xref: /linux/mm/damon/paddr.c (revision 9c5968db9e625019a0ee5226c7eebef5519d366a) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * DAMON Primitives for The Physical Address Space
4  *
5  * Author: SeongJae Park <sj@kernel.org>
6  */
7 
8 #define pr_fmt(fmt) "damon-pa: " fmt
9 
10 #include <linux/mmu_notifier.h>
11 #include <linux/page_idle.h>
12 #include <linux/pagemap.h>
13 #include <linux/rmap.h>
14 #include <linux/swap.h>
15 #include <linux/memory-tiers.h>
16 #include <linux/migrate.h>
17 #include <linux/mm_inline.h>
18 
19 #include "../internal.h"
20 #include "ops-common.h"
21 
22 static bool damon_folio_mkold_one(struct folio *folio,
23 		struct vm_area_struct *vma, unsigned long addr, void *arg)
24 {
25 	DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0);
26 
27 	while (page_vma_mapped_walk(&pvmw)) {
28 		addr = pvmw.address;
29 		if (pvmw.pte)
30 			damon_ptep_mkold(pvmw.pte, vma, addr);
31 		else
32 			damon_pmdp_mkold(pvmw.pmd, vma, addr);
33 	}
34 	return true;
35 }
36 
37 static void damon_folio_mkold(struct folio *folio)
38 {
39 	struct rmap_walk_control rwc = {
40 		.rmap_one = damon_folio_mkold_one,
41 		.anon_lock = folio_lock_anon_vma_read,
42 	};
43 	bool need_lock;
44 
45 	if (!folio_mapped(folio) || !folio_raw_mapping(folio)) {
46 		folio_set_idle(folio);
47 		return;
48 	}
49 
50 	need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
51 	if (need_lock && !folio_trylock(folio))
52 		return;
53 
54 	rmap_walk(folio, &rwc);
55 
56 	if (need_lock)
57 		folio_unlock(folio);
58 
59 }
60 
61 static void damon_pa_mkold(unsigned long paddr)
62 {
63 	struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
64 
65 	if (!folio)
66 		return;
67 
68 	damon_folio_mkold(folio);
69 	folio_put(folio);
70 }
71 
72 static void __damon_pa_prepare_access_check(struct damon_region *r)
73 {
74 	r->sampling_addr = damon_rand(r->ar.start, r->ar.end);
75 
76 	damon_pa_mkold(r->sampling_addr);
77 }
78 
79 static void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
80 {
81 	struct damon_target *t;
82 	struct damon_region *r;
83 
84 	damon_for_each_target(t, ctx) {
85 		damon_for_each_region(r, t)
86 			__damon_pa_prepare_access_check(r);
87 	}
88 }
89 
90 static bool damon_folio_young_one(struct folio *folio,
91 		struct vm_area_struct *vma, unsigned long addr, void *arg)
92 {
93 	bool *accessed = arg;
94 	DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0);
95 
96 	*accessed = false;
97 	while (page_vma_mapped_walk(&pvmw)) {
98 		addr = pvmw.address;
99 		if (pvmw.pte) {
100 			*accessed = pte_young(ptep_get(pvmw.pte)) ||
101 				!folio_test_idle(folio) ||
102 				mmu_notifier_test_young(vma->vm_mm, addr);
103 		} else {
104 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
105 			*accessed = pmd_young(pmdp_get(pvmw.pmd)) ||
106 				!folio_test_idle(folio) ||
107 				mmu_notifier_test_young(vma->vm_mm, addr);
108 #else
109 			WARN_ON_ONCE(1);
110 #endif	/* CONFIG_TRANSPARENT_HUGEPAGE */
111 		}
112 		if (*accessed) {
113 			page_vma_mapped_walk_done(&pvmw);
114 			break;
115 		}
116 	}
