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45ceebf7 PG |
1 | /* |
2 | * kernel/sched/proc.c | |
3 | * | |
4 | * Kernel load calculations, forked from sched/core.c | |
5 | */ | |
6 | ||
7 | #include <linux/export.h> | |
8 | ||
9 | #include "sched.h" | |
10 | ||
45ceebf7 PG |
11 | /* |
12 | * Global load-average calculations | |
13 | * | |
14 | * We take a distributed and async approach to calculating the global load-avg | |
15 | * in order to minimize overhead. | |
16 | * | |
17 | * The global load average is an exponentially decaying average of nr_running + | |
18 | * nr_uninterruptible. | |
19 | * | |
20 | * Once every LOAD_FREQ: | |
21 | * | |
22 | * nr_active = 0; | |
23 | * for_each_possible_cpu(cpu) | |
24 | * nr_active += cpu_of(cpu)->nr_running + cpu_of(cpu)->nr_uninterruptible; | |
25 | * | |
26 | * avenrun[n] = avenrun[0] * exp_n + nr_active * (1 - exp_n) | |
27 | * | |
28 | * Due to a number of reasons the above turns in the mess below: | |
29 | * | |
30 | * - for_each_possible_cpu() is prohibitively expensive on machines with | |
31 | * serious number of cpus, therefore we need to take a distributed approach | |
32 | * to calculating nr_active. | |
33 | * | |
34 | * \Sum_i x_i(t) = \Sum_i x_i(t) - x_i(t_0) | x_i(t_0) := 0 | |
35 | * = \Sum_i { \Sum_j=1 x_i(t_j) - x_i(t_j-1) } | |
36 | * | |
37 | * So assuming nr_active := 0 when we start out -- true per definition, we | |
38 | * can simply take per-cpu deltas and fold those into a global accumulate | |
39 | * to obtain the same result. See calc_load_fold_active(). | |
40 | * | |
41 | * Furthermore, in order to avoid synchronizing all per-cpu delta folding | |
42 | * across the machine, we assume 10 ticks is sufficient time for every | |
43 | * cpu to have completed this task. | |
44 | * | |
45 | * This places an upper-bound on the IRQ-off latency of the machine. Then | |
46 | * again, being late doesn't loose the delta, just wrecks the sample. | |
47 | * | |
48 | * - cpu_rq()->nr_uninterruptible isn't accurately tracked per-cpu because | |
49 | * this would add another cross-cpu cacheline miss and atomic operation | |
50 | * to the wakeup path. Instead we increment on whatever cpu the task ran | |
51 | * when it went into uninterruptible state and decrement on whatever cpu | |
52 | * did the wakeup. This means that only the sum of nr_uninterruptible over | |
53 | * all cpus yields the correct result. | |
54 | * | |
55 | * This covers the NO_HZ=n code, for extra head-aches, see the comment below. | |
56 | */ | |
57 | ||
58 | /* Variables and functions for calc_load */ | |
59 | atomic_long_t calc_load_tasks; | |
60 | unsigned long calc_load_update; | |
61 | unsigned long avenrun[3]; | |
62 | EXPORT_SYMBOL(avenrun); /* should be removed */ | |
63 | ||
64 | /** | |
65 | * get_avenrun - get the load average array | |
66 | * @loads: pointer to dest load array | |
67 | * @offset: offset to add | |
68 | * @shift: shift count to shift the result left | |
69 | * | |
70 | * These values are estimates at best, so no need for locking. | |
71 | */ | |
72 | void get_avenrun(unsigned long *loads, unsigned long offset, int shift) | |
73 | { | |
74 | loads[0] = (avenrun[0] + offset) << shift; | |
75 | loads[1] = (avenrun[1] + offset) << shift; | |
76 | loads[2] = (avenrun[2] + offset) << shift; | |
77 | } | |
78 | ||
79 | long calc_load_fold_active(struct rq *this_rq) | |
80 | { | |
81 | long nr_active, delta = 0; | |
82 | ||
83 | nr_active = this_rq->nr_running; | |
84 | nr_active += (long) this_rq->nr_uninterruptible; | |
85 | ||
86 | if (nr_active != this_rq->calc_load_active) { | |
