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1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Resource Director Technology(RDT)
4  * - Monitoring code
5  *
6  * Copyright (C) 2017 Intel Corporation
7  *
8  * Author:
9  *    Vikas Shivappa <vikas.shivappa@intel.com>
10  *
11  * This replaces the cqm.c based on perf but we reuse a lot of
12  * code and datastructures originally from Peter Zijlstra and Matt Fleming.
13  *
14  * More information about RDT be found in the Intel (R) x86 Architecture
15  * Software Developer Manual June 2016, volume 3, section 17.17.
16  */
17 
18 #include <linux/module.h>
19 #include <linux/slab.h>
20 #include <asm/cpu_device_id.h>
21 #include "internal.h"
22 
23 struct rmid_entry {
24 	u32				rmid;
25 	int				busy;
26 	struct list_head		list;
27 };
28 
29 /**
30  * @rmid_free_lru    A least recently used list of free RMIDs
31  *     These RMIDs are guaranteed to have an occupancy less than the
32  *     threshold occupancy
33  */
34 static LIST_HEAD(rmid_free_lru);
35 
36 /**
37  * @rmid_limbo_count     count of currently unused but (potentially)
38  *     dirty RMIDs.
39  *     This counts RMIDs that no one is currently using but that
40  *     may have a occupancy value > intel_cqm_threshold. User can change
41  *     the threshold occupancy value.
42  */
43 static unsigned int rmid_limbo_count;
44 
45 /**
46  * @rmid_entry - The entry in the limbo and free lists.
47  */
48 static struct rmid_entry	*rmid_ptrs;
49 
50 /*
51  * Global boolean for rdt_monitor which is true if any
52  * resource monitoring is enabled.
53  */
54 bool rdt_mon_capable;
55 
56 /*
57  * Global to indicate which monitoring events are enabled.
58  */
59 unsigned int rdt_mon_features;
60 
61 /*
62  * This is the threshold cache occupancy at which we will consider an
63  * RMID available for re-allocation.
64  */
65 unsigned int resctrl_cqm_threshold;
66 
__rmid_entry(u32 rmid)67 static inline struct rmid_entry *__rmid_entry(u32 rmid)
68 {
69 	struct rmid_entry *entry;
70 
71 	entry = &rmid_ptrs[rmid];
72 	WARN_ON(entry->rmid != rmid);
73 
74 	return entry;
75 }
76 
__rmid_read(u32 rmid,u32 eventid)77 static u64 __rmid_read(u32 rmid, u32 eventid)
78 {
79 	u64 val;
80 
81 	/*
82 	 * As per the SDM, when IA32_QM_EVTSEL.EvtID (bits 7:0) is configured
83 	 * with a valid event code for supported resource type and the bits
84 	 * IA32_QM_EVTSEL.RMID (bits 41:32) are configured with valid RMID,
85 	 * IA32_QM_CTR.data (bits 61:0) reports the monitored data.
86 	 * IA32_QM_CTR.Error (bit 63) and IA32_QM_CTR.Unavailable (bit 62)
87 	 * are error bits.
88 	 */
89 	wrmsr(MSR_IA32_QM_EVTSEL, eventid, rmid);
90 	rdmsrl(MSR_IA32_QM_CTR, val);
91 
92 	return val;
93 }
94 
rmid_dirty(struct rmid_entry * entry)95 static bool rmid_dirty(struct rmid_entry *entry)
96 {
97 	u64 val = __rmid_read(entry->rmid, QOS_L3_OCCUP_EVENT_ID);
98 
99 	return val >= resctrl_cqm_threshold;
100 }
101 
102 /*
103  * Check the RMIDs that are marked as busy for this domain. If the
104  * reported LLC occupancy is below the threshold clear the busy bit and
105  * decrement the count. If the busy count gets to zero on an RMID, we
106  * free the RMID
107  */
__check_limbo(struct rdt_domain * d,bool force_free)108 void __check_limbo(struct rdt_domain *d, bool force_free)
109 {
110 	struct rmid_entry *entry;
111 	struct rdt_resource *r;
112 	u32 crmid = 1, nrmid;
113 
114 	r = &rdt_resources_all[RDT_RESOURCE_L3];
115 
116 	/*
117 	 * Skip RMID 0 and start from RMID 1 and check all the RMIDs that
118 	 * are marked as busy for occupancy < threshold. If the occupancy
119 	 * is less than the threshold decrement the busy counter of the
120 	 * RMID and move it to the free list when the counter reaches 0.
