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3f49584b SP |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * DAMON Primitives for Virtual Address Spaces | |
4 | * | |
5 | * Author: SeongJae Park <sjpark@amazon.de> | |
6 | */ | |
7 | ||
8 | #define pr_fmt(fmt) "damon-va: " fmt | |
9 | ||
10 | #include <linux/damon.h> | |
11 | #include <linux/hugetlb.h> | |
12 | #include <linux/mm.h> | |
13 | #include <linux/mmu_notifier.h> | |
14 | #include <linux/highmem.h> | |
15 | #include <linux/page_idle.h> | |
16 | #include <linux/pagewalk.h> | |
17 | #include <linux/random.h> | |
18 | #include <linux/sched/mm.h> | |
19 | #include <linux/slab.h> | |
20 | ||
17ccae8b SP |
21 | #ifdef CONFIG_DAMON_VADDR_KUNIT_TEST |
22 | #undef DAMON_MIN_REGION | |
23 | #define DAMON_MIN_REGION 1 | |
24 | #endif | |
25 | ||
3f49584b SP |
26 | /* Get a random number in [l, r) */ |
27 | #define damon_rand(l, r) (l + prandom_u32_max(r - l)) | |
28 | ||
29 | /* | |
30 | * 't->id' should be the pointer to the relevant 'struct pid' having reference | |
31 | * count. Caller must put the returned task, unless it is NULL. | |
32 | */ | |
33 | #define damon_get_task_struct(t) \ | |
34 | (get_pid_task((struct pid *)t->id, PIDTYPE_PID)) | |
35 | ||
36 | /* | |
37 | * Get the mm_struct of the given target | |
38 | * | |
39 | * Caller _must_ put the mm_struct after use, unless it is NULL. | |
40 | * | |
41 | * Returns the mm_struct of the target on success, NULL on failure | |
42 | */ | |
43 | static struct mm_struct *damon_get_mm(struct damon_target *t) | |
44 | { | |
45 | struct task_struct *task; | |
46 | struct mm_struct *mm; | |
47 | ||
48 | task = damon_get_task_struct(t); | |
49 | if (!task) | |
50 | return NULL; | |
51 | ||
52 | mm = get_task_mm(task); | |
53 | put_task_struct(task); | |
54 | return mm; | |
55 | } | |
56 | ||
57 | /* | |
58 | * Functions for the initial monitoring target regions construction | |
59 | */ | |
60 | ||
61 | /* | |
62 | * Size-evenly split a region into 'nr_pieces' small regions | |
63 | * | |
64 | * Returns 0 on success, or negative error code otherwise. | |
65 | */ | |
66 | static int damon_va_evenly_split_region(struct damon_target *t, | |
67 | struct damon_region *r, unsigned int nr_pieces) | |
68 | { | |
69 | unsigned long sz_orig, sz_piece, orig_end; | |
70 | struct damon_region *n = NULL, *next; | |
71 | unsigned long start; | |
72 | ||
73 | if (!r || !nr_pieces) | |
74 | return -EINVAL; | |
75 | ||
76 | orig_end = r->ar.end; | |
77 | sz_orig = r->ar.end - r->ar.start; | |
78 | sz_piece = ALIGN_DOWN(sz_orig / nr_pieces, DAMON_MIN_REGION); | |
79 | ||
80 | if (!sz_piece) | |
81 | return -EINVAL; | |
82 | ||
83 | r->ar.end = r->ar.start + sz_piece; | |
84 | next = damon_next_region(r); | |
85 | for (start = r->ar.end; start + sz_piece <= orig_end; | |
86 | start += sz_piece) { | |
87 | n = damon_new_region(start, start + sz_piece); | |
88 | if (!n) | |
89 | return -ENOMEM; | |
90 | damon_insert_region(n, r, next, t); | |
91 | r = n; | |
92 | } | |
93 | /* complement last region for possible rounding error */ | |
94 | if (n) | |
95 | n->ar.end = orig_end; | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | static unsigned long sz_range(struct damon_addr_range *r) | |
101 | { | |
