1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * DAMON Primitives 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 16 #include "../internal.h" 17 #include "ops-common.h" 18 19 static bool __damon_pa_mkold(struct folio *folio, struct vm_area_struct *vma, 20 unsigned long addr, void *arg) 21 { 22 DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0); 23 24 while (page_vma_mapped_walk(&pvmw)) { 25 addr = pvmw.address; 26 if (pvmw.pte) 27 damon_ptep_mkold(pvmw.pte, vma->vm_mm, addr); 28 else 29 damon_pmdp_mkold(pvmw.pmd, vma->vm_mm, addr); 30 } 31 return true; 32 } 33 34 static void damon_pa_mkold(unsigned long paddr) 35 { 36 struct folio *folio = damon_get_folio(PHYS_PFN(paddr)); 37 struct rmap_walk_control rwc = { 38 .rmap_one = __damon_pa_mkold, 39 .anon_lock = folio_lock_anon_vma_read, 40 }; 41 bool need_lock; 42 43 if (!folio) 44 return; 45 46 if (!folio_mapped(folio) || !folio_raw_mapping(folio)) { 47 folio_set_idle(folio); 48 goto out; 49 } 50 51 need_lock = !folio_test_anon(folio) || folio_test_ksm(folio); 52 if (need_lock && !folio_trylock(folio)) 53 goto out; 54 55 rmap_walk(folio, &rwc); 56 57 if (need_lock) 58 folio_unlock(folio); 59 60 out: 61 folio_put(folio); 62 } 63 64 static void __damon_pa_prepare_access_check(struct damon_region *r) 65 { 66 r->sampling_addr = damon_rand(r->ar.start, r->ar.end); 67 68 damon_pa_mkold(r->sampling_addr); 69 } 70 71 static void damon_pa_prepare_access_checks(struct damon_ctx *ctx) 72 { 73 struct damon_target *t; 74 struct damon_region *r; 75 76 damon_for_each_target(t, ctx) { 77 damon_for_each_region(r, t) 78 __damon_pa_prepare_access_check(r); 79 } 80 } 81 82 struct damon_pa_access_chk_result { 83 unsigned long page_sz; 84 bool accessed; 85 }; 86 87 static bool __damon_pa_young(struct folio *folio, struct vm_area_struct *vma, 88 unsigned long addr, void *arg) 89 { 90 struct damon_pa_access_chk_result *result = arg; 91 DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0); 92 93 result->accessed = false; 94 result->page_sz = PAGE_SIZE; 95 while (page_vma_mapped_walk(&pvmw)) { 96 addr = pvmw.address; 97 if (pvmw.pte) { 98 result->accessed = pte_young(*pvmw.pte) || 99 !folio_test_idle(folio) || 100 mmu_notifier_test_young(vma->vm_mm, addr); 101 } else { 102 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 103 result->accessed = pmd_young(*pvmw.pmd) || 104 !folio_test_idle(folio) || 105 mmu_notifier_test_young(vma->vm_mm, addr); 106 result->page_sz = HPAGE_PMD_SIZE; 107 #else 108 WARN_ON_ONCE(1); 109 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 110 } 111 if (result->accessed) { 112 page_vma_mapped_walk_done(&pvmw); 113 break; 114 } 115 } 116 117 /* If accessed, stop walking */ 118 return !result->accessed; 119 } 120 121 static bool damon_pa_young(unsigned long paddr, unsigned long *page_sz) 122 { 123 struct folio *folio = damon_get_folio(PHYS_PFN(paddr)); 124 struct damon_pa_access_chk_result result = { 125 .page_sz = PAGE_SIZE, 126 .accessed = false, 127 }; 128 struct rmap_walk_control rwc = { 129 .arg = &result, 130 .rmap_one = __damon_pa_young, 131 .anon_lock = folio_lock_anon_vma_read, 132 }; 133 bool need_lock; 134 135 if (!folio) 136 return false; 137 138 if (!folio_mapped(folio) || !folio_raw_mapping(folio)) { 139 if (folio_test_idle(folio)) 140 result.accessed = false; 141 else 142 result.accessed = true; 143 folio_put(folio); 144 goto out; 145 } 146 147 need_lock = !folio_test_anon(folio) || folio_test_ksm(folio); 148 if (need_lock && !folio_trylock(folio)) { 149 folio_put(folio); 150 return false; 151 } 152 153 rmap_walk(folio, &rwc); 154 155 if (need_lock) 156 folio_unlock(folio); 157 folio_put(folio); 158 159 out: 160 *page_sz = result.page_sz; 161 return result.accessed; 162 } 163 164 static void __damon_pa_check_access(struct damon_region *r) 165 { 166 static unsigned long last_addr; 167 static unsigned long last_page_sz = PAGE_SIZE; 168 static bool last_accessed; 169 170 /* If the region is in the last checked page, reuse the result */ 171 if (ALIGN_DOWN(last_addr, last_page_sz) == 172 ALIGN_DOWN(r->sampling_addr, last_page_sz)) { 173 if (last_accessed) 174 r->nr_accesses++; 175 return; 176 } 177 178 last_accessed = damon_pa_young(r->sampling_addr, &last_page_sz); 179 if (last_accessed) 180 r->nr_accesses++; 181 182 last_addr = r->sampling_addr; 183 } 184 185 static unsigned int damon_pa_check_accesses(struct damon_ctx *ctx) 186 { 187 struct damon_target *t; 188 struct damon_region *r; 189 unsigned int