117 
118 	/* If accessed, stop walking */
119 	return *accessed == false;
120 }
121 
122 static bool damon_folio_young(struct folio *folio)
123 {
124 	bool accessed = false;
125 	struct rmap_walk_control rwc = {
126 		.arg = &accessed,
127 		.rmap_one = damon_folio_young_one,
128 		.anon_lock = folio_lock_anon_vma_read,
129 	};
130 	bool need_lock;
131 
132 	if (!folio_mapped(folio) || !folio_raw_mapping(folio)) {
133 		if (folio_test_idle(folio))
134 			return false;
135 		else
136 			return true;
137 	}
138 
139 	need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
140 	if (need_lock && !folio_trylock(folio))
141 		return false;
142 
143 	rmap_walk(folio, &rwc);
144 
145 	if (need_lock)
146 		folio_unlock(folio);
147 
148 	return accessed;
149 }
150 
151 static bool damon_pa_young(unsigned long paddr, unsigned long *folio_sz)
152 {
153 	struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
154 	bool accessed;
155 
156 	if (!folio)
157 		return false;
158 
159 	accessed = damon_folio_young(folio);
160 	*folio_sz = folio_size(folio);
161 	folio_put(folio);
162 	return accessed;
163 }
164 
165 static void __damon_pa_check_access(struct damon_region *r,
166 		struct damon_attrs *attrs)
167 {
168 	static unsigned long last_addr;
169 	static unsigned long last_folio_sz = PAGE_SIZE;
170 	static bool last_accessed;
171 
172 	/* If the region is in the last checked page, reuse the result */
173 	if (ALIGN_DOWN(last_addr, last_folio_sz) ==
174 				ALIGN_DOWN(r->sampling_addr, last_folio_sz)) {
175 		damon_update_region_access_rate(r, last_accessed, attrs);
176 		return;
177 	}
178 
179 	last_accessed = damon_pa_young(r->sampling_addr, &last_folio_sz);
180 	damon_update_region_access_rate(r, last_accessed, attrs);
181 
182 	last_addr = r->sampling_addr;
183 }
184 
185 static unsigned int damon_pa_check_accesses(struct damon_ctx *ctx)
186 {
187 	struct damon_target *t;
188 	struct damon_region *r;
189 	unsigned int max_nr_accesses = 0;
190 
191 	damon_for_each_target(t, ctx) {
192 		damon_for_each_region(r, t) {
193 			__damon_pa_check_access(r, &ctx->attrs);
194 			max_nr_accesses = max(r->nr_accesses, max_nr_accesses);
195 		}
196 	}
197 
198 	return max_nr_accesses;
199 }
200 
201 static bool damos_pa_filter_match(struct damos_filter *filter,
202 		struct folio *folio)
203 {
204 	bool matched = false;
205 	struct mem_cgroup *memcg;
206 
207 	switch (filter->type) {
208 	case DAMOS_FILTER_TYPE_ANON:
209 		matched = folio_test_anon(folio);
210 		break;
211 	case DAMOS_FILTER_TYPE_MEMCG:
212 		rcu_read_lock();
213 		memcg = folio_memcg_check(folio);
214 		if (!memcg)
215 			matched = false;
216 		else
217 			matched = filter->memcg_id == mem_cgroup_id(memcg);
218 		rcu_read_unlock();
219 		break;
220 	case DAMOS_FILTER_TYPE_YOUNG:
221 		matched = damon_folio_young(folio);
222 		if (matched)
223 			damon_folio_mkold(folio);
224 		break;
225 	default:
226 		break;
227 	}
228 
229 	return matched == filter->matching;
230 }
231 
232 /*
233  * damos_pa_filter_out - Return true if the page should be filtered out.