102 | return r->end - r->start; | |
103 | } | |
104 | ||
105 | static void swap_ranges(struct damon_addr_range *r1, | |
106 | struct damon_addr_range *r2) | |
107 | { | |
108 | struct damon_addr_range tmp; | |
109 | ||
110 | tmp = *r1; | |
111 | *r1 = *r2; | |
112 | *r2 = tmp; | |
113 | } | |
114 | ||
115 | /* | |
116 | * Find three regions separated by two biggest unmapped regions | |
117 | * | |
118 | * vma the head vma of the target address space | |
119 | * regions an array of three address ranges that results will be saved | |
120 | * | |
121 | * This function receives an address space and finds three regions in it which | |
122 | * separated by the two biggest unmapped regions in the space. Please refer to | |
123 | * below comments of '__damon_va_init_regions()' function to know why this is | |
124 | * necessary. | |
125 | * | |
126 | * Returns 0 if success, or negative error code otherwise. | |
127 | */ | |
128 | static int __damon_va_three_regions(struct vm_area_struct *vma, | |
129 | struct damon_addr_range regions[3]) | |
130 | { | |
131 | struct damon_addr_range gap = {0}, first_gap = {0}, second_gap = {0}; | |
132 | struct vm_area_struct *last_vma = NULL; | |
133 | unsigned long start = 0; | |
134 | struct rb_root rbroot; | |
135 | ||
136 | /* Find two biggest gaps so that first_gap > second_gap > others */ | |
137 | for (; vma; vma = vma->vm_next) { | |
138 | if (!last_vma) { | |
139 | start = vma->vm_start; | |
140 | goto next; | |
141 | } | |
142 | ||
143 | if (vma->rb_subtree_gap <= sz_range(&second_gap)) { | |
144 | rbroot.rb_node = &vma->vm_rb; | |
145 | vma = rb_entry(rb_last(&rbroot), | |
146 | struct vm_area_struct, vm_rb); | |
147 | goto next; | |
148 | } | |
149 | ||
150 | gap.start = last_vma->vm_end; | |
151 | gap.end = vma->vm_start; | |
152 | if (sz_range(&gap) > sz_range(&second_gap)) { | |
153 | swap_ranges(&gap, &second_gap); | |
154 | if (sz_range(&second_gap) > sz_range(&first_gap)) | |
155 | swap_ranges(&second_gap, &first_gap); | |
156 | } | |
157 | next: | |
158 | last_vma = vma; | |
159 | } | |
160 | ||
161 | if (!sz_range(&second_gap) || !sz_range(&first_gap)) | |
162 | return -EINVAL; | |
163 | ||
164 | /* Sort the two biggest gaps by address */ | |
165 | if (first_gap.start > second_gap.start) | |
166 | swap_ranges(&first_gap, &second_gap); | |
167 | ||
168 | /* Store the result */ | |
169 | regions[0].start = ALIGN(start, DAMON_MIN_REGION); | |
170 | regions[0].end = ALIGN(first_gap.start, DAMON_MIN_REGION); | |
171 | regions[1].start = ALIGN(first_gap.end, DAMON_MIN_REGION); | |
172 | regions[1].end = ALIGN(second_gap.start, DAMON_MIN_REGION); | |
173 | regions[2].start = ALIGN(second_gap.end, DAMON_MIN_REGION); | |
174 | regions[2].end = ALIGN(last_vma->vm_end, DAMON_MIN_REGION); | |
175 | ||
176 | return 0; | |
177 | } | |
178 | ||
179 | /* | |
180 | * Get the three regions in the given target (task) | |
181 | * | |
182 | * Returns 0 on success, negative error code otherwise. | |
183 | */ | |
184 | static int damon_va_three_regions(struct damon_target *t, | |
185 | struct damon_addr_range regions[3]) | |
186 | { | |
187 | struct mm_struct *mm; | |
188 | int rc; | |
189 | ||
190 | mm = damon_get_mm(t); | |
191 | if (!mm) | |
192 | return -EINVAL; | |
