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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 BLOCKFILE_BACKEND_IMPL_OBJ to be a disk_cache::BackendImpl* in order | |
| 44 // to use the CACHE_UMA histogram macro. | |
| 45 #define BLOCKFILE_BACKEND_IMPL_OBJ backend_ | |
| 46 #include "net/disk_cache/histogram_macros.h" | |
| 47 | |
| 48 using base::Time; | |
| 49 using base::TimeTicks; | |
| 50 | |
| 51 namespace { | |
| 52 | |
| 53 const int kCleanUpMargin = 1024 * 1024; | |
| 54 const int kHighUse = 10; // Reuse count to be on the HIGH_USE list. | |
| 55 const int kTargetTime = 24 * 7; // Time to be evicted (hours since last use). | |
| 56 const int kMaxDelayedTrims = 60; | |
| 57 | |
| 58 int LowWaterAdjust(int high_water) { | |
| 59 if (high_water < kCleanUpMargin) | |
| 60 return 0; | |
| 61 | |
| 62 return high_water - kCleanUpMargin; | |
| 63 } | |
| 64 | |
| 65 bool FallingBehind(int current_size, int max_size) { | |
| 66 return current_size > max_size - kCleanUpMargin * 20; | |
| 67 } | |
| 68 | |
| 69 } // namespace | |
| 70 | |
| 71 namespace disk_cache { | |
| 72 | |
| 73 // The real initialization happens during Init(), init_ is the only member that | |
| 74 // has to be initialized here. | |
| 75 Eviction::Eviction() | |
| 76 : backend_(NULL), | |
| 77 init_(false), | |
| 78 ptr_factory_(this) { | |
| 79 } | |
| 80 | |
| 81 Eviction::~Eviction() { | |
| 82 } | |
| 83 | |
| 84 void Eviction::Init(BackendImpl* backend) { | |
| 85 // We grab a bunch of info from the backend to make the code a little cleaner | |
| 86 // when we're actually doing work. | |
| 87 backend_ = backend; | |
| 88 rankings_ = &backend->rankings_; | |
| 89 header_ = &backend_->data_->header; | |
| 90 max_size_ = LowWaterAdjust(backend_->max_size_); | |
| 91 index_size_ = backend->mask_ + 1; | |
| 92 new_eviction_ = backend->new_eviction_; | |
| 93 first_trim_ = true; | |
| 94 trimming_ = false; | |
| 95 delay_trim_ = false; | |
| 96 trim_delays_ = 0; | |
| 97 init_ = true; | |
| 98 test_mode_ = false; | |
| 99 } | |
| 100 | |
| 101 void Eviction::Stop() { | |
| 102 // It is possible for the backend initialization to fail, in which case this | |
| 103 // object was never initialized... and there is nothing to do. | |
| 104 if (!init_) | |
| 105 return; | |
| 106 | |
| 107 // We want to stop further evictions, so let's pretend that we are busy from | |
| 108 // this point on. | |
| 109 DCHECK(!trimming_); | |
| 110 trimming_ = true; | |
| 111 ptr_factory_.InvalidateWeakPtrs(); | |
| 112 } | |
| 113 | |
| 114 void Eviction::TrimCache(bool empty) { | |
| 115 if (backend_->disabled_ || trimming_) | |
| 116 return; | |
| 117 | |
| 118 if (!empty && !ShouldTrim()) | |
| 119 return PostDelayedTrim(); | |
| 120 | |
| 121 if (new_eviction_) | |
| 122 return TrimCacheV2(empty); | |
| 123 | |
| 124 Trace("*** Trim Cache ***"); | |
| 125 trimming_ = true; | |
| 126 TimeTicks start = TimeTicks::Now(); | |
| 127 Rankings::ScopedRankingsBlock node(rankings_); | |