121 	 */
122 	for (;;) {
123 		nrmid = find_next_bit(d->rmid_busy_llc, r->num_rmid, crmid);
124 		if (nrmid >= r->num_rmid)
125 			break;
126 
127 		entry = __rmid_entry(nrmid);
128 		if (force_free || !rmid_dirty(entry)) {
129 			clear_bit(entry->rmid, d->rmid_busy_llc);
130 			if (!--entry->busy) {
131 				rmid_limbo_count--;
132 				list_add_tail(&entry->list, &rmid_free_lru);
133 			}
134 		}
135 		crmid = nrmid + 1;
136 	}
137 }
138 
has_busy_rmid(struct rdt_resource * r,struct rdt_domain * d)139 bool has_busy_rmid(struct rdt_resource *r, struct rdt_domain *d)
140 {
141 	return find_first_bit(d->rmid_busy_llc, r->num_rmid) != r->num_rmid;
142 }
143 
144 /*
145  * As of now the RMIDs allocation is global.
146  * However we keep track of which packages the RMIDs
147  * are used to optimize the limbo list management.
148  */
alloc_rmid(void)149 int alloc_rmid(void)
150 {
151 	struct rmid_entry *entry;
152 
153 	lockdep_assert_held(&rdtgroup_mutex);
154 
155 	if (list_empty(&rmid_free_lru))
156 		return rmid_limbo_count ? -EBUSY : -ENOSPC;
157 
158 	entry = list_first_entry(&rmid_free_lru,
159 				 struct rmid_entry, list);
160 	list_del(&entry->list);
161 
162 	return entry->rmid;
163 }
164 
add_rmid_to_limbo(struct rmid_entry * entry)165 static void add_rmid_to_limbo(struct rmid_entry *entry)
166 {
167 	struct rdt_resource *r;
168 	struct rdt_domain *d;
169 	int cpu;
170 	u64 val;
171 
172 	r = &rdt_resources_all[RDT_RESOURCE_L3];
173 
174 	entry->busy = 0;
175 	cpu = get_cpu();
176 	list_for_each_entry(d, &r->domains, list) {
177 		if (cpumask_test_cpu(cpu, &d->cpu_mask)) {
178 			val = __rmid_read(entry->rmid, QOS_L3_OCCUP_EVENT_ID);
179 			if (val <= resctrl_cqm_threshold)
180 				continue;
181 		}
182 
183 		/*
184 		 * For the first limbo RMID in the domain,
185 		 * setup up the limbo worker.
186 		 */
187 		if (!has_busy_rmid(r, d))
188 			cqm_setup_limbo_handler(d, CQM_LIMBOCHECK_INTERVAL);
189 		set_bit(entry->rmid, d->rmid_busy_llc);
190 		entry->busy++;
191 	}
192 	put_cpu();
193 
194 	if (entry->busy)
195 		rmid_limbo_count++;
196 	else
197 		list_add_tail(&entry->list, &rmid_free_lru);
198 }
199 
free_rmid(u32 rmid)200 void free_rmid(u32 rmid)
201 {
202 	struct rmid_entry *entry;
203 
204 	if (!rmid)
205 		return;
206 
207 	lockdep_assert_held(&rdtgroup_mutex);
208 
209 	entry = __rmid_entry(rmid);
210 
211 	if (is_llc_occupancy_enabled())
212 		add_rmid_to_limbo(entry);
213 	else
214 		list_add_tail(&entry->list, &rmid_free_lru);
215 }
216 
mbm_overflow_count(u64 prev_msr,u64 cur_msr)217 static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr)
218 {
219 	u64 shift, chunks;
220 
221 	shift = 64 - rdt_resources_all[RDT_RESOURCE_MBA].membw.mbm_width;
222 	chunks = (cur_msr << shift) - (prev_msr << shift);
223 	return chunks >>= shift;
224 }
225 
__mon_event_count(u32 rmid,struct rmid_read * rr)226 static u64 __mon_event_count(u32 rmid, struct rmid_read *rr)
227 {
228 	struct mbm_state *m;
229 	u64 chunks, tval;
230 
231 	tval = __rmid_read(rmid, rr->evtid);
232 	if (tval & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL)) {
233 		return tval;
234 	}
235 	switch (rr->evtid) {
236 	case QOS_L3_OCCUP_EVENT_ID:
237 		rr->val += tval;
238 		return 0;
239 	case QOS_L3_MBM_TOTAL_EVENT_ID:
240 		m = &rr->d->mbm_total[rmid];
241 		break;
242 	case QOS_L3_MBM_LOCAL_EVENT_ID:
243 		m = &rr->d->mbm_local[rmid];
244 		break;
245 	default:
246 		/*
247 		 * Code would never reach here because an invalid
248 		 * event id would fail the __rmid_read.
