This source file includes following definitions.
- power_saving_mwait_init
- round_robin_cpu
- exit_round_robin
- power_saving_thread
- create_power_saving_task
- destroy_power_saving_task
- set_power_saving_task_num
- acpi_pad_idle_cpus
- acpi_pad_idle_cpus_num
- acpi_pad_rrtime_store
- acpi_pad_rrtime_show
- acpi_pad_idlepct_store
- acpi_pad_idlepct_show
- acpi_pad_idlecpus_store
- acpi_pad_idlecpus_show
- acpi_pad_add_sysfs
- acpi_pad_remove_sysfs
- acpi_pad_pur
- acpi_pad_handle_notify
- acpi_pad_notify
- acpi_pad_add
- acpi_pad_remove
- acpi_pad_init
- acpi_pad_exit
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8 #include <linux/kernel.h>
9 #include <linux/cpumask.h>
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/types.h>
13 #include <linux/kthread.h>
14 #include <uapi/linux/sched/types.h>
15 #include <linux/freezer.h>
16 #include <linux/cpu.h>
17 #include <linux/tick.h>
18 #include <linux/slab.h>
19 #include <linux/acpi.h>
20 #include <asm/mwait.h>
21 #include <xen/xen.h>
22
23 #define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
24 #define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
25 #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
26 static DEFINE_MUTEX(isolated_cpus_lock);
27 static DEFINE_MUTEX(round_robin_lock);
28
29 static unsigned long power_saving_mwait_eax;
30
31 static unsigned char tsc_detected_unstable;
32 static unsigned char tsc_marked_unstable;
33
34 static void power_saving_mwait_init(void)
35 {
36 unsigned int eax, ebx, ecx, edx;
37 unsigned int highest_cstate = 0;
38 unsigned int highest_subcstate = 0;
39 int i;
40
41 if (!boot_cpu_has(X86_FEATURE_MWAIT))
42 return;
43 if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
44 return;
45
46 cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
47
48 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
49 !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
50 return;
51
52 edx >>= MWAIT_SUBSTATE_SIZE;
53 for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
54 if (edx & MWAIT_SUBSTATE_MASK) {
55 highest_cstate = i;
56 highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
57 }
58 }
59 power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
60 (highest_subcstate - 1);
61
62 #if defined(CONFIG_X86)
63 switch (boot_cpu_data.x86_vendor) {
64 case X86_VENDOR_HYGON:
65 case X86_VENDOR_AMD:
66 case X86_VENDOR_INTEL:
67 case X86_VENDOR_ZHAOXIN:
68
69
70
71
72 if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
73 tsc_detected_unstable = 1;
74 break;
75 default:
76
77 tsc_detected_unstable = 1;
78 }
79 #endif
80 }
81
82 static unsigned long cpu_weight[NR_CPUS];
83 static int tsk_in_cpu[NR_CPUS] = {[0 ... NR_CPUS-1] = -1};
84 static DECLARE_BITMAP(pad_busy_cpus_bits, NR_CPUS);
85 static void round_robin_cpu(unsigned int tsk_index)
86 {
87 struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
88 cpumask_var_t tmp;
89 int cpu;
90 unsigned long min_weight = -1;
91 unsigned long uninitialized_var(preferred_cpu);
92
93 if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
94 return;
95
96 mutex_lock(&round_robin_lock);
97 cpumask_clear(tmp);
98 for_each_cpu(cpu, pad_busy_cpus)
99 cpumask_or(tmp, tmp, topology_sibling_cpumask(cpu));
100 cpumask_andnot(tmp, cpu_online_mask, tmp);
101
102 if (cpumask_empty(tmp))