193 | ||
194 | mmap_read_lock(mm); | |
195 | rc = __damon_va_three_regions(mm->mmap, regions); | |
196 | mmap_read_unlock(mm); | |
197 | ||
198 | mmput(mm); | |
199 | return rc; | |
200 | } | |
201 | ||
202 | /* | |
203 | * Initialize the monitoring target regions for the given target (task) | |
204 | * | |
205 | * t the given target | |
206 | * | |
207 | * Because only a number of small portions of the entire address space | |
208 | * is actually mapped to the memory and accessed, monitoring the unmapped | |
209 | * regions is wasteful. That said, because we can deal with small noises, | |
210 | * tracking every mapping is not strictly required but could even incur a high | |
211 | * overhead if the mapping frequently changes or the number of mappings is | |
212 | * high. The adaptive regions adjustment mechanism will further help to deal | |
213 | * with the noise by simply identifying the unmapped areas as a region that | |
214 | * has no access. Moreover, applying the real mappings that would have many | |
215 | * unmapped areas inside will make the adaptive mechanism quite complex. That | |
216 | * said, too huge unmapped areas inside the monitoring target should be removed | |
217 | * to not take the time for the adaptive mechanism. | |
218 | * | |
219 | * For the reason, we convert the complex mappings to three distinct regions | |
220 | * that cover every mapped area of the address space. Also the two gaps | |
221 | * between the three regions are the two biggest unmapped areas in the given | |
222 | * address space. In detail, this function first identifies the start and the | |
223 | * end of the mappings and the two biggest unmapped areas of the address space. | |
224 | * Then, it constructs the three regions as below: | |
225 | * | |
226 | * [mappings[0]->start, big_two_unmapped_areas[0]->start) | |
227 | * [big_two_unmapped_areas[0]->end, big_two_unmapped_areas[1]->start) | |
228 | * [big_two_unmapped_areas[1]->end, mappings[nr_mappings - 1]->end) | |
229 | * | |
230 | * As usual memory map of processes is as below, the gap between the heap and | |
231 | * the uppermost mmap()-ed region, and the gap between the lowermost mmap()-ed | |
232 | * region and the stack will be two biggest unmapped regions. Because these | |
233 | * gaps are exceptionally huge areas in usual address space, excluding these | |
234 | * two biggest unmapped regions will be sufficient to make a trade-off. | |
235 | * | |
236 | * <heap> | |
237 | * <BIG UNMAPPED REGION 1> | |
238 | * <uppermost mmap()-ed region> | |
239 | * (other mmap()-ed regions and small unmapped regions) | |
240 | * <lowermost mmap()-ed region> | |
241 | * <BIG UNMAPPED REGION 2> | |
242 | * <stack> | |
243 | */ | |
244 | static void __damon_va_init_regions(struct damon_ctx *ctx, | |
245 | struct damon_target *t) | |
246 | { | |
247 | struct damon_region *r; | |
248 | struct damon_addr_range regions[3]; | |
249 | unsigned long sz = 0, nr_pieces; | |
250 | int i; | |
251 | ||
252 | if (damon_va_three_regions(t, regions)) { | |
253 | pr_err("Failed to get three regions of target %lu\n", t->id); | |
254 | return; | |
255 | } | |
256 | ||
257 | for (i = 0; i < 3; i++) | |
258 | sz += regions[i].end - regions[i].start; | |
