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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 | ||
11 | unsigned long this_cpu_load(void) | |
12 | { | |
13 | struct rq *this = this_rq(); | |
14 | return this->cpu_load[0]; | |
15 | } | |
16 | ||
17 | ||
18 | /* | |
19 | * Global load-average calculations | |
20 | * | |
21 | * We take a distributed and async approach to calculating the global load-avg | |
22 | * in order to minimize overhead. | |
23 | * | |
24 | * The global load average is an exponentially decaying average of nr_running + | |
25 | * nr_uninterruptible. | |
26 | * | |
27 | * Once every LOAD_FREQ: | |
28 | * | |
29 | * nr_active = 0; | |
30 | * for_each_possible_cpu(cpu) | |
31 | * nr_active += cpu_of(cpu)->nr_running + cpu_of(cpu)->nr_uninterruptible; | |
32 | * | |
33 | * avenrun[n] = avenrun[0] * exp_n + nr_active * (1 - exp_n) | |
34 | * | |
35 | * Due to a number of reasons the above turns in the mess below: | |
36 | * | |
37 | * - for_each_possible_cpu() is prohibitively expensive on machines with | |
38 | * serious number of cpus, therefore we need to take a distributed approach | |
39 | * to calculating nr_active. | |
40 | * | |
41 | * \Sum_i x_i(t) = \Sum_i x_i(t) - x_i(t_0) | x_i(t_0) := 0 | |
42 | * = \Sum_i { \Sum_j=1 x_i(t_j) - x_i(t_j-1) } | |
43 | * | |
44 | * So assuming nr_active := 0 when we start out -- true per definition, we | |
45 | * can simply take per-cpu deltas and fold those into a global accumulate | |
46 | * to obtain the same result. See calc_load_fold_active(). | |
47 | * | |
48 | * Furthermore, in order to avoid synchronizing all per-cpu delta folding | |
49 | * across the machine, we assume 10 ticks is sufficient time for every | |
50 | * cpu to have completed this task. | |
51 | * | |
52 | * This places an upper-bound on the IRQ-off latency of the machine. Then | |
53 | * again, being late doesn't loose the delta, just wrecks the sample. | |
54 | * | |
55 | * - cpu_rq()->nr_uninterruptible isn't accurately tracked per-cpu because | |
56 | * this would add another cross-cpu cacheline miss and atomic operation | |
57 | * to the wakeup path. Instead we increment on whatever cpu the task ran | |
58 | * when it went into uninterruptible state and decrement on whatever cpu | |
59 | * did the wakeup. This means that only the sum of nr_uninterruptible over | |
60 | * all cpus yields the correct result. | |
61 | * | |
62 | * This covers the NO_HZ=n code, for extra head-aches, see the comment below. | |
63 | */ | |
64 | ||
65 | /* Variables and functions for calc_load */ | |
66 | atomic_long_t calc_load_tasks; | |
67 | unsigned long calc_load_update; | |
68 | unsigned long avenrun[3]; | |
69 | EXPORT_SYMBOL(avenrun); /* should be removed */ | |
70 | ||
71 | /** | |
72 | * get_avenrun - get the load average array | |
73 | * @loads: pointer to dest load array | |
74 | * @offset: offset to add | |
75 | * @shift: shift count to shift the result left | |
76 | * | |
77 | * These values are estimates at best, so no need for locking. | |
78 | */ | |
79 | void get_avenrun(unsigned long *loads, unsigned long offset, int shift) | |
80 | { | |
81 | loads[0] = (avenrun[0] + offset) << shift; | |
82 | loads[1] = (avenrun[1] + offset) << shift; | |
83 | loads[2] = (avenrun[2] + offset) << shift; | |
84 | } | |
85 | ||
86 | long calc_load_fold_active(struct rq *this_rq) | |
87 | { | |
88 | long nr_active, delta = 0; | |
89 | ||
90 | nr_active = this_rq->nr_running; | |
91 | nr_active += (long) this_rq->nr_uninterruptible; | |
92 | ||
93 | if (nr_active != this_rq->calc_load_active) { | |