249 		 */
250 		return RMID_VAL_ERROR;
251 	}
252 
253 	if (rr->first) {
254 		memset(m, 0, sizeof(struct mbm_state));
255 		m->prev_bw_msr = m->prev_msr = tval;
256 		return 0;
257 	}
258 
259 	chunks = mbm_overflow_count(m->prev_msr, tval);
260 	m->chunks += chunks;
261 	m->prev_msr = tval;
262 
263 	rr->val += m->chunks;
264 	return 0;
265 }
266 
267 /*
268  * Supporting function to calculate the memory bandwidth
269  * and delta bandwidth in MBps.
270  */
mbm_bw_count(u32 rmid,struct rmid_read * rr)271 static void mbm_bw_count(u32 rmid, struct rmid_read *rr)
272 {
273 	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3];
274 	struct mbm_state *m = &rr->d->mbm_local[rmid];
275 	u64 tval, cur_bw, chunks;
276 
277 	tval = __rmid_read(rmid, rr->evtid);
278 	if (tval & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))
279 		return;
280 
281 	chunks = mbm_overflow_count(m->prev_bw_msr, tval);
282 	cur_bw = (chunks * r->mon_scale) >> 20;
283 
284 	if (m->delta_comp)
285 		m->delta_bw = abs(cur_bw - m->prev_bw);
286 	m->delta_comp = false;
287 	m->prev_bw = cur_bw;
288 	m->prev_bw_msr = tval;
289 }
290 
291 /*
292  * This is called via IPI to read the CQM/MBM counters
293  * on a domain.
294  */
mon_event_count(void * info)295 void mon_event_count(void *info)
296 {
297 	struct rdtgroup *rdtgrp, *entry;
298 	struct rmid_read *rr = info;
299 	struct list_head *head;
300 	u64 ret_val;
301 
302 	rdtgrp = rr->rgrp;
303 
304 	ret_val = __mon_event_count(rdtgrp->mon.rmid, rr);
305 
306 	/*
307 	 * For Ctrl groups read data from child monitor groups and
308 	 * add them together. Count events which are read successfully.
309 	 * Discard the rmid_read's reporting errors.
310 	 */
311 	head = &rdtgrp->mon.crdtgrp_list;
312 
313 	if (rdtgrp->type == RDTCTRL_GROUP) {
314 		list_for_each_entry(entry, head, mon.crdtgrp_list) {
315 			if (__mon_event_count(entry->mon.rmid, rr) == 0)
316 				ret_val = 0;
317 		}
318 	}
319 
320 	/* Report error if none of rmid_reads are successful */
321 	if (ret_val)
322 		rr->val = ret_val;
323 }
324 
325 /*
326  * Feedback loop for MBA software controller (mba_sc)
327  *
328  * mba_sc is a feedback loop where we periodically read MBM counters and
329  * adjust the bandwidth percentage values via the IA32_MBA_THRTL_MSRs so
330  * that:
331  *
332  *   current bandwdith(cur_bw) < user specified bandwidth(user_bw)
333  *
334  * This uses the MBM counters to measure the bandwidth and MBA throttle
335  * MSRs to control the bandwidth for a particular rdtgrp. It builds on the
336  * fact that resctrl rdtgroups have both monitoring and control.
337  *
338  * The frequency of the checks is 1s and we just tag along the MBM overflow
339  * timer. Having 1s interval makes the calculation of bandwidth simpler.
340  *
341  * Although MBA's goal is to restrict the bandwidth to a maximum, there may
342  * be a need to increase the bandwidth to avoid uncecessarily restricting
343  * the L2 <-> L3 traffic.