259 | if (ctx->min_nr_regions) | |
260 | sz /= ctx->min_nr_regions; | |
261 | if (sz < DAMON_MIN_REGION) | |
262 | sz = DAMON_MIN_REGION; | |
263 | ||
264 | /* Set the initial three regions of the target */ | |
265 | for (i = 0; i < 3; i++) { | |
266 | r = damon_new_region(regions[i].start, regions[i].end); | |
267 | if (!r) { | |
268 | pr_err("%d'th init region creation failed\n", i); | |
269 | return; | |
270 | } | |
271 | damon_add_region(r, t); | |
272 | ||
273 | nr_pieces = (regions[i].end - regions[i].start) / sz; | |
274 | damon_va_evenly_split_region(t, r, nr_pieces); | |
275 | } | |
276 | } | |
277 | ||
278 | /* Initialize '->regions_list' of every target (task) */ | |
279 | void damon_va_init(struct damon_ctx *ctx) | |
280 | { | |
281 | struct damon_target *t; | |
282 | ||
283 | damon_for_each_target(t, ctx) { | |
284 | /* the user may set the target regions as they want */ | |
285 | if (!damon_nr_regions(t)) | |
286 | __damon_va_init_regions(ctx, t); | |
287 | } | |
288 | } | |
289 | ||
290 | /* | |
291 | * Functions for the dynamic monitoring target regions update | |
292 | */ | |
293 | ||
294 | /* | |
295 | * Check whether a region is intersecting an address range | |
296 | * | |
297 | * Returns true if it is. | |
298 | */ | |
299 | static bool damon_intersect(struct damon_region *r, struct damon_addr_range *re) | |
300 | { | |
301 | return !(r->ar.end <= re->start || re->end <= r->ar.start); | |
302 | } | |
303 | ||
304 | /* | |
305 | * Update damon regions for the three big regions of the given target | |
306 | * | |
307 | * t the given target | |
308 | * bregions the three big regions of the target | |
309 | */ | |
310 | static void damon_va_apply_three_regions(struct damon_target *t, | |
311 | struct damon_addr_range bregions[3]) | |
312 | { | |
313 | struct damon_region *r, *next; | |
314 | unsigned int i = 0; | |
315 | ||
316 | /* Remove regions which are not in the three big regions now */ | |
317 | damon_for_each_region_safe(r, next, t) { | |
318 | for (i = 0; i < 3; i++) { | |
319 | if (damon_intersect(r, &bregions[i])) | |
320 | break; | |
321 | } | |
322 | if (i == 3) | |
323 | damon_destroy_region(r, t); | |
324 | } | |
325 | ||
326 | /* Adjust intersecting regions to fit with the three big regions */ | |
327 | for (i = 0; i < 3; i++) { | |
328 | struct damon_region *first = NULL, *last; | |
329 | struct damon_region *newr; | |
330 | struct damon_addr_range *br; | |
331 | ||
332 | br = &bregions[i]; | |
333 | /* Get the first and last regions which intersects with br */ | |
334 | damon_for_each_region(r, t) { | |
335 | if (damon_intersect(r, br)) { | |
336 | if (!first) | |
337 | first = r; | |
338 | last = r; | |
339 | } | |
340 | if (r->ar.start >= br->end) | |
341 | break; | |
342 | } | |
343 | if (!first) { | |
344 | /* no damon_region intersects with this big region */ | |
345 | newr = damon_new_region( | |
346 | ALIGN_DOWN(br->start, | |
347 | DAMON_MIN_REGION), | |
348 | ALIGN(br->end, DAMON_MIN_REGION)); | |
349 | if (!newr) | |
350 | continue; | |
351 | damon_insert_region(newr, damon_prev_region(r), r, t); | |
352 | } else { | |
353 | first->ar.start = ALIGN_DOWN(br->start, | |
354 | DAMON_MIN_REGION); | |
355 | last->ar.end = ALIGN(br->end, DAMON_MIN_REGION); | |
356 | } | |