103 cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
104 if (cpumask_empty(tmp)) {
105 mutex_unlock(&round_robin_lock);
106 free_cpumask_var(tmp);
107 return;
108 }
109 for_each_cpu(cpu, tmp) {
110 if (cpu_weight[cpu] < min_weight) {
111 min_weight = cpu_weight[cpu];
112 preferred_cpu = cpu;
113 }
114 }
115
116 if (tsk_in_cpu[tsk_index] != -1)
117 cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
118 tsk_in_cpu[tsk_index] = preferred_cpu;
119 cpumask_set_cpu(preferred_cpu, pad_busy_cpus);
120 cpu_weight[preferred_cpu]++;
121 mutex_unlock(&round_robin_lock);
122
123 set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
124
125 free_cpumask_var(tmp);
126 }
127
128 static void exit_round_robin(unsigned int tsk_index)
129 {
130 struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
131 cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
132 tsk_in_cpu[tsk_index] = -1;
133 }
134
135 static unsigned int idle_pct = 5;
136 static unsigned int round_robin_time = 1;
137 static int power_saving_thread(void *data)
138 {
139 struct sched_param param = {.sched_priority = 1};
140 int do_sleep;
141 unsigned int tsk_index = (unsigned long)data;
142 u64 last_jiffies = 0;
143
144 sched_setscheduler(current, SCHED_RR, ¶m);
145
146 while (!kthread_should_stop()) {
147 unsigned long expire_time;
148
149
150 expire_time = last_jiffies + round_robin_time * HZ;
151 if (time_before(expire_time, jiffies)) {
152 last_jiffies = jiffies;
153 round_robin_cpu(tsk_index);
154 }
155
156 do_sleep = 0;
157
158 expire_time = jiffies + HZ * (100 - idle_pct) / 100;
159
160 while (!need_resched()) {
161 if (tsc_detected_unstable && !tsc_marked_unstable) {
162
163 mark_tsc_unstable("TSC halts in idle");
164 tsc_marked_unstable = 1;
165 }
166 local_irq_disable();
167 tick_broadcast_enable();
168 tick_broadcast_enter();
169 stop_critical_timings();
170
171 mwait_idle_with_hints(power_saving_mwait_eax, 1);
172
173 start_critical_timings();
174 tick_broadcast_exit();
175 local_irq_enable();
176
177 if (time_before(expire_time, jiffies)) {
178 do_sleep = 1;
179 break;
180 }
181 }
182
183
184
185
186
187
188
189
190
191
192 if (unlikely(do_sleep))
193 schedule_timeout_killable(HZ * idle_pct / 100);
194
195
196
197
198
199 if (unlikely(need_resched()))
200 schedule();
201 }
202
203 exit_round_robin(tsk_index);
204 return 0;
205 }
206
207 static struct task_struct *ps_tsks[NR_CPUS];
208 static unsigned int ps_tsk_num;
209 static int create_power_saving_task(void)
210 {
211 int rc;
212
213 ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread,
214 (void *)(unsigned long)ps_tsk_num,
215 "acpi_pad/%d", ps_tsk_num);
216
217 if (IS_ERR(ps_tsks[ps_tsk_num])) {
218 rc = PTR_ERR(ps_tsks[ps_tsk_num]);
219 ps_tsks[ps_tsk_num] = NULL;
220 } else {
221 rc = 0;
222 ps_tsk_num++;
223 }
224
225 return rc;
226 }
227
228 static void destroy_power_saving_task(void)
229 {
230 if (ps_tsk_num > 0) {
231 ps_tsk_num--;
232 kthread_stop(ps_tsks[ps_tsk_num]);
233 ps_tsks[ps_tsk_num] = NULL;
234 }
235 }
236
237 static void set_power_saving_task_num(unsigned int num)
238 {
239 if (num > ps_tsk_num) {
240 while (ps_tsk_num < num) {
241 if (create_power_saving_task())
242 return;
243 }
244 } else if (num < ps_tsk_num) {
245 while (ps_tsk_num > num)
246 destroy_power_saving_task();
247 }
248 }
249