344  *
345  * Since MBA controls the L2 external bandwidth where as MBM measures the
346  * L3 external bandwidth the following sequence could lead to such a
347  * situation.
348  *
349  * Consider an rdtgroup which had high L3 <-> memory traffic in initial
350  * phases -> mba_sc kicks in and reduced bandwidth percentage values -> but
351  * after some time rdtgroup has mostly L2 <-> L3 traffic.
352  *
353  * In this case we may restrict the rdtgroup's L2 <-> L3 traffic as its
354  * throttle MSRs already have low percentage values.  To avoid
355  * unnecessarily restricting such rdtgroups, we also increase the bandwidth.
356  */
update_mba_bw(struct rdtgroup * rgrp,struct rdt_domain * dom_mbm)357 static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
358 {
359 	u32 closid, rmid, cur_msr, cur_msr_val, new_msr_val;
360 	struct mbm_state *pmbm_data, *cmbm_data;
361 	u32 cur_bw, delta_bw, user_bw;
362 	struct rdt_resource *r_mba;
363 	struct rdt_domain *dom_mba;
364 	struct list_head *head;
365 	struct rdtgroup *entry;
366 
367 	if (!is_mbm_local_enabled())
368 		return;
369 
370 	r_mba = &rdt_resources_all[RDT_RESOURCE_MBA];
371 	closid = rgrp->closid;
372 	rmid = rgrp->mon.rmid;
373 	pmbm_data = &dom_mbm->mbm_local[rmid];
374 
375 	dom_mba = get_domain_from_cpu(smp_processor_id(), r_mba);
376 	if (!dom_mba) {
377 		pr_warn_once("Failure to get domain for MBA update\n");
378 		return;
379 	}
380 
381 	cur_bw = pmbm_data->prev_bw;
382 	user_bw = dom_mba->mbps_val[closid];
383 	delta_bw = pmbm_data->delta_bw;
384 	cur_msr_val = dom_mba->ctrl_val[closid];
385 
386 	/*
387 	 * For Ctrl groups read data from child monitor groups.
388 	 */
389 	head = &rgrp->mon.crdtgrp_list;
390 	list_for_each_entry(entry, head, mon.crdtgrp_list) {
391 		cmbm_data = &dom_mbm->mbm_local[entry->mon.rmid];
392 		cur_bw += cmbm_data->prev_bw;
393 		delta_bw += cmbm_data->delta_bw;
394 	}
395 
396 	/*
397 	 * Scale up/down the bandwidth linearly for the ctrl group.  The
398 	 * bandwidth step is the bandwidth granularity specified by the
399 	 * hardware.
400 	 *
401 	 * The delta_bw is used when increasing the bandwidth so that we
402 	 * dont alternately increase and decrease the control values
403 	 * continuously.
404 	 *
405 	 * For ex: consider cur_bw = 90MBps, user_bw = 100MBps and if
406 	 * bandwidth step is 20MBps(> user_bw - cur_bw), we would keep
407 	 * switching between 90 and 110 continuously if we only check
408 	 * cur_bw < user_bw.
409 	 */
410 	if (cur_msr_val > r_mba->membw.min_bw && user_bw < cur_bw) {
411 		new_msr_val = cur_msr_val - r_mba->membw.bw_gran;
412 	} else if (cur_msr_val < MAX_MBA_BW &&
413 		   (user_bw > (cur_bw + delta_bw))) {
414 		new_msr_val = cur_msr_val + r_mba->membw.bw_gran;
415 	} else {
416 		return;
417 	}
418 
419 	cur_msr = r_mba->msr_base + closid;
420 	wrmsrl(cur_msr, delay_bw_map(new_msr_val, r_mba));
421 	dom_mba->ctrl_val[closid] = new_msr_val;
422 
423 	/*
424 	 * Delta values are updated dynamically package wise for each
425 	 * rdtgrp everytime the throttle MSR changes value.
426 	 *
427 	 * This is because (1)the increase in bandwidth is not perfectly
428 	 * linear and only "approximately" linear even when the hardware
429 	 * says it is linear.(2)Also since MBA is a core specific
430 	 * mechanism, the delta values vary based on number of cores used
431 	 * by the rdtgrp.