357 | } | |
358 | } | |
359 | ||
360 | /* | |
361 | * Update regions for current memory mappings | |
362 | */ | |
363 | void damon_va_update(struct damon_ctx *ctx) | |
364 | { | |
365 | struct damon_addr_range three_regions[3]; | |
366 | struct damon_target *t; | |
367 | ||
368 | damon_for_each_target(t, ctx) { | |
369 | if (damon_va_three_regions(t, three_regions)) | |
370 | continue; | |
371 | damon_va_apply_three_regions(t, three_regions); | |
372 | } | |
373 | } | |
374 | ||
375 | /* | |
376 | * Get an online page for a pfn if it's in the LRU list. Otherwise, returns | |
377 | * NULL. | |
378 | * | |
379 | * The body of this function is stolen from the 'page_idle_get_page()'. We | |
380 | * steal rather than reuse it because the code is quite simple. | |
381 | */ | |
382 | static struct page *damon_get_page(unsigned long pfn) | |
383 | { | |
384 | struct page *page = pfn_to_online_page(pfn); | |
385 | ||
386 | if (!page || !PageLRU(page) || !get_page_unless_zero(page)) | |
387 | return NULL; | |
388 | ||
389 | if (unlikely(!PageLRU(page))) { | |
390 | put_page(page); | |
391 | page = NULL; | |
392 | } | |
393 | return page; | |
394 | } | |
395 | ||
396 | static void damon_ptep_mkold(pte_t *pte, struct mm_struct *mm, | |
397 | unsigned long addr) | |
398 | { | |
399 | bool referenced = false; | |
400 | struct page *page = damon_get_page(pte_pfn(*pte)); | |
401 | ||
402 | if (!page) | |
403 | return; | |
404 | ||
405 | if (pte_young(*pte)) { | |
406 | referenced = true; | |
407 | *pte = pte_mkold(*pte); | |
408 | } | |
409 | ||
410 | #ifdef CONFIG_MMU_NOTIFIER | |
411 | if (mmu_notifier_clear_young(mm, addr, addr + PAGE_SIZE)) | |
412 | referenced = true; | |
413 | #endif /* CONFIG_MMU_NOTIFIER */ | |
414 | ||
415 | if (referenced) | |
416 | set_page_young(page); | |
417 | ||
418 | set_page_idle(page); | |
419 | put_page(page); | |
420 | } | |
421 | ||
422 | static void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, | |
423 | unsigned long addr) | |
424 | { | |
425 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
426 | bool referenced = false; | |
427 | struct page *page = damon_get_page(pmd_pfn(*pmd)); | |
428 | ||
429 | if (!page) | |
430 | return; | |
431 | ||
432 | if (pmd_young(*pmd)) { | |
433 | referenced = true; | |
434 | *pmd = pmd_mkold(*pmd); | |
435 | } | |
436 | ||
437 | #ifdef CONFIG_MMU_NOTIFIER | |
438 | if (mmu_notifier_clear_young(mm, addr, | |
439 | addr + ((1UL) << HPAGE_PMD_SHIFT))) | |
440 | referenced = true; | |
441 | #endif /* CONFIG_MMU_NOTIFIER */ | |
442 | ||
443 | if (referenced) | |
444 | set_page_young(page); | |
445 | ||
446 | set_page_idle(page); | |
447 | put_page(page); | |
448 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ | |
449 | } | |
450 | ||
451 | static int damon_mkold_pmd_entry(pmd_t *pmd, unsigned long addr, | |
452 | unsigned long next, struct mm_walk *walk) | |
453 | { | |
454 | pte_t *pte; | |
455 | spinlock_t *ptl; | |
456 | ||
457 | if (pmd_huge(*pmd)) { | |
458 | ptl = pmd_lock(walk->mm, pmd); | |
459 | if (pmd_huge(*pmd)) { | |
460 | damon_pmdp_mkold(pmd, walk->mm, addr); | |
461 | spin_unlock(ptl); | |
462 | return 0; | |
463 | } | |
464 | spin_unlock(ptl); | |
465 | } | |
466 | ||
467 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) | |