max_nr_accesses = 0; 190 191 damon_for_each_target(t, ctx) { 192 damon_for_each_region(r, t) { 193 __damon_pa_check_access(r); 194 max_nr_accesses = max(r->nr_accesses, max_nr_accesses); 195 } 196 } 197 198 return max_nr_accesses; 199 } 200 201 static bool __damos_pa_filter_out(struct damos_filter *filter, 202 struct folio *folio) 203 { 204 bool matched = false; 205 struct mem_cgroup *memcg; 206 207 switch (filter->type) { 208 case DAMOS_FILTER_TYPE_ANON: 209 matched = folio_test_anon(folio); 210 break; 211 case DAMOS_FILTER_TYPE_MEMCG: 212 rcu_read_lock(); 213 memcg = folio_memcg_check(folio); 214 if (!memcg) 215 matched = false; 216 else 217 matched = filter->memcg_id == mem_cgroup_id(memcg); 218 rcu_read_unlock(); 219 break; 220 default: 221 break; 222 } 223 224 return matched == filter->matching; 225 } 226 227 /* 228 * damos_pa_filter_out - Return true if the page should be filtered out. 229 */ 230 static bool damos_pa_filter_out(struct damos *scheme, struct folio *folio) 231 { 232 struct damos_filter *filter; 233 234 damos_for_each_filter(filter, scheme) { 235 if (__damos_pa_filter_out(filter, folio)) 236 return true; 237 } 238 return false; 239 } 240 241 static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s) 242 { 243 unsigned long addr, applied; 244 LIST_HEAD(folio_list); 245 246 for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) { 247 struct folio *folio = damon_get_folio(PHYS_PFN(addr)); 248 249 if (!folio) 250 continue; 251 252 if (damos_pa_filter_out(s, folio)) { 253 folio_put(folio); 254 continue; 255 } 256 257 folio_clear_referenced(folio); 258 folio_test_clear_young(folio); 259 if (folio_isolate_lru(folio)) { 260 folio_put(folio); 261 continue; 262 } 263 if (folio_test_unevictable(folio)) { 264 folio_putback_lru(folio); 265 } else { 266 list_add(&folio->lru, &folio_list); 267 folio_put(folio); 268 } 269 } 270 applied = reclaim_pages(&folio_list); 271 cond_resched(); 272 return applied * PAGE_SIZE; 273 } 274 275 static inline unsigned long damon_pa_mark_accessed_or_deactivate( 276 struct damon_region *r, struct damos *s, bool mark_accessed) 277 { 278 unsigned long addr, applied = 0; 279 280 for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) { 281 struct folio *folio = damon_get_folio(PHYS_PFN(addr)); 282 283 if (!folio) 284 continue; 285 286 if (damos_pa_filter_out(s, folio)) { 287 folio_put(folio); 288 continue; 289 } 290 291 if (mark_accessed) 292 folio_mark_accessed(folio); 293 else 294 folio_deactivate(folio); 295 folio_put(folio); 296 applied += folio_nr_pages(folio); 297 } 298 return applied * PAGE_SIZE; 299 } 300 301 static unsigned long damon_pa_mark_accessed(struct damon_region *r, 302 struct damos *s) 303 { 304 return damon_pa_mark_accessed_or_deactivate(r, s, true); 305 } 306 307 static unsigned long damon_pa_deactivate_pages(struct damon_region *r, 308 struct damos *s) 309 { 310 return damon_pa_mark_accessed_or_deactivate(r, s, false); 311 } 312 313 static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx, 314 struct damon_target *t, struct damon_region *r, 315 struct damos *scheme) 316 { 317 switch (scheme->action) { 318 case DAMOS_PAGEOUT: 319 return damon_pa_pageout(r, scheme); 320 case DAMOS_LRU_PRIO: 321 return damon_pa_mark_accessed(r, scheme); 322 case DAMOS_LRU_DEPRIO: 323 return damon_pa_deactivate_pages(r, scheme); 324 case DAMOS_STAT: 325 break; 326 default: 327 /* DAMOS actions that not yet supported by 'paddr'. */ 328 break; 329 } 330 return 0; 331 } 332 333 static int damon_pa_scheme_score(struct damon_ctx *context, 334 struct damon_target *t, struct damon_region *r, 335 struct damos *scheme) 336 { 337 switch (scheme->action) { 338 case DAMOS_PAGEOUT: 339 return damon_cold_score(context, r, scheme); 340 case DAMOS_LRU_PRIO: 341 return damon_hot_score(context, r, scheme); 342 case DAMOS_LRU_DEPRIO: 343 return damon_cold_score(context, r, scheme); 344 default: 345 break; 346 } 347 348 return DAMOS_MAX_SCORE; 349 } 350 351 static int __init damon_pa_initcall(void) 352 { 353 struct damon_operations ops = { 354 .id = DAMON_OPS_PADDR, 355 .init = NULL, 356 .update = NULL, 357 .prepare_access_checks = damon_pa_prepare_access_checks, 358 .check_accesses = damon_pa_check_accesses, 359 .reset_aggregated = NULL, 360 .target_valid = NULL, 361 .cleanup = NULL, 362 .apply_scheme = damon_pa_apply_scheme, 363 .get_scheme_score = damon_pa_scheme_score, 364 }; 365 366 return damon_register_ops(&ops); 367 }; 368 369 subsys_initcall(damon_pa_initcall); 370