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-rw-r--r--arch/x86/include/asm/cpufeature.h9
-rw-r--r--arch/x86/include/asm/processor.h3
-rw-r--r--arch/x86/kernel/cpu/Makefile2
-rw-r--r--arch/x86/kernel/cpu/common.c39
-rw-r--r--arch/x86/kernel/cpu/perf_event_intel_cqm.c1379
5 files changed, 1430 insertions, 2 deletions
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 90a54851aedc..361922dcc9b1 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -12,7 +12,7 @@
12#include <asm/disabled-features.h> 12#include <asm/disabled-features.h>
13#endif 13#endif
14 14
15#define NCAPINTS 11 /* N 32-bit words worth of info */ 15#define NCAPINTS 13 /* N 32-bit words worth of info */
16#define NBUGINTS 1 /* N 32-bit bug flags */ 16#define NBUGINTS 1 /* N 32-bit bug flags */
17 17
18/* 18/*
@@ -226,6 +226,7 @@
226#define X86_FEATURE_ERMS ( 9*32+ 9) /* Enhanced REP MOVSB/STOSB */ 226#define X86_FEATURE_ERMS ( 9*32+ 9) /* Enhanced REP MOVSB/STOSB */
227#define X86_FEATURE_INVPCID ( 9*32+10) /* Invalidate Processor Context ID */ 227#define X86_FEATURE_INVPCID ( 9*32+10) /* Invalidate Processor Context ID */
228#define X86_FEATURE_RTM ( 9*32+11) /* Restricted Transactional Memory */ 228#define X86_FEATURE_RTM ( 9*32+11) /* Restricted Transactional Memory */
229#define X86_FEATURE_CQM ( 9*32+12) /* Cache QoS Monitoring */
229#define X86_FEATURE_MPX ( 9*32+14) /* Memory Protection Extension */ 230#define X86_FEATURE_MPX ( 9*32+14) /* Memory Protection Extension */
230#define X86_FEATURE_AVX512F ( 9*32+16) /* AVX-512 Foundation */ 231#define X86_FEATURE_AVX512F ( 9*32+16) /* AVX-512 Foundation */
231#define X86_FEATURE_RDSEED ( 9*32+18) /* The RDSEED instruction */ 232#define X86_FEATURE_RDSEED ( 9*32+18) /* The RDSEED instruction */
@@ -242,6 +243,12 @@
242#define X86_FEATURE_XGETBV1 (10*32+ 2) /* XGETBV with ECX = 1 */ 243#define X86_FEATURE_XGETBV1 (10*32+ 2) /* XGETBV with ECX = 1 */
243#define X86_FEATURE_XSAVES (10*32+ 3) /* XSAVES/XRSTORS */ 244#define X86_FEATURE_XSAVES (10*32+ 3) /* XSAVES/XRSTORS */
244 245
246/* Intel-defined CPU QoS Sub-leaf, CPUID level 0x0000000F:0 (edx), word 11 */
247#define X86_FEATURE_CQM_LLC (11*32+ 1) /* LLC QoS if 1 */
248
249/* Intel-defined CPU QoS Sub-leaf, CPUID level 0x0000000F:1 (edx), word 12 */
250#define X86_FEATURE_CQM_OCCUP_LLC (12*32+ 0) /* LLC occupancy monitoring if 1 */
251
245/* 252/*
246 * BUG word(s) 253 * BUG word(s)
247 */ 254 */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index ec1c93588cef..a12d50e04d7a 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -109,6 +109,9 @@ struct cpuinfo_x86 {
109 /* in KB - valid for CPUS which support this call: */ 109 /* in KB - valid for CPUS which support this call: */
110 int x86_cache_size; 110 int x86_cache_size;
111 int x86_cache_alignment; /* In bytes */ 111 int x86_cache_alignment; /* In bytes */
112 /* Cache QoS architectural values: */
113 int x86_cache_max_rmid; /* max index */
114 int x86_cache_occ_scale; /* scale to bytes */
112 int x86_power; 115 int x86_power;
113 unsigned long loops_per_jiffy; 116 unsigned long loops_per_jiffy;
114 /* cpuid returned max cores value: */ 117 /* cpuid returned max cores value: */
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index 80091ae54c2b..6c1ca139f736 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -39,7 +39,7 @@ obj-$(CONFIG_CPU_SUP_AMD) += perf_event_amd_iommu.o
39endif 39endif
40obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_p6.o perf_event_knc.o perf_event_p4.o 40obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_p6.o perf_event_knc.o perf_event_p4.o
41obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_lbr.o perf_event_intel_ds.o perf_event_intel.o 41obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_lbr.o perf_event_intel_ds.o perf_event_intel.o
42obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_rapl.o 42obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_rapl.o perf_event_intel_cqm.o
43 43
44obj-$(CONFIG_PERF_EVENTS_INTEL_UNCORE) += perf_event_intel_uncore.o \ 44obj-$(CONFIG_PERF_EVENTS_INTEL_UNCORE) += perf_event_intel_uncore.o \
45 perf_event_intel_uncore_snb.o \ 45 perf_event_intel_uncore_snb.o \
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 2346c95c6ab1..1cd4a1a44b95 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -646,6 +646,30 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
646 c->x86_capability[10] = eax; 646 c->x86_capability[10] = eax;
647 } 647 }
648 648
649 /* Additional Intel-defined flags: level 0x0000000F */
650 if (c->cpuid_level >= 0x0000000F) {
651 u32 eax, ebx, ecx, edx;
652
653 /* QoS sub-leaf, EAX=0Fh, ECX=0 */
654 cpuid_count(0x0000000F, 0, &eax, &ebx, &ecx, &edx);
655 c->x86_capability[11] = edx;
656 if (cpu_has(c, X86_FEATURE_CQM_LLC)) {
657 /* will be overridden if occupancy monitoring exists */
658 c->x86_cache_max_rmid = ebx;
659
660 /* QoS sub-leaf, EAX=0Fh, ECX=1 */
661 cpuid_count(0x0000000F, 1, &eax, &ebx, &ecx, &edx);
662 c->x86_capability[12] = edx;
663 if (cpu_has(c, X86_FEATURE_CQM_OCCUP_LLC)) {
664 c->x86_cache_max_rmid = ecx;
665 c->x86_cache_occ_scale = ebx;
666 }
667 } else {
668 c->x86_cache_max_rmid = -1;
669 c->x86_cache_occ_scale = -1;
670 }
671 }
672
649 /* AMD-defined flags: level 0x80000001 */ 673 /* AMD-defined flags: level 0x80000001 */
650 xlvl = cpuid_eax(0x80000000); 674 xlvl = cpuid_eax(0x80000000);
651 c->extended_cpuid_level = xlvl; 675 c->extended_cpuid_level = xlvl;
@@ -834,6 +858,20 @@ static void generic_identify(struct cpuinfo_x86 *c)
834 detect_nopl(c); 858 detect_nopl(c);
835} 859}
836 860
861static void x86_init_cache_qos(struct cpuinfo_x86 *c)
862{
863 /*
864 * The heavy lifting of max_rmid and cache_occ_scale are handled
865 * in get_cpu_cap(). Here we just set the max_rmid for the boot_cpu
866 * in case CQM bits really aren't there in this CPU.