468 | return 0; | |
469 | pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); | |
470 | if (!pte_present(*pte)) | |
471 | goto out; | |
472 | damon_ptep_mkold(pte, walk->mm, addr); | |
473 | out: | |
474 | pte_unmap_unlock(pte, ptl); | |
475 | return 0; | |
476 | } | |
477 | ||
478 | static struct mm_walk_ops damon_mkold_ops = { | |
479 | .pmd_entry = damon_mkold_pmd_entry, | |
480 | }; | |
481 | ||
482 | static void damon_va_mkold(struct mm_struct *mm, unsigned long addr) | |
483 | { | |
484 | mmap_read_lock(mm); | |
485 | walk_page_range(mm, addr, addr + 1, &damon_mkold_ops, NULL); | |
486 | mmap_read_unlock(mm); | |
487 | } | |
488 | ||
489 | /* | |
490 | * Functions for the access checking of the regions | |
491 | */ | |
492 | ||
493 | static void damon_va_prepare_access_check(struct damon_ctx *ctx, | |
494 | struct mm_struct *mm, struct damon_region *r) | |
495 | { | |
496 | r->sampling_addr = damon_rand(r->ar.start, r->ar.end); | |
497 | ||
498 | damon_va_mkold(mm, r->sampling_addr); | |
499 | } | |
500 | ||
501 | void damon_va_prepare_access_checks(struct damon_ctx *ctx) | |
502 | { | |
503 | struct damon_target *t; | |
504 | struct mm_struct *mm; | |
505 | struct damon_region *r; | |
506 | ||
507 | damon_for_each_target(t, ctx) { | |
508 | mm = damon_get_mm(t); | |
509 | if (!mm) | |
510 | continue; | |
511 | damon_for_each_region(r, t) | |
512 | damon_va_prepare_access_check(ctx, mm, r); | |
513 | mmput(mm); | |
514 | } | |
515 | } | |
516 | ||
517 | struct damon_young_walk_private { | |
518 | unsigned long *page_sz; | |
519 | bool young; | |
520 | }; | |
521 | ||
522 | static int damon_young_pmd_entry(pmd_t *pmd, unsigned long addr, | |
523 | unsigned long next, struct mm_walk *walk) | |
524 | { | |
525 | pte_t *pte; | |
526 | spinlock_t *ptl; | |
527 | struct page *page; | |
528 | struct damon_young_walk_private *priv = walk->private; | |
529 | ||
530 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
531 | if (pmd_huge(*pmd)) { | |
532 | ptl = pmd_lock(walk->mm, pmd); | |
533 | if (!pmd_huge(*pmd)) { | |
534 | spin_unlock(ptl); | |
535 | goto regular_page; | |
536 | } | |
537 | page = damon_get_page(pmd_pfn(*pmd)); | |
538 | if (!page) | |
539 | goto huge_out; | |
540 | if (pmd_young(*pmd) || !page_is_idle(page) || | |
541 | mmu_notifier_test_young(walk->mm, | |
542 | addr)) { | |
543 | *priv->page_sz = ((1UL) << HPAGE_PMD_SHIFT); | |
544 | priv->young = true; | |
545 | } | |
546 | put_page(page); | |
547 | huge_out: | |
548 | spin_unlock(ptl); | |
549 | return 0; | |
550 | } | |
551 | ||
552 | regular_page: | |
553 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ | |
554 | ||
555 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) | |
556 | return -EINVAL; | |
557 | pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); | |
558 | if (!pte_present(*pte)) | |
559 | goto out; | |
560 | page = damon_get_page(pte_pfn(*pte)); | |
561 | if (!page) | |
562 | goto out; | |
563 | if (pte_young(*pte) || !page_is_idle(page) || | |
564 | mmu_notifier_test_young(walk->mm, addr)) { | |
565 | *priv->page_sz = PAGE_SIZE; | |
566 | priv->young = true; | |
567 | } | |
568 | put_page(page); | |
569 | out: | |
570 | pte_unmap_unlock(pte, ptl); | |
