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1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Common Primitives for Data Access Monitoring | |
4 | * | |
5 | * Author: SeongJae Park <sj@kernel.org> | |
6 | */ | |
7 | ||
8 | #include <linux/mmu_notifier.h> | |
9 | #include <linux/page_idle.h> | |
10 | #include <linux/pagemap.h> | |
11 | #include <linux/rmap.h> | |
12 | ||
f7d911c3 | 13 | #include "ops-common.h" |
46c3a0ac SP |
14 | |
15 | /* | |
16 | * Get an online page for a pfn if it's in the LRU list. Otherwise, returns | |
17 | * NULL. | |
18 | * | |
5e012bba | 19 | * The body of this function is stolen from the 'page_idle_get_folio()'. We |
46c3a0ac SP |
20 | * steal rather than reuse it because the code is quite simple. |
21 | */ | |
5e012bba | 22 | struct folio *damon_get_folio(unsigned long pfn) |
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23 | { |
24 | struct page *page = pfn_to_online_page(pfn); | |
5e012bba | 25 | struct folio *folio; |
46c3a0ac | 26 | |
5e012bba | 27 | if (!page || PageTail(page)) |
46c3a0ac SP |
28 | return NULL; |
29 | ||
5e012bba KW |
30 | folio = page_folio(page); |
31 | if (!folio_test_lru(folio) || !folio_try_get(folio)) | |
32 | return NULL; | |
33 | if (unlikely(page_folio(page) != folio || !folio_test_lru(folio))) { | |
34 | folio_put(folio); | |
35 | folio = NULL; | |
46c3a0ac | 36 | } |
5e012bba | 37 | return folio; |
46c3a0ac SP |
38 | } |
39 | ||
c11d34fa | 40 | void damon_ptep_mkold(pte_t *pte, struct vm_area_struct *vma, unsigned long addr) |
46c3a0ac | 41 | { |
c33c7948 | 42 | struct folio *folio = damon_get_folio(pte_pfn(ptep_get(pte))); |
46c3a0ac | 43 | |
70e314c9 | 44 | if (!folio) |
46c3a0ac SP |
45 | return; |
46 | ||
fa8c919d | 47 | if (ptep_clear_young_notify(vma, addr, pte)) |
70e314c9 | 48 | folio_set_young(folio); |
46c3a0ac | 49 | |
70e314c9 KW |
50 | folio_set_idle(folio); |
51 | folio_put(folio); | |
46c3a0ac SP |
52 | } |
53 | ||
c11d34fa | 54 | void damon_pmdp_mkold(pmd_t *pmd, struct vm_area_struct *vma, unsigned long addr) |
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55 | { |
56 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
e7ee3f97 | 57 | struct folio *folio = damon_get_folio(pmd_pfn(pmdp_get(pmd))); |
46c3a0ac | 58 | |
70e314c9 | 59 | if (!folio) |
46c3a0ac SP |
60 | return; |
61 | ||
fa8c919d | 62 | if (pmdp_clear_young_notify(vma, addr, pmd)) |
70e314c9 | 63 | folio_set_young(folio); |
46c3a0ac | 64 | |
70e314c9 KW |
65 | folio_set_idle(folio); |
66 | folio_put(folio); | |
46c3a0ac SP |
67 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
68 | } | |
198f0f4c SP |
69 | |
70 | #define DAMON_MAX_SUBSCORE (100) | |
71 | #define DAMON_MAX_AGE_IN_LOG (32) | |
72 | ||
8eabc77c | 73 | int damon_hot_score(struct damon_ctx *c, struct damon_region *r, |
198f0f4c SP |
74 | struct damos *s) |
75 | { | |
198f0f4c SP |
76 | int freq_subscore; |
77 | unsigned int age_in_sec; | |
78 | int age_in_log, age_subscore; | |
79 | unsigned int freq_weight = s->quota.weight_nr_accesses; | |
80 | unsigned int age_weight = s->quota.weight_age; | |
81 | int hotness; | |
82 | ||
3bafc47d SP |
83 | freq_subscore = r->nr_accesses * DAMON_MAX_SUBSCORE / |
84 | damon_max_nr_accesses(&c->attrs); | |
198f0f4c | 85 | |
cbeaa77b | 86 | age_in_sec = (unsigned long)r->age * c->attrs.aggr_interval / 1000000; |
198f0f4c SP |
87 | for (age_in_log = 0; age_in_log < DAMON_MAX_AGE_IN_LOG && age_in_sec; |
88 | age_in_log++, age_in_sec >>= 1) | |
89 | ; | |
90 | ||
91 | /* If frequency is 0, higher age means it's colder */ | |
92 | if (freq_subscore == 0) | |
93 | age_in_log *= -1; | |
94 | ||
95 | /* | |
96 | * Now age_in_log is in [-DAMON_MAX_AGE_IN_LOG, DAMON_MAX_AGE_IN_LOG]. | |
97 | * Scale it to be in [0, 100] and set it as age subscore. | |
98 | */ | |
99 | age_in_log += DAMON_MAX_AGE_IN_LOG; | |
100 | age_subscore = age_in_log * DAMON_MAX_SUBSCORE / | |
101 | DAMON_MAX_AGE_IN_LOG / 2; | |
102 | ||
103 | hotness = (freq_weight * freq_subscore + age_weight * age_subscore); | |
104 | if (freq_weight + age_weight) | |
105 | hotness /= freq_weight + age_weight; | |
106 | /* | |
107 | * Transform it to fit in [0, DAMOS_MAX_SCORE] | |
108 | */ | |
109 | hotness = hotness * DAMOS_MAX_SCORE / DAMON_MAX_SUBSCORE; | |
110 | ||
8eabc77c | 111 | return hotness; |
198f0f4c | 112 | } |
8cdcc532 | 113 | |
e3e486e6 | 114 | int damon_cold_score(struct damon_ctx *c, struct damon_region *r, |
8cdcc532 SP |
115 | struct damos *s) |
116 | { | |
8eabc77c | 117 | int hotness = damon_hot_score(c, r, s); |
8cdcc532 | 118 | |
8eabc77c KX |
119 | /* Return coldness of the region */ |
120 | return DAMOS_MAX_SCORE - hotness; | |
8cdcc532 | 121 | } |