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1// SPDX-License-Identifier: GPL-2.02/*3 * Common Primitives for Data Access Monitoring4 *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 13#include "ops-common.h"14 15/*16 * Get an online page for a pfn if it's in the LRU list. Otherwise, returns17 * NULL.18 *19 * The body of this function is stolen from the 'page_idle_get_folio()'. We20 * steal rather than reuse it because the code is quite simple.21 */22struct folio *damon_get_folio(unsigned long pfn)23{24 struct page *page = pfn_to_online_page(pfn);25 struct folio *folio;26 27 if (!page || PageTail(page))28 return NULL;29 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;36 }37 return folio;38}39 40void damon_ptep_mkold(pte_t *pte, struct vm_area_struct *vma, unsigned long addr)41{42 struct folio *folio = damon_get_folio(pte_pfn(ptep_get(pte)));43 44 if (!folio)45 return;46 47 if (ptep_clear_young_notify(vma, addr, pte))48 folio_set_young(folio);49 50 folio_set_idle(folio);51 folio_put(folio);52}53 54void damon_pmdp_mkold(pmd_t *pmd, struct vm_area_struct *vma, unsigned long addr)55{56#ifdef CONFIG_TRANSPARENT_HUGEPAGE57 struct folio *folio = damon_get_folio(pmd_pfn(pmdp_get(pmd)));58 59 if (!folio)60 return;61 62 if (pmdp_clear_young_notify(vma, addr, pmd))63 folio_set_young(folio);64 65 folio_set_idle(folio);66 folio_put(folio);67#endif /* CONFIG_TRANSPARENT_HUGEPAGE */68}69 70#define DAMON_MAX_SUBSCORE (100)71#define DAMON_MAX_AGE_IN_LOG (32)72 73int damon_hot_score(struct damon_ctx *c, struct damon_region *r,74 struct damos *s)75{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 83 freq_subscore = r->nr_accesses * DAMON_MAX_SUBSCORE /84 damon_max_nr_accesses(&c->attrs);85 86 age_in_sec = (unsigned long)r->age * c->attrs.aggr_interval / 1000000;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;110 111 return hotness;112}113 114int damon_cold_score(struct damon_ctx *c, struct damon_region *r,115 struct damos *s)116{117 int hotness = damon_hot_score(c, r, s);118 119 /* Return coldness of the region */120 return DAMOS_MAX_SCORE - hotness;121}122