867 */
868 if (c != &boot_cpu_data) {
869 boot_cpu_data.x86_cache_max_rmid =
870 min(boot_cpu_data.x86_cache_max_rmid,
871 c->x86_cache_max_rmid);
872 }
873}
874
837/* 875/*
838 * This does the hard work of actually picking apart the CPU stuff... 876 * This does the hard work of actually picking apart the CPU stuff...
839 */ 877 */
@@ -923,6 +961,7 @@ static void identify_cpu(struct cpuinfo_x86 *c)
923 961
924 init_hypervisor(c); 962 init_hypervisor(c);
925 x86_init_rdrand(c); 963 x86_init_rdrand(c);
964 x86_init_cache_qos(c);
926 965
927 /* 966 /*
928 * Clear/Set all flags overriden by options, need do it 967 * Clear/Set all flags overriden by options, need do it
diff --git a/arch/x86/kernel/cpu/perf_event_intel_cqm.c b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
new file mode 100644
index 000000000000..e4d1b8b738fa
--- /dev/null
+++ b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
@@ -0,0 +1,1379 @@
1/*
2 * Intel Cache Quality-of-Service Monitoring (CQM) support.
3 *
4 * Based very, very heavily on work by Peter Zijlstra.
5 */
6
7#include <linux/perf_event.h>
8#include <linux/slab.h>
9#include <asm/cpu_device_id.h>
10#include "perf_event.h"
11
12#define MSR_IA32_PQR_ASSOC 0x0c8f
13#define MSR_IA32_QM_CTR 0x0c8e
14#define MSR_IA32_QM_EVTSEL 0x0c8d
15
16static unsigned int cqm_max_rmid = -1;
17static unsigned int cqm_l3_scale; /* supposedly cacheline size */
18
19struct intel_cqm_state {
20 raw_spinlock_t lock;
21 int rmid;
22 int cnt;
23};
24
25static DEFINE_PER_CPU(struct intel_cqm_state, cqm_state);
26
27/*
28 * Protects cache_cgroups and cqm_rmid_free_lru and cqm_rmid_limbo_lru.
29 * Also protects event->hw.cqm_rmid
30 *
31 * Hold either for stability, both for modification of ->hw.cqm_rmid.
32 */
33static DEFINE_MUTEX(cache_mutex);
34static DEFINE_RAW_SPINLOCK(cache_lock);
35
36/*
37 * Groups of events that have the same target(s), one RMID per group.
38 */
39static LIST_HEAD(cache_groups);
40
41/*
42 * Mask of CPUs for reading CQM values. We only need one per-socket.
43 */
44static cpumask_t cqm_cpumask;
45
46#define RMID_VAL_ERROR (1ULL << 63)
47#define RMID_VAL_UNAVAIL (1ULL << 62)
48
49#define QOS_L3_OCCUP_EVENT_ID (1 << 0)
50
51#define QOS_EVENT_MASK QOS_L3_OCCUP_EVENT_ID
52
53/*
54 * This is central to the rotation algorithm in __intel_cqm_rmid_rotate().
55 *
56 * This rmid is always free and is guaranteed to have an associated
57 * near-zero occupancy value, i.e. no cachelines are tagged with this
58 * RMID, once __intel_cqm_rmid_rotate() returns.
59 */
60static unsigned int intel_cqm_rotation_rmid;
61
62#define INVALID_RMID (-1)
63
64/*
65 * Is @rmid valid for programming the hardware?
66 *
67 * rmid 0 is reserved by the hardware for all non-monitored tasks, which
68 * means that we should never come across an rmid with that value.
69 * Likewise, an rmid value of -1 is used to indicate "no rmid currently
70 * assigned" and is used as part of the rotation code.
71 */
72static inline bool __rmid_valid(unsigned int rmid)
73{
74 if (!rmid || rmid == INVALID_RMID)
75 return false;
76
77 return true;
78}
79
80static u64 __rmid_read(unsigned int rmid)
81{
82 u64 val;
83
84 /*
85 * Ignore the SDM, this thing is _NOTHING_ like a regular perfcnt,
86 * it just says that to increase confusion.
87 */
88 wrmsr(MSR_IA32_QM_EVTSEL, QOS_L3_OCCUP_EVENT_ID, rmid);
89 rdmsrl(MSR_IA32_QM_CTR, val);
90
91 /*
92 * Aside from the ERROR and UNAVAIL bits, assume this thing returns
93 * the number of cachelines tagged with @rmid.
94 */
95 return val;
96}
97
98enum rmid_recycle_state {
99 RMID_YOUNG = 0,
100 RMID_AVAILABLE,
101 RMID_DIRTY,
102};
103
104struct cqm_rmid_entry {
105 unsigned int rmid;
106 enum rmid_recycle_state state;
107 struct list_head list;
108 unsigned long queue_time;
109};
110
111/*
112 * cqm_rmid_free_lru - A least recently used list of RMIDs.
113 *
114 * Oldest entry at the head, newest (most recently used) entry at the
115 * tail. This list is never traversed, it's only used to keep track of
116 * the lru order. That is, we only pick entries of the head or insert
117 * them on the tail.
118 *
119 * All entries on the list are 'free', and their RMIDs are not currently
120 * in use. To mark an RMID as in use, remove its entry from the lru
121 * list.
122 *
123 *
124 * cqm_rmid_limbo_lru - list of currently unused but (potentially) dirty RMIDs.
125 *
126 * This list is contains RMIDs that no one is currently using but that
127 * may have a non-zero occupancy value associated with them. The
128 * rotation worker moves RMIDs from the limbo list to the free list once
129 * the occupancy value drops below __intel_cqm_threshold.
130 *
131 * Both lists are protected by cache_mutex.
132 */
133static LIST_HEAD(cqm_rmid_free_lru);
134static LIST_HEAD(cqm_rmid_limbo_lru);
135
136/*
137 * We use a simple array of pointers so that we can lookup a struct
138 * cqm_rmid_entry in O(1). This alleviates the callers of __get_rmid()
139 * and __put_rmid() from having to worry about dealing with struct
140 * cqm_rmid_entry - they just deal with rmids, i.e. integers.
141 *
142 * Once this array is initialized it is read-only. No locks are required
143 * to access it.