94 | delta = nr_active - this_rq->calc_load_active; | |
95 | this_rq->calc_load_active = nr_active; | |
96 | } | |
97 | ||
98 | return delta; | |
99 | } | |
100 | ||
101 | /* | |
102 | * a1 = a0 * e + a * (1 - e) | |
103 | */ | |
104 | static unsigned long | |
105 | calc_load(unsigned long load, unsigned long exp, unsigned long active) | |
106 | { | |
107 | load *= exp; | |
108 | load += active * (FIXED_1 - exp); | |
109 | load += 1UL << (FSHIFT - 1); | |
110 | return load >> FSHIFT; | |
111 | } | |
112 | ||
113 | #ifdef CONFIG_NO_HZ_COMMON | |
114 | /* | |
115 | * Handle NO_HZ for the global load-average. | |
116 | * | |
117 | * Since the above described distributed algorithm to compute the global | |
118 | * load-average relies on per-cpu sampling from the tick, it is affected by | |
119 | * NO_HZ. | |
120 | * | |
121 | * The basic idea is to fold the nr_active delta into a global idle-delta upon | |
122 | * entering NO_HZ state such that we can include this as an 'extra' cpu delta | |
123 | * when we read the global state. | |
124 | * | |
125 | * Obviously reality has to ruin such a delightfully simple scheme: | |
126 | * | |
127 | * - When we go NO_HZ idle during the window, we can negate our sample | |
128 | * contribution, causing under-accounting. | |
129 | * | |
130 | * We avoid this by keeping two idle-delta counters and flipping them | |
131 | * when the window starts, thus separating old and new NO_HZ load. | |
132 | * | |
133 | * The only trick is the slight shift in index flip for read vs write. | |
134 | * | |
135 | * 0s 5s 10s 15s | |
136 | * +10 +10 +10 +10 | |
137 | * |-|-----------|-|-----------|-|-----------|-| | |
138 | * r:0 0 1 1 0 0 1 1 0 | |
139 | * w:0 1 1 0 0 1 1 0 0 | |
140 | * | |
141 | * This ensures we'll fold the old idle contribution in this window while | |
142 | * accumlating the new one. | |
143 | * | |
144 | * - When we wake up from NO_HZ idle during the window, we push up our | |
145 | * contribution, since we effectively move our sample point to a known | |
146 | * busy state. | |
147 | * | |
148 | * This is solved by pushing the window forward, and thus skipping the | |
149 | * sample, for this cpu (effectively using the idle-delta for this cpu which | |
150 | * was in effect at the time the window opened). This also solves the issue | |
151 | * of having to deal with a cpu having been in NOHZ idle for multiple | |
152 | * LOAD_FREQ intervals. | |
153 | * | |
154 | * When making the ILB scale, we should try to pull this in as well. | |
155 | */ | |
156 | static atomic_long_t calc_load_idle[2]; | |
157 | static int calc_load_idx; | |
158 | ||
159 | static inline int calc_load_write_idx(void) | |
160 | { | |
161 | int idx = calc_load_idx; | |
162 | ||
163 | /* | |
164 | * See calc_global_nohz(), if we observe the new index, we also | |
165 | * need to observe the new update time. | |
166 | */ | |
167 | smp_rmb(); | |
168 | ||
169 | /* | |
170 | * If the folding window started, make sure we start writing in the | |
171 | * next idle-delta. | |
172 | */ | |
173 | if (!time_before(jiffies, calc_load_update)) | |
174 | idx++; | |
175 | ||
176 | return idx & 1; | |
177 | } | |
178 | ||
179 | static inline int calc_load_read_idx(void) | |
180 | { | |
181 | return calc_load_idx & 1; | |
182 | } | |
183 | ||
184 | void calc_load_enter_idle(void) | |
185 | { | |
186 | struct rq *this_rq = this_rq(); | |
187 | long delta; | |
188 | ||
189 | /* | |
190 | * We're going into NOHZ mode, if there's any pending delta, fold it | |
191 | * into the pending idle delta. | |
192 | */ | |
193 | delta = calc_load_fold_active(this_rq); | |
