summaryrefslogtreecommitdiff
path: root/mm/damon/paddr.c
blob: 21474ae63bc7a8807a79f074b89c9b5e998daafe (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
// SPDX-License-Identifier: GPL-2.0
/*
 * DAMON Primitives for The Physical Address Space
 *
 * Author: SeongJae Park <sj@kernel.org>
 */

#define pr_fmt(fmt) "damon-pa: " fmt

#include <linux/mmu_notifier.h>
#include <linux/page_idle.h>
#include <linux/pagemap.h>
#include <linux/rmap.h>
#include <linux/swap.h>

#include "../internal.h"
#include "ops-common.h"

static bool __damon_pa_mkold(struct folio *folio, struct vm_area_struct *vma,
		unsigned long addr, void *arg)
{
	DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0);

	while (page_vma_mapped_walk(&pvmw)) {
		addr = pvmw.address;
		if (pvmw.pte)
			damon_ptep_mkold(pvmw.pte, vma->vm_mm, addr);
		else
			damon_pmdp_mkold(pvmw.pmd, vma->vm_mm, addr);
	}
	return true;
}

static void damon_pa_mkold(unsigned long paddr)
{
	struct folio *folio;
	struct page *page = damon_get_page(PHYS_PFN(paddr));
	struct rmap_walk_control rwc = {
		.rmap_one = __damon_pa_mkold,
		.anon_lock = folio_lock_anon_vma_read,
	};
	bool need_lock;

	if (!page)
		return;
	folio = page_folio(page);

	if (!folio_mapped(folio) || !folio_raw_mapping(folio)) {
		folio_set_idle(folio);
		goto out;
	}

	need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
	if (need_lock && !folio_trylock(folio))
		goto out;

	rmap_walk(folio, &rwc);

	if (need_lock)
		folio_unlock(folio);

out:
	folio_put(folio);
}

static void __damon_pa_prepare_access_check(struct damon_ctx *ctx,
					    struct damon_region *r)
{
	r->sampling_addr = damon_rand(r->ar.start, r->ar.end);

	damon_pa_mkold(r->sampling_addr);
}

static void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
{
	struct damon_target *t;
	struct damon_region *r;

	damon_for_each_target(t, ctx) {
		damon_for_each_region(r, t)
			__damon_pa_prepare_access_check(ctx, r);
	}
}

struct damon_pa_access_chk_result {
	unsigned long page_sz;
	bool accessed;
};

static bool __damon_pa_young(struct folio *folio, struct vm_area_struct *vma,
		unsigned long addr, void *arg)
{
	struct damon_pa_access_chk_result *result = arg;
	DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0);

	result->accessed = false;
	result->page_sz = PAGE_SIZE;
	while (page_vma_mapped_walk(&pvmw)) {
		addr = pvmw.address;
		if (pvmw.pte) {
			result->accessed = pte_young(*pvmw.pte) ||
				!folio_test_idle(folio) ||
				mmu_notifier_test_young(vma->vm_mm, addr);
		} else {
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
			result->accessed = pmd_young(*pvmw.pmd) ||
				!folio_test_idle(folio) ||
				mmu_notifier_test_young(vma->vm_mm, addr);
			result->page_sz = ((1UL) << HPAGE_PMD_SHIFT);
#else
			WARN_ON_ONCE(1);
#endif	/* CONFIG_TRANSPARENT_HUGEPAGE */
		}
		if (result->accessed) {
			page_vma_mapped_walk_done(&pvmw);
			break;
		}
	}

	/* If accessed, stop walking */
	return !result->accessed;
}

static bool damon_pa_young(unsigned long paddr, unsigned long *page_sz)
{
	struct folio *folio;
	struct page *page = damon_get_page(PHYS_PFN(paddr));
	struct damon_pa_access_chk_result result = {
		.page_sz = PAGE_SIZE,
		.accessed = false,
	};
	struct rmap_walk_control rwc = {
		.arg = &result,
		.rmap_one = __damon_pa_young,
		.anon_lock = folio_lock_anon_vma_read,
	};
	bool need_lock;

	if (!page)
		return false;
	folio = page_folio(page);

	if (!folio_mapped(folio) || !folio_raw_mapping(folio)) {
		if (folio_test_idle(folio))
			result.accessed = false;
		else
			result.accessed = true;
		folio_put(folio);
		goto out;
	}

	need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
	if (need_lock && !folio_trylock(folio)) {
		folio_put(folio);
		return false;
	}

	rmap_walk(folio, &rwc);

	if (need_lock)
		folio_unlock(folio);
	folio_put(folio);

out:
	*page_sz = result.page_sz;
	return result.accessed;
}

static void __damon_pa_check_access(struct damon_ctx *ctx,
				    struct damon_region *r)
{
	static unsigned long last_addr;
	static unsigned long last_page_sz = PAGE_SIZE;
	static bool last_accessed;

	/* If the region is in the last checked page, reuse the result */
	if (ALIGN_DOWN(last_addr, last_page_sz) ==
				ALIGN_DOWN(r->sampling_addr, last_page_sz)) {
		if (last_accessed)
			r->nr_accesses++;
		return;
	}

	last_accessed = damon_pa_young(r->sampling_addr, &last_page_sz);
	if (last_accessed)
		r->nr_accesses++;

	last_addr = r->sampling_addr;
}

static unsigned int damon_pa_check_accesses(struct damon_ctx *ctx)
{
	struct damon_target *t;
	struct damon_region *r;
	unsigned int max_nr_accesses = 0;

	damon_for_each_target(t, ctx) {
		damon_for_each_region(r, t) {
			__damon_pa_check_access(ctx, r);
			max_nr_accesses = max(r->nr_accesses, max_nr_accesses);
		}
	}

	return max_nr_accesses;
}

static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
		struct damon_target *t, struct damon_region *r,
		struct damos *scheme)
{
	unsigned long addr, applied;
	LIST_HEAD(page_list);

	if (scheme->action != DAMOS_PAGEOUT)
		return 0;

	for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
		struct page *page = damon_get_page(PHYS_PFN(addr));

		if (!page)
			continue;

		ClearPageReferenced(page);
		test_and_clear_page_young(page);
		if (isolate_lru_page(page)) {
			put_page(page);
			continue;
		}
		if (PageUnevictable(page)) {
			putback_lru_page(page);
		} else {
			list_add(&page->lru, &page_list);
			put_page(page);
		}
	}
	applied = reclaim_pages(&page_list);
	cond_resched();
	return applied * PAGE_SIZE;
}

static int damon_pa_scheme_score(struct damon_ctx *context,
		struct damon_target *t, struct damon_region *r,
		struct damos *scheme)
{
	switch (scheme->action) {
	case DAMOS_PAGEOUT:
		return damon_pageout_score(context, r, scheme);
	default:
		break;
	}

	return DAMOS_MAX_SCORE;
}

static int __init damon_pa_initcall(void)
{
	struct damon_operations ops = {
		.id = DAMON_OPS_PADDR,
		.init = NULL,
		.update = NULL,
		.prepare_access_checks = damon_pa_prepare_access_checks,
		.check_accesses = damon_pa_check_accesses,
		.reset_aggregated = NULL,
		.target_valid = NULL,
		.cleanup = NULL,
		.apply_scheme = damon_pa_apply_scheme,
		.get_scheme_score = damon_pa_scheme_score,
	};

	return damon_register_ops(&ops);
};

subsys_initcall(damon_pa_initcall);