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| 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 // The eviction policy is a very simple pure LRU, so the elements at the end of | |
| 6 // the list are evicted until kCleanUpMargin free space is available. There is | |
| 7 // only one list in use (Rankings::NO_USE), and elements are sent to the front | |
| 8 // of the list whenever they are accessed. | |
| 9 | |
| 10 // The new (in-development) eviction policy adds re-use as a factor to evict | |
| 11 // an entry. The story so far: | |
| 12 | |
| 13 // Entries are linked on separate lists depending on how often they are used. | |
| 14 // When we see an element for the first time, it goes to the NO_USE list; if | |
| 15 // the object is reused later on, we move it to the LOW_USE list, until it is | |
| 16 // used kHighUse times, at which point it is moved to the HIGH_USE list. | |
| 17 // Whenever an element is evicted, we move it to the DELETED list so that if the | |
| 18 // element is accessed again, we remember the fact that it was already stored | |
| 19 // and maybe in the future we don't evict that element. | |
| 20 | |
| 21 // When we have to evict an element, first we try to use the last element from | |
| 22 // the NO_USE list, then we move to the LOW_USE and only then we evict an entry | |
| 23 // from the HIGH_USE. We attempt to keep entries on the cache for at least | |
| 24 // kTargetTime hours (with frequently accessed items stored for longer periods), | |
| 25 // but if we cannot do that, we fall-back to keep each list roughly the same | |
| 26 // size so that we have a chance to see an element again and move it to another | |
| 27 // list. | |
| 28 | |
| 29 #include "net/disk_cache/eviction.h" | |
| 30 | |
| 31 #include "base/bind.h" | |
| 32 #include "base/compiler_specific.h" | |
| 33 #include "base/logging.h" | |
| 34 #include "base/message_loop/message_loop.h" | |
| 35 #include "base/strings/string_util.h" | |
| 36 #include "base/time/time.h" | |
| 37 #include "net/disk_cache/backend_impl.h" | |
| 38 #include "net/disk_cache/disk_format.h" | |
| 39 #include "net/disk_cache/entry_impl.h" | |
| 40 #include "net/disk_cache/experiments.h" | |
| 41 #include "net/disk_cache/trace.h" | |
| 42 | |
| 43 #define CACHE_HISTOGRAM_MACROS_BACKEND_IMPL_OBJ backend_ | |
| 44 #include "net/disk_cache/histogram_macros.h" | |
| 45 | |
| 46 using base::Time; | |
| 47 using base::TimeTicks; | |
| 48 | |
| 49 namespace { | |
| 50 | |
| 51 const int kCleanUpMargin = 1024 * 1024; | |
| 52 const int kHighUse = 10; // Reuse count to be on the HIGH_USE list. | |
| 53 const int kTargetTime = 24 * 7; // Time to be evicted (hours since last use). | |
| 54 const int kMaxDelayedTrims = 60; | |
| 55 | |
| 56 int LowWaterAdjust(int high_water) { | |
| 57 if (high_water < kCleanUpMargin) | |
| 58 return 0; | |
| 59 | |
| 60 return high_water - kCleanUpMargin; | |
| 61 } | |
| 62 | |
| 63 bool FallingBehind(int current_size, int max_size) { | |
| 64 return current_size > max_size - kCleanUpMargin * 20; | |
| 65 } | |
| 66 | |
| 67 } // namespace | |
| 68 | |
| 69 namespace disk_cache { | |
| 70 | |
| 71 // The real initialization happens during Init(), init_ is the only member that | |
