Commit | Line | Data |
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76369139 FW |
1 | /* |
2 | * Performance events ring-buffer code: | |
3 | * | |
4 | * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> | |
5 | * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar | |
90eec103 | 6 | * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra |
d36b6910 | 7 | * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> |
76369139 FW |
8 | * |
9 | * For licensing details see kernel-base/COPYING | |
10 | */ | |
11 | ||
12 | #include <linux/perf_event.h> | |
13 | #include <linux/vmalloc.h> | |
14 | #include <linux/slab.h> | |
26c86da8 | 15 | #include <linux/circ_buf.h> |
7c60fc0e | 16 | #include <linux/poll.h> |
76369139 FW |
17 | |
18 | #include "internal.h" | |
19 | ||
76369139 FW |
20 | static void perf_output_wakeup(struct perf_output_handle *handle) |
21 | { | |
7c60fc0e | 22 | atomic_set(&handle->rb->poll, POLLIN); |
76369139 | 23 | |
a8b0ca17 PZ |
24 | handle->event->pending_wakeup = 1; |
25 | irq_work_queue(&handle->event->pending); | |
76369139 FW |
26 | } |
27 | ||
28 | /* | |
29 | * We need to ensure a later event_id doesn't publish a head when a former | |
30 | * event isn't done writing. However since we need to deal with NMIs we | |
31 | * cannot fully serialize things. | |
32 | * | |
33 | * We only publish the head (and generate a wakeup) when the outer-most | |
34 | * event completes. | |
35 | */ | |
36 | static void perf_output_get_handle(struct perf_output_handle *handle) | |
37 | { | |
38 | struct ring_buffer *rb = handle->rb; | |
39 | ||
40 | preempt_disable(); | |
41 | local_inc(&rb->nest); | |
42 | handle->wakeup = local_read(&rb->wakeup); | |
43 | } | |
44 | ||
45 | static void perf_output_put_handle(struct perf_output_handle *handle) | |
46 | { | |
47 | struct ring_buffer *rb = handle->rb; | |
48 | unsigned long head; | |
49 | ||
50 | again: | |
51 | head = local_read(&rb->head); | |
52 | ||
53 | /* | |
54 | * IRQ/NMI can happen here, which means we can miss a head update. | |
55 | */ | |
56 | ||
57 | if (!local_dec_and_test(&rb->nest)) | |
58 | goto out; | |
59 | ||
60 | /* | |
bf378d34 PZ |
61 | * Since the mmap() consumer (userspace) can run on a different CPU: |
62 | * | |
63 | * kernel user | |
64 | * | |
c7f2e3cd PZ |
65 | * if (LOAD ->data_tail) { LOAD ->data_head |
66 | * (A) smp_rmb() (C) | |
67 | * STORE $data LOAD $data | |
68 | * smp_wmb() (B) smp_mb() (D) | |
69 | * STORE ->data_head STORE ->data_tail | |
70 | * } | |
bf378d34 PZ |
71 | * |
72 | * Where A pairs with D, and B pairs with C. | |
73 | * | |
c7f2e3cd PZ |
74 | * In our case (A) is a control dependency that separates the load of |
75 | * the ->data_tail and the stores of $data. In case ->data_tail | |
76 | * indicates there is no room in the buffer to store $data we do not. | |
bf378d34 | 77 | * |
c7f2e3cd | 78 | * D needs to be a full barrier since it separates the data READ |
bf378d34 PZ |
79 | * from the tail WRITE. |
80 | * | |
81 | * For B a WMB is sufficient since it separates two WRITEs, and for C | |
82 | * an RMB is sufficient since it separates two READs. | |
83 | * | |
84 | * See perf_output_begin(). | |
76369139 | 85 | */ |
c7f2e3cd | 86 | smp_wmb(); /* B, matches C */ |
76369139 FW |
87 | rb->user_page->data_head = head; |
88 | ||
