Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
/*
 * Common Primitives for Data Access Monitoring
 *
 * Author: SeongJae Park <sj@kernel.org>
 */
 
#include <linux/mmu_notifier.h>
#include <linux/page_idle.h>
#include <linux/pagemap.h>
#include <linux/rmap.h>
 
#include "prmtv-common.h"
 
/*
 * Get an online page for a pfn if it's in the LRU list.  Otherwise, returns
 * NULL.
 *
 * The body of this function is stolen from the 'page_idle_get_page()'.  We
 * steal rather than reuse it because the code is quite simple.
 */
struct page *damon_get_page(unsigned long pfn)
{
<------>struct page *page = pfn_to_online_page(pfn);
 
<------>if (!page || !PageLRU(page) || !get_page_unless_zero(page))
<------><------>return NULL;
 
<------>if (unlikely(!PageLRU(page))) {
<------><------>put_page(page);
<------><------>page = NULL;
<------>}
<------>return page;
}
 
void damon_ptep_mkold(pte_t *pte, struct mm_struct *mm, unsigned long addr)
{
<------>bool referenced = false;
<------>struct page *page = damon_get_page(pte_pfn(*pte));
 
<------>if (!page)
<------><------>return;
 
<------>if (pte_young(*pte)) {
<------><------>referenced = true;
<------><------>*pte = pte_mkold(*pte);
<------>}
 
#ifdef CONFIG_MMU_NOTIFIER
<------>if (mmu_notifier_clear_young(mm, addr, addr + PAGE_SIZE))
<------><------>referenced = true;
#endif /* CONFIG_MMU_NOTIFIER */
 
<------>if (referenced)
<------><------>set_page_young(page);
 
<------>set_page_idle(page);
<------>put_page(page);
}
 
void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, unsigned long addr)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
<------>bool referenced = false;
<------>struct page *page = damon_get_page(pmd_pfn(*pmd));
 
<------>if (!page)
<------><------>return;
 
<------>if (pmd_young(*pmd)) {
<------><------>referenced = true;
<------><------>*pmd = pmd_mkold(*pmd);
<------>}
 
#ifdef CONFIG_MMU_NOTIFIER
<------>if (mmu_notifier_clear_young(mm, addr,
<------><------><------><------>addr + ((1UL) << HPAGE_PMD_SHIFT)))
<------><------>referenced = true;
#endif /* CONFIG_MMU_NOTIFIER */
 
<------>if (referenced)
<------><------>set_page_young(page);
 
<------>set_page_idle(page);
<------>put_page(page);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
}
 
#define DAMON_MAX_SUBSCORE	(100)
#define DAMON_MAX_AGE_IN_LOG	(32)
 
int damon_pageout_score(struct damon_ctx *c, struct damon_region *r,
<------><------><------>struct damos *s)
{
<------>unsigned int max_nr_accesses;
<------>int freq_subscore;
<------>unsigned int age_in_sec;
<------>int age_in_log, age_subscore;
<------>unsigned int freq_weight = s->quota.weight_nr_accesses;
<------>unsigned int age_weight = s->quota.weight_age;
<------>int hotness;
 
<------>max_nr_accesses = c->aggr_interval / c->sample_interval;
<------>freq_subscore = r->nr_accesses * DAMON_MAX_SUBSCORE / max_nr_accesses;
 
<------>age_in_sec = (unsigned long)r->age * c->aggr_interval / 1000000;
<------>for (age_in_log = 0; age_in_log < DAMON_MAX_AGE_IN_LOG && age_in_sec;
<------><------><------>age_in_log++, age_in_sec >>= 1)
<------><------>;
 
<------>/* If frequency is 0, higher age means it's colder */
<------>if (freq_subscore == 0)
<------><------>age_in_log *= -1;
 
<------>/*
<------> * Now age_in_log is in [-DAMON_MAX_AGE_IN_LOG, DAMON_MAX_AGE_IN_LOG].
<------> * Scale it to be in [0, 100] and set it as age subscore.
<------> */
<------>age_in_log += DAMON_MAX_AGE_IN_LOG;
<------>age_subscore = age_in_log * DAMON_MAX_SUBSCORE /
<------><------>DAMON_MAX_AGE_IN_LOG / 2;
 
<------>hotness = (freq_weight * freq_subscore + age_weight * age_subscore);
<------>if (freq_weight + age_weight)
<------><------>hotness /= freq_weight + age_weight;
<------>/*
<------> * Transform it to fit in [0, DAMOS_MAX_SCORE]
<------> */
<------>hotness = hotness * DAMOS_MAX_SCORE / DAMON_MAX_SUBSCORE;
 
<------>/* Return coldness of the region */
<------>return DAMOS_MAX_SCORE - hotness;
}