| 72 // has to be initialized here. | |
| 73 Eviction::Eviction() | |
| 74 : backend_(NULL), | |
| 75 init_(false), | |
| 76 ptr_factory_(this) { | |
| 77 } | |
| 78 | |
| 79 Eviction::~Eviction() { | |
| 80 } | |
| 81 | |
| 82 void Eviction::Init(BackendImpl* backend) { | |
| 83 // We grab a bunch of info from the backend to make the code a little cleaner | |
| 84 // when we're actually doing work. | |
| 85 backend_ = backend; | |
| 86 rankings_ = &backend->rankings_; | |
| 87 header_ = &backend_->data_->header; | |
| 88 max_size_ = LowWaterAdjust(backend_->max_size_); | |
| 89 index_size_ = backend->mask_ + 1; | |
| 90 new_eviction_ = backend->new_eviction_; | |
| 91 first_trim_ = true; | |
| 92 trimming_ = false; | |
| 93 delay_trim_ = false; | |
| 94 trim_delays_ = 0; | |
| 95 init_ = true; | |
| 96 test_mode_ = false; | |
| 97 } | |
| 98 | |
| 99 void Eviction::Stop() { | |
| 100 // It is possible for the backend initialization to fail, in which case this | |
| 101 // object was never initialized... and there is nothing to do. | |
| 102 if (!init_) | |
| 103 return; | |
| 104 | |
| 105 // We want to stop further evictions, so let's pretend that we are busy from | |
| 106 // this point on. | |
| 107 DCHECK(!trimming_); | |
| 108 trimming_ = true; | |
| 109 ptr_factory_.InvalidateWeakPtrs(); | |
| 110 } | |
| 111 | |
| 112 void Eviction::TrimCache(bool empty) { | |
| 113 if (backend_->disabled_ || trimming_) | |
| 114 return; | |
| 115 | |
| 116 if (!empty && !ShouldTrim()) | |
| 117 return PostDelayedTrim(); | |
| 118 | |
| 119 if (new_eviction_) | |
| 120 return TrimCacheV2(empty); | |
| 121 | |
| 122 Trace("*** Trim Cache ***"); | |
| 123 trimming_ = true; | |
| 124 TimeTicks start = TimeTicks::Now(); | |
| 125 Rankings::ScopedRankingsBlock node(rankings_); | |
| 126 Rankings::ScopedRankingsBlock next( | |
| 127 rankings_, rankings_->GetPrev(node.get(), Rankings::NO_USE)); | |
| 128 int deleted_entries = 0; | |
| 129 int target_size = empty ? 0 : max_size_; | |
| 130 while ((header_->num_bytes > target_size || test_mode_) && next.get()) { | |
| 131 // The iterator could be invalidated within EvictEntry(). | |
| 132 if (!next->HasData()) | |
| 133 break; | |
| 134 node.reset(next.release()); | |
| 135 next.reset(rankings_->GetPrev(node.get(), Rankings::NO_USE)); | |
| 136 if (node->Data()->dirty != backend_->GetCurrentEntryId() || empty) { | |
| 137 // This entry is not being used by anybody. | |
| 138 // Do NOT use node as an iterator after this point. | |
| 139 rankings_->TrackRankingsBlock(node.get(), false); | |
| 140 if (EvictEntry(node.get(), empty, Rankings::NO_USE) && !test_mode_) | |
| 141 deleted_entries++; | |
| 142 | |
| 143 if (!empty && test_mode_) | |
| 144 break; | |
| 145 } | |
| 146 if (!empty && (deleted_entries > 20 || | |
| 147 (TimeTicks::Now() - start).InMilliseconds() > 20)) { | |
| 148 base::MessageLoop::current()->PostTask( | |
| 149 FROM_HERE, | |
| 150 base::Bind(&Eviction::TrimCache, ptr_factory_.GetWeakPtr(), false)); | |
| 151 break; | |
| 152 } | |
| 153 } | |
| 154 | |
| 155 if (empty) { | |
| 156 CACHE_UMA(AGE_MS, "TotalClearTimeV1", 0, start); | |
| 157 } else { | |
| 158 CACHE_UMA(AGE_MS, "TotalTrimTimeV1", 0, start); | |
| 159 } | |
