320 lines
7.0 KiB
C
320 lines
7.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* DAMON Primitives for The Physical Address Space
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*
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* Author: SeongJae Park <sj@kernel.org>
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*/
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#define pr_fmt(fmt) "damon-pa: " fmt
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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 <linux/swap.h>
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#include "../internal.h"
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#include "ops-common.h"
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static bool __damon_pa_mkold(struct folio *folio, struct vm_area_struct *vma,
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unsigned long addr, void *arg)
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{
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DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0);
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while (page_vma_mapped_walk(&pvmw)) {
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addr = pvmw.address;
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if (pvmw.pte)
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damon_ptep_mkold(pvmw.pte, vma, addr);
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else
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damon_pmdp_mkold(pvmw.pmd, vma, addr);
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}
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return true;
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}
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static void damon_pa_mkold(unsigned long paddr)
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{
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struct folio *folio;
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struct page *page = damon_get_page(PHYS_PFN(paddr));
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struct rmap_walk_control rwc = {
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.rmap_one = __damon_pa_mkold,
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.anon_lock = folio_lock_anon_vma_read,
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};
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bool need_lock;
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if (!page)
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return;
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folio = page_folio(page);
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if (!folio_mapped(folio) || !folio_raw_mapping(folio)) {
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folio_set_idle(folio);
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goto out;
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}
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need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
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if (need_lock && !folio_trylock(folio))
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goto out;
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rmap_walk(folio, &rwc);
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if (need_lock)
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folio_unlock(folio);
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out:
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folio_put(folio);
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}
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static void __damon_pa_prepare_access_check(struct damon_region *r)
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{
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r->sampling_addr = damon_rand(r->ar.start, r->ar.end);
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damon_pa_mkold(r->sampling_addr);
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}
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static void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
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{
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struct damon_target *t;
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struct damon_region *r;
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damon_for_each_target(t, ctx) {
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damon_for_each_region(r, t)
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__damon_pa_prepare_access_check(r);
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}
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}
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struct damon_pa_access_chk_result {
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unsigned long page_sz;
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bool accessed;
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};
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static bool __damon_pa_young(struct folio *folio, struct vm_area_struct *vma,
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unsigned long addr, void *arg)
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{
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struct damon_pa_access_chk_result *result = arg;
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DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0);
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result->accessed = false;
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result->page_sz = PAGE_SIZE;
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while (page_vma_mapped_walk(&pvmw)) {
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addr = pvmw.address;
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if (pvmw.pte) {
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result->accessed = pte_young(*pvmw.pte) ||
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!folio_test_idle(folio) ||
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mmu_notifier_test_young(vma->vm_mm, addr);
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} else {
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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result->accessed = pmd_young(*pvmw.pmd) ||
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!folio_test_idle(folio) ||
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mmu_notifier_test_young(vma->vm_mm, addr);
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result->page_sz = HPAGE_PMD_SIZE;
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#else
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WARN_ON_ONCE(1);
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
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}
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if (result->accessed) {
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page_vma_mapped_walk_done(&pvmw);
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break;
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}
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}
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/* If accessed, stop walking */
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return !result->accessed;
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}
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static bool damon_pa_young(unsigned long paddr, unsigned long *page_sz)
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{
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struct folio *folio;
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struct page *page = damon_get_page(PHYS_PFN(paddr));
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struct damon_pa_access_chk_result result = {
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.page_sz = PAGE_SIZE,
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.accessed = false,
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};
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struct rmap_walk_control rwc = {
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.arg = &result,
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.rmap_one = __damon_pa_young,
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.anon_lock = folio_lock_anon_vma_read,
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};
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bool need_lock;
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if (!page)
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return false;
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folio = page_folio(page);
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if (!folio_mapped(folio) || !folio_raw_mapping(folio)) {
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if (folio_test_idle(folio))
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result.accessed = false;
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else
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result.accessed = true;
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folio_put(folio);
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goto out;
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}
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need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
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if (need_lock && !folio_trylock(folio)) {
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folio_put(folio);
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return false;
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}
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rmap_walk(folio, &rwc);
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if (need_lock)
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folio_unlock(folio);
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folio_put(folio);
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out:
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*page_sz = result.page_sz;
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return result.accessed;
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}
