paddr.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * DAMON Code for The Physical Address Space
  4 *
  5 * Author: SeongJae Park <sj@kernel.org>
  6 */
  7
  8#define pr_fmt(fmt) "damon-pa: " fmt
  9
 10#include <linux/mmu_notifier.h>
 11#include <linux/page_idle.h>
 12#include <linux/pagemap.h>
 13#include <linux/rmap.h>
 14#include <linux/swap.h>
 15#include <linux/memory-tiers.h>
 16#include <linux/mm_inline.h>
 17
 18#include "../internal.h"
 19#include "ops-common.h"
 20
 21static phys_addr_t damon_pa_phys_addr(
 22		unsigned long addr, unsigned long addr_unit)
 23{
 24	return (phys_addr_t)addr * addr_unit;
 25}
 26
 27static unsigned long damon_pa_core_addr(
 28		phys_addr_t pa, unsigned long addr_unit)
 29{
 30	/*
 31	 * Use div_u64() for avoiding linking errors related with __udivdi3,
 32	 * __aeabi_uldivmod, or similar problems.  This should also improve the
 33	 * performance optimization (read div_u64() comment for the detail).
 34	 */
 35	if (sizeof(pa) == 8 && sizeof(addr_unit) == 4)
 36		return div_u64(pa, addr_unit);
 37	return pa / addr_unit;
 38}
 39
 40static void damon_pa_mkold(phys_addr_t paddr)
 41{
 42	struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
 43
 44	if (!folio)
 45		return;
 46
 47	damon_folio_mkold(folio);
 48	folio_put(folio);
 49}
 50
 51static void __damon_pa_prepare_access_check(struct damon_region *r,
 52		unsigned long addr_unit)
 53{
 54	r->sampling_addr = damon_rand(r->ar.start, r->ar.end);
 55
 56	damon_pa_mkold(damon_pa_phys_addr(r->sampling_addr, addr_unit));
 57}
 58
 59static void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
 60{
 61	struct damon_target *t;
 62	struct damon_region *r;
 63
 64	damon_for_each_target(t, ctx) {
 65		damon_for_each_region(r, t)
 66			__damon_pa_prepare_access_check(r, ctx->addr_unit);
 67	}
 68}
 69
 70static bool damon_pa_young(phys_addr_t paddr, unsigned long *folio_sz)
 71{
 72	struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
 73	bool accessed;
 74
 75	if (!folio)
 76		return false;
 77
 78	accessed = damon_folio_young(folio);
 79	*folio_sz = folio_size(folio);
 80	folio_put(folio);
 81	return accessed;
 82}
 83
 84static void __damon_pa_check_access(struct damon_region *r,
 85		struct damon_attrs *attrs, unsigned long addr_unit)
 86{
 87	static phys_addr_t last_addr;
 88	static unsigned long last_folio_sz = PAGE_SIZE;
 89	static bool last_accessed;
 90	phys_addr_t sampling_addr = damon_pa_phys_addr(
 91			r->sampling_addr, addr_unit);
 92
 93	/* If the region is in the last checked page, reuse the result */
 94	if (ALIGN_DOWN(last_addr, last_folio_sz) ==
 95				ALIGN_DOWN(sampling_addr, last_folio_sz)) {
 96		damon_update_region_access_rate(r, last_accessed, attrs);
 97		return;
 98	}
 99
100	last_accessed = damon_pa_young(sampling_addr, &last_folio_sz);
101	damon_update_region_access_rate(r, last_accessed, attrs);
102
103	last_addr = sampling_addr;
104}
105
106static unsigned int damon_pa_check_accesses(struct damon_ctx *ctx)
107{
108	struct damon_target *t;
109	struct damon_region *r;
110	unsigned int max_nr_accesses = 0;
111
112	damon_for_each_target(t, ctx) {
113		damon_for_each_region(r, t) {
114			__damon_pa_check_access(
115					r, &ctx->attrs, ctx->addr_unit);
116			max_nr_accesses = max(r->nr_accesses, max_nr_accesses);
117		}
118	}
119
120	return max_nr_accesses;
121}
122
123/*
124 * damos_pa_filter_out - Return true if the page should be filtered out.