| 160 CACHE_UMA(COUNTS, "TrimItemsV1", 0, deleted_entries); | |
| 161 | |
| 162 trimming_ = false; | |
| 163 Trace("*** Trim Cache end ***"); | |
| 164 return; | |
| 165 } | |
| 166 | |
| 167 void Eviction::UpdateRank(EntryImpl* entry, bool modified) { | |
| 168 if (new_eviction_) | |
| 169 return UpdateRankV2(entry, modified); | |
| 170 | |
| 171 rankings_->UpdateRank(entry->rankings(), modified, GetListForEntry(entry)); | |
| 172 } | |
| 173 | |
| 174 void Eviction::OnOpenEntry(EntryImpl* entry) { | |
| 175 if (new_eviction_) | |
| 176 return OnOpenEntryV2(entry); | |
| 177 } | |
| 178 | |
| 179 void Eviction::OnCreateEntry(EntryImpl* entry) { | |
| 180 if (new_eviction_) | |
| 181 return OnCreateEntryV2(entry); | |
| 182 | |
| 183 rankings_->Insert(entry->rankings(), true, GetListForEntry(entry)); | |
| 184 } | |
| 185 | |
| 186 void Eviction::OnDoomEntry(EntryImpl* entry) { | |
| 187 if (new_eviction_) | |
| 188 return OnDoomEntryV2(entry); | |
| 189 | |
| 190 if (entry->LeaveRankingsBehind()) | |
| 191 return; | |
| 192 | |
| 193 rankings_->Remove(entry->rankings(), GetListForEntry(entry), true); | |
| 194 } | |
| 195 | |
| 196 void Eviction::OnDestroyEntry(EntryImpl* entry) { | |
| 197 if (new_eviction_) | |
| 198 return OnDestroyEntryV2(entry); | |
| 199 } | |
| 200 | |
| 201 void Eviction::SetTestMode() { | |
| 202 test_mode_ = true; | |
| 203 } | |
| 204 | |
| 205 void Eviction::TrimDeletedList(bool empty) { | |
| 206 DCHECK(test_mode_ && new_eviction_); | |
| 207 TrimDeleted(empty); | |
| 208 } | |
| 209 | |
| 210 void Eviction::PostDelayedTrim() { | |
| 211 // Prevent posting multiple tasks. | |
| 212 if (delay_trim_) | |
| 213 return; | |
| 214 delay_trim_ = true; | |
| 215 trim_delays_++; | |
| 216 base::MessageLoop::current()->PostDelayedTask( | |
| 217 FROM_HERE, | |
| 218 base::Bind(&Eviction::DelayedTrim, ptr_factory_.GetWeakPtr()), | |
| 219 base::TimeDelta::FromMilliseconds(1000)); | |
| 220 } | |
| 221 | |
| 222 void Eviction::DelayedTrim() { | |
| 223 delay_trim_ = false; | |
| 224 if (trim_delays_ < kMaxDelayedTrims && backend_->IsLoaded()) | |
| 225 return PostDelayedTrim(); | |
| 226 | |
| 227 TrimCache(false); | |
| 228 } | |
| 229 | |
| 230 bool Eviction::ShouldTrim() { | |
| 231 if (!FallingBehind(header_->num_bytes, max_size_) && | |
| 232 trim_delays_ < kMaxDelayedTrims && backend_->IsLoaded()) { | |
| 233 return false; | |
| 234 } | |
| 235 | |
| 236 UMA_HISTOGRAM_COUNTS("DiskCache.TrimDelays", trim_delays_); | |
| 237 trim_delays_ = 0; | |
| 238 return true; | |
| 239 } | |
| 240 | |
| 241 bool Eviction::ShouldTrimDeleted() { | |
| 242 int index_load = header_->num_entries * 100 / index_size_; | |
| 243 | |
| 244 // If the index is not loaded, the deleted list will tend to double the size | |
| 245 // of the other lists 3 lists (40% of the total). Otherwise, all lists will be | |
| 246 // about the same size. | |
| 247 int max_length = (index_load < 25) ? header_->num_entries * 2 / 5 : | |
| 248 header_->num_entries / 4; | |
| 249 return (!test_mode_ && header_->lru.sizes[Rankings::DELETED] > max_length); | |
| 250 } | |
| 251 | |
| 252 void Eviction::ReportTrimTimes(EntryImpl* entry) { | |
| 253 if (first_trim_) { | |
| 254 first_trim_ = false; | |
| 255 if (backend_->ShouldReportAgain()) { | |
