1 files changed, 386 insertions, 0 deletions
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
new file mode 100644
index 000000000000..07a8aead439e
--- /dev/null
+++ b/mm/damon/paddr.c
@@ -0,0 +1,386 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DAMON Code for The Physical Address Space
+ *
+ * Author: SeongJae Park <sj@kernel.org>
+ */
+
+#define pr_fmt(fmt) "damon-pa: " fmt
+
+#include <linux/mmu_notifier.h>
+#include <linux/page_idle.h>
+#include <linux/pagemap.h>
+#include <linux/rmap.h>
+#include <linux/swap.h>
+#include <linux/memory-tiers.h>
+#include <linux/mm_inline.h>
+
+#include "../internal.h"
+#include "ops-common.h"
+
+static phys_addr_t damon_pa_phys_addr(
+		unsigned long addr, unsigned long addr_unit)
+{
+	return (phys_addr_t)addr * addr_unit;
+}
+
+static unsigned long damon_pa_core_addr(
+		phys_addr_t pa, unsigned long addr_unit)
+{
+	/*
+	 * Use div_u64() for avoiding linking errors related with __udivdi3,
+	 * __aeabi_uldivmod, or similar problems.  This should also improve the
+	 * performance optimization (read div_u64() comment for the detail).
+	 */
+	if (sizeof(pa) == 8 && sizeof(addr_unit) == 4)
+		return div_u64(pa, addr_unit);
+	return pa / addr_unit;
+}
+
+static void damon_pa_mkold(phys_addr_t paddr)
+{
+	struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
+
+	if (!folio)
+		return;
+
+	damon_folio_mkold(folio);
+	folio_put(folio);
+}
+
+static void __damon_pa_prepare_access_check(struct damon_region *r,
+		unsigned long addr_unit)
+{
+	r->sampling_addr = damon_rand(r->ar.start, r->ar.end);
+
+	damon_pa_mkold(damon_pa_phys_addr(r->sampling_addr, addr_unit));
+}
+
+static void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
+{
+	struct damon_target *t;
+	struct damon_region *r;
+
+	damon_for_each_target(t, ctx) {
+		damon_for_each_region(r, t)
+			__damon_pa_prepare_access_check(r, ctx->addr_unit);
+	}
+}
+
+static bool damon_pa_young(phys_addr_t paddr, unsigned long *folio_sz)
+{
+	struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
+	bool accessed;
+
+	if (!folio)
+		return false;
+
+	accessed = damon_folio_young(folio);
+	*folio_sz = folio_size(folio);
+	folio_put(folio);
+	return accessed;
+}
+
+static void __damon_pa_check_access(struct damon_region *r,
+		struct damon_attrs *attrs, unsigned long addr_unit)
+{
+	static phys_addr_t last_addr;
+	static unsigned long last_folio_sz = PAGE_SIZE;
+	static bool last_accessed;
+	phys_addr_t sampling_addr = damon_pa_phys_addr(
+			r->sampling_addr, addr_unit);
+
+	/* If the region is in the last checked page, reuse the result */
+	if (ALIGN_DOWN(last_addr, last_folio_sz) ==
+				ALIGN_DOWN(sampling_addr, last_folio_sz)) {
+		damon_update_region_access_rate(r, last_accessed, attrs);
+		return;
+	}
+
+	last_accessed = damon_pa_young(sampling_addr, &last_folio_sz);
+	damon_update_region_access_rate(r, last_accessed, attrs);
+
+	last_addr = sampling_addr;
+}
+
+static unsigned int damon_pa_check_accesses(struct damon_ctx *ctx)
+{
+	struct damon_target *t;
+	struct damon_region *r;
+	unsigned int max_nr_accesses = 0;
+
+	damon_for_each_target(t, ctx) {
+		damon_for_each_region(r, t) {
+			__damon_pa_check_access(
+					r, &ctx->attrs, ctx->addr_unit);
+			max_nr_accesses = max(r->nr_accesses, max_nr_accesses);
+		}
+	}
+
+	return max_nr_accesses;
+}
+
+/*
+ * damos_pa_filter_out - Return true if the page should be filtered out.