89 | /* | |
394570b7 PZ |
90 | * Now check if we missed an update -- rely on previous implied |
91 | * compiler barriers to force a re-read. | |
76369139 FW |
92 | */ |
93 | if (unlikely(head != local_read(&rb->head))) { | |
94 | local_inc(&rb->nest); | |
95 | goto again; | |
96 | } | |
97 | ||
98 | if (handle->wakeup != local_read(&rb->wakeup)) | |
99 | perf_output_wakeup(handle); | |
100 | ||
101 | out: | |
102 | preempt_enable(); | |
103 | } | |
104 | ||
105 | int perf_output_begin(struct perf_output_handle *handle, | |
a7ac67ea | 106 | struct perf_event *event, unsigned int size) |
76369139 FW |
107 | { |
108 | struct ring_buffer *rb; | |
109 | unsigned long tail, offset, head; | |
524feca5 | 110 | int have_lost, page_shift; |
76369139 FW |
111 | struct { |
112 | struct perf_event_header header; | |
113 | u64 id; | |
114 | u64 lost; | |
115 | } lost_event; | |
116 | ||
117 | rcu_read_lock(); | |
118 | /* | |
119 | * For inherited events we send all the output towards the parent. | |
120 | */ | |
121 | if (event->parent) | |
122 | event = event->parent; | |
123 | ||
124 | rb = rcu_dereference(event->rb); | |
c72b42a3 | 125 | if (unlikely(!rb)) |
76369139 FW |
126 | goto out; |
127 | ||
c72b42a3 | 128 | if (unlikely(!rb->nr_pages)) |
76369139 FW |
129 | goto out; |
130 | ||
c72b42a3 PZ |
131 | handle->rb = rb; |
132 | handle->event = event; | |
133 | ||
76369139 | 134 | have_lost = local_read(&rb->lost); |
c72b42a3 | 135 | if (unlikely(have_lost)) { |
d20a973f PZ |
136 | size += sizeof(lost_event); |
137 | if (event->attr.sample_id_all) | |
138 | size += event->id_header_size; | |
76369139 FW |
139 | } |
140 | ||
141 | perf_output_get_handle(handle); | |
142 | ||
143 | do { | |
105ff3cb | 144 | tail = READ_ONCE(rb->user_page->data_tail); |
76369139 | 145 | offset = head = local_read(&rb->head); |
26c86da8 PZ |
146 | if (!rb->overwrite && |
147 | unlikely(CIRC_SPACE(head, tail, perf_data_size(rb)) < size)) | |
76369139 | 148 | goto fail; |
c7f2e3cd PZ |
149 | |
150 | /* | |
151 | * The above forms a control dependency barrier separating the | |
152 | * @tail load above from the data stores below. Since the @tail | |
153 | * load is required to compute the branch to fail below. | |
154 | * | |
155 | * A, matches D; the full memory barrier userspace SHOULD issue | |
156 | * after reading the data and before storing the new tail | |
157 | * position. | |
158 | * | |
159 | * See perf_output_put_handle(). | |
160 | */ | |
161 | ||
26c86da8 | 162 | head += size; |
76369139 FW |
163 | } while (local_cmpxchg(&rb->head, offset, head) != offset); |
164 | ||
85f59edf | 165 | /* |
c7f2e3cd PZ |
166 | * We rely on the implied barrier() by local_cmpxchg() to ensure |
167 | * none of the data stores below can be lifted up by the compiler. | |
85f59edf | 168 | */ |
85f59edf | 169 | |
c72b42a3 | 170 | if (unlikely(head - local_read(&rb->wakeup) > rb->watermark)) |
76369139 FW |
171 | local_add(rb->watermark, &rb->wakeup); |
172 | ||
524feca5 PZ |
173 | page_shift = PAGE_SHIFT + page_order(rb); |
174 | ||
175 | handle->page = (offset >> page_shift) & (rb->nr_pages - 1); | |
176 | offset &= (1UL << page_shift) - 1; | |
177 | handle->addr = rb->data_pages[handle->page] + offset; | |
178 | handle->size = (1UL << page_shift) - offset; | |
76369139 | 179 | |