| 256 CACHE_UMA(AGE, "TrimAge", 0, entry->GetLastUsed()); | |
| 257 ReportListStats(); | |
| 258 } | |
| 259 | |
| 260 if (header_->lru.filled) | |
| 261 return; | |
| 262 | |
| 263 header_->lru.filled = 1; | |
| 264 | |
| 265 if (header_->create_time) { | |
| 266 // This is the first entry that we have to evict, generate some noise. | |
| 267 backend_->FirstEviction(); | |
| 268 } else { | |
| 269 // This is an old file, but we may want more reports from this user so | |
| 270 // lets save some create_time. | |
| 271 Time::Exploded old = {0}; | |
| 272 old.year = 2009; | |
| 273 old.month = 3; | |
| 274 old.day_of_month = 1; | |
| 275 header_->create_time = Time::FromLocalExploded(old).ToInternalValue(); | |
| 276 } | |
| 277 } | |
| 278 } | |
| 279 | |
| 280 Rankings::List Eviction::GetListForEntry(EntryImpl* entry) { | |
| 281 return Rankings::NO_USE; | |
| 282 } | |
| 283 | |
| 284 bool Eviction::EvictEntry(CacheRankingsBlock* node, bool empty, | |
| 285 Rankings::List list) { | |
| 286 EntryImpl* entry = backend_->GetEnumeratedEntry(node, list); | |
| 287 if (!entry) { | |
| 288 Trace("NewEntry failed on Trim 0x%x", node->address().value()); | |
| 289 return false; | |
| 290 } | |
| 291 | |
| 292 ReportTrimTimes(entry); | |
| 293 if (empty || !new_eviction_) { | |
| 294 entry->DoomImpl(); | |
| 295 } else { | |
| 296 entry->DeleteEntryData(false); | |
| 297 EntryStore* info = entry->entry()->Data(); | |
| 298 DCHECK_EQ(ENTRY_NORMAL, info->state); | |
| 299 | |
| 300 rankings_->Remove(entry->rankings(), GetListForEntryV2(entry), true); | |
| 301 info->state = ENTRY_EVICTED; | |
| 302 entry->entry()->Store(); | |
| 303 rankings_->Insert(entry->rankings(), true, Rankings::DELETED); | |
| 304 } | |
| 305 if (!empty) | |
| 306 backend_->OnEvent(Stats::TRIM_ENTRY); | |
| 307 | |
| 308 entry->Release(); | |
| 309 | |
| 310 return true; | |
| 311 } | |
| 312 | |
| 313 // ----------------------------------------------------------------------- | |
| 314 | |
| 315 void Eviction::TrimCacheV2(bool empty) { | |
| 316 Trace("*** Trim Cache ***"); | |
| 317 trimming_ = true; | |
| 318 TimeTicks start = TimeTicks::Now(); | |
| 319 | |
| 320 const int kListsToSearch = 3; | |
| 321 Rankings::ScopedRankingsBlock next[kListsToSearch]; | |
| 322 int list = Rankings::LAST_ELEMENT; | |
| 323 | |
| 324 // Get a node from each list. | |
| 325 for (int i = 0; i < kListsToSearch; i++) { | |
| 326 bool done = false; | |
| 327 next[i].set_rankings(rankings_); | |
| 328 if (done) | |
| 329 continue; | |
| 330 next[i].reset(rankings_->GetPrev(NULL, static_cast<Rankings::List>(i))); | |
| 331 if (!empty && NodeIsOldEnough(next[i].get(), i)) { | |
| 332 list = static_cast<Rankings::List>(i); | |
| 333 done = true; | |
| 334 } | |
| 335 } | |
| 336 | |
| 337 // If we are not meeting the time targets lets move on to list length. | |
| 338 if (!empty && Rankings::LAST_ELEMENT == list) | |
| 339 list = SelectListByLength(next); | |
| 340 | |
| 341 if (empty) | |
| 342 list = 0; | |
| 343 | |
| 344 Rankings::ScopedRankingsBlock node(rankings_); | |
| 345 int deleted_entries = 0; | |
| 346 int target_size = empty ? 0 : max_size_; | |
| 347 | |
| 348 for (; list < kListsToSearch; list++) { | |
