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, addr); 28 else 29 damon_pmdp_mkold(pvmw.pmd, vma, 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(ptep_get(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(pmdp_get(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 struct damon_attrs *attrs) 153 { 154 static unsigned long last_addr; 155 static unsigned long last_folio_sz = PAGE_SIZE; 156 static bool last_accessed; 157 158 /* If the region is in the last checked page, reuse the result */ 159 if (ALIGN_DOWN(last_addr, last_folio_sz) == 160 ALIGN_DOWN(r->sampling_addr, last_folio_sz)) { 161 damon_update_region_access_rate(r, last_accessed, attrs); 162 return; 163 } 164 165 last_accessed = damon_pa_young(r->sampling_addr, &last_folio_sz); 166 damon_update_region_access_rate(r, last_accessed, attrs); 167 168 last_addr = r->sampling_addr; 169 } 170 171 static unsigned int damon_pa_check_accesses(struct damon_ctx *ctx) 172 { 173 struct damon_target *t; 174 struct damon_region *r; 175 unsigned int max_nr_accesses = 0; 176 177 damon_for_each_target(t, ctx) { 178 damon_for_each_region(r, t) { 179 __damon_pa_check_access(r, &ctx->attrs); 180 max_nr_accesses = max(r->nr_accesses, max_nr_accesses); 181 } 182 } 183 184 return max_nr_accesses; 185 } 186 187 static bool __damos_pa_filter_out(struct damos_filter *filter, 188 struct folio *folio) 189 { 190 bool matched = false; 191 struct mem_cgroup *memcg; 192 193 switch (filter->type) { 194 case DAMOS_FILTER_TYPE_ANON: 195 matched = folio_test_anon(folio); 196 break; 197 case DAMOS_FILTER_TYPE_MEMCG: 198 rcu_read_lock(); 199 memcg = folio_memcg_check(folio); 200 if (!memcg) 201 matched = false; 202 else 203 matched = filter->memcg_id == mem_cgroup_id(memcg); 204 rcu_read_unlock(); 205 break; 206 default: 207 break; 208 } 209 210 return matched == filter->matching; 211 } 212 213 /* 214 * damos_pa_filter_out - Return true if the page should be filtered out. 215 */ 216 static bool damos_pa_filter_out(struct damos *scheme, struct folio *folio) 217 { 218 struct damos_filter *filter; 219 220 damos_for_each_filter(filter, scheme) { 221 if (__damos_pa_filter_out(filter, folio)) 222 return true; 223 } 224 return false; 225 } 226 227 static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s) 228 { 229 unsigned long addr, applied; 230 LIST_HEAD(folio_list); 231 232 for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) { 233 struct folio *folio = damon_get_folio(PHYS_PFN(addr)); 234 235 if (!folio) 236 continue; 237 238 if (damos_pa_filter_out(s, folio)) 239 goto put_folio; 240 241 folio_clear_referenced(folio); 242 folio_test_clear_young(folio); 243 if (!folio_isolate_lru(folio)) 244 goto put_folio; 245 if (folio_test_unevictable(folio)) 246 folio_putback_lru(folio); 247 else 248 list_add(&folio->lru, &folio_list); 249 put_folio: 250 folio_put(folio); 251 } 252 applied = reclaim_pages(&folio_list, false); 253 cond_resched(); 254 return applied * PAGE_SIZE; 255 } 256 257 static inline unsigned long damon_pa_mark_accessed_or_deactivate( 258 struct damon_region *r, struct damos *s, bool mark_accessed) 259 { 260 unsigned long addr, applied = 0; 261 262 for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) { 263 struct folio *folio = damon_get_folio(PHYS_PFN(addr)); 264 265 if (!folio) 266 continue; 267 268 if (damos_pa_filter_out(s, folio)) 269 goto put_folio; 270 271 if (mark_accessed) 272 folio_mark_accessed(folio); 273 else 274 folio_deactivate(folio); 275 applied += folio_nr_pages(folio); 276 put_folio: 277 folio_put(folio); 278 } 279 return applied * PAGE_SIZE; 280 } 281 282 static unsigned long damon_pa_mark_accessed(struct damon_region *r, 283 struct damos *s) 284 { 285 return damon_pa_mark_accessed_or_deactivate(r, s, true); 286 } 287 288 static unsigned long damon_pa_deactivate_pages(struct damon_region *r, 289 struct damos *s) 290 { 291 return damon_pa_mark_accessed_or_deactivate(r, s, false); 292 } 293 294 static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx, 295 struct damon_target *t, struct damon_region *r, 296 struct damos *scheme) 297 { 298 switch (scheme->action) { 299 case DAMOS_PAGEOUT: 300 return damon_pa_pageout(r, scheme); 301 case DAMOS_LRU_PRIO: 302 return damon_pa_mark_accessed(r, scheme); 303 case DAMOS_LRU_DEPRIO: 304 return damon_pa_deactivate_pages(r, scheme); 305 case DAMOS_STAT: 306 break; 307 default: 308 /* DAMOS actions that not yet supported by 'paddr'. */ 309 break; 310 } 311 return 0; 312 } 313 314 static int damon_pa_scheme_score(struct damon_ctx *context, 315 struct damon_target *t, struct damon_region *r, 316 struct damos *scheme) 317 { 318 switch (scheme->action) { 319 case DAMOS_PAGEOUT: 320 return damon_cold_score(context, r, scheme); 321 case DAMOS_LRU_PRIO: 322 return damon_hot_score(context, r, scheme); 323 case DAMOS_LRU_DEPRIO: 324 return damon_cold_score(context, r, scheme); 325 default: 326 break; 327 } 328 329 return DAMOS_MAX_SCORE; 330 } 331 332 static int __init damon_pa_initcall(void) 333 { 334 struct damon_operations ops = { 335 .id = DAMON_OPS_PADDR, 336 .init = NULL, 337 .update = NULL, 338 .prepare_access_checks = damon_pa_prepare_access_checks, 339 .check_accesses = damon_pa_check_accesses, 340 .reset_aggregated = NULL, 341 .target_valid = NULL, 342 .cleanup = NULL, 343 .apply_scheme = damon_pa_apply_scheme, 344 .get_scheme_score = damon_pa_scheme_score, 345 }; 346 347 return damon_register_ops(&ops); 348 }; 349 350 subsys_initcall(damon_pa_initcall); 351