194 | if (delta) { | |
195 | int idx = calc_load_write_idx(); | |
196 | atomic_long_add(delta, &calc_load_idle[idx]); | |
197 | } | |
198 | } | |
199 | ||
200 | void calc_load_exit_idle(void) | |
201 | { | |
202 | struct rq *this_rq = this_rq(); | |
203 | ||
204 | /* | |
205 | * If we're still before the sample window, we're done. | |
206 | */ | |
207 | if (time_before(jiffies, this_rq->calc_load_update)) | |
208 | return; | |
209 | ||
210 | /* | |
211 | * We woke inside or after the sample window, this means we're already | |
212 | * accounted through the nohz accounting, so skip the entire deal and | |
213 | * sync up for the next window. | |
214 | */ | |
215 | this_rq->calc_load_update = calc_load_update; | |
216 | if (time_before(jiffies, this_rq->calc_load_update + 10)) | |
217 | this_rq->calc_load_update += LOAD_FREQ; | |
218 | } | |
219 | ||
220 | static long calc_load_fold_idle(void) | |
221 | { | |
222 | int idx = calc_load_read_idx(); | |
223 | long delta = 0; | |
224 | ||
225 | if (atomic_long_read(&calc_load_idle[idx])) | |
226 | delta = atomic_long_xchg(&calc_load_idle[idx], 0); | |
227 | ||
228 | return delta; | |
229 | } | |
230 | ||
231 | /** | |
232 | * fixed_power_int - compute: x^n, in O(log n) time | |
233 | * | |
234 | * @x: base of the power | |
235 | * @frac_bits: fractional bits of @x | |
236 | * @n: power to raise @x to. | |
237 | * | |
238 | * By exploiting the relation between the definition of the natural power | |
239 | * function: x^n := x*x*...*x (x multiplied by itself for n times), and | |
240 | * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i, | |
241 | * (where: n_i \elem {0, 1}, the binary vector representing n), | |
242 | * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is | |
243 | * of course trivially computable in O(log_2 n), the length of our binary | |
244 | * vector. | |
245 | */ | |
246 | static unsigned long | |
247 | fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n) | |
248 | { | |
249 | unsigned long result = 1UL << frac_bits; | |
250 | ||
251 | if (n) for (;;) { | |
252 | if (n & 1) { | |
253 | result *= x; | |
254 | result += 1UL << (frac_bits - 1); | |
255 | result >>= frac_bits; | |
256 | } | |
257 | n >>= 1; | |
258 | if (!n) | |
259 | break; | |
260 | x *= x; | |
261 | x += 1UL << (frac_bits - 1); | |
262 | x >>= frac_bits; | |
263 | } | |
264 | ||
265 | return result; | |
266 | } | |
267 | ||
268 | /* | |
269 | * a1 = a0 * e + a * (1 - e) | |
270 | * | |
271 | * a2 = a1 * e + a * (1 - e) | |
272 | * = (a0 * e + a * (1 - e)) * e + a * (1 - e) | |
273 | * = a0 * e^2 + a * (1 - e) * (1 + e) | |
274 | * | |
275 | * a3 = a2 * e + a * (1 - e) | |
276 | * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e) | |
277 | * = a0 * e^3 + a * (1 - e) * (1 + e + e^2) | |
278 | * | |
279 | * ... | |
280 | * | |
281 | * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1] | |
282 | * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e) | |
283 | * = a0 * e^n + a * (1 - e^n) | |
284 | * | |
285 | * [1] application of the geometric series: | |
286 | * | |
287 | * n 1 - x^(n+1) | |
288 | * S_n := \Sum x^i = ------------- | |
289 | * i=0 1 - x | |
290 | */ | |
291 | static unsigned long | |
292 | calc_load_n(unsigned long load, unsigned long exp, | |
293 | unsigned long active, unsigned int n) | |
294 | { | |
295 | ||
296 | return calc_load(load, fixed_power_int(exp, FSHIFT, n), active); | |
297 | } | |
298 | ||
299 | /* | |
300 | * NO_HZ can leave us missing all per-cpu ticks calling | |
301 | * calc_load_account_active(), but since an idle CPU folds its delta into | |