| 349 while ((header_->num_bytes > target_size || test_mode_) && | |
| 350 next[list].get()) { | |
| 351 // The iterator could be invalidated within EvictEntry(). | |
| 352 if (!next[list]->HasData()) | |
| 353 break; | |
| 354 node.reset(next[list].release()); | |
| 355 next[list].reset(rankings_->GetPrev(node.get(), | |
| 356 static_cast<Rankings::List>(list))); | |
| 357 if (node->Data()->dirty != backend_->GetCurrentEntryId() || empty) { | |
| 358 // This entry is not being used by anybody. | |
| 359 // Do NOT use node as an iterator after this point. | |
| 360 rankings_->TrackRankingsBlock(node.get(), false); | |
| 361 if (EvictEntry(node.get(), empty, static_cast<Rankings::List>(list))) | |
| 362 deleted_entries++; | |
| 363 | |
| 364 if (!empty && test_mode_) | |
| 365 break; | |
| 366 } | |
| 367 if (!empty && (deleted_entries > 20 || | |
| 368 (TimeTicks::Now() - start).InMilliseconds() > 20)) { | |
| 369 base::MessageLoop::current()->PostTask( | |
| 370 FROM_HERE, | |
| 371 base::Bind(&Eviction::TrimCache, ptr_factory_.GetWeakPtr(), false)); | |
| 372 break; | |
| 373 } | |
| 374 } | |
| 375 if (!empty) | |
| 376 list = kListsToSearch; | |
| 377 } | |
| 378 | |
| 379 if (empty) { | |
| 380 TrimDeleted(true); | |
| 381 } else if (ShouldTrimDeleted()) { | |
| 382 base::MessageLoop::current()->PostTask( | |
| 383 FROM_HERE, | |
| 384 base::Bind(&Eviction::TrimDeleted, ptr_factory_.GetWeakPtr(), empty)); | |
| 385 } | |
| 386 | |
| 387 if (empty) { | |
| 388 CACHE_UMA(AGE_MS, "TotalClearTimeV2", 0, start); | |
| 389 } else { | |
| 390 CACHE_UMA(AGE_MS, "TotalTrimTimeV2", 0, start); | |
| 391 } | |
| 392 CACHE_UMA(COUNTS, "TrimItemsV2", 0, deleted_entries); | |
| 393 | |
| 394 Trace("*** Trim Cache end ***"); | |
| 395 trimming_ = false; | |
| 396 return; | |
| 397 } | |
| 398 | |
| 399 void Eviction::UpdateRankV2(EntryImpl* entry, bool modified) { | |
| 400 rankings_->UpdateRank(entry->rankings(), modified, GetListForEntryV2(entry)); | |
| 401 } | |
| 402 | |
| 403 void Eviction::OnOpenEntryV2(EntryImpl* entry) { | |
| 404 EntryStore* info = entry->entry()->Data(); | |
| 405 DCHECK_EQ(ENTRY_NORMAL, info->state); | |
| 406 | |
| 407 if (info->reuse_count < kint32max) { | |
| 408 info->reuse_count++; | |
| 409 entry->entry()->set_modified(); | |
| 410 | |
| 411 // We may need to move this to a new list. | |
| 412 if (1 == info->reuse_count) { | |
| 413 rankings_->Remove(entry->rankings(), Rankings::NO_USE, true); | |
| 414 rankings_->Insert(entry->rankings(), false, Rankings::LOW_USE); | |
| 415 entry->entry()->Store(); | |
| 416 } else if (kHighUse == info->reuse_count) { | |
| 417 rankings_->Remove(entry->rankings(), Rankings::LOW_USE, true); | |
| 418 rankings_->Insert(entry->rankings(), false, Rankings::HIGH_USE); | |
| 419 entry->entry()->Store(); | |
| 420 } | |
| 421 } | |
| 422 } | |
| 423 | |
| 424 void Eviction::OnCreateEntryV2(EntryImpl* entry) { | |
| 425 EntryStore* info = entry->entry()->Data(); | |
| 426 switch (info->state) { | |
| 427 case ENTRY_NORMAL: { | |
| 428 DCHECK(!info->reuse_count); | |
| 429 DCHECK(!info->refetch_count); | |
| 430 break; | |
| 431 }; | |
| 432 case ENTRY_EVICTED: { | |
| 433 if (info->refetch_count < kint32max) | |
| 434 info->refetch_count++; | |