234  */
235 static bool damos_pa_filter_out(struct damos *scheme, struct folio *folio)
236 {
237 	struct damos_filter *filter;
238 
239 	damos_for_each_filter(filter, scheme) {
240 		if (damos_pa_filter_match(filter, folio))
241 			return !filter->allow;
242 	}
243 	return false;
244 }
245 
246 static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s,
247 		unsigned long *sz_filter_passed)
248 {
249 	unsigned long addr, applied;
250 	LIST_HEAD(folio_list);
251 	bool install_young_filter = true;
252 	struct damos_filter *filter;
253 
254 	/* check access in page level again by default */
255 	damos_for_each_filter(filter, s) {
256 		if (filter->type == DAMOS_FILTER_TYPE_YOUNG) {
257 			install_young_filter = false;
258 			break;
259 		}
260 	}
261 	if (install_young_filter) {
262 		filter = damos_new_filter(
263 				DAMOS_FILTER_TYPE_YOUNG, true, false);
264 		if (!filter)
265 			return 0;
266 		damos_add_filter(s, filter);
267 	}
268 
269 	for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
270 		struct folio *folio = damon_get_folio(PHYS_PFN(addr));
271 
272 		if (!folio)
273 			continue;
274 
275 		if (damos_pa_filter_out(s, folio))
276 			goto put_folio;
277 		else
278 			*sz_filter_passed += folio_size(folio);
279 
280 		folio_clear_referenced(folio);
281 		folio_test_clear_young(folio);
282 		if (!folio_isolate_lru(folio))
283 			goto put_folio;
284 		if (folio_test_unevictable(folio))
285 			folio_putback_lru(folio);
286 		else
287 			list_add(&folio->lru, &folio_list);
288 put_folio:
289 		folio_put(folio);
290 	}
291 	if (install_young_filter)
292 		damos_destroy_filter(filter);
293 	applied = reclaim_pages(&folio_list);
294 	cond_resched();
295 	return applied * PAGE_SIZE;
296 }
297 
298 static inline unsigned long damon_pa_mark_accessed_or_deactivate(
299 		struct damon_region *r, struct damos *s, bool mark_accessed,
300 		unsigned long *sz_filter_passed)
301 {
302 	unsigned long addr, applied = 0;
303 
304 	for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
305 		struct folio *folio = damon_get_folio(PHYS_PFN(addr));
306 
307 		if (!folio)
308 			continue;
309 
310 		if (damos_pa_filter_out(s, folio))
311 			goto put_folio;
312 		else
313 			*sz_filter_passed += folio_size(folio);
314 
315 		if (mark_accessed)
316 			folio_mark_accessed(folio);
317 		else
318 			folio_deactivate(folio);
319 		applied += folio_nr_pages(folio);
320 put_folio:
321 		folio_put(folio);
322 	}
323 	return applied * PAGE_SIZE;
324 }
325 
326 static unsigned long damon_pa_mark_accessed(struct damon_region *r,
327 	struct damos *s, unsigned long *sz_filter_passed)
328 {
329 	return damon_pa_mark_accessed_or_deactivate(r, s, true,
330 			sz_filter_passed);
331 }
332 
333 static unsigned long damon_pa_deactivate_pages(struct damon_region *r,
334 	struct damos *s, unsigned long *sz_filter_passed)
335 {
336 	return damon_pa_mark_accessed_or_deactivate(r, s, false,
337 			sz_filter_passed);
338 }
339 
340 static unsigned int __damon_pa_migrate_folio_list(
341 		struct list_head *migrate_folios, struct pglist_data *pgdat,
342 		int target_nid)
343 {
344 	unsigned int nr_succeeded = 0;
345 	nodemask_t allowed_mask = NODE_MASK_NONE;
346 	struct migration_target_control mtc = {
347 		/*
348 		 * Allocate from 'node', or fail quickly and quietly.
349 		 * When this happens, 'page' will likely just be discarded
350 		 * instead of migrated.