302 | * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold | |
303 | * in the pending idle delta if our idle period crossed a load cycle boundary. | |
304 | * | |
305 | * Once we've updated the global active value, we need to apply the exponential | |
306 | * weights adjusted to the number of cycles missed. | |
307 | */ | |
308 | static void calc_global_nohz(void) | |
309 | { | |
310 | long delta, active, n; | |
311 | ||
312 | if (!time_before(jiffies, calc_load_update + 10)) { | |
313 | /* | |
314 | * Catch-up, fold however many we are behind still | |
315 | */ | |
316 | delta = jiffies - calc_load_update - 10; | |
317 | n = 1 + (delta / LOAD_FREQ); | |
318 | ||
319 | active = atomic_long_read(&calc_load_tasks); | |
320 | active = active > 0 ? active * FIXED_1 : 0; | |
321 | ||
322 | avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n); | |
323 | avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n); | |
324 | avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n); | |
325 | ||
326 | calc_load_update += n * LOAD_FREQ; | |
327 | } | |
328 | ||
329 | /* | |
330 | * Flip the idle index... | |
331 | * | |
332 | * Make sure we first write the new time then flip the index, so that | |
333 | * calc_load_write_idx() will see the new time when it reads the new | |
334 | * index, this avoids a double flip messing things up. | |
335 | */ | |
336 | smp_wmb(); | |
337 | calc_load_idx++; | |
338 | } | |
339 | #else /* !CONFIG_NO_HZ_COMMON */ | |
340 | ||
341 | static inline long calc_load_fold_idle(void) { return 0; } | |
342 | static inline void calc_global_nohz(void) { } | |
343 | ||
344 | #endif /* CONFIG_NO_HZ_COMMON */ | |
345 | ||
346 | /* | |
347 | * calc_load - update the avenrun load estimates 10 ticks after the | |
348 | * CPUs have updated calc_load_tasks. | |
349 | */ | |
350 | void calc_global_load(unsigned long ticks) | |
351 | { | |
352 | long active, delta; | |
353 | ||
354 | if (time_before(jiffies, calc_load_update + 10)) | |
355 | return; | |
356 | ||
357 | /* | |
358 | * Fold the 'old' idle-delta to include all NO_HZ cpus. | |
359 | */ | |
360 | delta = calc_load_fold_idle(); | |
361 | if (delta) | |
362 | atomic_long_add(delta, &calc_load_tasks); | |
363 | ||
364 | active = atomic_long_read(&calc_load_tasks); | |
365 | active = active > 0 ? active * FIXED_1 : 0; | |
366 | ||
367 | avenrun[0] = calc_load(avenrun[0], EXP_1, active); | |
368 | avenrun[1] = calc_load(avenrun[1], EXP_5, active); | |
369 | avenrun[2] = calc_load(avenrun[2], EXP_15, active); | |
370 | ||
371 | calc_load_update += LOAD_FREQ; | |
372 | ||
373 | /* | |
374 | * In case we idled for multiple LOAD_FREQ intervals, catch up in bulk. | |
375 | */ | |
376 | calc_global_nohz(); | |
377 | } | |
378 | ||
379 | /* | |
380 | * Called from update_cpu_load() to periodically update this CPU's | |
381 | * active count. | |
382 | */ | |
383 | static void calc_load_account_active(struct rq *this_rq) | |
384 | { | |
385 | long delta; | |
386 | ||
387 | if (time_before(jiffies, this_rq->calc_load_update)) | |
388 | return; | |
389 | ||
390 | delta = calc_load_fold_active(this_rq); | |
391 | if (delta) | |
392 | atomic_long_add(delta, &calc_load_tasks); | |
393 | ||
394 | this_rq->calc_load_update += LOAD_FREQ; | |
395 | } | |
396 | ||
397 | /* | |
398 | * End of global load-average stuff | |
399 | */ | |
400 | ||
401 | /* | |
402 | * The exact cpuload at various idx values, calculated at every tick would be | |
403 | * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load | |
404 | * | |
405 | * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called | |