87 | delta = nr_active - this_rq->calc_load_active; | |
88 | this_rq->calc_load_active = nr_active; | |
89 | } | |
90 | ||
91 | return delta; | |
92 | } | |
93 | ||
94 | /* | |
95 | * a1 = a0 * e + a * (1 - e) | |
96 | */ | |
97 | static unsigned long | |
98 | calc_load(unsigned long load, unsigned long exp, unsigned long active) | |
99 | { | |
100 | load *= exp; | |
101 | load += active * (FIXED_1 - exp); | |
102 | load += 1UL << (FSHIFT - 1); | |
103 | return load >> FSHIFT; | |
104 | } | |
105 | ||
106 | #ifdef CONFIG_NO_HZ_COMMON | |
107 | /* | |
108 | * Handle NO_HZ for the global load-average. | |
109 | * | |
110 | * Since the above described distributed algorithm to compute the global | |
111 | * load-average relies on per-cpu sampling from the tick, it is affected by | |
112 | * NO_HZ. | |
113 | * | |
114 | * The basic idea is to fold the nr_active delta into a global idle-delta upon | |
115 | * entering NO_HZ state such that we can include this as an 'extra' cpu delta | |
116 | * when we read the global state. | |
117 | * | |
118 | * Obviously reality has to ruin such a delightfully simple scheme: | |
119 | * | |
120 | * - When we go NO_HZ idle during the window, we can negate our sample | |
121 | * contribution, causing under-accounting. | |
122 | * | |
123 | * We avoid this by keeping two idle-delta counters and flipping them | |
124 | * when the window starts, thus separating old and new NO_HZ load. | |
125 | * | |
126 | * The only trick is the slight shift in index flip for read vs write. | |
127 | * | |
128 | * 0s 5s 10s 15s | |
129 | * +10 +10 +10 +10 | |
130 | * |-|-----------|-|-----------|-|-----------|-| | |
131 | * r:0 0 1 1 0 0 1 1 0 | |
132 | * w:0 1 1 0 0 1 1 0 0 | |
133 | * | |
134 | * This ensures we'll fold the old idle contribution in this window while | |
135 | * accumlating the new one. | |
136 | * | |
137 | * - When we wake up from NO_HZ idle during the window, we push up our | |
138 | * contribution, since we effectively move our sample point to a known | |
139 | * busy state. | |
140 | * | |
141 | * This is solved by pushing the window forward, and thus skipping the | |
142 | * sample, for this cpu (effectively using the idle-delta for this cpu which | |
143 | * was in effect at the time the window opened). This also solves the issue | |
144 | * of having to deal with a cpu having been in NOHZ idle for multiple | |
145 | * LOAD_FREQ intervals. | |
146 | * | |
147 | * When making the ILB scale, we should try to pull this in as well. | |
148 | */ | |
149 | static atomic_long_t calc_load_idle[2]; | |
150 | static int calc_load_idx; | |
151 | ||
152 | static inline int calc_load_write_idx(void) | |
153 | { | |
154 | int idx = calc_load_idx; | |
155 | ||
156 | /* | |
157 | * See calc_global_nohz(), if we observe the new index, we also | |
158 | * need to observe the new update time. | |
159 | */ | |
160 | smp_rmb(); | |
161 | ||
162 | /* | |
163 | * If the folding window started, make sure we start writing in the | |
164 | * next idle-delta. | |
165 | */ | |
166 | if (!time_before(jiffies, calc_load_update)) | |
167 | idx++; | |
168 | ||
169 | return idx & 1; | |
170 | } | |
171 | ||
172 | static inline int calc_load_read_idx(void) | |
173 | { | |
174 | return calc_load_idx & 1; | |
175 | } | |
176 | ||
177 | void calc_load_enter_idle(void) | |
178 | { | |
179 | struct rq *this_rq = this_rq(); | |
180 | long delta; | |
181 | ||
182 | /* | |
183 | * We're going into NOHZ mode, if there's any pending delta, fold it | |
184 | * into the pending idle delta. | |
185 | */ | |
186 | delta = calc_load_fold_active(this_rq); | |
