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