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8cdcc53226
This commit adds a new DAMOS action called 'LRU_PRIO' for the physical address space. The action prioritizes pages in the memory regions of the user-specified target access pattern on their LRU lists. This is hence supposed to be used for frequently accessed (hot) memory regions so that hot pages could be more likely protected under memory pressure. Internally, it simply calls 'mark_page_accessed()'. Link: https://lkml.kernel.org/r/20220613192301.8817-5-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
175 lines
4.3 KiB
C
175 lines
4.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Common Primitives for Data Access Monitoring
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*
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* Author: SeongJae Park <sj@kernel.org>
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*/
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#include <linux/mmu_notifier.h>
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#include <linux/page_idle.h>
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#include <linux/pagemap.h>
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#include <linux/rmap.h>
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#include "ops-common.h"
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/*
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* Get an online page for a pfn if it's in the LRU list. Otherwise, returns
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* NULL.
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*
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* The body of this function is stolen from the 'page_idle_get_page()'. We
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* steal rather than reuse it because the code is quite simple.
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*/
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struct page *damon_get_page(unsigned long pfn)
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{
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struct page *page = pfn_to_online_page(pfn);
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if (!page || !PageLRU(page) || !get_page_unless_zero(page))
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return NULL;
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if (unlikely(!PageLRU(page))) {
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put_page(page);
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page = NULL;
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}
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return page;
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}
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void damon_ptep_mkold(pte_t *pte, struct mm_struct *mm, unsigned long addr)
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{
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bool referenced = false;
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struct page *page = damon_get_page(pte_pfn(*pte));
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if (!page)
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return;
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if (pte_young(*pte)) {
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referenced = true;
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*pte = pte_mkold(*pte);
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}
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#ifdef CONFIG_MMU_NOTIFIER
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if (mmu_notifier_clear_young(mm, addr, addr + PAGE_SIZE))
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referenced = true;
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#endif /* CONFIG_MMU_NOTIFIER */
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if (referenced)
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set_page_young(page);
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set_page_idle(page);
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put_page(page);
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}
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void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, unsigned long addr)
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{
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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bool referenced = false;
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struct page *page = damon_get_page(pmd_pfn(*pmd));
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if (!page)
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return;
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if (pmd_young(*pmd)) {
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referenced = true;
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*pmd = pmd_mkold(*pmd);
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}
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#ifdef CONFIG_MMU_NOTIFIER
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if (mmu_notifier_clear_young(mm, addr, addr + HPAGE_PMD_SIZE))
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referenced = true;
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#endif /* CONFIG_MMU_NOTIFIER */
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if (referenced)
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set_page_young(page);
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set_page_idle(page);
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put_page(page);
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
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}
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#define DAMON_MAX_SUBSCORE (100)
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#define DAMON_MAX_AGE_IN_LOG (32)
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int damon_pageout_score(struct damon_ctx *c, struct damon_region *r,
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struct damos *s)
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{
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unsigned int max_nr_accesses;
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int freq_subscore;
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unsigned int age_in_sec;
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int age_in_log, age_subscore;
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unsigned int freq_weight = s->quota.weight_nr_accesses;
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unsigned int age_weight = s->quota.weight_age;
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int hotness;
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max_nr_accesses = c->aggr_interval / c->sample_interval;
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freq_subscore = r->nr_accesses * DAMON_MAX_SUBSCORE / max_nr_accesses;
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age_in_sec = (unsigned long)r->age * c->aggr_interval / 1000000;
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for (age_in_log = 0; age_in_log < DAMON_MAX_AGE_IN_LOG && age_in_sec;
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age_in_log++, age_in_sec >>= 1)
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;
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/* If frequency is 0, higher age means it's colder */
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if (freq_subscore == 0)
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age_in_log *= -1;
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/*
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* Now age_in_log is in [-DAMON_MAX_AGE_IN_LOG, DAMON_MAX_AGE_IN_LOG].
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* Scale it to be in [0, 100] and set it as age subscore.
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*/
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age_in_log += DAMON_MAX_AGE_IN_LOG;
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age_subscore = age_in_log * DAMON_MAX_SUBSCORE /
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DAMON_MAX_AGE_IN_LOG / 2;
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hotness = (freq_weight * freq_subscore + age_weight * age_subscore);
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if (freq_weight + age_weight)
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hotness /= freq_weight + age_weight;
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/*
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* Transform it to fit in [0, DAMOS_MAX_SCORE]
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*/
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hotness = hotness * DAMOS_MAX_SCORE / DAMON_MAX_SUBSCORE;
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/* Return coldness of the region */
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return DAMOS_MAX_SCORE - hotness;
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}
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int damon_hot_score(struct damon_ctx *c, struct damon_region *r,
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struct damos *s)
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{
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unsigned int max_nr_accesses;
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int freq_subscore;
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unsigned int age_in_sec;
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int age_in_log, age_subscore;
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unsigned int freq_weight = s->quota.weight_nr_accesses;
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unsigned int age_weight = s->quota.weight_age;
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int hotness;
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max_nr_accesses = c->aggr_interval / c->sample_interval;
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freq_subscore = r->nr_accesses * DAMON_MAX_SUBSCORE / max_nr_accesses;
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age_in_sec = (unsigned long)r->age * c->aggr_interval / 1000000;
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for (age_in_log = 0; age_in_log < DAMON_MAX_AGE_IN_LOG && age_in_sec;
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age_in_log++, age_in_sec >>= 1)
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;
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/* If frequency is 0, higher age means it's colder */
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if (freq_subscore == 0)
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age_in_log *= -1;
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/*
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* Now age_in_log is in [-DAMON_MAX_AGE_IN_LOG, DAMON_MAX_AGE_IN_LOG].
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* Scale it to be in [0, 100] and set it as age subscore.
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*/
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age_in_log += DAMON_MAX_AGE_IN_LOG;
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age_subscore = age_in_log * DAMON_MAX_SUBSCORE /
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DAMON_MAX_AGE_IN_LOG / 2;
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hotness = (freq_weight * freq_subscore + age_weight * age_subscore);
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if (freq_weight + age_weight)
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hotness /= freq_weight + age_weight;
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/*
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* Transform it to fit in [0, DAMOS_MAX_SCORE]
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*/
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hotness = hotness * DAMOS_MAX_SCORE / DAMON_MAX_SUBSCORE;
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return hotness;
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}
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