| 435 | |
| 436 if (info->refetch_count > kHighUse && info->reuse_count < kHighUse) { | |
| 437 info->reuse_count = kHighUse; | |
| 438 } else { | |
| 439 info->reuse_count++; | |
| 440 } | |
| 441 info->state = ENTRY_NORMAL; | |
| 442 entry->entry()->Store(); | |
| 443 rankings_->Remove(entry->rankings(), Rankings::DELETED, true); | |
| 444 break; | |
| 445 }; | |
| 446 default: | |
| 447 NOTREACHED(); | |
| 448 } | |
| 449 | |
| 450 rankings_->Insert(entry->rankings(), true, GetListForEntryV2(entry)); | |
| 451 } | |
| 452 | |
| 453 void Eviction::OnDoomEntryV2(EntryImpl* entry) { | |
| 454 EntryStore* info = entry->entry()->Data(); | |
| 455 if (ENTRY_NORMAL != info->state) | |
| 456 return; | |
| 457 | |
| 458 if (entry->LeaveRankingsBehind()) { | |
| 459 info->state = ENTRY_DOOMED; | |
| 460 entry->entry()->Store(); | |
| 461 return; | |
| 462 } | |
| 463 | |
| 464 rankings_->Remove(entry->rankings(), GetListForEntryV2(entry), true); | |
| 465 | |
| 466 info->state = ENTRY_DOOMED; | |
| 467 entry->entry()->Store(); | |
| 468 rankings_->Insert(entry->rankings(), true, Rankings::DELETED); | |
| 469 } | |
| 470 | |
| 471 void Eviction::OnDestroyEntryV2(EntryImpl* entry) { | |
| 472 if (entry->LeaveRankingsBehind()) | |
| 473 return; | |
| 474 | |
| 475 rankings_->Remove(entry->rankings(), Rankings::DELETED, true); | |
| 476 } | |
| 477 | |
| 478 Rankings::List Eviction::GetListForEntryV2(EntryImpl* entry) { | |
| 479 EntryStore* info = entry->entry()->Data(); | |
| 480 DCHECK_EQ(ENTRY_NORMAL, info->state); | |
| 481 | |
| 482 if (!info->reuse_count) | |
| 483 return Rankings::NO_USE; | |
| 484 | |
| 485 if (info->reuse_count < kHighUse) | |
| 486 return Rankings::LOW_USE; | |
| 487 | |
| 488 return Rankings::HIGH_USE; | |
| 489 } | |
| 490 | |
| 491 // This is a minimal implementation that just discards the oldest nodes. | |
| 492 // TODO(rvargas): Do something better here. | |
| 493 void Eviction::TrimDeleted(bool empty) { | |
| 494 Trace("*** Trim Deleted ***"); | |
| 495 if (backend_->disabled_) | |
| 496 return; | |
| 497 | |
| 498 TimeTicks start = TimeTicks::Now(); | |
| 499 Rankings::ScopedRankingsBlock node(rankings_); | |
| 500 Rankings::ScopedRankingsBlock next( | |
| 501 rankings_, rankings_->GetPrev(node.get(), Rankings::DELETED)); | |
| 502 int deleted_entries = 0; | |
| 503 while (next.get() && | |
| 504 (empty || (deleted_entries < 20 && | |
| 505 (TimeTicks::Now() - start).InMilliseconds() < 20))) { | |
| 506 node.reset(next.release()); | |
| 507 next.reset(rankings_->GetPrev(node.get(), Rankings::DELETED)); | |
| 508 if (RemoveDeletedNode(node.get())) | |
| 509 deleted_entries++; | |
| 510 if (test_mode_) | |
| 511 break; | |
| 512 } | |
| 513 | |
| 514 if (deleted_entries && !empty && ShouldTrimDeleted()) { | |
| 515 base::MessageLoop::current()->PostTask( | |
| 516 FROM_HERE, | |
| 517 base::Bind(&Eviction::TrimDeleted, ptr_factory_.GetWeakPtr(), false)); | |
| 518 } | |
| 519 | |
| 520 CACHE_UMA(AGE_MS, "TotalTrimDeletedTime", 0, start); | |
| 521 CACHE_UMA(COUNTS, "TrimDeletedItems", 0, deleted_entries); | |
| 522 Trace("*** Trim Deleted end ***"); | |
| 523 return; | |
| 524 } | |
| 525 | |
| 526 bool Eviction::RemoveDeletedNode(CacheRankingsBlock* node) { | |