250 static void acpi_pad_idle_cpus(unsigned int num_cpus)
251 {
252 get_online_cpus();
253
254 num_cpus = min_t(unsigned int, num_cpus, num_online_cpus());
255 set_power_saving_task_num(num_cpus);
256
257 put_online_cpus();
258 }
259
260 static uint32_t acpi_pad_idle_cpus_num(void)
261 {
262 return ps_tsk_num;
263 }
264
265 static ssize_t acpi_pad_rrtime_store(struct device *dev,
266 struct device_attribute *attr, const char *buf, size_t count)
267 {
268 unsigned long num;
269 if (kstrtoul(buf, 0, &num))
270 return -EINVAL;
271 if (num < 1 || num >= 100)
272 return -EINVAL;
273 mutex_lock(&isolated_cpus_lock);
274 round_robin_time = num;
275 mutex_unlock(&isolated_cpus_lock);
276 return count;
277 }
278
279 static ssize_t acpi_pad_rrtime_show(struct device *dev,
280 struct device_attribute *attr, char *buf)
281 {
282 return scnprintf(buf, PAGE_SIZE, "%d\n", round_robin_time);
283 }
284 static DEVICE_ATTR(rrtime, S_IRUGO|S_IWUSR,
285 acpi_pad_rrtime_show,
286 acpi_pad_rrtime_store);
287
288 static ssize_t acpi_pad_idlepct_store(struct device *dev,
289 struct device_attribute *attr, const char *buf, size_t count)
290 {
291 unsigned long num;
292 if (kstrtoul(buf, 0, &num))
293 return -EINVAL;
294 if (num < 1 || num >= 100)
295 return -EINVAL;
296 mutex_lock(&isolated_cpus_lock);
297 idle_pct = num;
298 mutex_unlock(&isolated_cpus_lock);
299 return count;
300 }
301
302 static ssize_t acpi_pad_idlepct_show(struct device *dev,
303 struct device_attribute *attr, char *buf)
304 {
305 return scnprintf(buf, PAGE_SIZE, "%d\n", idle_pct);
306 }
307 static DEVICE_ATTR(idlepct, S_IRUGO|S_IWUSR,
308 acpi_pad_idlepct_show,
309 acpi_pad_idlepct_store);
310
311 static ssize_t acpi_pad_idlecpus_store(struct device *dev,
312 struct device_attribute *attr, const char *buf, size_t count)
313 {
314 unsigned long num;
315 if (kstrtoul(buf, 0, &num))
316 return -EINVAL;
317 mutex_lock(&isolated_cpus_lock);
318 acpi_pad_idle_cpus(num);
319 mutex_unlock(&isolated_cpus_lock);
320 return count;
321 }
322
323 static ssize_t acpi_pad_idlecpus_show(struct device *dev,
324 struct device_attribute *attr, char *buf)
325 {
326 return cpumap_print_to_pagebuf(false, buf,
327 to_cpumask(pad_busy_cpus_bits));
328 }
329
330 static DEVICE_ATTR(idlecpus, S_IRUGO|S_IWUSR,
331 acpi_pad_idlecpus_show,
332 acpi_pad_idlecpus_store);
333
334 static int acpi_pad_add_sysfs(struct acpi_device *device)
335 {
336 int result;
337
338 result = device_create_file(&device->dev, &dev_attr_idlecpus);
339 if (result)
340 return -ENODEV;
341 result = device_create_file(&device->dev, &dev_attr_idlepct);
342 if (result) {
343 device_remove_file(&device->dev, &dev_attr_idlecpus);
344 return -ENODEV;
345 }
346 result = device_create_file(&device->dev, &dev_attr_rrtime);
347 if (result) {
348 device_remove_file(&device->dev, &dev_attr_idlecpus);
349 device_remove_file(&device->dev, &dev_attr_idlepct);
350 return -ENODEV;
351 }
352 return 0;
353 }
354
355 static void acpi_pad_remove_sysfs(struct acpi_device *device)
356 {
357 device_remove_file(&device->dev, &dev_attr_idlecpus);
358 device_remove_file(&device->dev, &dev_attr_idlepct);
359 device_remove_file(&device->dev, &dev_attr_rrtime);
360 }
361
362
363
364
365
366 static int acpi_pad_pur(acpi_handle handle)
367 {
368 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