571 | return 0; | |
572 | } | |
573 | ||
574 | static struct mm_walk_ops damon_young_ops = { | |
575 | .pmd_entry = damon_young_pmd_entry, | |
576 | }; | |
577 | ||
578 | static bool damon_va_young(struct mm_struct *mm, unsigned long addr, | |
579 | unsigned long *page_sz) | |
580 | { | |
581 | struct damon_young_walk_private arg = { | |
582 | .page_sz = page_sz, | |
583 | .young = false, | |
584 | }; | |
585 | ||
586 | mmap_read_lock(mm); | |
587 | walk_page_range(mm, addr, addr + 1, &damon_young_ops, &arg); | |
588 | mmap_read_unlock(mm); | |
589 | return arg.young; | |
590 | } | |
591 | ||
592 | /* | |
593 | * Check whether the region was accessed after the last preparation | |
594 | * | |
595 | * mm 'mm_struct' for the given virtual address space | |
596 | * r the region to be checked | |
597 | */ | |
598 | static void damon_va_check_access(struct damon_ctx *ctx, | |
599 | struct mm_struct *mm, struct damon_region *r) | |
600 | { | |
601 | static struct mm_struct *last_mm; | |
602 | static unsigned long last_addr; | |
603 | static unsigned long last_page_sz = PAGE_SIZE; | |
604 | static bool last_accessed; | |
605 | ||
606 | /* If the region is in the last checked page, reuse the result */ | |
607 | if (mm == last_mm && (ALIGN_DOWN(last_addr, last_page_sz) == | |
608 | ALIGN_DOWN(r->sampling_addr, last_page_sz))) { | |
609 | if (last_accessed) | |
610 | r->nr_accesses++; | |
611 | return; | |
612 | } | |
613 | ||
614 | last_accessed = damon_va_young(mm, r->sampling_addr, &last_page_sz); | |
615 | if (last_accessed) | |
616 | r->nr_accesses++; | |
617 | ||
618 | last_mm = mm; | |
619 | last_addr = r->sampling_addr; | |
620 | } | |
621 | ||
622 | unsigned int damon_va_check_accesses(struct damon_ctx *ctx) | |
623 | { | |
624 | struct damon_target *t; | |
625 | struct mm_struct *mm; | |
626 | struct damon_region *r; | |
627 | unsigned int max_nr_accesses = 0; | |
628 | ||
629 | damon_for_each_target(t, ctx) { | |
630 | mm = damon_get_mm(t); | |
631 | if (!mm) | |
632 | continue; | |
633 | damon_for_each_region(r, t) { | |
634 | damon_va_check_access(ctx, mm, r); | |
635 | max_nr_accesses = max(r->nr_accesses, max_nr_accesses); | |
636 | } | |
637 | mmput(mm); | |
638 | } | |
639 | ||
640 | return max_nr_accesses; | |
641 | } | |
642 | ||
643 | /* | |
644 | * Functions for the target validity check and cleanup | |
645 | */ | |
646 | ||
647 | bool damon_va_target_valid(void *target) | |
648 | { | |
649 | struct damon_target *t = target; | |
650 | struct task_struct *task; | |
651 | ||
652 | task = damon_get_task_struct(t); | |
653 | if (task) { | |
654 | put_task_struct(task); | |
655 | return true; | |
656 | } | |
657 | ||
658 | return false; | |
659 | } | |
660 | ||
661 | void damon_va_set_primitives(struct damon_ctx *ctx) | |
662 | { | |
663 | ctx->primitive.init = damon_va_init; | |
664 | ctx->primitive.update = damon_va_update; | |
665 | ctx->primitive.prepare_access_checks = damon_va_prepare_access_checks; | |
666 | ctx->primitive.check_accesses = damon_va_check_accesses; | |
667 | ctx->primitive.reset_aggregated = NULL; | |
668 | ctx->primitive.target_valid = damon_va_target_valid; | |
669 | ctx->primitive.cleanup = NULL; | |
670 | } | |
17ccae8b SP |
671 | |
672 | #include "vaddr-test.h" |