144 *
145 * All entries for all RMIDs can be looked up in the this array at all
146 * times.
147 */
148static struct cqm_rmid_entry **cqm_rmid_ptrs;
149
150static inline struct cqm_rmid_entry *__rmid_entry(int rmid)
151{
152 struct cqm_rmid_entry *entry;
153
154 entry = cqm_rmid_ptrs[rmid];
155 WARN_ON(entry->rmid != rmid);
156
157 return entry;
158}
159
160/*
161 * Returns < 0 on fail.
162 *
163 * We expect to be called with cache_mutex held.
164 */
165static int __get_rmid(void)
166{
167 struct cqm_rmid_entry *entry;
168
169 lockdep_assert_held(&cache_mutex);
170
171 if (list_empty(&cqm_rmid_free_lru))
172 return INVALID_RMID;
173
174 entry = list_first_entry(&cqm_rmid_free_lru, struct cqm_rmid_entry, list);
175 list_del(&entry->list);
176
177 return entry->rmid;
178}
179
180static void __put_rmid(unsigned int rmid)
181{
182 struct cqm_rmid_entry *entry;
183
184 lockdep_assert_held(&cache_mutex);
185
186 WARN_ON(!__rmid_valid(rmid));
187 entry = __rmid_entry(rmid);
188
189 entry->queue_time = jiffies;
190 entry->state = RMID_YOUNG;
191
192 list_add_tail(&entry->list, &cqm_rmid_limbo_lru);
193}
194
195static int intel_cqm_setup_rmid_cache(void)
196{
197 struct cqm_rmid_entry *entry;
198 unsigned int nr_rmids;
199 int r = 0;
200
201 nr_rmids = cqm_max_rmid + 1;
202 cqm_rmid_ptrs = kmalloc(sizeof(struct cqm_rmid_entry *) *
203 nr_rmids, GFP_KERNEL);
204 if (!cqm_rmid_ptrs)
205 return -ENOMEM;
206
207 for (; r <= cqm_max_rmid; r++) {
208 struct cqm_rmid_entry *entry;
209
210 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
211 if (!entry)
212 goto fail;
213
214 INIT_LIST_HEAD(&entry->list);
215 entry->rmid = r;
216 cqm_rmid_ptrs[r] = entry;
217
218 list_add_tail(&entry->list, &cqm_rmid_free_lru);
219 }
220
221 /*
222 * RMID 0 is special and is always allocated. It's used for all
223 * tasks that are not monitored.
224 */
225 entry = __rmid_entry(0);
226 list_del(&entry->list);
227
228 mutex_lock(&cache_mutex);
229 intel_cqm_rotation_rmid = __get_rmid();
230 mutex_unlock(&cache_mutex);
231
232 return 0;
233fail:
234 while (r--)
235 kfree(cqm_rmid_ptrs[r]);
236
237 kfree(cqm_rmid_ptrs);
238 return -ENOMEM;
239}
240
241/*
242 * Determine if @a and @b measure the same set of tasks.
243 *
244 * If @a and @b measure the same set of tasks then we want to share a
245 * single RMID.
246 */
247static bool __match_event(struct perf_event *a, struct perf_event *b)
248{
249 /* Per-cpu and task events don't mix */
250 if ((a->attach_state & PERF_ATTACH_TASK) !=
251 (b->attach_state & PERF_ATTACH_TASK))
252 return false;
253
254#ifdef CONFIG_CGROUP_PERF
255 if (a->cgrp != b->cgrp)
256 return false;
257#endif
258
259 /* If not task event, we're machine wide */
260 if (!(b->attach_state & PERF_ATTACH_TASK))
261 return true;
262
263 /*
264 * Events that target same task are placed into the same cache group.
265 */
266 if (a->hw.target == b->hw.target)
267 return true;
268
269 /*
270 * Are we an inherited event?
271 */
272 if (b->parent == a)
273 return true;
274
275 return false;
276}
277
278#ifdef CONFIG_CGROUP_PERF
279static inline struct perf_cgroup *event_to_cgroup(struct perf_event *event)
280{
281 if (event->attach_state & PERF_ATTACH_TASK)
282 return perf_cgroup_from_task(event->hw.target);
283
284 return event->cgrp;
285}
286#endif
287
288/*
289 * Determine if @a's tasks intersect with @b's tasks
290 *
291 * There are combinations of events that we explicitly prohibit,
292 *
293 * PROHIBITS
294 * system-wide -> cgroup and task
295 * cgroup -> system-wide
296 * -> task in cgroup
297 * task -> system-wide
298 * -> task in cgroup
299 *
300 * Call this function before allocating an RMID.
301 */
302static bool __conflict_event(struct perf_event *a, struct perf_event *b)
303{
304#ifdef CONFIG_CGROUP_PERF
305 /*
306 * We can have any number of cgroups but only one system-wide
307 * event at a time.
308 */
309 if (a->cgrp && b->cgrp) {
310 struct perf_cgroup *ac = a->cgrp;
311 struct perf_cgroup *bc = b->cgrp;
312
313 /*
314 * This condition should have been caught in
315 * __match_event() and we should be sharing an RMID.
316 */
317 WARN_ON_ONCE(ac == bc);
318
319 if (cgroup_is_descendant(ac->css.cgroup, bc->css.cgroup) ||
320 cgroup_is_descendant(bc->css.cgroup, ac->css.cgroup))
321 return true;
322
323 return false;
324 }
325
326 if (a->cgrp || b->cgrp) {
327 struct perf_cgroup *ac, *bc;
328
329 /*
330 * cgroup and system-wide events are mutually exclusive
331 */
332 if ((a->cgrp && !(b->attach_state & PERF_ATTACH_TASK)) ||
333 (b->cgrp && !(a->attach_state & PERF_ATTACH_TASK)))
334 return true;
335
336 /*
337 * Ensure neither event is part of the other's cgroup
338 */
339 ac = event_to_cgroup(a);
340 bc = event_to_cgroup(b);
341 if (ac == bc)
342 return true;
343
344 /*
345 * Must have cgroup and non-intersecting task events.
346 */
347 if (!ac || !bc)
348 return false;
349
350 /*
351 * We have cgroup and task events, and the task belongs
352 * to a cgroup. Check for for overlap.
353 */
354 if (cgroup_is_descendant(ac->css.cgroup, bc->css.cgroup) ||
355 cgroup_is_descendant(bc->css.cgroup, ac->css.cgroup))
356 return true;
357
358 return false;
359 }
360#endif
361 /*
362 * If one of them is not a task, same story as above with cgroups.
363 */
364 if (!(a->attach_state & PERF_ATTACH_TASK) ||
365 !(b->attach_state & PERF_ATTACH_TASK))
366 return true;
367
368 /*
369 * Must be non-overlapping.