| 128 Rankings::ScopedRankingsBlock next( | |
| 129 rankings_, rankings_->GetPrev(node.get(), Rankings::NO_USE)); | |
| 130 int deleted_entries = 0; | |
| 131 int target_size = empty ? 0 : max_size_; | |
| 132 while ((header_->num_bytes > target_size || test_mode_) && next.get()) { | |
| 133 // The iterator could be invalidated within EvictEntry(). | |
| 134 if (!next->HasData()) | |
| 135 break; | |
| 136 node.reset(next.release()); | |
| 137 next.reset(rankings_->GetPrev(node.get(), Rankings::NO_USE)); | |
| 138 if (node->Data()->dirty != backend_->GetCurrentEntryId() || empty) { | |
| 139 // This entry is not being used by anybody. | |
| 140 // Do NOT use node as an iterator after this point. | |
| 141 rankings_->TrackRankingsBlock(node.get(), false); | |
| 142 if (EvictEntry(node.get(), empty, Rankings::NO_USE) && !test_mode_) | |
| 143 deleted_entries++; | |
| 144 | |
| 145 if (!empty && test_mode_) | |
| 146 break; | |
| 147 } | |
| 148 if (!empty && (deleted_entries > 20 || | |
| 149 (TimeTicks::Now() - start).InMilliseconds() > 20)) { | |
| 150 base::MessageLoop::current()->PostTask( | |
| 151 FROM_HERE, | |
| 152 base::Bind(&Eviction::TrimCache, ptr_factory_.GetWeakPtr(), false)); | |
| 153 break; | |
| 154 } | |
| 155 } | |
| 156 | |
| 157 if (empty) { | |
| 158 CACHE_UMA(AGE_MS, "TotalClearTimeV1", 0, start); | |
| 159 } else { | |
| 160 CACHE_UMA(AGE_MS, "TotalTrimTimeV1", 0, start); | |
| 161 } | |
| 162 CACHE_UMA(COUNTS, "TrimItemsV1", 0, deleted_entries); | |
| 163 | |
| 164 trimming_ = false; | |
| 165 Trace("*** Trim Cache end ***"); | |
| 166 return; | |
| 167 } | |
| 168 | |
| 169 void Eviction::UpdateRank(EntryImpl* entry, bool modified) { | |
| 170 if (new_eviction_) | |
| 171 return UpdateRankV2(entry, modified); | |
| 172 | |
| 173 rankings_->UpdateRank(entry->rankings(), modified, GetListForEntry(entry)); | |
| 174 } | |
| 175 | |
| 176 void Eviction::OnOpenEntry(EntryImpl* entry) { | |
| 177 if (new_eviction_) | |
| 178 return OnOpenEntryV2(entry); | |
| 179 } | |
| 180 | |
| 181 void Eviction::OnCreateEntry(EntryImpl* entry) { | |
| 182 if (new_eviction_) | |
| 183 return OnCreateEntryV2(entry); | |
| 184 | |
| 185 rankings_->Insert(entry->rankings(), true, GetListForEntry(entry)); | |
| 186 } | |
| 187 | |
| 188 void Eviction::OnDoomEntry(EntryImpl* entry) { | |
| 189 if (new_eviction_) | |
| 190 return OnDoomEntryV2(entry); | |
| 191 | |
| 192 if (entry->LeaveRankingsBehind()) | |
| 193 return; | |
| 194 | |
| 195 rankings_->Remove(entry->rankings(), GetListForEntry(entry), true); | |
| 196 } | |
| 197 | |
| 198 void Eviction::OnDestroyEntry(EntryImpl* entry) { | |
| 199 if (new_eviction_) | |
| 200 return OnDestroyEntryV2(entry); | |
| 201 } | |
| 202 | |
| 203 void Eviction::SetTestMode() { | |
| 204 test_mode_ = true; | |
| 205 } | |
| 206 | |
| 207 void Eviction::TrimDeletedList(bool empty) { | |
| 208 DCHECK(test_mode_ && new_eviction_); | |
| 209 TrimDeleted(empty); | |
| 210 } | |
| 211 | |
| 212 void Eviction::PostDelayedTrim() { | |