369 union acpi_object *package;
370 int num = -1;
371
372 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
373 return num;
374
375 if (!buffer.length || !buffer.pointer)
376 return num;
377
378 package = buffer.pointer;
379
380 if (package->type == ACPI_TYPE_PACKAGE &&
381 package->package.count == 2 &&
382 package->package.elements[0].integer.value == 1)
383
384 num = package->package.elements[1].integer.value;
385
386 kfree(buffer.pointer);
387 return num;
388 }
389
390 static void acpi_pad_handle_notify(acpi_handle handle)
391 {
392 int num_cpus;
393 uint32_t idle_cpus;
394 struct acpi_buffer param = {
395 .length = 4,
396 .pointer = (void *)&idle_cpus,
397 };
398
399 mutex_lock(&isolated_cpus_lock);
400 num_cpus = acpi_pad_pur(handle);
401 if (num_cpus < 0) {
402 mutex_unlock(&isolated_cpus_lock);
403 return;
404 }
405 acpi_pad_idle_cpus(num_cpus);
406 idle_cpus = acpi_pad_idle_cpus_num();
407 acpi_evaluate_ost(handle, ACPI_PROCESSOR_AGGREGATOR_NOTIFY, 0, ¶m);
408 mutex_unlock(&isolated_cpus_lock);
409 }
410
411 static void acpi_pad_notify(acpi_handle handle, u32 event,
412 void *data)
413 {
414 struct acpi_device *device = data;
415
416 switch (event) {
417 case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
418 acpi_pad_handle_notify(handle);
419 acpi_bus_generate_netlink_event(device->pnp.device_class,
420 dev_name(&device->dev), event, 0);
421 break;
422 default:
423 pr_warn("Unsupported event [0x%x]\n", event);
424 break;
425 }
426 }
427
428 static int acpi_pad_add(struct acpi_device *device)
429 {
430 acpi_status status;
431
432 strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
433 strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
434
435 if (acpi_pad_add_sysfs(device))
436 return -ENODEV;
437
438 status = acpi_install_notify_handler(device->handle,
439 ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
440 if (ACPI_FAILURE(status)) {
441 acpi_pad_remove_sysfs(device);
442 return -ENODEV;
443 }
444
445 return 0;
446 }
447
448 static int acpi_pad_remove(struct acpi_device *device)
449 {
450 mutex_lock(&isolated_cpus_lock);
451 acpi_pad_idle_cpus(0);
452 mutex_unlock(&isolated_cpus_lock);
453
454 acpi_remove_notify_handler(device->handle,
455 ACPI_DEVICE_NOTIFY, acpi_pad_notify);
456 acpi_pad_remove_sysfs(device);
457 return 0;
458 }
459
460 static const struct acpi_device_id pad_device_ids[] = {
461 {"ACPI000C", 0},
462 {"", 0},
463 };
464 MODULE_DEVICE_TABLE(acpi, pad_device_ids);
465
466 static struct acpi_driver acpi_pad_driver = {
467 .name = "processor_aggregator",
468 .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
469 .ids = pad_device_ids,
470 .ops = {
471 .add = acpi_pad_add,
472 .remove = acpi_pad_remove,
473 },
474 };
475
476 static int __init acpi_pad_init(void)
477 {
478
479 if (xen_initial_domain())
480 return -ENODEV;
481
482 power_saving_mwait_init();
483 if (power_saving_mwait_eax == 0)
484 return -EINVAL;
485
486 return acpi_bus_register_driver(&acpi_pad_driver);
487 }
488
489 static void __exit acpi_pad_exit(void)
490 {
491 acpi_bus_unregister_driver(&acpi_pad_driver);
492 }
493
494 module_init(acpi_pad_init);
495 module_exit(acpi_pad_exit);
496 MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>");
497 MODULE_DESCRIPTION("ACPI Processor Aggregator Driver");
498 MODULE_LICENSE("GPL");