125 */
126static bool damos_pa_filter_out(struct damos *scheme, struct folio *folio)
127{
128	struct damos_filter *filter;
129
130	if (scheme->core_filters_allowed)
131		return false;
132
133	damos_for_each_ops_filter(filter, scheme) {
134		if (damos_folio_filter_match(filter, folio))
135			return !filter->allow;
136	}
137	return scheme->ops_filters_default_reject;
138}
139
140static bool damon_pa_invalid_damos_folio(struct folio *folio, struct damos *s)
141{
142	if (!folio)
143		return true;
144	if (folio == s->last_applied) {
145		folio_put(folio);
146		return true;
147	}
148	return false;
149}
150
151static unsigned long damon_pa_pageout(struct damon_region *r,
152		unsigned long addr_unit, struct damos *s,
153		unsigned long *sz_filter_passed)
154{
155	phys_addr_t addr, applied;
156	LIST_HEAD(folio_list);
157	bool install_young_filter = true;
158	struct damos_filter *filter;
159	struct folio *folio;
160
161	/* check access in page level again by default */
162	damos_for_each_ops_filter(filter, s) {
163		if (filter->type == DAMOS_FILTER_TYPE_YOUNG) {
164			install_young_filter = false;
165			break;
166		}
167	}
168	if (install_young_filter) {
169		filter = damos_new_filter(
170				DAMOS_FILTER_TYPE_YOUNG, true, false);
171		if (!filter)
172			return 0;
173		damos_add_filter(s, filter);
174	}
175
176	addr = damon_pa_phys_addr(r->ar.start, addr_unit);
177	while (addr < damon_pa_phys_addr(r->ar.end, addr_unit)) {
178		folio = damon_get_folio(PHYS_PFN(addr));
179		if (damon_pa_invalid_damos_folio(folio, s)) {
180			addr += PAGE_SIZE;
181			continue;
182		}
183
184		if (damos_pa_filter_out(s, folio))
185			goto put_folio;
186		else
187			*sz_filter_passed += folio_size(folio) / addr_unit;
188
189		folio_clear_referenced(folio);
190		folio_test_clear_young(folio);
191		if (!folio_isolate_lru(folio))
192			goto put_folio;
193		if (folio_test_unevictable(folio))
194			folio_putback_lru(folio);
195		else
196			list_add(&folio->lru, &folio_list);
197put_folio:
198		addr += folio_size(folio);
199		folio_put(folio);
200	}
201	if (install_young_filter)
202		damos_destroy_filter(filter);
203	applied = reclaim_pages(&folio_list);
204	cond_resched();
205	s->last_applied = folio;
206	return damon_pa_core_addr(applied * PAGE_SIZE, addr_unit);
207}
208
209static inline unsigned long damon_pa_mark_accessed_or_deactivate(
210		struct damon_region *r, unsigned long addr_unit,
211		struct damos *s, bool mark_accessed,
212		unsigned long *sz_filter_passed)
213{
214	phys_addr_t addr, applied = 0;
215	struct folio *folio;
216
217	addr = damon_pa_phys_addr(r->ar.start, addr_unit);
218	while (addr < damon_pa_phys_addr(r->ar.end, addr_unit)) {
219		folio = damon_get_folio(PHYS_PFN(addr));
220		if (damon_pa_invalid_damos_folio(folio, s)) {
221			addr += PAGE_SIZE;
222			continue;
223		}
224
225		if (damos_pa_filter_out(s, folio))
226			goto put_folio;
227		else
228			*sz_filter_passed += folio_size(folio) / addr_unit;
229
230		if (mark_accessed)
231			folio_mark_accessed(folio);
232		else
233			folio_deactivate(folio);
234		applied += folio_nr_pages(folio);
235put_folio:
236		addr += folio_size(folio);
237		folio_put(folio);
238	}
239	s->last_applied = folio;
240	return damon_pa_core_addr(applied * PAGE_SIZE, addr_unit);
241}
242
243static unsigned long damon_pa_mark_accessed(struct damon_region *r,
244		unsigned long addr_unit, struct damos *s,
245		unsigned long *sz_filter_passed)
246{
247	return damon_pa_mark_accessed_or_deactivate(r, addr_unit, s, true,
248			sz_filter_passed);
249}
250
251static unsigned long damon_pa_deactivate_pages(struct damon_region *r,
252		unsigned long addr_unit, struct damos *s,
253		unsigned long *sz_filter_passed)
254{
255	return damon_pa_mark_accessed_or_deactivate(r, addr_unit, s, false,