| 213 // Prevent posting multiple tasks. | |
| 214 if (delay_trim_) | |
| 215 return; | |
| 216 delay_trim_ = true; | |
| 217 trim_delays_++; | |
| 218 base::MessageLoop::current()->PostDelayedTask( | |
| 219 FROM_HERE, | |
| 220 base::Bind(&Eviction::DelayedTrim, ptr_factory_.GetWeakPtr()), | |
| 221 base::TimeDelta::FromMilliseconds(1000)); | |
| 222 } | |
| 223 | |
| 224 void Eviction::DelayedTrim() { | |
| 225 delay_trim_ = false; | |
| 226 if (trim_delays_ < kMaxDelayedTrims && backend_->IsLoaded()) | |
| 227 return PostDelayedTrim(); | |
| 228 | |
| 229 TrimCache(false); | |
| 230 } | |
| 231 | |
| 232 bool Eviction::ShouldTrim() { | |
| 233 if (!FallingBehind(header_->num_bytes, max_size_) && | |
| 234 trim_delays_ < kMaxDelayedTrims && backend_->IsLoaded()) { | |
| 235 return false; | |
| 236 } | |
| 237 | |
| 238 UMA_HISTOGRAM_COUNTS("DiskCache.TrimDelays", trim_delays_); | |
| 239 trim_delays_ = 0; | |
| 240 return true; | |
| 241 } | |
| 242 | |
| 243 bool Eviction::ShouldTrimDeleted() { | |
| 244 int index_load = header_->num_entries * 100 / index_size_; | |
| 245 | |
| 246 // If the index is not loaded, the deleted list will tend to double the size | |
| 247 // of the other lists 3 lists (40% of the total). Otherwise, all lists will be | |
| 248 // about the same size. | |
| 249 int max_length = (index_load < 25) ? header_->num_entries * 2 / 5 : | |
| 250 header_->num_entries / 4; | |
| 251 return (!test_mode_ && header_->lru.sizes[Rankings::DELETED] > max_length); | |
| 252 } | |
| 253 | |
| 254 void Eviction::ReportTrimTimes(EntryImpl* entry) { | |
| 255 if (first_trim_) { | |
| 256 first_trim_ = false; | |
| 257 if (backend_->ShouldReportAgain()) { | |
| 258 CACHE_UMA(AGE, "TrimAge", 0, entry->GetLastUsed()); | |
| 259 ReportListStats(); | |
| 260 } | |
| 261 | |
| 262 if (header_->lru.filled) | |
| 263 return; | |
| 264 | |
| 265 header_->lru.filled = 1; | |
| 266 | |
| 267 if (header_->create_time) { | |
| 268 // This is the first entry that we have to evict, generate some noise. | |
| 269 backend_->FirstEviction(); | |
| 270 } else { | |
| 271 // This is an old file, but we may want more reports from this user so | |
| 272 // lets save some create_time. | |
| 273 Time::Exploded old = {0}; | |
| 274 old.year = 2009; | |
| 275 old.month = 3; | |
| 276 old.day_of_month = 1; | |
| 277 header_->create_time = Time::FromLocalExploded(old).ToInternalValue(); | |
| 278 } | |
| 279 } | |
| 280 } | |
| 281 | |
| 282 Rankings::List Eviction::GetListForEntry(EntryImpl* entry) { | |
| 283 return Rankings::NO_USE; | |
| 284 } | |
| 285 | |
| 286 bool Eviction::EvictEntry(CacheRankingsBlock* node, bool empty, | |
| 287 Rankings::List list) { | |
| 288 EntryImpl* entry = backend_->GetEnumeratedEntry(node, list); | |
| 289 if (!entry) { | |
| 290 Trace("NewEntry failed on Trim 0x%x", node->address().value()); | |
| 291 return false; | |
| 292 } | |
| 293 | |
| 294 ReportTrimTimes(entry); | |
| 295 if (empty || !new_eviction_) { | |
| 296 entry->DoomImpl(); | |