370 */
371 return false;
372}
373
374struct rmid_read {
375 unsigned int rmid;
376 atomic64_t value;
377};
378
379static void __intel_cqm_event_count(void *info);
380
381/*
382 * Exchange the RMID of a group of events.
383 */
384static unsigned int
385intel_cqm_xchg_rmid(struct perf_event *group, unsigned int rmid)
386{
387 struct perf_event *event;
388 unsigned int old_rmid = group->hw.cqm_rmid;
389 struct list_head *head = &group->hw.cqm_group_entry;
390
391 lockdep_assert_held(&cache_mutex);
392
393 /*
394 * If our RMID is being deallocated, perform a read now.
395 */
396 if (__rmid_valid(old_rmid) && !__rmid_valid(rmid)) {
397 struct rmid_read rr = {
398 .value = ATOMIC64_INIT(0),
399 .rmid = old_rmid,
400 };
401
402 on_each_cpu_mask(&cqm_cpumask, __intel_cqm_event_count,
403 &rr, 1);
404 local64_set(&group->count, atomic64_read(&rr.value));
405 }
406
407 raw_spin_lock_irq(&cache_lock);
408
409 group->hw.cqm_rmid = rmid;
410 list_for_each_entry(event, head, hw.cqm_group_entry)
411 event->hw.cqm_rmid = rmid;
412
413 raw_spin_unlock_irq(&cache_lock);
414
415 return old_rmid;
416}
417
418/*
419 * If we fail to assign a new RMID for intel_cqm_rotation_rmid because
420 * cachelines are still tagged with RMIDs in limbo, we progressively
421 * increment the threshold until we find an RMID in limbo with <=
422 * __intel_cqm_threshold lines tagged. This is designed to mitigate the
423 * problem where cachelines tagged with an RMID are not steadily being
424 * evicted.
425 *
426 * On successful rotations we decrease the threshold back towards zero.
427 *
428 * __intel_cqm_max_threshold provides an upper bound on the threshold,
429 * and is measured in bytes because it's exposed to userland.
430 */
431static unsigned int __intel_cqm_threshold;
432static unsigned int __intel_cqm_max_threshold;
433
434/*
435 * Test whether an RMID has a zero occupancy value on this cpu.
436 */
437static void intel_cqm_stable(void *arg)
438{
439 struct cqm_rmid_entry *entry;
440
441 list_for_each_entry(entry, &cqm_rmid_limbo_lru, list) {
442 if (entry->state != RMID_AVAILABLE)
443 break;
444
445 if (__rmid_read(entry->rmid) > __intel_cqm_threshold)
446 entry->state = RMID_DIRTY;
447 }
448}
449
450/*
451 * If we have group events waiting for an RMID that don't conflict with
452 * events already running, assign @rmid.
453 */
454static bool intel_cqm_sched_in_event(unsigned int rmid)
455{
456 struct perf_event *leader, *event;
457
458 lockdep_assert_held(&cache_mutex);
459
460 leader = list_first_entry(&cache_groups, struct perf_event,
461 hw.cqm_groups_entry);
462 event = leader;
463
464 list_for_each_entry_continue(event, &cache_groups,
465 hw.cqm_groups_entry) {
466 if (__rmid_valid(event->hw.cqm_rmid))
467 continue;
468
469 if (__conflict_event(event, leader))
470 continue;
471
472 intel_cqm_xchg_rmid(event, rmid);
473 return true;
474 }
475
476 return false;
477}
478
479/*
480 * Initially use this constant for both the limbo queue time and the
481 * rotation timer interval, pmu::hrtimer_interval_ms.
482 *
483 * They don't need to be the same, but the two are related since if you
484 * rotate faster than you recycle RMIDs, you may run out of available
485 * RMIDs.
486 */
487#define RMID_DEFAULT_QUEUE_TIME 250 /* ms */
488
489static unsigned int __rmid_queue_time_ms = RMID_DEFAULT_QUEUE_TIME;
490
491/*
492 * intel_cqm_rmid_stabilize - move RMIDs from limbo to free list
493 * @nr_available: number of freeable RMIDs on the limbo list
494 *
495 * Quiescent state; wait for all 'freed' RMIDs to become unused, i.e. no
496 * cachelines are tagged with those RMIDs. After this we can reuse them
497 * and know that the current set of active RMIDs is stable.
498 *
499 * Return %true or %false depending on whether stabilization needs to be
500 * reattempted.
501 *
502 * If we return %true then @nr_available is updated to indicate the
503 * number of RMIDs on the limbo list that have been queued for the
504 * minimum queue time (RMID_AVAILABLE), but whose data occupancy values
505 * are above __intel_cqm_threshold.
506 */
507static bool intel_cqm_rmid_stabilize(unsigned int *available)
508{
509 struct cqm_rmid_entry *entry, *tmp;
510
511 lockdep_assert_held(&cache_mutex);
512
513 *available = 0;
514 list_for_each_entry(entry, &cqm_rmid_limbo_lru, list) {
515 unsigned long min_queue_time;
516 unsigned long now = jiffies;
517
518 /*
519 * We hold RMIDs placed into limbo for a minimum queue
520 * time. Before the minimum queue time has elapsed we do
521 * not recycle RMIDs.
522 *
523 * The reasoning is that until a sufficient time has
524 * passed since we stopped using an RMID, any RMID
525 * placed onto the limbo list will likely still have
526 * data tagged in the cache, which means we'll probably
527 * fail to recycle it anyway.
528 *
529 * We can save ourselves an expensive IPI by skipping
530 * any RMIDs that have not been queued for the minimum
531 * time.
532 */
533 min_queue_time = entry->queue_time +
534 msecs_to_jiffies(__rmid_queue_time_ms);
535
536 if (time_after(min_queue_time, now))
537 break;
538
539 entry->state = RMID_AVAILABLE;
540 (*available)++;
541 }
542
543 /*
544 * Fast return if none of the RMIDs on the limbo list have been
545 * sitting on the queue for the minimum queue time.
546 */
547 if (!*available)
548 return false;
549
550 /*
551 * Test whether an RMID is free for each package.
552 */
553 on_each_cpu_mask(&cqm_cpumask, intel_cqm_stable, NULL, true);
554
555 list_for_each_entry_safe(entry, tmp, &cqm_rmid_limbo_lru, list) {
556 /*
557 * Exhausted all RMIDs that have waited min queue time.
558 */
559 if (entry->state == RMID_YOUNG)
560 break;
561
562 if (entry->state == RMID_DIRTY)
563 continue;
564
565 list_del(&entry->list); /* remove from limbo */
566
567 /*
568 * The rotation RMID gets priority if it's
569 * currently invalid. In which case, skip adding
570 * the RMID to the the free lru.