+ */
+static bool damos_pa_filter_out(struct damos *scheme, struct folio *folio)
+{
+	struct damos_filter *filter;
+
+	if (scheme->core_filters_allowed)
+		return false;
+
+	damos_for_each_ops_filter(filter, scheme) {
+		if (damos_folio_filter_match(filter, folio))
+			return !filter->allow;
+	}
+	return scheme->ops_filters_default_reject;
+}
+
+static bool damon_pa_invalid_damos_folio(struct folio *folio, struct damos *s)
+{
+	if (!folio)
+		return true;
+	if (folio == s->last_applied) {
+		folio_put(folio);
+		return true;
+	}
+	return false;
+}
+
+static unsigned long damon_pa_pageout(struct damon_region *r,
+		unsigned long addr_unit, struct damos *s,
+		unsigned long *sz_filter_passed)
+{
+	phys_addr_t addr, applied;
+	LIST_HEAD(folio_list);
+	bool install_young_filter = true;
+	struct damos_filter *filter;
+	struct folio *folio;
+
+	/* check access in page level again by default */
+	damos_for_each_ops_filter(filter, s) {
+		if (filter->type == DAMOS_FILTER_TYPE_YOUNG) {
+			install_young_filter = false;
+			break;
+		}
+	}
+	if (install_young_filter) {
+		filter = damos_new_filter(
+				DAMOS_FILTER_TYPE_YOUNG, true, false);
+		if (!filter)
+			return 0;
+		damos_add_filter(s, filter);
+	}
+
+	addr = damon_pa_phys_addr(r->ar.start, addr_unit);
+	while (addr < damon_pa_phys_addr(r->ar.end, addr_unit)) {
+		folio = damon_get_folio(PHYS_PFN(addr));
+		if (damon_pa_invalid_damos_folio(folio, s)) {
+			addr += PAGE_SIZE;
+			continue;
+		}
+
+		if (damos_pa_filter_out(s, folio))
+			goto put_folio;
+		else
+			*sz_filter_passed += folio_size(folio) / addr_unit;
+
+		folio_clear_referenced(folio);
+		folio_test_clear_young(folio);
+		if (!folio_isolate_lru(folio))
+			goto put_folio;
+		if (folio_test_unevictable(folio))
+			folio_putback_lru(folio);
+		else
+			list_add(&folio->lru, &folio_list);
+put_folio:
+		addr += folio_size(folio);
+		folio_put(folio);
+	}
+	if (install_young_filter)
+		damos_destroy_filter(filter);
+	applied = reclaim_pages(&folio_list);
+	cond_resched();
+	s->last_applied = folio;
+	return damon_pa_core_addr(applied * PAGE_SIZE, addr_unit);
+}
+
+static inline unsigned long damon_pa_mark_accessed_or_deactivate(
+		struct damon_region *r, unsigned long addr_unit,
+		struct damos *s, bool mark_accessed,
+		unsigned long *sz_filter_passed)
+{
+	phys_addr_t addr, applied = 0;
+	struct folio *folio;
+
+	addr = damon_pa_phys_addr(r->ar.start, addr_unit);
+	while (addr < damon_pa_phys_addr(r->ar.end, addr_unit)) {
+		folio = damon_get_folio(PHYS_PFN(addr));
+		if (damon_pa_invalid_damos_folio(folio, s)) {
+			addr += PAGE_SIZE;
+			continue;
+		}
+
+		if (damos_pa_filter_out(s, folio))
+			goto put_folio;
+		else
+			*sz_filter_passed += folio_size(folio) / addr_unit;
+
+		if (mark_accessed)
+			folio_mark_accessed(folio);
+		else
+			folio_deactivate(folio);
+		applied += folio_nr_pages(folio);
+put_folio:
+		addr += folio_size(folio);
+		folio_put(folio);
+	}
+	s->last_applied = folio;
+	return damon_pa_core_addr(applied * PAGE_SIZE, addr_unit);
+}
+
+static unsigned long damon_pa_mark_accessed(struct damon_region *r,
+		unsigned long addr_unit, struct damos *s,
+		unsigned long *sz_filter_passed)
+{
+	return damon_pa_mark_accessed_or_deactivate(r, addr_unit, s, true,
+			sz_filter_passed);
+}
+
+static unsigned long damon_pa_deactivate_pages(struct damon_region *r,
+		unsigned long addr_unit, struct damos *s,
+		unsigned long *sz_filter_passed)
+{
+	return damon_pa_mark_accessed_or_deactivate(r, addr_unit, s, false,