187 | if (delta) { | |
188 | int idx = calc_load_write_idx(); | |
189 | atomic_long_add(delta, &calc_load_idle[idx]); | |
190 | } | |
191 | } | |
192 | ||
193 | void calc_load_exit_idle(void) | |
194 | { | |
195 | struct rq *this_rq = this_rq(); | |
196 | ||
197 | /* | |
198 | * If we're still before the sample window, we're done. | |
199 | */ | |
200 | if (time_before(jiffies, this_rq->calc_load_update)) | |
201 | return; | |
202 | ||
203 | /* | |
204 | * We woke inside or after the sample window, this means we're already | |
205 | * accounted through the nohz accounting, so skip the entire deal and | |
206 | * sync up for the next window. | |
207 | */ | |
208 | this_rq->calc_load_update = calc_load_update; | |
209 | if (time_before(jiffies, this_rq->calc_load_update + 10)) | |
210 | this_rq->calc_load_update += LOAD_FREQ; | |
211 | } | |
212 | ||
213 | static long calc_load_fold_idle(void) | |
214 | { | |
215 | int idx = calc_load_read_idx(); | |
216 | long delta = 0; | |
217 | ||
218 | if (atomic_long_read(&calc_load_idle[idx])) | |
219 | delta = atomic_long_xchg(&calc_load_idle[idx], 0); | |
220 | ||
221 | return delta; | |
222 | } | |
223 | ||
224 | /** | |
225 | * fixed_power_int - compute: x^n, in O(log n) time | |
226 | * | |
227 | * @x: base of the power | |
228 | * @frac_bits: fractional bits of @x | |
229 | * @n: power to raise @x to. | |
230 | * | |
231 | * By exploiting the relation between the definition of the natural power | |
232 | * function: x^n := x*x*...*x (x multiplied by itself for n times), and | |
233 | * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i, | |
234 | * (where: n_i \elem {0, 1}, the binary vector representing n), | |
235 | * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is | |
236 | * of course trivially computable in O(log_2 n), the length of our binary | |
237 | * vector. | |
238 | */ | |
239 | static unsigned long | |
240 | fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n) | |
241 | { | |
242 | unsigned long result = 1UL << frac_bits; | |
243 | ||
244 | if (n) for (;;) { | |
245 | if (n & 1) { | |
246 | result *= x; | |
247 | result += 1UL << (frac_bits - 1); | |
248 | result >>= frac_bits; | |
249 | } | |
250 | n >>= 1; | |
251 | if (!n) | |
252 | break; | |
253 | x *= x; | |
254 | x += 1UL << (frac_bits - 1); | |
255 | x >>= frac_bits; | |
256 | } | |
257 | ||
258 | return result; | |
259 | } | |
260 | ||
261 | /* | |
262 | * a1 = a0 * e + a * (1 - e) | |
263 | * | |
264 | * a2 = a1 * e + a * (1 - e) | |
265 | * = (a0 * e + a * (1 - e)) * e + a * (1 - e) | |
266 | * = a0 * e^2 + a * (1 - e) * (1 + e) | |
267 | * | |
268 | * a3 = a2 * e + a * (1 - e) | |
269 | * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e) | |
270 | * = a0 * e^3 + a * (1 - e) * (1 + e + e^2) | |
271 | * | |
272 | * ... | |
273 | * | |
274 | * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1] | |
275 | * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e) | |
276 | * = a0 * e^n + a * (1 - e^n) | |
277 | * | |
278 | * [1] application of the geometric series: | |
279 | * | |
280 | * n 1 - x^(n+1) | |
281 | * S_n := \Sum x^i = ------------- | |
282 | * i=0 1 - x | |
283 | */ | |
284 | static unsigned long | |
285 | calc_load_n(unsigned long load, unsigned long exp, | |
286 | unsigned long active, unsigned int n) | |
287 | { | |
288 | ||
289 | return calc_load(load, fixed_power_int(exp, FSHIFT, n), active); | |
290 | } | |
291 | ||
292 | /* | |
293 | * NO_HZ can leave us missing all per-cpu ticks calling | |
294 | * calc_load_account_active(), but since an idle CPU folds its delta into | |