571 */
572 if (!__rmid_valid(intel_cqm_rotation_rmid)) {
573 intel_cqm_rotation_rmid = entry->rmid;
574 continue;
575 }
576
577 /*
578 * If we have groups waiting for RMIDs, hand
579 * them one now provided they don't conflict.
580 */
581 if (intel_cqm_sched_in_event(entry->rmid))
582 continue;
583
584 /*
585 * Otherwise place it onto the free list.
586 */
587 list_add_tail(&entry->list, &cqm_rmid_free_lru);
588 }
589
590
591 return __rmid_valid(intel_cqm_rotation_rmid);
592}
593
594/*
595 * Pick a victim group and move it to the tail of the group list.
596 * @next: The first group without an RMID
597 */
598static void __intel_cqm_pick_and_rotate(struct perf_event *next)
599{
600 struct perf_event *rotor;
601 unsigned int rmid;
602
603 lockdep_assert_held(&cache_mutex);
604
605 rotor = list_first_entry(&cache_groups, struct perf_event,
606 hw.cqm_groups_entry);
607
608 /*
609 * The group at the front of the list should always have a valid
610 * RMID. If it doesn't then no groups have RMIDs assigned and we
611 * don't need to rotate the list.
612 */
613 if (next == rotor)
614 return;
615
616 rmid = intel_cqm_xchg_rmid(rotor, INVALID_RMID);
617 __put_rmid(rmid);
618
619 list_rotate_left(&cache_groups);
620}
621
622/*
623 * Deallocate the RMIDs from any events that conflict with @event, and
624 * place them on the back of the group list.
625 */
626static void intel_cqm_sched_out_conflicting_events(struct perf_event *event)
627{
628 struct perf_event *group, *g;
629 unsigned int rmid;
630
631 lockdep_assert_held(&cache_mutex);
632
633 list_for_each_entry_safe(group, g, &cache_groups, hw.cqm_groups_entry) {
634 if (group == event)
635 continue;
636
637 rmid = group->hw.cqm_rmid;
638
639 /*
640 * Skip events that don't have a valid RMID.
641 */
642 if (!__rmid_valid(rmid))
643 continue;
644
645 /*
646 * No conflict? No problem! Leave the event alone.
647 */
648 if (!__conflict_event(group, event))
649 continue;
650
651 intel_cqm_xchg_rmid(group, INVALID_RMID);
652 __put_rmid(rmid);
653 }
654}
655
656/*
657 * Attempt to rotate the groups and assign new RMIDs.
658 *
659 * We rotate for two reasons,
660 * 1. To handle the scheduling of conflicting events
661 * 2. To recycle RMIDs
662 *
663 * Rotating RMIDs is complicated because the hardware doesn't give us
664 * any clues.
665 *
666 * There's problems with the hardware interface; when you change the
667 * task:RMID map cachelines retain their 'old' tags, giving a skewed
668 * picture. In order to work around this, we must always keep one free
669 * RMID - intel_cqm_rotation_rmid.
670 *
671 * Rotation works by taking away an RMID from a group (the old RMID),
672 * and assigning the free RMID to another group (the new RMID). We must
673 * then wait for the old RMID to not be used (no cachelines tagged).
674 * This ensure that all cachelines are tagged with 'active' RMIDs. At
675 * this point we can start reading values for the new RMID and treat the
676 * old RMID as the free RMID for the next rotation.
677 *
678 * Return %true or %false depending on whether we did any rotating.
679 */
680static bool __intel_cqm_rmid_rotate(void)
681{
682 struct perf_event *group, *start = NULL;
683 unsigned int threshold_limit;
684 unsigned int nr_needed = 0;
685 unsigned int nr_available;
686 bool rotated = false;
687
688 mutex_lock(&cache_mutex);
689
690again:
691 /*
692 * Fast path through this function if there are no groups and no
693 * RMIDs that need cleaning.
694 */
695 if (list_empty(&cache_groups) && list_empty(&cqm_rmid_limbo_lru))
696 goto out;
697
698 list_for_each_entry(group, &cache_groups, hw.cqm_groups_entry) {
699 if (!__rmid_valid(group->hw.cqm_rmid)) {
700 if (!start)
701 start = group;
702 nr_needed++;
703 }
704 }
705
706 /*
707 * We have some event groups, but they all have RMIDs assigned
708 * and no RMIDs need cleaning.
709 */
710 if (!nr_needed && list_empty(&cqm_rmid_limbo_lru))
711 goto out;
712
713 if (!nr_needed)
714 goto stabilize;
715
716 /*
717 * We have more event groups without RMIDs than available RMIDs,
718 * or we have event groups that conflict with the ones currently
719 * scheduled.
720 *
721 * We force deallocate the rmid of the group at the head of
722 * cache_groups. The first event group without an RMID then gets
723 * assigned intel_cqm_rotation_rmid. This ensures we always make
724 * forward progress.
725 *
726 * Rotate the cache_groups list so the previous head is now the
727 * tail.
728 */
729 __intel_cqm_pick_and_rotate(start);
730
731 /*
732 * If the rotation is going to succeed, reduce the threshold so
733 * that we don't needlessly reuse dirty RMIDs.
734 */
735 if (__rmid_valid(intel_cqm_rotation_rmid)) {
736 intel_cqm_xchg_rmid(start, intel_cqm_rotation_rmid);
737 intel_cqm_rotation_rmid = __get_rmid();
738
739 intel_cqm_sched_out_conflicting_events(start);
740
741 if (__intel_cqm_threshold)
742 __intel_cqm_threshold--;
743 }
744
745 rotated = true;
746
747stabilize:
748 /*
749 * We now need to stablize the RMID we freed above (if any) to
750 * ensure that the next time we rotate we have an RMID with zero
751 * occupancy value.
752 *
753 * Alternatively, if we didn't need to perform any rotation,
754 * we'll have a bunch of RMIDs in limbo that need stabilizing.
755 */
756 threshold_limit = __intel_cqm_max_threshold / cqm_l3_scale;
757
758 while (intel_cqm_rmid_stabilize(&nr_available) &&
759 __intel_cqm_threshold < threshold_limit) {
760 unsigned int steal_limit;
761
762 /*
763 * Don't spin if nobody is actively waiting for an RMID,
764 * the rotation worker will be kicked as soon as an
765 * event needs an RMID anyway.
766 */
767 if (!nr_needed)
768 break;
769
770 /* Allow max 25% of RMIDs to be in limbo. */
771 steal_limit = (cqm_max_rmid + 1) / 4;
772
773 /*
774 * We failed to stabilize any RMIDs so our rotation
775 * logic is now stuck. In order to make forward progress
776 * we have a few options:
777 *
778 * 1. rotate ("steal") another RMID
779 * 2. increase the threshold
780 * 3. do nothing
781 *
782 * We do both of 1. and 2. until we hit the steal limit.