+			sz_filter_passed);
+}
+
+static unsigned long damon_pa_migrate(struct damon_region *r,
+		unsigned long addr_unit, struct damos *s,
+		unsigned long *sz_filter_passed)
+{
+	phys_addr_t addr, applied;
+	LIST_HEAD(folio_list);
+	struct folio *folio;
+
+	addr = damon_pa_phys_addr(r->ar.start, addr_unit);
+	while (addr < damon_pa_phys_addr(r->ar.end, addr_unit)) {
+		folio = damon_get_folio(PHYS_PFN(addr));
+		if (damon_pa_invalid_damos_folio(folio, s)) {
+			addr += PAGE_SIZE;
+			continue;
+		}
+
+		if (damos_pa_filter_out(s, folio))
+			goto put_folio;
+		else
+			*sz_filter_passed += folio_size(folio) / addr_unit;
+
+		if (!folio_isolate_lru(folio))
+			goto put_folio;
+		list_add(&folio->lru, &folio_list);
+put_folio:
+		addr += folio_size(folio);
+		folio_put(folio);
+	}
+	applied = damon_migrate_pages(&folio_list, s->target_nid);
+	cond_resched();
+	s->last_applied = folio;
+	return damon_pa_core_addr(applied * PAGE_SIZE, addr_unit);
+}
+
+static unsigned long damon_pa_stat(struct damon_region *r,
+		unsigned long addr_unit, struct damos *s,
+		unsigned long *sz_filter_passed)
+{
+	phys_addr_t addr;
+	struct folio *folio;
+
+	if (!damos_ops_has_filter(s))
+		return 0;
+
+	addr = damon_pa_phys_addr(r->ar.start, addr_unit);
+	while (addr < damon_pa_phys_addr(r->ar.end, addr_unit)) {
+		folio = damon_get_folio(PHYS_PFN(addr));
+		if (damon_pa_invalid_damos_folio(folio, s)) {
+			addr += PAGE_SIZE;
+			continue;
+		}
+
+		if (!damos_pa_filter_out(s, folio))
+			*sz_filter_passed += folio_size(folio) / addr_unit;
+		addr += folio_size(folio);
+		folio_put(folio);
+	}
+	s->last_applied = folio;
+	return 0;
+}
+
+static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
+		struct damon_target *t, struct damon_region *r,
+		struct damos *scheme, unsigned long *sz_filter_passed)
+{
+	unsigned long aunit = ctx->addr_unit;
+
+	switch (scheme->action) {
+	case DAMOS_PAGEOUT:
+		return damon_pa_pageout(r, aunit, scheme, sz_filter_passed);
+	case DAMOS_LRU_PRIO:
+		return damon_pa_mark_accessed(r, aunit, scheme,
+				sz_filter_passed);
+	case DAMOS_LRU_DEPRIO:
+		return damon_pa_deactivate_pages(r, aunit, scheme,
+				sz_filter_passed);
+	case DAMOS_MIGRATE_HOT:
+	case DAMOS_MIGRATE_COLD:
+		return damon_pa_migrate(r, aunit, scheme, sz_filter_passed);
+	case DAMOS_STAT:
+		return damon_pa_stat(r, aunit, scheme, sz_filter_passed);
+	default:
+		/* DAMOS actions that not yet supported by 'paddr'. */
+		break;
+	}
+	return 0;
+}
+
+static int damon_pa_scheme_score(struct damon_ctx *context,
+		struct damon_target *t, struct damon_region *r,
+		struct damos *scheme)
+{
+	switch (scheme->action) {
+	case DAMOS_PAGEOUT:
+		return damon_cold_score(context, r, scheme);
+	case DAMOS_LRU_PRIO:
+		return damon_hot_score(context, r, scheme);
+	case DAMOS_LRU_DEPRIO:
+		return damon_cold_score(context, r, scheme);
+	case DAMOS_MIGRATE_HOT:
+		return damon_hot_score(context, r, scheme);
+	case DAMOS_MIGRATE_COLD:
+		return damon_cold_score(context, r, scheme);
+	default:
+		break;
+	}
+
+	return DAMOS_MAX_SCORE;
+}
+
+static int __init damon_pa_initcall(void)
+{
+	struct damon_operations ops = {
+		.id = DAMON_OPS_PADDR,
+		.init = NULL,
+		.update = NULL,
+		.prepare_access_checks = damon_pa_prepare_access_checks,
+		.check_accesses = damon_pa_check_accesses,
+		.target_valid = NULL,
+		.cleanup = NULL,
+		.apply_scheme = damon_pa_apply_scheme,
+		.get_scheme_score = damon_pa_scheme_score,
+	};
+
+	return damon_register_ops(&ops);
+};
+
+subsys_initcall(damon_pa_initcall);