351 		 */
352 		.gfp_mask = (GFP_HIGHUSER_MOVABLE & ~__GFP_RECLAIM) |
353 			__GFP_NOWARN | __GFP_NOMEMALLOC | GFP_NOWAIT,
354 		.nid = target_nid,
355 		.nmask = &allowed_mask
356 	};
357 
358 	if (pgdat->node_id == target_nid || target_nid == NUMA_NO_NODE)
359 		return 0;
360 
361 	if (list_empty(migrate_folios))
362 		return 0;
363 
364 	/* Migration ignores all cpuset and mempolicy settings */
365 	migrate_pages(migrate_folios, alloc_migrate_folio, NULL,
366 		      (unsigned long)&mtc, MIGRATE_ASYNC, MR_DAMON,
367 		      &nr_succeeded);
368 
369 	return nr_succeeded;
370 }
371 
372 static unsigned int damon_pa_migrate_folio_list(struct list_head *folio_list,
373 						struct pglist_data *pgdat,
374 						int target_nid)
375 {
376 	unsigned int nr_migrated = 0;
377 	struct folio *folio;
378 	LIST_HEAD(ret_folios);
379 	LIST_HEAD(migrate_folios);
380 
381 	while (!list_empty(folio_list)) {
382 		struct folio *folio;
383 
384 		cond_resched();
385 
386 		folio = lru_to_folio(folio_list);
387 		list_del(&folio->lru);
388 
389 		if (!folio_trylock(folio))
390 			goto keep;
391 
392 		/* Relocate its contents to another node. */
393 		list_add(&folio->lru, &migrate_folios);
394 		folio_unlock(folio);
395 		continue;
396 keep:
397 		list_add(&folio->lru, &ret_folios);
398 	}
399 	/* 'folio_list' is always empty here */
400 
401 	/* Migrate folios selected for migration */
402 	nr_migrated += __damon_pa_migrate_folio_list(
403 			&migrate_folios, pgdat, target_nid);
404 	/*
405 	 * Folios that could not be migrated are still in @migrate_folios.  Add
406 	 * those back on @folio_list
407 	 */
408 	if (!list_empty(&migrate_folios))
409 		list_splice_init(&migrate_folios, folio_list);
410 
411 	try_to_unmap_flush();
412 
413 	list_splice(&ret_folios, folio_list);
414 
415 	while (!list_empty(folio_list)) {
416 		folio = lru_to_folio(folio_list);
417 		list_del(&folio->lru);
418 		folio_putback_lru(folio);
419 	}
420 
421 	return nr_migrated;
422 }
423 
424 static unsigned long damon_pa_migrate_pages(struct list_head *folio_list,
425 					    int target_nid)
426 {
427 	int nid;
428 	unsigned long nr_migrated = 0;
429 	LIST_HEAD(node_folio_list);
430 	unsigned int noreclaim_flag;
431 
432 	if (list_empty(folio_list))
433 		return nr_migrated;
434 
435 	noreclaim_flag = memalloc_noreclaim_save();
436 
437 	nid = folio_nid(lru_to_folio(folio_list));
438 	do {
439 		struct folio *folio = lru_to_folio(folio_list);
440 
441 		if (nid == folio_nid(folio)) {
442 			list_move(&folio->lru, &node_folio_list);
443 			continue;
444 		}
445 
446 		nr_migrated += damon_pa_migrate_folio_list(&node_folio_list,
447 							   NODE_DATA(nid),
448 							   target_nid);
449 		nid = folio_nid(lru_to_folio(folio_list));
450 	} while (!list_empty(folio_list));
451 
452 	nr_migrated += damon_pa_migrate_folio_list(&node_folio_list,
453 						   NODE_DATA(nid),
454 						   target_nid);
455 
456 	memalloc_noreclaim_restore(noreclaim_flag);
457 
458 	return nr_migrated;
459 }
460 
461 static unsigned long damon_pa_migrate(struct damon_region *r, struct damos *s,
462 		unsigned long *sz_filter_passed)
463 {
464 	unsigned long addr, applied;
465 	LIST_HEAD(folio_list);
466 
467 	for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
468 		struct folio *folio = damon_get_folio(PHYS_PFN(addr));
