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