295 | * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold | |
296 | * in the pending idle delta if our idle period crossed a load cycle boundary. | |
297 | * | |
298 | * Once we've updated the global active value, we need to apply the exponential | |
299 | * weights adjusted to the number of cycles missed. | |
300 | */ | |
301 | static void calc_global_nohz(void) | |
302 | { | |
303 | long delta, active, n; | |
304 | ||
305 | if (!time_before(jiffies, calc_load_update + 10)) { | |
306 | /* | |
307 | * Catch-up, fold however many we are behind still | |
308 | */ | |
309 | delta = jiffies - calc_load_update - 10; | |
310 | n = 1 + (delta / LOAD_FREQ); | |
311 | ||
312 | active = atomic_long_read(&calc_load_tasks); | |
313 | active = active > 0 ? active * FIXED_1 : 0; | |
314 | ||
315 | avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n); | |
316 | avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n); | |
317 | avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n); | |
318 | ||
319 | calc_load_update += n * LOAD_FREQ; | |
320 | } | |
321 | ||
322 | /* | |
323 | * Flip the idle index... | |
324 | * | |
325 | * Make sure we first write the new time then flip the index, so that | |
326 | * calc_load_write_idx() will see the new time when it reads the new | |
327 | * index, this avoids a double flip messing things up. | |
328 | */ | |
329 | smp_wmb(); | |
330 | calc_load_idx++; | |
331 | } | |
332 | #else /* !CONFIG_NO_HZ_COMMON */ | |
333 | ||
334 | static inline long calc_load_fold_idle(void) { return 0; } | |
335 | static inline void calc_global_nohz(void) { } | |
336 | ||
337 | #endif /* CONFIG_NO_HZ_COMMON */ | |
338 | ||
339 | /* | |
340 | * calc_load - update the avenrun load estimates 10 ticks after the | |
341 | * CPUs have updated calc_load_tasks. | |
342 | */ | |
343 | void calc_global_load(unsigned long ticks) | |
344 | { | |
345 | long active, delta; | |
346 | ||
347 | if (time_before(jiffies, calc_load_update + 10)) | |
348 | return; | |
349 | ||
350 | /* | |
351 | * Fold the 'old' idle-delta to include all NO_HZ cpus. | |
352 | */ | |
353 | delta = calc_load_fold_idle(); | |
354 | if (delta) | |
355 | atomic_long_add(delta, &calc_load_tasks); | |
356 | ||
357 | active = atomic_long_read(&calc_load_tasks); | |
358 | active = active > 0 ? active * FIXED_1 : 0; | |
359 | ||
360 | avenrun[0] = calc_load(avenrun[0], EXP_1, active); | |
361 | avenrun[1] = calc_load(avenrun[1], EXP_5, active); | |
362 | avenrun[2] = calc_load(avenrun[2], EXP_15, active); | |
363 | ||
364 | calc_load_update += LOAD_FREQ; | |
365 | ||
366 | /* | |
367 | * In case we idled for multiple LOAD_FREQ intervals, catch up in bulk. | |
368 | */ | |
369 | calc_global_nohz(); | |
370 | } | |
371 | ||
372 | /* | |
373 | * Called from update_cpu_load() to periodically update this CPU's | |
374 | * active count. | |
375 | */ | |
376 | static void calc_load_account_active(struct rq *this_rq) | |
377 | { | |
378 | long delta; | |
379 | ||
380 | if (time_before(jiffies, this_rq->calc_load_update)) | |
381 | return; | |
382 | ||
383 | delta = calc_load_fold_active(this_rq); | |
384 | if (delta) | |
385 | atomic_long_add(delta, &calc_load_tasks); | |
386 | ||
387 | this_rq->calc_load_update += LOAD_FREQ; | |
388 | } | |
389 | ||
390 | /* | |
391 | * End of global load-average stuff | |
392 | */ | |
393 | ||
394 | /* | |
395 | * The exact cpuload at various idx values, calculated at every tick would be | |
396 | * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load | |
397 | * | |
398 | * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called | |