| 527 EntryImpl* entry = backend_->GetEnumeratedEntry(node, Rankings::DELETED); | |
| 528 if (!entry) { | |
| 529 Trace("NewEntry failed on Trim 0x%x", node->address().value()); | |
| 530 return false; | |
| 531 } | |
| 532 | |
| 533 bool doomed = (entry->entry()->Data()->state == ENTRY_DOOMED); | |
| 534 entry->entry()->Data()->state = ENTRY_DOOMED; | |
| 535 entry->DoomImpl(); | |
| 536 entry->Release(); | |
| 537 return !doomed; | |
| 538 } | |
| 539 | |
| 540 bool Eviction::NodeIsOldEnough(CacheRankingsBlock* node, int list) { | |
| 541 if (!node) | |
| 542 return false; | |
| 543 | |
| 544 // If possible, we want to keep entries on each list at least kTargetTime | |
| 545 // hours. Each successive list on the enumeration has 2x the target time of | |
| 546 // the previous list. | |
| 547 Time used = Time::FromInternalValue(node->Data()->last_used); | |
| 548 int multiplier = 1 << list; | |
| 549 return (Time::Now() - used).InHours() > kTargetTime * multiplier; | |
| 550 } | |
| 551 | |
| 552 int Eviction::SelectListByLength(Rankings::ScopedRankingsBlock* next) { | |
| 553 int data_entries = header_->num_entries - | |
| 554 header_->lru.sizes[Rankings::DELETED]; | |
| 555 // Start by having each list to be roughly the same size. | |
| 556 if (header_->lru.sizes[0] > data_entries / 3) | |
| 557 return 0; | |
| 558 | |
| 559 int list = (header_->lru.sizes[1] > data_entries / 3) ? 1 : 2; | |
| 560 | |
| 561 // Make sure that frequently used items are kept for a minimum time; we know | |
| 562 // that this entry is not older than its current target, but it must be at | |
| 563 // least older than the target for list 0 (kTargetTime), as long as we don't | |
| 564 // exhaust list 0. | |
| 565 if (!NodeIsOldEnough(next[list].get(), 0) && | |
| 566 header_->lru.sizes[0] > data_entries / 10) | |
| 567 list = 0; | |
| 568 | |
| 569 return list; | |
| 570 } | |
| 571 | |
| 572 void Eviction::ReportListStats() { | |
| 573 if (!new_eviction_) | |
| 574 return; | |
| 575 | |
| 576 Rankings::ScopedRankingsBlock last1(rankings_, | |
| 577 rankings_->GetPrev(NULL, Rankings::NO_USE)); | |
| 578 Rankings::ScopedRankingsBlock last2(rankings_, | |
| 579 rankings_->GetPrev(NULL, Rankings::LOW_USE)); | |
| 580 Rankings::ScopedRankingsBlock last3(rankings_, | |
| 581 rankings_->GetPrev(NULL, Rankings::HIGH_USE)); | |
| 582 Rankings::ScopedRankingsBlock last4(rankings_, | |
| 583 rankings_->GetPrev(NULL, Rankings::DELETED)); | |
| 584 | |
| 585 if (last1.get()) | |
| 586 CACHE_UMA(AGE, "NoUseAge", 0, | |
| 587 Time::FromInternalValue(last1.get()->Data()->last_used)); | |
| 588 if (last2.get()) | |
| 589 CACHE_UMA(AGE, "LowUseAge", 0, | |
| 590 Time::FromInternalValue(last2.get()->Data()->last_used)); | |
| 591 if (last3.get()) | |
| 592 CACHE_UMA(AGE, "HighUseAge", 0, | |
| 593 Time::FromInternalValue(last3.get()->Data()->last_used)); | |
| 594 if (last4.get()) | |
| 595 CACHE_UMA(AGE, "DeletedAge", 0, | |
| 596 Time::FromInternalValue(last4.get()->Data()->last_used)); | |
| 597 } | |
| 598 | |
| 599 } // namespace disk_cache | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 121643003:
Reorganize net/disk_cache into backend specific directories. (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src