783 *
784 * The steal limit prevents all RMIDs ending up on the
785 * limbo list. This can happen if every RMID has a
786 * non-zero occupancy above threshold_limit, and the
787 * occupancy values aren't dropping fast enough.
788 *
789 * Note that there is prioritisation at work here - we'd
790 * rather increase the number of RMIDs on the limbo list
791 * than increase the threshold, because increasing the
792 * threshold skews the event data (because we reuse
793 * dirty RMIDs) - threshold bumps are a last resort.
794 */
795 if (nr_available < steal_limit)
796 goto again;
797
798 __intel_cqm_threshold++;
799 }
800
801out:
802 mutex_unlock(&cache_mutex);
803 return rotated;
804}
805
806static void intel_cqm_rmid_rotate(struct work_struct *work);
807
808static DECLARE_DELAYED_WORK(intel_cqm_rmid_work, intel_cqm_rmid_rotate);
809
810static struct pmu intel_cqm_pmu;
811
812static void intel_cqm_rmid_rotate(struct work_struct *work)
813{
814 unsigned long delay;
815
816 __intel_cqm_rmid_rotate();
817
818 delay = msecs_to_jiffies(intel_cqm_pmu.hrtimer_interval_ms);
819 schedule_delayed_work(&intel_cqm_rmid_work, delay);
820}
821
822/*
823 * Find a group and setup RMID.
824 *
825 * If we're part of a group, we use the group's RMID.
826 */
827static void intel_cqm_setup_event(struct perf_event *event,
828 struct perf_event **group)
829{
830 struct perf_event *iter;
831 unsigned int rmid;
832 bool conflict = false;
833
834 list_for_each_entry(iter, &cache_groups, hw.cqm_groups_entry) {
835 rmid = iter->hw.cqm_rmid;
836
837 if (__match_event(iter, event)) {
838 /* All tasks in a group share an RMID */
839 event->hw.cqm_rmid = rmid;
840 *group = iter;
841 return;
842 }
843
844 /*
845 * We only care about conflicts for events that are
846 * actually scheduled in (and hence have a valid RMID).
847 */
848 if (__conflict_event(iter, event) && __rmid_valid(rmid))
849 conflict = true;
850 }
851
852 if (conflict)
853 rmid = INVALID_RMID;
854 else
855 rmid = __get_rmid();
856
857 event->hw.cqm_rmid = rmid;
858}
859
860static void intel_cqm_event_read(struct perf_event *event)
861{
862 unsigned long flags;
863 unsigned int rmid;
864 u64 val;
865
866 /*
867 * Task events are handled by intel_cqm_event_count().
868 */
869 if (event->cpu == -1)
870 return;
871
872 raw_spin_lock_irqsave(&cache_lock, flags);
873 rmid = event->hw.cqm_rmid;
874
875 if (!__rmid_valid(rmid))
876 goto out;
877
878 val = __rmid_read(rmid);
879
880 /*
881 * Ignore this reading on error states and do not update the value.
882 */
883 if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))
884 goto out;
885
886 local64_set(&event->count, val);
887out:
888 raw_spin_unlock_irqrestore(&cache_lock, flags);
889}
890
891static void __intel_cqm_event_count(void *info)
892{
893 struct rmid_read *rr = info;
894 u64 val;
895
896 val = __rmid_read(rr->rmid);
897
898 if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))
899 return;
900
901 atomic64_add(val, &rr->value);
902}
903
904static inline bool cqm_group_leader(struct perf_event *event)
905{
906 return !list_empty(&event->hw.cqm_groups_entry);
907}
908
909static u64 intel_cqm_event_count(struct perf_event *event)
910{
911 unsigned long flags;
912 struct rmid_read rr = {
913 .value = ATOMIC64_INIT(0),
914 };
915
916 /*
917 * We only need to worry about task events. System-wide events
918 * are handled like usual, i.e. entirely with
919 * intel_cqm_event_read().
920 */
921 if (event->cpu != -1)
922 return __perf_event_count(event);
923
924 /*
925 * Only the group leader gets to report values. This stops us
926 * reporting duplicate values to userspace, and gives us a clear
927 * rule for which task gets to report the values.
928 *
929 * Note that it is impossible to attribute these values to
930 * specific packages - we forfeit that ability when we create
931 * task events.
932 */
933 if (!cqm_group_leader(event))
934 return 0;
935
936 /*
937 * Notice that we don't perform the reading of an RMID
938 * atomically, because we can't hold a spin lock across the
939 * IPIs.
940 *
941 * Speculatively perform the read, since @event might be
942 * assigned a different (possibly invalid) RMID while we're
943 * busying performing the IPI calls. It's therefore necessary to
944 * check @event's RMID afterwards, and if it has changed,
945 * discard the result of the read.
946 */
947 rr.rmid = ACCESS_ONCE(event->hw.cqm_rmid);
948
949 if (!__rmid_valid(rr.rmid))
950 goto out;
951
952 on_each_cpu_mask(&cqm_cpumask, __intel_cqm_event_count, &rr, 1);
953
954 raw_spin_lock_irqsave(&cache_lock, flags);
955 if (event->hw.cqm_rmid == rr.rmid)
956 local64_set(&event->count, atomic64_read(&rr.value));
957 raw_spin_unlock_irqrestore(&cache_lock, flags);
958out:
959 return __perf_event_count(event);
960}
961
962static void intel_cqm_event_start(struct perf_event *event, int mode)
963{
964 struct intel_cqm_state *state = this_cpu_ptr(&cqm_state);
965 unsigned int rmid = event->hw.cqm_rmid;
966 unsigned long flags;
967
968 if (!(event->hw.cqm_state & PERF_HES_STOPPED))
969 return;
970
971 event->hw.cqm_state &= ~PERF_HES_STOPPED;
972
973 raw_spin_lock_irqsave(&state->lock, flags);
974
975 if (state->cnt++)
976 WARN_ON_ONCE(state->rmid != rmid);
977 else
978 WARN_ON_ONCE(state->rmid);
979
980 state->rmid = rmid;
981 wrmsrl(MSR_IA32_PQR_ASSOC, state->rmid);
982
983 raw_spin_unlock_irqrestore(&state->lock, flags);
984}
985
986static void intel_cqm_event_stop(struct perf_event *event, int mode)
987{
988 struct intel_cqm_state *state = this_cpu_ptr(&cqm_state);
989 unsigned long flags;
990
991 if (event->hw.cqm_state & PERF_HES_STOPPED)
992 return;
993
994 event->hw.cqm_state |= PERF_HES_STOPPED;
995
996 raw_spin_lock_irqsave(&state->lock, flags);
997 intel_cqm_event_read(event);
998
999 if (!--state->cnt) {
1000 state->rmid = 0;
1001 wrmsrl(MSR_IA32_PQR_ASSOC, 0);
1002 } else {
1003 WARN_ON_ONCE(!state->rmid);
1004 }
1005
1006 raw_spin_unlock_irqrestore(&state->lock, flags);
1007}
1008
1009static int intel_cqm_event_add(struct perf_event *event, int mode)
1010{
1011 unsigned long flags;
1012 unsigned int rmid;
1013
1014 raw_spin_lock_irqsave(&cache_lock, flags);
1015
1016 event->hw.cqm_state = PERF_HES_STOPPED;
1017 rmid = event->hw.cqm_rmid;
1018
1019 if (__rmid_valid(rmid) && (mode & PERF_EF_START))
1020 intel_cqm_event_start(event, mode);
1021
1022 raw_spin_unlock_irqrestore(&cache_lock, flags);
1023
1024 return 0;
1025}
1026
1027static void intel_cqm_event_del(struct perf_event *event, int mode)
1028{
1029 intel_cqm_event_stop(event, mode);
1030}
1031
1032static void intel_cqm_event_destroy(struct perf_event *event)
1033{
1034 struct perf_event *group_other = NULL;
1035
1036 mutex_lock(&cache_mutex);
1037
1038 /*
1039 * If there's another event in this group...
