlist_head *head) |
1da177e4 LT |
1854 | { |
1855 | struct timer_list *timer; | |
0eeda71b | 1856 | int cpu = new_base->cpu; |
1da177e4 | 1857 | |
1dabbcec TG |
1858 | while (!hlist_empty(head)) { |
1859 | timer = hlist_entry(head->first, struct timer_list, entry); | |
ec44bc7a | 1860 | detach_timer(timer, false); |
0eeda71b | 1861 | timer->flags = (timer->flags & ~TIMER_BASEMASK) | cpu; |
1da177e4 | 1862 | internal_add_timer(new_base, timer); |
1da177e4 | 1863 | } |
1da177e4 LT |
1864 | } |
1865 | ||
26456f87 TG |
1866 | int timers_prepare_cpu(unsigned int cpu) |
1867 | { | |
1868 | struct timer_base *base; | |
1869 | int b; | |
1870 | ||
1871 | for (b = 0; b < NR_BASES; b++) { | |
1872 | base = per_cpu_ptr(&timer_bases[b], cpu); | |
1873 | base->clk = jiffies; | |
1874 | base->next_expiry = base->clk + NEXT_TIMER_MAX_DELTA; | |
1875 | base->is_idle = false; | |
1876 | base->must_forward_clk = true; | |
1877 | } | |
1878 | return 0; | |
1879 | } | |
1880 | ||
24f73b99 | 1881 | int timers_dead_cpu(unsigned int cpu) |
1da177e4 | 1882 | { |
494af3ed TG |
1883 | struct timer_base *old_base; |
1884 | struct timer_base *new_base; | |
500462a9 | 1885 | int b, i; |
1da177e4 LT |
1886 | |
1887 | BUG_ON(cpu_online(cpu)); | |
55c888d6 | 1888 | |
500462a9 TG |
1889 | for (b = 0; b < NR_BASES; b++) { |
1890 | old_base = per_cpu_ptr(&timer_bases[b], cpu); | |
1891 | new_base = get_cpu_ptr(&timer_bases[b]); | |
1892 | /* | |
1893 | * The caller is globally serialized and nobody else | |
1894 | * takes two locks at once, deadlock is not possible. | |
1895 | */ | |
2287d866 SAS |
1896 | raw_spin_lock_irq(&new_base->lock); |
1897 | raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); | |
500462a9 | 1898 | |
c52232a4 LC |
1899 | /* |
1900 | * The current CPUs base clock might be stale. Update it | |
1901 | * before moving the timers over. | |
1902 | */ | |
1903 | forward_timer_base(new_base); | |
1904 | ||
500462a9 TG |
1905 | BUG_ON(old_base->running_timer); |
1906 | ||
1907 | for (i = 0; i < WHEEL_SIZE; i++) | |
1908 | migrate_timer_list(new_base, old_base->vectors + i); | |
8def9060 | 1909 | |
2287d866 SAS |
1910 | raw_spin_unlock(&old_base->lock); |
1911 | raw_spin_unlock_irq(&new_base->lock); | |
500462a9 TG |
1912 | put_cpu_ptr(&timer_bases); |
1913 | } | |
24f73b99 | 1914 | return 0; |
1da177e4 | 1915 | } |
1da177e4 | 1916 | |
3650b57f | 1917 | #endif /* CONFIG_HOTPLUG_CPU */ |
1da177e4 | 1918 | |
0eeda71b | 1919 | static void __init init_timer_cpu(int cpu) |
8def9060 | 1920 | { |
500462a9 TG |
1921 | struct timer_base *base; |
1922 | int i; | |
8def9060 | 1923 | |
500462a9 TG |
1924 | for (i = 0; i < NR_BASES; i++) { |
1925 | base = per_cpu_ptr(&timer_bases[i], cpu); | |
1926 | base->cpu = cpu; | |
2287d866 | 1927 | raw_spin_lock_init(&base->lock); |
500462a9 TG |
1928 | base->clk = jiffies; |
1929 | } | |
8def9060 VK |
1930 | } |
1931 | ||
1932 | static void __init init_timer_cpus(void) | |
1da177e4 | 1933 | { |
8def9060 VK |
1934 | int cpu; |
1935 | ||
0eeda71b TG |
1936 | for_each_possible_cpu(cpu) |
1937 | init_timer_cpu(cpu); | |
8def9060 | 1938 | } |
e52b1db3 | 1939 | |
8def9060 VK |
1940 | void __init init_timers(void) |
1941 | { | |
8def9060 | 1942 | init_timer_cpus(); |
962cf36c | 1943 | open_softirq(TIMER_SOFTIRQ, run_timer_softirq); |
1da177e4 LT |
1944 | } |
1945 | ||
1da177e4 LT |
1946 | /** |
1947 | * msleep - sleep safely even with waitqueue interruptions | |
1948 | * @msecs: Time in milliseconds to sleep for | |
1949 | */ | |
1950 | void msleep(unsigned int msecs) | |
1951 | { | |
1952 | unsigned long timeout = msecs_to_jiffies(msecs) + 1; | |
1953 | ||
75bcc8c5 NA |
1954 | while (timeout) |
1955 | timeout = schedule_timeout_uninterruptible(timeout); | |
1da177e4 LT |
1956 | } |
1957 | ||
1958 | EXPORT_SYMBOL(msleep); | |
1959 | ||
1960 | /** | |
96ec3efd | 1961 | * msleep_interruptible - sleep waiting for signals |
1da177e4 LT |
1962 | * @msecs: Time in milliseconds to sleep for |
1963 | */ | |
1964 | unsigned long msleep_interruptible(unsigned int msecs) | |
1965 | { | |
1966 | unsigned long timeout = msecs_to_jiffies(msecs) + 1; | |
1967 | ||
75bcc8c5 NA |
1968 | while (timeout && !signal_pending(current)) |
1969 | timeout = schedule_timeout_interruptible(timeout); | |
1da177e4 LT |
1970 | return jiffies_to_msecs(timeout); |
1971 | } | |
1972 | ||
1973 | EXPORT_SYMBOL(msleep_interruptible); | |
5e7f5a17 | 1974 | |
5e7f5a17 | 1975 | /** |
b5227d03 | 1976 | * usleep_range - Sleep for an approximate time |
5e7f5a17 PP |
1977 | * @min: Minimum time in usecs to sleep |
1978 | * @max: Maximum time in usecs to sleep | |
b5227d03 BH |
1979 | * |
1980 | * In non-atomic context where the exact wakeup time is flexible, use | |
1981 | * usleep_range() instead of udelay(). The sleep improves responsiveness | |
1982 | * by avoiding the CPU-hogging busy-wait of udelay(), and the range reduces | |
1983 | * power usage by allowing hrtimers to take advantage of an already- | |
1984 | * scheduled interrupt instead of scheduling a new one just for this sleep. | |
5e7f5a17 | 1985 | */ |
2ad5d327 | 1986 | void __sched usleep_range(unsigned long min, unsigned long max) |
5e7f5a17 | 1987 | { |
6c5e9059 DA |
1988 | ktime_t exp = ktime_add_us(ktime_get(), min); |
1989 | u64 delta = (u64)(max - min) * NSEC_PER_USEC; | |
1990 | ||
1991 | for (;;) { | |
1992 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
1993 | /* Do not return before the requested sleep time has elapsed */ | |
1994 | if (!schedule_hrtimeout_range(&exp, delta, HRTIMER_MODE_ABS)) | |
1995 | break; | |
1996 | } | |
5e7f5a17 PP |
1997 | } |
1998 | EXPORT_SYMBOL(usleep_range); |