256			sz_filter_passed);
257}
258
259static unsigned long damon_pa_migrate(struct damon_region *r,
260		unsigned long addr_unit, struct damos *s,
261		unsigned long *sz_filter_passed)
262{
263	phys_addr_t addr, applied;
264	LIST_HEAD(folio_list);
265	struct folio *folio;
266
267	addr = damon_pa_phys_addr(r->ar.start, addr_unit);
268	while (addr < damon_pa_phys_addr(r->ar.end, addr_unit)) {
269		folio = damon_get_folio(PHYS_PFN(addr));
270		if (damon_pa_invalid_damos_folio(folio, s)) {
271			addr += PAGE_SIZE;
272			continue;
273		}
274
275		if (damos_pa_filter_out(s, folio))
276			goto put_folio;
277		else
278			*sz_filter_passed += folio_size(folio) / addr_unit;
279
280		if (!folio_isolate_lru(folio))
281			goto put_folio;
282		list_add(&folio->lru, &folio_list);
283put_folio:
284		addr += folio_size(folio);
285		folio_put(folio);
286	}
287	applied = damon_migrate_pages(&folio_list, s->target_nid);
288	cond_resched();
289	s->last_applied = folio;
290	return damon_pa_core_addr(applied * PAGE_SIZE, addr_unit);
291}
292
293static unsigned long damon_pa_stat(struct damon_region *r,
294		unsigned long addr_unit, struct damos *s,
295		unsigned long *sz_filter_passed)
296{
297	phys_addr_t addr;
298	struct folio *folio;
299
300	if (!damos_ops_has_filter(s))
301		return 0;
302
303	addr = damon_pa_phys_addr(r->ar.start, addr_unit);
304	while (addr < damon_pa_phys_addr(r->ar.end, addr_unit)) {
305		folio = damon_get_folio(PHYS_PFN(addr));
306		if (damon_pa_invalid_damos_folio(folio, s)) {
307			addr += PAGE_SIZE;
308			continue;
309		}
310
311		if (!damos_pa_filter_out(s, folio))
312			*sz_filter_passed += folio_size(folio) / addr_unit;
313		addr += folio_size(folio);
314		folio_put(folio);
315	}
316	s->last_applied = folio;
317	return 0;
318}
319
320static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
321		struct damon_target *t, struct damon_region *r,
322		struct damos *scheme, unsigned long *sz_filter_passed)
323{
324	unsigned long aunit = ctx->addr_unit;
325
326	switch (scheme->action) {
327	case DAMOS_PAGEOUT:
328		return damon_pa_pageout(r, aunit, scheme, sz_filter_passed);
329	case DAMOS_LRU_PRIO:
330		return damon_pa_mark_accessed(r, aunit, scheme,
331				sz_filter_passed);
332	case DAMOS_LRU_DEPRIO:
333		return damon_pa_deactivate_pages(r, aunit, scheme,
334				sz_filter_passed);
335	case DAMOS_MIGRATE_HOT:
336	case DAMOS_MIGRATE_COLD:
337		return damon_pa_migrate(r, aunit, scheme, sz_filter_passed);
338	case DAMOS_STAT:
339		return damon_pa_stat(r, aunit, scheme, sz_filter_passed);
340	default:
341		/* DAMOS actions that not yet supported by 'paddr'. */
342		break;
343	}
344	return 0;
345}
346
347static int damon_pa_scheme_score(struct damon_ctx *context,
348		struct damon_target *t, struct damon_region *r,
349		struct damos *scheme)
350{
351	switch (scheme->action) {
352	case DAMOS_PAGEOUT:
353		return damon_cold_score(context, r, scheme);
354	case DAMOS_LRU_PRIO:
355		return damon_hot_score(context, r, scheme);
356	case DAMOS_LRU_DEPRIO:
357		return damon_cold_score(context, r, scheme);
358	case DAMOS_MIGRATE_HOT:
359		return damon_hot_score(context, r, scheme);
360	case DAMOS_MIGRATE_COLD:
361		return damon_cold_score(context, r, scheme);
362	default:
363		break;
364	}
365
366	return DAMOS_MAX_SCORE;
367}
368
369static int __init damon_pa_initcall(void)
370{
371	struct damon_operations ops = {
372		.id = DAMON_OPS_PADDR,
373		.init = NULL,
374		.update = NULL,
375		.prepare_access_checks = damon_pa_prepare_access_checks,
376		.check_accesses = damon_pa_check_accesses,
377		.target_valid = NULL,
378		.cleanup = NULL,
379		.apply_scheme = damon_pa_apply_scheme,
380		.get_scheme_score = damon_pa_scheme_score,
381	};
382
383	return damon_register_ops(&ops);
384};
385
386subsys_initcall(damon_pa_initcall);