406 | * on nth tick when cpu may be busy, then we have: | |
407 | * load = ((2^idx - 1) / 2^idx)^(n-1) * load | |
408 | * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load | |
409 | * | |
410 | * decay_load_missed() below does efficient calculation of | |
411 | * load = ((2^idx - 1) / 2^idx)^(n-1) * load | |
412 | * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load | |
413 | * | |
414 | * The calculation is approximated on a 128 point scale. | |
415 | * degrade_zero_ticks is the number of ticks after which load at any | |
416 | * particular idx is approximated to be zero. | |
417 | * degrade_factor is a precomputed table, a row for each load idx. | |
418 | * Each column corresponds to degradation factor for a power of two ticks, | |
419 | * based on 128 point scale. | |
420 | * Example: | |
421 | * row 2, col 3 (=12) says that the degradation at load idx 2 after | |
422 | * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8). | |
423 | * | |
424 | * With this power of 2 load factors, we can degrade the load n times | |
425 | * by looking at 1 bits in n and doing as many mult/shift instead of | |
426 | * n mult/shifts needed by the exact degradation. | |
427 | */ | |
428 | #define DEGRADE_SHIFT 7 | |
429 | static const unsigned char | |
430 | degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128}; | |
431 | static const unsigned char | |
432 | degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = { | |
433 | {0, 0, 0, 0, 0, 0, 0, 0}, | |
434 | {64, 32, 8, 0, 0, 0, 0, 0}, | |
435 | {96, 72, 40, 12, 1, 0, 0}, | |
436 | {112, 98, 75, 43, 15, 1, 0}, | |
437 | {120, 112, 98, 76, 45, 16, 2} }; | |
438 | ||
439 | /* | |
440 | * Update cpu_load for any missed ticks, due to tickless idle. The backlog | |
441 | * would be when CPU is idle and so we just decay the old load without | |
442 | * adding any new load. | |
443 | */ | |
444 | static unsigned long | |
445 | decay_load_missed(unsigned long load, unsigned long missed_updates, int idx) | |
446 | { | |
447 | int j = 0; | |
448 | ||
449 | if (!missed_updates) | |
450 | return load; | |
451 | ||
452 | if (missed_updates >= degrade_zero_ticks[idx]) | |
453 | return 0; | |
454 | ||
455 | if (idx == 1) | |
456 | return load >> missed_updates; | |
457 | ||
458 | while (missed_updates) { | |
459 | if (missed_updates % 2) | |
460 | load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT; | |
461 | ||
462 | missed_updates >>= 1; | |
463 | j++; | |
464 | } | |
465 | return load; | |
466 | } | |
467 | ||
468 | /* | |
469 | * Update rq->cpu_load[] statistics. This function is usually called every | |
470 | * scheduler tick (TICK_NSEC). With tickless idle this will not be called | |
471 | * every tick. We fix it up based on jiffies. | |
472 | */ | |
473 | static void __update_cpu_load(struct rq *this_rq, unsigned long this_load, | |
474 | unsigned long pending_updates) | |
475 | { | |
476 | int i, scale; | |
477 | ||
478 | this_rq->nr_load_updates++; | |
479 | ||
480 | /* Update our load: */ | |
481 | this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */ | |
482 | for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { | |
483 | unsigned long old_load, new_load; | |
484 | ||
485 | /* scale is effectively 1 << i now, and >> i divides by scale */ | |
486 | ||
487 | old_load = this_rq->cpu_load[i]; | |
488 | old_load = decay_load_missed(old_load, pending_updates - 1, i); | |
489 | new_load = this_load; | |
490 | /* | |
491 | * Round up the averaging division if load is increasing. This | |
492 | * prevents us from getting stuck on 9 if the load is 10, for | |