1040 */
1041 if (!list_empty(&event->hw.cqm_group_entry)) {
1042 group_other = list_first_entry(&event->hw.cqm_group_entry,
1043 struct perf_event,
1044 hw.cqm_group_entry);
1045 list_del(&event->hw.cqm_group_entry);
1046 }
1047
1048 /*
1049 * And we're the group leader..
1050 */
1051 if (cqm_group_leader(event)) {
1052 /*
1053 * If there was a group_other, make that leader, otherwise
1054 * destroy the group and return the RMID.
1055 */
1056 if (group_other) {
1057 list_replace(&event->hw.cqm_groups_entry,
1058 &group_other->hw.cqm_groups_entry);
1059 } else {
1060 unsigned int rmid = event->hw.cqm_rmid;
1061
1062 if (__rmid_valid(rmid))
1063 __put_rmid(rmid);
1064 list_del(&event->hw.cqm_groups_entry);
1065 }
1066 }
1067
1068 mutex_unlock(&cache_mutex);
1069}
1070
1071static int intel_cqm_event_init(struct perf_event *event)
1072{
1073 struct perf_event *group = NULL;
1074 bool rotate = false;
1075
1076 if (event->attr.type != intel_cqm_pmu.type)
1077 return -ENOENT;
1078
1079 if (event->attr.config & ~QOS_EVENT_MASK)
1080 return -EINVAL;
1081
1082 /* unsupported modes and filters */
1083 if (event->attr.exclude_user ||
1084 event->attr.exclude_kernel ||
1085 event->attr.exclude_hv ||
1086 event->attr.exclude_idle ||
1087 event->attr.exclude_host ||
1088 event->attr.exclude_guest ||
1089 event->attr.sample_period) /* no sampling */
1090 return -EINVAL;
1091
1092 INIT_LIST_HEAD(&event->hw.cqm_group_entry);
1093 INIT_LIST_HEAD(&event->hw.cqm_groups_entry);
1094
1095 event->destroy = intel_cqm_event_destroy;
1096
1097 mutex_lock(&cache_mutex);
1098
1099 /* Will also set rmid */
1100 intel_cqm_setup_event(event, &group);
1101
1102 if (group) {
1103 list_add_tail(&event->hw.cqm_group_entry,
1104 &group->hw.cqm_group_entry);
1105 } else {
1106 list_add_tail(&event->hw.cqm_groups_entry,
1107 &cache_groups);
1108
1109 /*
1110 * All RMIDs are either in use or have recently been
1111 * used. Kick the rotation worker to clean/free some.
1112 *
1113 * We only do this for the group leader, rather than for
1114 * every event in a group to save on needless work.
1115 */
1116 if (!__rmid_valid(event->hw.cqm_rmid))
1117 rotate = true;
1118 }
1119
1120 mutex_unlock(&cache_mutex);
1121
1122 if (rotate)
1123 schedule_delayed_work(&intel_cqm_rmid_work, 0);
1124
1125 return 0;
1126}
1127
1128EVENT_ATTR_STR(llc_occupancy, intel_cqm_llc, "event=0x01");
1129EVENT_ATTR_STR(llc_occupancy.per-pkg, intel_cqm_llc_pkg, "1");
1130EVENT_ATTR_STR(llc_occupancy.unit, intel_cqm_llc_unit, "Bytes");
1131EVENT_ATTR_STR(llc_occupancy.scale, intel_cqm_llc_scale, NULL);
1132EVENT_ATTR_STR(llc_occupancy.snapshot, intel_cqm_llc_snapshot, "1");
1133
1134static struct attribute *intel_cqm_events_attr[] = {
1135 EVENT_PTR(intel_cqm_llc),
1136 EVENT_PTR(intel_cqm_llc_pkg),
1137 EVENT_PTR(intel_cqm_llc_unit),
1138 EVENT_PTR(intel_cqm_llc_scale),
1139 EVENT_PTR(intel_cqm_llc_snapshot),
1140 NULL,
1141};
1142
1143static struct attribute_group intel_cqm_events_group = {
1144 .name = "events",
1145 .attrs = intel_cqm_events_attr,
1146};
1147
1148PMU_FORMAT_ATTR(event, "config:0-7");
1149static struct attribute *intel_cqm_formats_attr[] = {
1150 &format_attr_event.attr,
1151 NULL,
1152};
1153
1154static struct attribute_group intel_cqm_format_group = {
1155 .name = "format",
1156 .attrs = intel_cqm_formats_attr,
1157};
1158
1159static ssize_t
1160max_recycle_threshold_show(struct device *dev, struct device_attribute *attr,
1161 char *page)
1162{
1163 ssize_t rv;
1164
1165 mutex_lock(&cache_mutex);
1166 rv = snprintf(page, PAGE_SIZE-1, "%u\n", __intel_cqm_max_threshold);
1167 mutex_unlock(&cache_mutex);
1168
1169 return rv;
1170}
1171
1172static ssize_t
1173max_recycle_threshold_store(struct device *dev,
1174 struct device_attribute *attr,
1175 const char *buf, size_t count)
1176{
1177 unsigned int bytes, cachelines;
1178 int ret;
1179
1180 ret = kstrtouint(buf, 0, &bytes);
1181 if (ret)
1182 return ret;
1183
1184 mutex_lock(&cache_mutex);
1185
1186 __intel_cqm_max_threshold = bytes;
1187 cachelines = bytes / cqm_l3_scale;
1188
1189 /*
1190 * The new maximum takes effect immediately.