c72b42a3 | 180 | if (unlikely(have_lost)) { |
d20a973f PZ |
181 | struct perf_sample_data sample_data; |
182 | ||
183 | lost_event.header.size = sizeof(lost_event); | |
76369139 FW |
184 | lost_event.header.type = PERF_RECORD_LOST; |
185 | lost_event.header.misc = 0; | |
186 | lost_event.id = event->id; | |
187 | lost_event.lost = local_xchg(&rb->lost, 0); | |
188 | ||
d20a973f PZ |
189 | perf_event_header__init_id(&lost_event.header, |
190 | &sample_data, event); | |
76369139 FW |
191 | perf_output_put(handle, lost_event); |
192 | perf_event__output_id_sample(event, handle, &sample_data); | |
193 | } | |
194 | ||
195 | return 0; | |
196 | ||
197 | fail: | |
198 | local_inc(&rb->lost); | |
199 | perf_output_put_handle(handle); | |
200 | out: | |
201 | rcu_read_unlock(); | |
202 | ||
203 | return -ENOSPC; | |
204 | } | |
205 | ||
91d7753a | 206 | unsigned int perf_output_copy(struct perf_output_handle *handle, |
76369139 FW |
207 | const void *buf, unsigned int len) |
208 | { | |
91d7753a | 209 | return __output_copy(handle, buf, len); |
76369139 FW |
210 | } |
211 | ||
5685e0ff JO |
212 | unsigned int perf_output_skip(struct perf_output_handle *handle, |
213 | unsigned int len) | |
214 | { | |
215 | return __output_skip(handle, NULL, len); | |
216 | } | |
217 | ||
76369139 FW |
218 | void perf_output_end(struct perf_output_handle *handle) |
219 | { | |
76369139 FW |
220 | perf_output_put_handle(handle); |
221 | rcu_read_unlock(); | |
222 | } | |
223 | ||
57ffc5ca PZ |
224 | static void rb_irq_work(struct irq_work *work); |
225 | ||
76369139 FW |
226 | static void |
227 | ring_buffer_init(struct ring_buffer *rb, long watermark, int flags) | |
228 | { | |
229 | long max_size = perf_data_size(rb); | |
230 | ||
231 | if (watermark) | |
232 | rb->watermark = min(max_size, watermark); | |
233 | ||
234 | if (!rb->watermark) | |
235 | rb->watermark = max_size / 2; | |
236 | ||
237 | if (flags & RING_BUFFER_WRITABLE) | |
dd9c086d SE |
238 | rb->overwrite = 0; |
239 | else | |
240 | rb->overwrite = 1; | |
76369139 FW |
241 | |
242 | atomic_set(&rb->refcount, 1); | |
10c6db11 PZ |
243 | |
244 | INIT_LIST_HEAD(&rb->event_list); | |
245 | spin_lock_init(&rb->event_lock); | |
57ffc5ca PZ |
246 | init_irq_work(&rb->irq_work, rb_irq_work); |
247 | } | |
248 | ||
249 | static void ring_buffer_put_async(struct ring_buffer *rb) | |
250 | { | |
251 | if (!atomic_dec_and_test(&rb->refcount)) | |
252 | return; | |
253 | ||
254 | rb->rcu_head.next = (void *)rb; | |
255 | irq_work_queue(&rb->irq_work); | |
76369139 FW |
256 | } |
257 | ||
fdc26706 AS |
258 | /* |
259 | * This is called before hardware starts writing to the AUX area to | |
260 | * obtain an output handle and make sure there's room in the buffer. | |
261 | * When the capture completes, call perf_aux_output_end() to commit | |
262 | * the recorded data to the buffer. | |
263 | * | |
264 | * The ordering is similar to that of perf_output_{begin,end}, with | |
265 | * the exception of (B), which should be taken care of by the pmu | |
266 | * driver, since ordering rules will differ depending on hardware. | |
267 | */ | |
268 | void *perf_aux_output_begin(struct perf_output_handle *handle, | |
269 | struct perf_event *event) | |
270 | { | |
271 | struct perf_event *output_event = event; | |
272 | unsigned long aux_head, aux_tail; | |