399 | * on nth tick when cpu may be busy, then we have: | |
400 | * load = ((2^idx - 1) / 2^idx)^(n-1) * load | |
401 | * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load | |
402 | * | |
403 | * decay_load_missed() below does efficient calculation of | |
404 | * load = ((2^idx - 1) / 2^idx)^(n-1) * load | |
405 | * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load | |
406 | * | |
407 | * The calculation is approximated on a 128 point scale. | |
408 | * degrade_zero_ticks is the number of ticks after which load at any | |
409 | * particular idx is approximated to be zero. | |
410 | * degrade_factor is a precomputed table, a row for each load idx. | |
411 | * Each column corresponds to degradation factor for a power of two ticks, | |
412 | * based on 128 point scale. | |
413 | * Example: | |
414 | * row 2, col 3 (=12) says that the degradation at load idx 2 after | |
415 | * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8). | |
416 | * | |
417 | * With this power of 2 load factors, we can degrade the load n times | |
418 | * by looking at 1 bits in n and doing as many mult/shift instead of | |
419 | * n mult/shifts needed by the exact degradation. | |
420 | */ | |
421 | #define DEGRADE_SHIFT 7 | |
422 | static const unsigned char | |
423 | degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128}; | |
424 | static const unsigned char | |
425 | degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = { | |
426 | {0, 0, 0, 0, 0, 0, 0, 0}, | |
427 | {64, 32, 8, 0, 0, 0, 0, 0}, | |
428 | {96, 72, 40, 12, 1, 0, 0}, | |
429 | {112, 98, 75, 43, 15, 1, 0}, | |
430 | {120, 112, 98, 76, 45, 16, 2} }; | |
431 | ||
432 | /* | |
433 | * Update cpu_load for any missed ticks, due to tickless idle. The backlog | |
434 | * would be when CPU is idle and so we just decay the old load without | |
435 | * adding any new load. | |
436 | */ | |
437 | static unsigned long | |
438 | decay_load_missed(unsigned long load, unsigned long missed_updates, int idx) | |
439 | { | |
440 | int j = 0; | |
441 | ||
442 | if (!missed_updates) | |
443 | return load; | |
444 | ||
445 | if (missed_updates >= degrade_zero_ticks[idx]) | |
446 | return 0; | |
447 | ||
448 | if (idx == 1) | |
449 | return load >> missed_updates; | |
450 | ||
451 | while (missed_updates) { | |
452 | if (missed_updates % 2) | |
453 | load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT; | |
454 | ||
455 | missed_updates >>= 1; | |
456 | j++; | |
457 | } | |
458 | return load; | |
459 | } | |
460 | ||
461 | /* | |
462 | * Update rq->cpu_load[] statistics. This function is usually called every | |
463 | * scheduler tick (TICK_NSEC). With tickless idle this will not be called | |
464 | * every tick. We fix it up based on jiffies. | |
465 | */ | |
466 | static void __update_cpu_load(struct rq *this_rq, unsigned long this_load, | |
467 | unsigned long pending_updates) | |
468 | { | |
469 | int i, scale; | |
470 | ||
471 | this_rq->nr_load_updates++; | |
472 | ||
473 | /* Update our load: */ | |
474 | this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */ | |
475 | for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { | |
476 | unsigned long old_load, new_load; | |
477 | ||
478 | /* scale is effectively 1 << i now, and >> i divides by scale */ | |
479 | ||
480 | old_load = this_rq->cpu_load[i]; | |
481 | old_load = decay_load_missed(old_load, pending_updates - 1, i); | |
482 | new_load = this_load; | |
483 | /* | |
484 | * Round up the averaging division if load is increasing. This | |
485 | * prevents us from getting stuck on 9 if the load is 10, for | |