1191 */
1192 if (__intel_cqm_threshold > cachelines)
1193 __intel_cqm_threshold = cachelines;
1194
1195 mutex_unlock(&cache_mutex);
1196
1197 return count;
1198}
1199
1200static DEVICE_ATTR_RW(max_recycle_threshold);
1201
1202static struct attribute *intel_cqm_attrs[] = {
1203 &dev_attr_max_recycle_threshold.attr,
1204 NULL,
1205};
1206
1207static const struct attribute_group intel_cqm_group = {
1208 .attrs = intel_cqm_attrs,
1209};
1210
1211static const struct attribute_group *intel_cqm_attr_groups[] = {
1212 &intel_cqm_events_group,
1213 &intel_cqm_format_group,
1214 &intel_cqm_group,
1215 NULL,
1216};
1217
1218static struct pmu intel_cqm_pmu = {
1219 .hrtimer_interval_ms = RMID_DEFAULT_QUEUE_TIME,
1220 .attr_groups = intel_cqm_attr_groups,
1221 .task_ctx_nr = perf_sw_context,
1222 .event_init = intel_cqm_event_init,
1223 .add = intel_cqm_event_add,
1224 .del = intel_cqm_event_del,
1225 .start = intel_cqm_event_start,
1226 .stop = intel_cqm_event_stop,
1227 .read = intel_cqm_event_read,
1228 .count = intel_cqm_event_count,
1229};
1230
1231static inline void cqm_pick_event_reader(int cpu)
1232{
1233 int phys_id = topology_physical_package_id(cpu);
1234 int i;
1235
1236 for_each_cpu(i, &cqm_cpumask) {
1237 if (phys_id == topology_physical_package_id(i))
1238 return; /* already got reader for this socket */
1239 }
1240
1241 cpumask_set_cpu(cpu, &cqm_cpumask);
1242}
1243
1244static void intel_cqm_cpu_prepare(unsigned int cpu)
1245{
1246 struct intel_cqm_state *state = &per_cpu(cqm_state, cpu);
1247 struct cpuinfo_x86 *c = &cpu_data(cpu);
1248
1249 raw_spin_lock_init(&state->lock);
1250 state->rmid = 0;
1251 state->cnt = 0;
1252
1253 WARN_ON(c->x86_cache_max_rmid != cqm_max_rmid);
1254 WARN_ON(c->x86_cache_occ_scale != cqm_l3_scale);
1255}
1256
1257static void intel_cqm_cpu_exit(unsigned int cpu)
1258{
1259 int phys_id = topology_physical_package_id(cpu);
1260 int i;
1261
1262 /*
1263 * Is @cpu a designated cqm reader?
1264 */
1265 if (!cpumask_test_and_clear_cpu(cpu, &cqm_cpumask))
1266 return;
1267
1268 for_each_online_cpu(i) {
1269 if (i == cpu)
1270 continue;
1271
1272 if (phys_id == topology_physical_package_id(i)) {
1273 cpumask_set_cpu(i, &cqm_cpumask);
1274 break;
1275 }
1276 }
1277}
1278
1279static int intel_cqm_cpu_notifier(struct notifier_block *nb,
1280 unsigned long action, void *hcpu)
1281{
1282 unsigned int cpu = (unsigned long)hcpu;
1283
1284 switch (action & ~CPU_TASKS_FROZEN) {
1285 case CPU_UP_PREPARE:
1286 intel_cqm_cpu_prepare(cpu);
1287 break;
1288 case CPU_DOWN_PREPARE:
1289 intel_cqm_cpu_exit(cpu);
1290 break;
1291 case CPU_STARTING:
1292 cqm_pick_event_reader(cpu);
1293 break;
1294 }
1295
1296 return NOTIFY_OK;
1297}
1298
1299static const struct x86_cpu_id intel_cqm_match[] = {
1300 { .vendor = X86_VENDOR_INTEL, .feature = X86_FEATURE_CQM_OCCUP_LLC },
1301 {}
1302};
1303
1304static int __init intel_cqm_init(void)
1305{
1306 char *str, scale[20];
1307 int i, cpu, ret;
1308
1309 if (!x86_match_cpu(intel_cqm_match))
1310 return -ENODEV;
1311
1312 cqm_l3_scale = boot_cpu_data.x86_cache_occ_scale;
1313
1314 /*
1315 * It's possible that not all resources support the same number
1316 * of RMIDs. Instead of making scheduling much more complicated
1317 * (where we have to match a task's RMID to a cpu that supports
1318 * that many RMIDs) just find the minimum RMIDs supported across
1319 * all cpus.
1320 *
1321 * Also, check that the scales match on all cpus.
1322 */
1323 cpu_notifier_register_begin();
1324
1325 for_each_online_cpu(cpu) {
1326 struct cpuinfo_x86 *c = &cpu_data(cpu);
1327
1328 if (c->x86_cache_max_rmid < cqm_max_rmid)
1329 cqm_max_rmid = c->x86_cache_max_rmid;
1330
1331 if (c->x86_cache_occ_scale != cqm_l3_scale) {
1332 pr_err("Multiple LLC scale values, disabling\n");
1333 ret = -EINVAL;
1334 goto out;
1335 }
1336 }
1337
1338 /*
1339 * A reasonable upper limit on the max threshold is the number
1340 * of lines tagged per RMID if all RMIDs have the same number of
1341 * lines tagged in the LLC.
1342 *
1343 * For a 35MB LLC and 56 RMIDs, this is ~1.8% of the LLC.
1344 */
1345 __intel_cqm_max_threshold =
1346 boot_cpu_data.x86_cache_size * 1024 / (cqm_max_rmid + 1);
1347
1348 snprintf(scale, sizeof(scale), "%u", cqm_l3_scale);
1349 str = kstrdup(scale, GFP_KERNEL);
1350 if (!str) {
1351 ret = -ENOMEM;
1352 goto out;
1353 }
1354
1355 event_attr_intel_cqm_llc_scale.event_str = str;
1356
1357 ret = intel_cqm_setup_rmid_cache();
1358 if (ret)
1359 goto out;
1360
1361 for_each_online_cpu(i) {
1362 intel_cqm_cpu_prepare(i);
1363 cqm_pick_event_reader(i);
1364 }
1365
1366 __perf_cpu_notifier(intel_cqm_cpu_notifier);
1367
1368 ret = perf_pmu_register(&intel_cqm_pmu, "intel_cqm", -1);
1369 if (ret)
1370 pr_err("Intel CQM perf registration failed: %d\n", ret);
1371 else
1372 pr_info("Intel CQM monitoring enabled\n");
1373
1374out:
1375 cpu_notifier_register_done();
1376
1377 return ret;
1378}
1379device_initcall(intel_cqm_init);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-24 14:14:25 -0500