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