273 | struct ring_buffer *rb; | |
274 | ||
275 | if (output_event->parent) | |
276 | output_event = output_event->parent; | |
277 | ||
278 | /* | |
279 | * Since this will typically be open across pmu::add/pmu::del, we | |
280 | * grab ring_buffer's refcount instead of holding rcu read lock | |
281 | * to make sure it doesn't disappear under us. | |
282 | */ | |
283 | rb = ring_buffer_get(output_event); | |
284 | if (!rb) | |
285 | return NULL; | |
286 | ||
287 | if (!rb_has_aux(rb) || !atomic_inc_not_zero(&rb->aux_refcount)) | |
288 | goto err; | |
289 | ||
290 | /* | |
291 | * Nesting is not supported for AUX area, make sure nested | |
292 | * writers are caught early | |
293 | */ | |
294 | if (WARN_ON_ONCE(local_xchg(&rb->aux_nest, 1))) | |
295 | goto err_put; | |
296 | ||
297 | aux_head = local_read(&rb->aux_head); | |
fdc26706 AS |
298 | |
299 | handle->rb = rb; | |
300 | handle->event = event; | |
301 | handle->head = aux_head; | |
2023a0d2 | 302 | handle->size = 0; |
fdc26706 AS |
303 | |
304 | /* | |
2023a0d2 AS |
305 | * In overwrite mode, AUX data stores do not depend on aux_tail, |
306 | * therefore (A) control dependency barrier does not exist. The | |
307 | * (B) <-> (C) ordering is still observed by the pmu driver. | |
fdc26706 | 308 | */ |
2023a0d2 AS |
309 | if (!rb->aux_overwrite) { |
310 | aux_tail = ACCESS_ONCE(rb->user_page->aux_tail); | |
1a594131 | 311 | handle->wakeup = local_read(&rb->aux_wakeup) + rb->aux_watermark; |
2023a0d2 AS |
312 | if (aux_head - aux_tail < perf_aux_size(rb)) |
313 | handle->size = CIRC_SPACE(aux_head, aux_tail, perf_aux_size(rb)); | |
314 | ||
315 | /* | |
316 | * handle->size computation depends on aux_tail load; this forms a | |
317 | * control dependency barrier separating aux_tail load from aux data | |
318 | * store that will be enabled on successful return | |
319 | */ | |
320 | if (!handle->size) { /* A, matches D */ | |
321 | event->pending_disable = 1; | |
322 | perf_output_wakeup(handle); | |
323 | local_set(&rb->aux_nest, 0); | |
324 | goto err_put; | |
325 | } | |
fdc26706 AS |
326 | } |
327 | ||
328 | return handle->rb->aux_priv; | |
329 | ||
330 | err_put: | |
331 | rb_free_aux(rb); | |
332 | ||
333 | err: | |
57ffc5ca | 334 | ring_buffer_put_async(rb); |
fdc26706 AS |
335 | handle->event = NULL; |
336 | ||
337 | return NULL; | |
338 | } | |
339 | ||
340 | /* | |
341 | * Commit the data written by hardware into the ring buffer by adjusting | |
342 | * aux_head and posting a PERF_RECORD_AUX into the perf buffer. It is the | |
343 | * pmu driver's responsibility to observe ordering rules of the hardware, | |
344 | * so that all the data is externally visible before this is called. | |
345 | */ | |
346 | void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size, | |
347 | bool truncated) | |
348 | { | |
349 | struct ring_buffer *rb = handle->rb; | |
2023a0d2 | 350 | unsigned long aux_head; |
fdc26706 AS |
351 | u64 flags = 0; |
352 | ||
353 | if (truncated) | |
354 | flags |= PERF_AUX_FLAG_TRUNCATED; | |
355 | ||
2023a0d2 AS |
356 | /* in overwrite mode, driver provides aux_head via handle */ |
357 | if (rb->aux_overwrite) { | |
358 | flags |= PERF_AUX_FLAG_OVERWRITE; | |
359 | ||
360 | aux_head = handle->head; | |
361 | local_set(&rb->aux_head, aux_head); | |
362 | } else { | |