| 297 } else { | |
| 298 entry->DeleteEntryData(false); | |
| 299 EntryStore* info = entry->entry()->Data(); | |
| 300 DCHECK_EQ(ENTRY_NORMAL, info->state); | |
| 301 | |
| 302 rankings_->Remove(entry->rankings(), GetListForEntryV2(entry), true); | |
| 303 info->state = ENTRY_EVICTED; | |
| 304 entry->entry()->Store(); | |
| 305 rankings_->Insert(entry->rankings(), true, Rankings::DELETED); | |
| 306 } | |
| 307 if (!empty) | |
| 308 backend_->OnEvent(Stats::TRIM_ENTRY); | |
| 309 | |
| 310 entry->Release(); | |
| 311 | |
| 312 return true; | |
| 313 } | |
| 314 | |
| 315 // ----------------------------------------------------------------------- | |
| 316 | |
| 317 void Eviction::TrimCacheV2(bool empty) { | |
| 318 Trace("*** Trim Cache ***"); | |
| 319 trimming_ = true; | |
| 320 TimeTicks start = TimeTicks::Now(); | |
| 321 | |
| 322 const int kListsToSearch = 3; | |
| 323 Rankings::ScopedRankingsBlock next[kListsToSearch]; | |
| 324 int list = Rankings::LAST_ELEMENT; | |
| 325 | |
| 326 // Get a node from each list. | |
| 327 for (int i = 0; i < kListsToSearch; i++) { | |
| 328 bool done = false; | |
| 329 next[i].set_rankings(rankings_); | |
| 330 if (done) | |
| 331 continue; | |
| 332 next[i].reset(rankings_->GetPrev(NULL, static_cast<Rankings::List>(i))); | |
| 333 if (!empty && NodeIsOldEnough(next[i].get(), i)) { | |
| 334 list = static_cast<Rankings::List>(i); | |
| 335 done = true; | |
| 336 } | |
| 337 } | |
| 338 | |
| 339 // If we are not meeting the time targets lets move on to list length. | |
| 340 if (!empty && Rankings::LAST_ELEMENT == list) | |
| 341 list = SelectListByLength(next); | |
| 342 | |
| 343 if (empty) | |
| 344 list = 0; | |
| 345 | |
| 346 Rankings::ScopedRankingsBlock node(rankings_); | |
| 347 int deleted_entries = 0; | |
| 348 int target_size = empty ? 0 : max_size_; | |
| 349 | |
| 350 for (; list < kListsToSearch; list++) { | |
| 351 while ((header_->num_bytes > target_size || test_mode_) && | |
| 352 next[list].get()) { | |
| 353 // The iterator could be invalidated within EvictEntry(). | |
| 354 if (!next[list]->HasData()) | |
| 355 break; | |
| 356 node.reset(next[list].release()); | |
| 357 next[list].reset(rankings_->GetPrev(node.get(), | |
| 358 static_cast<Rankings::List>(list))); | |
| 359 if (node->Data()->dirty != backend_->GetCurrentEntryId() || empty) { | |
| 360 // This entry is not being used by anybody. | |
| 361 // Do NOT use node as an iterator after this point. | |
| 362 rankings_->TrackRankingsBlock(node.get(), false); | |
| 363 if (EvictEntry(node.get(), empty, static_cast<Rankings::List>(list))) | |
| 364 deleted_entries++; | |
| 365 | |
| 366 if (!empty && test_mode_) | |
| 367 break; | |
| 368 } | |
| 369 if (!empty && (deleted_entries > 20 || | |
| 370 (TimeTicks::Now() - start).InMilliseconds() > 20)) { | |
| 371 base::MessageLoop::current()->PostTask( | |
| 372 FROM_HERE, | |
| 373 base::Bind(&Eviction::TrimCache, ptr_factory_.GetWeakPtr(), false)); | |
| 374 break; | |
| 375 } | |
| 376 } | |
