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