363 | aux_head = local_read(&rb->aux_head); | |
364 | local_add(size, &rb->aux_head); | |
365 | } | |
fdc26706 AS |
366 | |
367 | if (size || flags) { | |
368 | /* | |
369 | * Only send RECORD_AUX if we have something useful to communicate | |
370 | */ | |
371 | ||
372 | perf_event_aux_event(handle->event, aux_head, size, flags); | |
373 | } | |
374 | ||
1a594131 | 375 | aux_head = rb->user_page->aux_head = local_read(&rb->aux_head); |
fdc26706 | 376 | |
1a594131 AS |
377 | if (aux_head - local_read(&rb->aux_wakeup) >= rb->aux_watermark) { |
378 | perf_output_wakeup(handle); | |
379 | local_add(rb->aux_watermark, &rb->aux_wakeup); | |
380 | } | |
fdc26706 AS |
381 | handle->event = NULL; |
382 | ||
383 | local_set(&rb->aux_nest, 0); | |
384 | rb_free_aux(rb); | |
57ffc5ca | 385 | ring_buffer_put_async(rb); |
fdc26706 AS |
386 | } |
387 | ||
388 | /* | |
389 | * Skip over a given number of bytes in the AUX buffer, due to, for example, | |
390 | * hardware's alignment constraints. | |
391 | */ | |
392 | int perf_aux_output_skip(struct perf_output_handle *handle, unsigned long size) | |
393 | { | |
394 | struct ring_buffer *rb = handle->rb; | |
395 | unsigned long aux_head; | |
396 | ||
397 | if (size > handle->size) | |
398 | return -ENOSPC; | |
399 | ||
400 | local_add(size, &rb->aux_head); | |
401 | ||
1a594131 AS |
402 | aux_head = rb->user_page->aux_head = local_read(&rb->aux_head); |
403 | if (aux_head - local_read(&rb->aux_wakeup) >= rb->aux_watermark) { | |
404 | perf_output_wakeup(handle); | |
405 | local_add(rb->aux_watermark, &rb->aux_wakeup); | |
406 | handle->wakeup = local_read(&rb->aux_wakeup) + | |
407 | rb->aux_watermark; | |
408 | } | |
409 | ||
fdc26706 AS |
410 | handle->head = aux_head; |
411 | handle->size -= size; | |
412 | ||
413 | return 0; | |
414 | } | |
415 | ||
416 | void *perf_get_aux(struct perf_output_handle *handle) | |
417 | { | |
418 | /* this is only valid between perf_aux_output_begin and *_end */ | |
419 | if (!handle->event) | |
420 | return NULL; | |
421 | ||
422 | return handle->rb->aux_priv; | |
423 | } | |
424 | ||
0a4e38e6 AS |
425 | #define PERF_AUX_GFP (GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_NORETRY) |
426 | ||
427 | static struct page *rb_alloc_aux_page(int node, int order) | |
428 | { | |
429 | struct page *page; | |
430 | ||
431 | if (order > MAX_ORDER) | |
432 | order = MAX_ORDER; | |
433 | ||
434 | do { | |
435 | page = alloc_pages_node(node, PERF_AUX_GFP, order); | |
436 | } while (!page && order--); | |
437 | ||
438 | if (page && order) { | |
439 | /* | |
c2ad6b51 AS |
440 | * Communicate the allocation size to the driver: |
441 | * if we managed to secure a high-order allocation, | |
442 | * set its first page's private to this order; | |
443 | * !PagePrivate(page) means it's just a normal page. | |
0a4e38e6 AS |
444 | */ |
445 | split_page(page, order); | |
446 | SetPagePrivate(page); | |
447 | set_page_private(page, order); | |
448 | } | |
449 | ||
450 | return page; | |
451 | } | |
452 | ||
453 | static void rb_free_aux_page(struct ring_buffer *rb, int idx) | |
454 | { | |
455 | struct page *page = virt_to_page(rb->aux_pages[idx]); | |
456 | ||
457 | ClearPagePrivate(page); | |
458 | page->mapping = NULL; | |
459 | __free_page(page); | |
460 | } | |
461 | ||
45c815f0 AS |