| 377 if (!empty) | |
| 378 list = kListsToSearch; | |
| 379 } | |
| 380 | |
| 381 if (empty) { | |
| 382 TrimDeleted(true); | |
| 383 } else if (ShouldTrimDeleted()) { | |
| 384 base::MessageLoop::current()->PostTask( | |
| 385 FROM_HERE, | |
| 386 base::Bind(&Eviction::TrimDeleted, ptr_factory_.GetWeakPtr(), empty)); | |
| 387 } | |
| 388 | |
| 389 if (empty) { | |
| 390 CACHE_UMA(AGE_MS, "TotalClearTimeV2", 0, start); | |
| 391 } else { | |
| 392 CACHE_UMA(AGE_MS, "TotalTrimTimeV2", 0, start); | |
| 393 } | |
| 394 CACHE_UMA(COUNTS, "TrimItemsV2", 0, deleted_entries); | |
| 395 | |
| 396 Trace("*** Trim Cache end ***"); | |
| 397 trimming_ = false; | |
| 398 return; | |
| 399 } | |
| 400 | |
| 401 void Eviction::UpdateRankV2(EntryImpl* entry, bool modified) { | |
| 402 rankings_->UpdateRank(entry->rankings(), modified, GetListForEntryV2(entry)); | |
| 403 } | |
| 404 | |
| 405 void Eviction::OnOpenEntryV2(EntryImpl* entry) { | |
| 406 EntryStore* info = entry->entry()->Data(); | |
| 407 DCHECK_EQ(ENTRY_NORMAL, info->state); | |
| 408 | |
| 409 if (info->reuse_count < kint32max) { | |
| 410 info->reuse_count++; | |
| 411 entry->entry()->set_modified(); | |
| 412 | |
| 413 // We may need to move this to a new list. | |
| 414 if (1 == info->reuse_count) { | |
| 415 rankings_->Remove(entry->rankings(), Rankings::NO_USE, true); | |
| 416 rankings_->Insert(entry->rankings(), false, Rankings::LOW_USE); | |
| 417 entry->entry()->Store(); | |
| 418 } else if (kHighUse == info->reuse_count) { | |
| 419 rankings_->Remove(entry->rankings(), Rankings::LOW_USE, true); | |
| 420 rankings_->Insert(entry->rankings(), false, Rankings::HIGH_USE); | |
| 421 entry->entry()->Store(); | |
| 422 } | |
| 423 } | |
| 424 } | |
| 425 | |
| 426 void Eviction::OnCreateEntryV2(EntryImpl* entry) { | |
| 427 EntryStore* info = entry->entry()->Data(); | |
| 428 switch (info->state) { | |
| 429 case ENTRY_NORMAL: { | |
| 430 DCHECK(!info->reuse_count); | |
| 431 DCHECK(!info->refetch_count); | |
| 432 break; | |
| 433 }; | |
| 434 case ENTRY_EVICTED: { | |
| 435 if (info->refetch_count < kint32max) | |
| 436 info->refetch_count++; | |
| 437 | |
| 438 if (info->refetch_count > kHighUse && info->reuse_count < kHighUse) { | |
| 439 info->reuse_count = kHighUse; | |
| 440 } else { | |
| 441 info->reuse_count++; | |
| 442 } | |
| 443 info->state = ENTRY_NORMAL; | |
| 444 entry->entry()->Store(); | |
| 445 rankings_->Remove(entry->rankings(), Rankings::DELETED, true); | |
| 446 break; | |
| 447 }; | |
| 448 default: | |
| 449 NOTREACHED(); | |
| 450 } | |
| 451 | |
| 452 rankings_->Insert(entry->rankings(), true, GetListForEntryV2(entry)); | |
| 453 } | |
| 454 | |
| 455 void Eviction::OnDoomEntryV2(EntryImpl* entry) { | |
| 456 EntryStore* info = entry->entry()->Data(); | |
| 457 if (ENTRY_NORMAL != info->state) | |
| 458 return; | |
| 459 | |
| 460 if (entry->LeaveRankingsBehind()) { | |
| 461 info->state = ENTRY_DOOMED; | |
| 462 entry->entry()->Store(); | |
| 463 return; | |
| 464 } | |