432 	 */
433 	pmbm_data->delta_comp = true;
434 	list_for_each_entry(entry, head, mon.crdtgrp_list) {
435 		cmbm_data = &dom_mbm->mbm_local[entry->mon.rmid];
436 		cmbm_data->delta_comp = true;
437 	}
438 }
439 
mbm_update(struct rdt_domain * d,int rmid)440 static void mbm_update(struct rdt_domain *d, int rmid)
441 {
442 	struct rmid_read rr;
443 
444 	rr.first = false;
445 	rr.d = d;
446 
447 	/*
448 	 * This is protected from concurrent reads from user
449 	 * as both the user and we hold the global mutex.
450 	 */
451 	if (is_mbm_total_enabled()) {
452 		rr.evtid = QOS_L3_MBM_TOTAL_EVENT_ID;
453 		__mon_event_count(rmid, &rr);
454 	}
455 	if (is_mbm_local_enabled()) {
456 		rr.evtid = QOS_L3_MBM_LOCAL_EVENT_ID;
457 		__mon_event_count(rmid, &rr);
458 
459 		/*
460 		 * Call the MBA software controller only for the
461 		 * control groups and when user has enabled
462 		 * the software controller explicitly.
463 		 */
464 		if (is_mba_sc(NULL))
465 			mbm_bw_count(rmid, &rr);
466 	}
467 }
468 
469 /*
470  * Handler to scan the limbo list and move the RMIDs
471  * to free list whose occupancy < threshold_occupancy.
472  */
cqm_handle_limbo(struct work_struct * work)473 void cqm_handle_limbo(struct work_struct *work)
474 {
475 	unsigned long delay = msecs_to_jiffies(CQM_LIMBOCHECK_INTERVAL);
476 	int cpu = smp_processor_id();
477 	struct rdt_resource *r;
478 	struct rdt_domain *d;
479 
480 	mutex_lock(&rdtgroup_mutex);
481 
482 	r = &rdt_resources_all[RDT_RESOURCE_L3];
483 	d = get_domain_from_cpu(cpu, r);
484 
485 	if (!d) {
486 		pr_warn_once("Failure to get domain for limbo worker\n");
487 		goto out_unlock;
488 	}
489 
490 	__check_limbo(d, false);
491 
492 	if (has_busy_rmid(r, d))
493 		schedule_delayed_work_on(cpu, &d->cqm_limbo, delay);
494 
495 out_unlock:
496 	mutex_unlock(&rdtgroup_mutex);
497 }
498 
cqm_setup_limbo_handler(struct rdt_domain * dom,unsigned long delay_ms)499 void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms)
500 {
501 	unsigned long delay = msecs_to_jiffies(delay_ms);
502 	int cpu;
503 
504 	cpu = cpumask_any(&dom->cpu_mask);
505 	dom->cqm_work_cpu = cpu;
506 
507 	schedule_delayed_work_on(cpu, &dom->cqm_limbo, delay);
508 }
509 
mbm_handle_overflow(struct work_struct * work)510 void mbm_handle_overflow(struct work_struct *work)
511 {
512 	unsigned long delay = msecs_to_jiffies(MBM_OVERFLOW_INTERVAL);
513 	struct rdtgroup *prgrp, *crgrp;
514 	int cpu = smp_processor_id();
515 	struct list_head *head;
516 	struct rdt_domain *d;
517 
518 	mutex_lock(&rdtgroup_mutex);
519 
520 	if (!static_branch_likely(&rdt_mon_enable_key))
521 		goto out_unlock;
522 
523 	d = get_domain_from_cpu(cpu, &rdt_resources_all[RDT_RESOURCE_L3]);
524 	if (!d)
525 		goto out_unlock;
526 
527 	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
528 		mbm_update(d, prgrp->mon.rmid);
529 
530 		head = &prgrp->mon.crdtgrp_list;
531 		list_for_each_entry(crgrp, head, mon.crdtgrp_list)
532 			mbm_update(d, crgrp->mon.rmid);
533 
534 		if (is_mba_sc(NULL))
535 			update_mba_bw(prgrp, d);
536 	}
537 
538 	schedule_delayed_work_on(cpu, &d->mbm_over, delay);
539 
540 out_unlock:
541 	mutex_unlock(&rdtgroup_mutex);