462 | static void __rb_free_aux(struct ring_buffer *rb) |
463 | { | |
464 | int pg; | |
465 | ||
466 | if (rb->aux_priv) { | |
467 | rb->free_aux(rb->aux_priv); | |
468 | rb->free_aux = NULL; | |
469 | rb->aux_priv = NULL; | |
470 | } | |
471 | ||
472 | if (rb->aux_nr_pages) { | |
473 | for (pg = 0; pg < rb->aux_nr_pages; pg++) | |
474 | rb_free_aux_page(rb, pg); | |
475 | ||
476 | kfree(rb->aux_pages); | |
477 | rb->aux_nr_pages = 0; | |
478 | } | |
479 | } | |
480 | ||
45bfb2e5 | 481 | int rb_alloc_aux(struct ring_buffer *rb, struct perf_event *event, |
1a594131 | 482 | pgoff_t pgoff, int nr_pages, long watermark, int flags) |
45bfb2e5 PZ |
483 | { |
484 | bool overwrite = !(flags & RING_BUFFER_WRITABLE); | |
485 | int node = (event->cpu == -1) ? -1 : cpu_to_node(event->cpu); | |
0a4e38e6 | 486 | int ret = -ENOMEM, max_order = 0; |
45bfb2e5 PZ |
487 | |
488 | if (!has_aux(event)) | |
489 | return -ENOTSUPP; | |
490 | ||
6a279230 | 491 | if (event->pmu->capabilities & PERF_PMU_CAP_AUX_NO_SG) { |
0a4e38e6 AS |
492 | /* |
493 | * We need to start with the max_order that fits in nr_pages, | |
494 | * not the other way around, hence ilog2() and not get_order. | |
495 | */ | |
496 | max_order = ilog2(nr_pages); | |
497 | ||
6a279230 AS |
498 | /* |
499 | * PMU requests more than one contiguous chunks of memory | |
500 | * for SW double buffering | |
501 | */ | |
502 | if ((event->pmu->capabilities & PERF_PMU_CAP_AUX_SW_DOUBLEBUF) && | |
503 | !overwrite) { | |
504 | if (!max_order) | |
505 | return -EINVAL; | |
506 | ||
507 | max_order--; | |
508 | } | |
509 | } | |
510 | ||
45bfb2e5 PZ |
511 | rb->aux_pages = kzalloc_node(nr_pages * sizeof(void *), GFP_KERNEL, node); |
512 | if (!rb->aux_pages) | |
513 | return -ENOMEM; | |
514 | ||
515 | rb->free_aux = event->pmu->free_aux; | |
0a4e38e6 | 516 | for (rb->aux_nr_pages = 0; rb->aux_nr_pages < nr_pages;) { |
45bfb2e5 | 517 | struct page *page; |
0a4e38e6 | 518 | int last, order; |
45bfb2e5 | 519 | |
0a4e38e6 AS |
520 | order = min(max_order, ilog2(nr_pages - rb->aux_nr_pages)); |
521 | page = rb_alloc_aux_page(node, order); | |
45bfb2e5 PZ |
522 | if (!page) |
523 | goto out; | |
524 | ||
0a4e38e6 AS |
525 | for (last = rb->aux_nr_pages + (1 << page_private(page)); |
526 | last > rb->aux_nr_pages; rb->aux_nr_pages++) | |
527 | rb->aux_pages[rb->aux_nr_pages] = page_address(page++); | |
45bfb2e5 PZ |
528 | } |
529 | ||
aa319bcd AS |
530 | /* |
531 | * In overwrite mode, PMUs that don't support SG may not handle more | |
532 | * than one contiguous allocation, since they rely on PMI to do double | |
533 | * buffering. In this case, the entire buffer has to be one contiguous | |
534 | * chunk. | |
535 | */ | |
536 | if ((event->pmu->capabilities & PERF_PMU_CAP_AUX_NO_SG) && | |
537 | overwrite) { | |
538 | struct page *page = virt_to_page(rb->aux_pages[0]); | |
539 | ||
540 | if (page_private(page) != max_order) | |
541 | goto out; | |
542 | } | |
543 | ||
45bfb2e5 PZ |
544 | rb->aux_priv = event->pmu->setup_aux(event->cpu, rb->aux_pages, nr_pages, |
545 | overwrite); | |
546 | if (!rb->aux_priv) | |
547 | goto out; | |
548 | ||
549 | ret = 0; | |
550 | ||
551 | /* | |
552 | * aux_pages (and pmu driver's private data, aux_priv) will be | |
553 | * referenced in both producer's and consumer's contexts, thus | |