493 | * example. | |
494 | */ | |
495 | if (new_load > old_load) | |
496 | new_load += scale - 1; | |
497 | ||
498 | this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i; | |
499 | } | |
500 | ||
501 | sched_avg_update(this_rq); | |
502 | } | |
503 | ||
b92486cb | 504 | #ifdef CONFIG_SMP |
a9dc5d0e | 505 | static inline unsigned long get_rq_runnable_load(struct rq *rq) |
b92486cb AS |
506 | { |
507 | return rq->cfs.runnable_load_avg; | |
508 | } | |
509 | #else | |
a9dc5d0e | 510 | static inline unsigned long get_rq_runnable_load(struct rq *rq) |
b92486cb AS |
511 | { |
512 | return rq->load.weight; | |
513 | } | |
514 | #endif | |
515 | ||
45ceebf7 PG |
516 | #ifdef CONFIG_NO_HZ_COMMON |
517 | /* | |
518 | * There is no sane way to deal with nohz on smp when using jiffies because the | |
519 | * cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading | |
520 | * causing off-by-one errors in observed deltas; {0,2} instead of {1,1}. | |
521 | * | |
522 | * Therefore we cannot use the delta approach from the regular tick since that | |
523 | * would seriously skew the load calculation. However we'll make do for those | |
524 | * updates happening while idle (nohz_idle_balance) or coming out of idle | |
525 | * (tick_nohz_idle_exit). | |
526 | * | |
527 | * This means we might still be one tick off for nohz periods. | |
528 | */ | |
529 | ||
530 | /* | |
531 | * Called from nohz_idle_balance() to update the load ratings before doing the | |
532 | * idle balance. | |
533 | */ | |
534 | void update_idle_cpu_load(struct rq *this_rq) | |
535 | { | |
536 | unsigned long curr_jiffies = ACCESS_ONCE(jiffies); | |
b92486cb | 537 | unsigned long load = get_rq_runnable_load(this_rq); |
45ceebf7 PG |
538 | unsigned long pending_updates; |
539 | ||
540 | /* | |
541 | * bail if there's load or we're actually up-to-date. | |
542 | */ | |
543 | if (load || curr_jiffies == this_rq->last_load_update_tick) | |
544 | return; | |
545 | ||
546 | pending_updates = curr_jiffies - this_rq->last_load_update_tick; | |
547 | this_rq->last_load_update_tick = curr_jiffies; | |
548 | ||
549 | __update_cpu_load(this_rq, load, pending_updates); | |
550 | } | |
551 | ||
552 | /* | |
553 | * Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed. | |
554 | */ | |
555 | void update_cpu_load_nohz(void) | |
556 | { | |
557 | struct rq *this_rq = this_rq(); | |
558 | unsigned long curr_jiffies = ACCESS_ONCE(jiffies); | |
559 | unsigned long pending_updates; | |
560 | ||
561 | if (curr_jiffies == this_rq->last_load_update_tick) | |
562 | return; | |
563 | ||
564 | raw_spin_lock(&this_rq->lock); | |
565 | pending_updates = curr_jiffies - this_rq->last_load_update_tick; | |
566 | if (pending_updates) { | |
567 | this_rq->last_load_update_tick = curr_jiffies; | |
568 | /* | |
569 | * We were idle, this means load 0, the current load might be | |
570 | * !0 due to remote wakeups and the sort. | |
571 | */ | |
572 | __update_cpu_load(this_rq, 0, pending_updates); | |
573 | } | |
574 | raw_spin_unlock(&this_rq->lock); | |
575 | } | |
576 | #endif /* CONFIG_NO_HZ */ | |
577 | ||
578 | /* | |
579 | * Called from scheduler_tick() | |
580 | */ | |
581 | void update_cpu_load_active(struct rq *this_rq) | |
582 | { | |
b92486cb | 583 | unsigned long load = get_rq_runnable_load(this_rq); |
45ceebf7 PG |
584 | /* |
585 | * See the mess around update_idle_cpu_load() / update_cpu_load_nohz(). | |
586 | */ | |
587 | this_rq->last_load_update_tick = jiffies; | |
b92486cb | 588 | __update_cpu_load(this_rq, load, 1); |
45ceebf7 PG |
589 | |
590 | calc_load_account_active(this_rq); | |
591 | } |