542 }
543 
mbm_setup_overflow_handler(struct rdt_domain * dom,unsigned long delay_ms)544 void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms)
545 {
546 	unsigned long delay = msecs_to_jiffies(delay_ms);
547 	int cpu;
548 
549 	if (!static_branch_likely(&rdt_mon_enable_key))
550 		return;
551 	cpu = cpumask_any(&dom->cpu_mask);
552 	dom->mbm_work_cpu = cpu;
553 	schedule_delayed_work_on(cpu, &dom->mbm_over, delay);
554 }
555 
dom_data_init(struct rdt_resource * r)556 static int dom_data_init(struct rdt_resource *r)
557 {
558 	struct rmid_entry *entry = NULL;
559 	int i, nr_rmids;
560 
561 	nr_rmids = r->num_rmid;
562 	rmid_ptrs = kcalloc(nr_rmids, sizeof(struct rmid_entry), GFP_KERNEL);
563 	if (!rmid_ptrs)
564 		return -ENOMEM;
565 
566 	for (i = 0; i < nr_rmids; i++) {
567 		entry = &rmid_ptrs[i];
568 		INIT_LIST_HEAD(&entry->list);
569 
570 		entry->rmid = i;
571 		list_add_tail(&entry->list, &rmid_free_lru);
572 	}
573 
574 	/*
575 	 * RMID 0 is special and is always allocated. It's used for all
576 	 * tasks that are not monitored.
577 	 */
578 	entry = __rmid_entry(0);
579 	list_del(&entry->list);
580 
581 	return 0;
582 }
583 
584 static struct mon_evt llc_occupancy_event = {
585 	.name		= "llc_occupancy",
586 	.evtid		= QOS_L3_OCCUP_EVENT_ID,
587 };
588 
589 static struct mon_evt mbm_total_event = {
590 	.name		= "mbm_total_bytes",
591 	.evtid		= QOS_L3_MBM_TOTAL_EVENT_ID,
592 };
593 
594 static struct mon_evt mbm_local_event = {
595 	.name		= "mbm_local_bytes",
596 	.evtid		= QOS_L3_MBM_LOCAL_EVENT_ID,
597 };
598 
599 /*
600  * Initialize the event list for the resource.
601  *
602  * Note that MBM events are also part of RDT_RESOURCE_L3 resource
603  * because as per the SDM the total and local memory bandwidth
604  * are enumerated as part of L3 monitoring.
605  */
l3_mon_evt_init(struct rdt_resource * r)606 static void l3_mon_evt_init(struct rdt_resource *r)
607 {
608 	INIT_LIST_HEAD(&r->evt_list);
609 
610 	if (is_llc_occupancy_enabled())
611 		list_add_tail(&llc_occupancy_event.list, &r->evt_list);
612 	if (is_mbm_total_enabled())
613 		list_add_tail(&mbm_total_event.list, &r->evt_list);
614 	if (is_mbm_local_enabled())
615 		list_add_tail(&mbm_local_event.list, &r->evt_list);
616 }
617 
rdt_get_mon_l3_config(struct rdt_resource * r)618 int rdt_get_mon_l3_config(struct rdt_resource *r)
619 {
620 	unsigned int cl_size = boot_cpu_data.x86_cache_size;
621 	int ret;
622 
623 	r->mon_scale = boot_cpu_data.x86_cache_occ_scale;
624 	r->num_rmid = boot_cpu_data.x86_cache_max_rmid + 1;
625 
626 	/*
627 	 * A reasonable upper limit on the max threshold is the number
628 	 * of lines tagged per RMID if all RMIDs have the same number of
629 	 * lines tagged in the LLC.
630 	 *
631 	 * For a 35MB LLC and 56 RMIDs, this is ~1.8% of the LLC.
632 	 */
633 	resctrl_cqm_threshold = cl_size * 1024 / r->num_rmid;
634 
635 	/* h/w works in units of "boot_cpu_data.x86_cache_occ_scale" */
636 	resctrl_cqm_threshold /= r->mon_scale;
637 
638 	ret = dom_data_init(r);
639 	if (ret)
640 		return ret;
641 
642 	l3_mon_evt_init(r);
643 
644 	r->mon_capable = true;
645 	r->mon_enabled = true;
646 
647 	return 0;
648 }
649