554 | * we keep a refcount here to make sure either of the two can | |
555 | * reference them safely. | |
556 | */ | |
557 | atomic_set(&rb->aux_refcount, 1); | |
558 | ||
2023a0d2 | 559 | rb->aux_overwrite = overwrite; |
1a594131 AS |
560 | rb->aux_watermark = watermark; |
561 | ||
562 | if (!rb->aux_watermark && !rb->aux_overwrite) | |
563 | rb->aux_watermark = nr_pages << (PAGE_SHIFT - 1); | |
2023a0d2 | 564 | |
45bfb2e5 PZ |
565 | out: |
566 | if (!ret) | |
567 | rb->aux_pgoff = pgoff; | |
568 | else | |
45c815f0 | 569 | __rb_free_aux(rb); |
45bfb2e5 PZ |
570 | |
571 | return ret; | |
572 | } | |
573 | ||
45bfb2e5 PZ |
574 | void rb_free_aux(struct ring_buffer *rb) |
575 | { | |
576 | if (atomic_dec_and_test(&rb->aux_refcount)) | |
57ffc5ca PZ |
577 | irq_work_queue(&rb->irq_work); |
578 | } | |
579 | ||
580 | static void rb_irq_work(struct irq_work *work) | |
581 | { | |
582 | struct ring_buffer *rb = container_of(work, struct ring_buffer, irq_work); | |
583 | ||
584 | if (!atomic_read(&rb->aux_refcount)) | |
45bfb2e5 | 585 | __rb_free_aux(rb); |
57ffc5ca PZ |
586 | |
587 | if (rb->rcu_head.next == (void *)rb) | |
588 | call_rcu(&rb->rcu_head, rb_free_rcu); | |
45bfb2e5 PZ |
589 | } |
590 | ||
76369139 FW |
591 | #ifndef CONFIG_PERF_USE_VMALLOC |
592 | ||
593 | /* | |
594 | * Back perf_mmap() with regular GFP_KERNEL-0 pages. | |
595 | */ | |
596 | ||
45bfb2e5 PZ |
597 | static struct page * |
598 | __perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff) | |
76369139 FW |
599 | { |
600 | if (pgoff > rb->nr_pages) | |
601 | return NULL; | |
602 | ||
603 | if (pgoff == 0) | |
604 | return virt_to_page(rb->user_page); | |
605 | ||
606 | return virt_to_page(rb->data_pages[pgoff - 1]); | |
607 | } | |
608 | ||
609 | static void *perf_mmap_alloc_page(int cpu) | |
610 | { | |
611 | struct page *page; | |
612 | int node; | |
613 | ||
614 | node = (cpu == -1) ? cpu : cpu_to_node(cpu); | |
615 | page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0); | |
616 | if (!page) | |
617 | return NULL; | |
618 | ||
619 | return page_address(page); | |
620 | } | |
621 | ||
622 | struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags) | |
623 | { | |
624 | struct ring_buffer *rb; | |
625 | unsigned long size; | |
626 | int i; | |
627 | ||
628 | size = sizeof(struct ring_buffer); | |
629 | size += nr_pages * sizeof(void *); | |
630 | ||
631 | rb = kzalloc(size, GFP_KERNEL); | |
632 | if (!rb) | |
633 | goto fail; | |
634 | ||
635 | rb->user_page = perf_mmap_alloc_page(cpu); | |
636 | if (!rb->user_page) | |
637 | goto fail_user_page; | |
638 | ||
639 | for (i = 0; i < nr_pages; i++) { | |
640 | rb->data_pages[i] = perf_mmap_alloc_page(cpu); | |
641 | if (!rb->data_pages[i]) | |
642 | goto fail_data_pages; | |
643 | } | |
644 | ||
645 | rb->nr_pages = nr_pages; | |
646 | ||
647 | ring_buffer_init(rb, watermark, flags); | |
648 | ||
649 | return rb; | |
650 | ||
651 | fail_data_pages: | |
652 | for (i--; i >= 0; i--) | |
653 | free_page((unsigned long)rb->data_pages[i]); | |
654 | ||
655 | free_page((unsigned long)rb->user_page); | |
656 | ||
657 | fail_user_page: | |
658 | kfree(rb); | |
659 | ||
660 | fail: | |
661 | return NULL; | |
662 | } | |
663 | ||
664 | static void perf_mmap_free_page(unsigned long addr) | |
665 | { | |