486 | * example. | |
487 | */ | |
488 | if (new_load > old_load) | |
489 | new_load += scale - 1; | |
490 | ||
491 | this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i; | |
492 | } | |
493 | ||
494 | sched_avg_update(this_rq); | |
495 | } | |
496 | ||
b92486cb | 497 | #ifdef CONFIG_SMP |
a9dc5d0e | 498 | static inline unsigned long get_rq_runnable_load(struct rq *rq) |
b92486cb AS |
499 | { |
500 | return rq->cfs.runnable_load_avg; | |
501 | } | |
502 | #else | |
a9dc5d0e | 503 | static inline unsigned long get_rq_runnable_load(struct rq *rq) |
b92486cb AS |
504 | { |
505 | return rq->load.weight; | |
506 | } | |
507 | #endif | |
508 | ||
45ceebf7 PG |
509 | #ifdef CONFIG_NO_HZ_COMMON |
510 | /* | |
511 | * There is no sane way to deal with nohz on smp when using jiffies because the | |
512 | * cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading | |
513 | * causing off-by-one errors in observed deltas; {0,2} instead of {1,1}. | |
514 | * | |
515 | * Therefore we cannot use the delta approach from the regular tick since that | |
516 | * would seriously skew the load calculation. However we'll make do for those | |
517 | * updates happening while idle (nohz_idle_balance) or coming out of idle | |
518 | * (tick_nohz_idle_exit). | |
519 | * | |
520 | * This means we might still be one tick off for nohz periods. | |
521 | */ | |
522 | ||
523 | /* | |
524 | * Called from nohz_idle_balance() to update the load ratings before doing the | |
525 | * idle balance. | |
526 | */ | |
527 | void update_idle_cpu_load(struct rq *this_rq) | |
528 | { | |
529 | unsigned long curr_jiffies = ACCESS_ONCE(jiffies); | |
b92486cb | 530 | unsigned long load = get_rq_runnable_load(this_rq); |
45ceebf7 PG |
531 | unsigned long pending_updates; |
532 | ||
533 | /* | |
534 | * bail if there's load or we're actually up-to-date. | |
535 | */ | |
536 | if (load || curr_jiffies == this_rq->last_load_update_tick) | |
537 | return; | |
538 | ||
539 | pending_updates = curr_jiffies - this_rq->last_load_update_tick; | |
540 | this_rq->last_load_update_tick = curr_jiffies; | |
541 | ||
542 | __update_cpu_load(this_rq, load, pending_updates); | |
543 | } | |
544 | ||
545 | /* | |
546 | * Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed. | |
547 | */ | |
548 | void update_cpu_load_nohz(void) | |
549 | { | |
550 | struct rq *this_rq = this_rq(); | |
551 | unsigned long curr_jiffies = ACCESS_ONCE(jiffies); | |
552 | unsigned long pending_updates; | |
553 | ||
554 | if (curr_jiffies == this_rq->last_load_update_tick) | |
555 | return; | |
556 | ||
557 | raw_spin_lock(&this_rq->lock); | |
558 | pending_updates = curr_jiffies - this_rq->last_load_update_tick; | |
559 | if (pending_updates) { | |
560 | this_rq->last_load_update_tick = curr_jiffies; | |
561 | /* | |
562 | * We were idle, this means load 0, the current load might be | |
563 | * !0 due to remote wakeups and the sort. | |
564 | */ | |
565 | __update_cpu_load(this_rq, 0, pending_updates); | |
566 | } | |
567 | raw_spin_unlock(&this_rq->lock); | |
568 | } | |
569 | #endif /* CONFIG_NO_HZ */ | |
570 | ||
571 | /* | |
572 | * Called from scheduler_tick() | |
573 | */ | |
574 | void update_cpu_load_active(struct rq *this_rq) | |
575 | { | |
b92486cb | 576 | unsigned long load = get_rq_runnable_load(this_rq); |
45ceebf7 PG |
577 | /* |
578 | * See the mess around update_idle_cpu_load() / update_cpu_load_nohz(). | |
579 | */ | |
580 | this_rq->last_load_update_tick = jiffies; | |
b92486cb | 581 | __update_cpu_load(this_rq, load, 1); |
45ceebf7 PG |
582 | |
583 | calc_load_account_active(this_rq); | |
584 | } |