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static void __damon_pa_check_access(struct damon_region *r)
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{
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static unsigned long last_addr;
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static unsigned long last_page_sz = PAGE_SIZE;
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static bool last_accessed;
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/* If the region is in the last checked page, reuse the result */
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if (ALIGN_DOWN(last_addr, last_page_sz) ==
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ALIGN_DOWN(r->sampling_addr, last_page_sz)) {
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if (last_accessed)
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r->nr_accesses++;
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return;
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}
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last_accessed = damon_pa_young(r->sampling_addr, &last_page_sz);
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if (last_accessed)
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r->nr_accesses++;
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last_addr = r->sampling_addr;
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}
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static unsigned int damon_pa_check_accesses(struct damon_ctx *ctx)
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{
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struct damon_target *t;
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struct damon_region *r;
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unsigned int max_nr_accesses = 0;
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damon_for_each_target(t, ctx) {
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damon_for_each_region(r, t) {
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__damon_pa_check_access(r);
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max_nr_accesses = max(r->nr_accesses, max_nr_accesses);
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}
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}
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return max_nr_accesses;
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}
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static unsigned long damon_pa_pageout(struct damon_region *r)
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{
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unsigned long addr, applied;
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LIST_HEAD(page_list);
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for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
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struct page *page = damon_get_page(PHYS_PFN(addr));
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if (!page)
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continue;
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ClearPageReferenced(page);
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test_and_clear_page_young(page);
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if (isolate_lru_page(page)) {
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put_page(page);
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continue;
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}
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if (PageUnevictable(page))
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putback_lru_page(page);
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else
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list_add(&page->lru, &page_list);
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put_page(page);
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}
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applied = reclaim_pages(&page_list);
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cond_resched();
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return applied * PAGE_SIZE;
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}
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static inline unsigned long damon_pa_mark_accessed_or_deactivate(
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struct damon_region *r, bool mark_accessed)
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{
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unsigned long addr, applied = 0;
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for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
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struct page *page = damon_get_page(PHYS_PFN(addr));
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if (!page)
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continue;
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if (mark_accessed)
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mark_page_accessed(page);
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else
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deactivate_page(page);
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put_page(page);
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applied++;
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}
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return applied * PAGE_SIZE;
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}
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static unsigned long damon_pa_mark_accessed(struct damon_region *r)
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{
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return damon_pa_mark_accessed_or_deactivate(r, true);
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}
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static unsigned long damon_pa_deactivate_pages(struct damon_region *r)
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{
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return damon_pa_mark_accessed_or_deactivate(r, false);
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}
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static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
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struct damon_target *t, struct damon_region *r,
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struct damos *scheme)
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{
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switch (scheme->action) {
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case DAMOS_PAGEOUT:
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return damon_pa_pageout(r);
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case DAMOS_LRU_PRIO:
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return damon_pa_mark_accessed(r);
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case DAMOS_LRU_DEPRIO:
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return damon_pa_deactivate_pages(r);
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case DAMOS_STAT:
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break;
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default:
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/* DAMOS actions that not yet supported by 'paddr'. */
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break;
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}
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return 0;
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}
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static int damon_pa_scheme_score(struct damon_ctx *context,
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struct damon_target *t, struct damon_region *r,
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struct damos *scheme)
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{
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switch (scheme->action) {
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case DAMOS_PAGEOUT:
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return damon_cold_score(context, r, scheme);
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case DAMOS_LRU_PRIO:
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return damon_hot_score(context, r, scheme);
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case DAMOS_LRU_DEPRIO:
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return damon_cold_score(context, r, scheme);
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default:
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break;
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}
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return DAMOS_MAX_SCORE;
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}
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static int __init damon_pa_initcall(void)
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{
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struct damon_operations ops = {
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.id = DAMON_OPS_PADDR,
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.init = NULL,
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.update = NULL,
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.prepare_access_checks = damon_pa_prepare_access_checks,
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.check_accesses = damon_pa_check_accesses,
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.reset_aggregated = NULL,
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.target_valid = NULL,
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.cleanup = NULL,
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.apply_scheme = damon_pa_apply_scheme,
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.get_scheme_score = damon_pa_scheme_score,
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};
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return damon_register_ops(&ops);
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};
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subsys_initcall(damon_pa_initcall);
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