666 | struct page *page = virt_to_page((void *)addr); | |
667 | ||
668 | page->mapping = NULL; | |
669 | __free_page(page); | |
670 | } | |
671 | ||
672 | void rb_free(struct ring_buffer *rb) | |
673 | { | |
674 | int i; | |
675 | ||
676 | perf_mmap_free_page((unsigned long)rb->user_page); | |
677 | for (i = 0; i < rb->nr_pages; i++) | |
678 | perf_mmap_free_page((unsigned long)rb->data_pages[i]); | |
679 | kfree(rb); | |
680 | } | |
681 | ||
682 | #else | |
5919b309 JO |
683 | static int data_page_nr(struct ring_buffer *rb) |
684 | { | |
685 | return rb->nr_pages << page_order(rb); | |
686 | } | |
76369139 | 687 | |
45bfb2e5 PZ |
688 | static struct page * |
689 | __perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff) | |
76369139 | 690 | { |
5919b309 JO |
691 | /* The '>' counts in the user page. */ |
692 | if (pgoff > data_page_nr(rb)) | |
76369139 FW |
693 | return NULL; |
694 | ||
695 | return vmalloc_to_page((void *)rb->user_page + pgoff * PAGE_SIZE); | |
696 | } | |
697 | ||
698 | static void perf_mmap_unmark_page(void *addr) | |
699 | { | |
700 | struct page *page = vmalloc_to_page(addr); | |
701 | ||
702 | page->mapping = NULL; | |
703 | } | |
704 | ||
705 | static void rb_free_work(struct work_struct *work) | |
706 | { | |
707 | struct ring_buffer *rb; | |
708 | void *base; | |
709 | int i, nr; | |
710 | ||
711 | rb = container_of(work, struct ring_buffer, work); | |
5919b309 | 712 | nr = data_page_nr(rb); |
76369139 FW |
713 | |
714 | base = rb->user_page; | |
5919b309 JO |
715 | /* The '<=' counts in the user page. */ |
716 | for (i = 0; i <= nr; i++) | |
76369139 FW |
717 | perf_mmap_unmark_page(base + (i * PAGE_SIZE)); |
718 | ||
719 | vfree(base); | |
720 | kfree(rb); | |
721 | } | |
722 | ||
723 | void rb_free(struct ring_buffer *rb) | |
724 | { | |
725 | schedule_work(&rb->work); | |
726 | } | |
727 | ||
728 | struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags) | |
729 | { | |
730 | struct ring_buffer *rb; | |
731 | unsigned long size; | |
732 | void *all_buf; | |
733 | ||
734 | size = sizeof(struct ring_buffer); | |
735 | size += sizeof(void *); | |
736 | ||
737 | rb = kzalloc(size, GFP_KERNEL); | |
738 | if (!rb) | |
739 | goto fail; | |
740 | ||
741 | INIT_WORK(&rb->work, rb_free_work); | |
742 | ||
743 | all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE); | |
744 | if (!all_buf) | |
745 | goto fail_all_buf; | |
746 | ||
747 | rb->user_page = all_buf; | |
748 | rb->data_pages[0] = all_buf + PAGE_SIZE; | |
749 | rb->page_order = ilog2(nr_pages); | |
5919b309 | 750 | rb->nr_pages = !!nr_pages; |
76369139 FW |
751 | |
752 | ring_buffer_init(rb, watermark, flags); | |
753 | ||
754 | return rb; | |
755 | ||
756 | fail_all_buf: | |
757 | kfree(rb); | |
758 | ||
759 | fail: | |
760 | return NULL; | |
761 | } | |
762 | ||
763 | #endif | |
45bfb2e5 PZ |
764 | |
765 | struct page * | |
766 | perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff) | |
767 | { | |
768 | if (rb->aux_nr_pages) { | |
769 | /* above AUX space */ | |
770 | if (pgoff > rb->aux_pgoff + rb->aux_nr_pages) | |
771 | return NULL; | |
772 | ||
773 | /* AUX space */ | |
774 | if (pgoff >= rb->aux_pgoff) | |
775 | return virt_to_page(rb->aux_pages[pgoff - rb->aux_pgoff]); | |
776 | } | |
777 | ||
778 | return __perf_mmap_to_page(rb, pgoff); | |
779 | } |