469 
470 		if (!folio)
471 			continue;
472 
473 		if (damos_pa_filter_out(s, folio))
474 			goto put_folio;
475 		else
476 			*sz_filter_passed += folio_size(folio);
477 
478 		if (!folio_isolate_lru(folio))
479 			goto put_folio;
480 		list_add(&folio->lru, &folio_list);
481 put_folio:
482 		folio_put(folio);
483 	}
484 	applied = damon_pa_migrate_pages(&folio_list, s->target_nid);
485 	cond_resched();
486 	return applied * PAGE_SIZE;
487 }
488 
489 static bool damon_pa_scheme_has_filter(struct damos *s)
490 {
491 	struct damos_filter *f;
492 
493 	damos_for_each_filter(f, s)
494 		return true;
495 	return false;
496 }
497 
498 static unsigned long damon_pa_stat(struct damon_region *r, struct damos *s,
499 		unsigned long *sz_filter_passed)
500 {
501 	unsigned long addr;
502 	LIST_HEAD(folio_list);
503 
504 	if (!damon_pa_scheme_has_filter(s))
505 		return 0;
506 
507 	addr = r->ar.start;
508 	while (addr < r->ar.end) {
509 		struct folio *folio = damon_get_folio(PHYS_PFN(addr));
510 
511 		if (!folio) {
512 			addr += PAGE_SIZE;
513 			continue;
514 		}
515 
516 		if (!damos_pa_filter_out(s, folio))
517 			*sz_filter_passed += folio_size(folio);
518 		addr += folio_size(folio);
519 		folio_put(folio);
520 	}
521 	return 0;
522 }
523 
524 static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
525 		struct damon_target *t, struct damon_region *r,
526 		struct damos *scheme, unsigned long *sz_filter_passed)
527 {
528 	switch (scheme->action) {
529 	case DAMOS_PAGEOUT:
530 		return damon_pa_pageout(r, scheme, sz_filter_passed);
531 	case DAMOS_LRU_PRIO:
532 		return damon_pa_mark_accessed(r, scheme, sz_filter_passed);
533 	case DAMOS_LRU_DEPRIO:
534 		return damon_pa_deactivate_pages(r, scheme, sz_filter_passed);
535 	case DAMOS_MIGRATE_HOT:
536 	case DAMOS_MIGRATE_COLD:
537 		return damon_pa_migrate(r, scheme, sz_filter_passed);
538 	case DAMOS_STAT:
539 		return damon_pa_stat(r, scheme, sz_filter_passed);
540 	default:
541 		/* DAMOS actions that not yet supported by 'paddr'. */
542 		break;
543 	}
544 	return 0;
545 }
546 
547 static int damon_pa_scheme_score(struct damon_ctx *context,
548 		struct damon_target *t, struct damon_region *r,
549 		struct damos *scheme)
550 {
551 	switch (scheme->action) {
552 	case DAMOS_PAGEOUT:
553 		return damon_cold_score(context, r, scheme);
554 	case DAMOS_LRU_PRIO:
555 		return damon_hot_score(context, r, scheme);
556 	case DAMOS_LRU_DEPRIO:
557 		return damon_cold_score(context, r, scheme);
558 	case DAMOS_MIGRATE_HOT:
559 		return damon_hot_score(context, r, scheme);
560 	case DAMOS_MIGRATE_COLD:
561 		return damon_cold_score(context, r, scheme);
562 	default:
563 		break;
564 	}
565 
566 	return DAMOS_MAX_SCORE;
567 }
568 
569 static int __init damon_pa_initcall(void)
570 {
571 	struct damon_operations ops = {
572 		.id = DAMON_OPS_PADDR,
573 		.init = NULL,
574 		.update = NULL,
575 		.prepare_access_checks = damon_pa_prepare_access_checks,
576 		.check_accesses = damon_pa_check_accesses,
577 		.reset_aggregated = NULL,
578 		.target_valid = NULL,
579 		.cleanup = NULL,
580 		.apply_scheme = damon_pa_apply_scheme,
581 		.get_scheme_score = damon_pa_scheme_score,
582 	};
583 
584 	return damon_register_ops(&ops);
585 };
586 
587 subsys_initcall(damon_pa_initcall);
588