| 465 | |
| 466 rankings_->Remove(entry->rankings(), GetListForEntryV2(entry), true); | |
| 467 | |
| 468 info->state = ENTRY_DOOMED; | |
| 469 entry->entry()->Store(); | |
| 470 rankings_->Insert(entry->rankings(), true, Rankings::DELETED); | |
| 471 } | |
| 472 | |
| 473 void Eviction::OnDestroyEntryV2(EntryImpl* entry) { | |
| 474 if (entry->LeaveRankingsBehind()) | |
| 475 return; | |
| 476 | |
| 477 rankings_->Remove(entry->rankings(), Rankings::DELETED, true); | |
| 478 } | |
| 479 | |
| 480 Rankings::List Eviction::GetListForEntryV2(EntryImpl* entry) { | |
| 481 EntryStore* info = entry->entry()->Data(); | |
| 482 DCHECK_EQ(ENTRY_NORMAL, info->state); | |
| 483 | |
| 484 if (!info->reuse_count) | |
| 485 return Rankings::NO_USE; | |
| 486 | |
| 487 if (info->reuse_count < kHighUse) | |
| 488 return Rankings::LOW_USE; | |
| 489 | |
| 490 return Rankings::HIGH_USE; | |
| 491 } | |
| 492 | |
| 493 // This is a minimal implementation that just discards the oldest nodes. | |
| 494 // TODO(rvargas): Do something better here. | |
| 495 void Eviction::TrimDeleted(bool empty) { | |
| 496 Trace("*** Trim Deleted ***"); | |
| 497 if (backend_->disabled_) | |
| 498 return; | |
| 499 | |
| 500 TimeTicks start = TimeTicks::Now(); | |
| 501 Rankings::ScopedRankingsBlock node(rankings_); | |
| 502 Rankings::ScopedRankingsBlock next( | |
| 503 rankings_, rankings_->GetPrev(node.get(), Rankings::DELETED)); | |
| 504 int deleted_entries = 0; | |
| 505 while (next.get() && | |
| 506 (empty || (deleted_entries < 20 && | |
| 507 (TimeTicks::Now() - start).InMilliseconds() < 20))) { | |
| 508 node.reset(next.release()); | |
| 509 next.reset(rankings_->GetPrev(node.get(), Rankings::DELETED)); | |
| 510 if (RemoveDeletedNode(node.get())) | |
| 511 deleted_entries++; | |
| 512 if (test_mode_) | |
| 513 break; | |
| 514 } | |
| 515 | |
| 516 if (deleted_entries && !empty && ShouldTrimDeleted()) { | |
| 517 base::MessageLoop::current()->PostTask( | |
| 518 FROM_HERE, | |
| 519 base::Bind(&Eviction::TrimDeleted, ptr_factory_.GetWeakPtr(), false)); | |
| 520 } | |
| 521 | |
| 522 CACHE_UMA(AGE_MS, "TotalTrimDeletedTime", 0, start); | |
| 523 CACHE_UMA(COUNTS, "TrimDeletedItems", 0, deleted_entries); | |
| 524 Trace("*** Trim Deleted end ***"); | |
| 525 return; | |
| 526 } | |
| 527 | |
| 528 bool Eviction::RemoveDeletedNode(CacheRankingsBlock* node) { | |
| 529 EntryImpl* entry = backend_->GetEnumeratedEntry(node, Rankings::DELETED); | |
| 530 if (!entry) { | |
| 531 Trace("NewEntry failed on Trim 0x%x", node->address().value()); | |
| 532 return false; | |
| 533 } | |
| 534 | |
| 535 bool doomed = (entry->entry()->Data()->state == ENTRY_DOOMED); | |
| 536 entry->entry()->Data()->state = ENTRY_DOOMED; | |
| 537 entry->DoomImpl(); | |
| 538 entry->Release(); | |
| 539 return !doomed; | |
| 540 } | |
| 541 | |
| 542 bool Eviction::NodeIsOldEnough(CacheRankingsBlock* node, int list) { | |
| 543 if (!node) | |
| 544 return false; | |
| 545 | |
| 546 // If possible, we want to keep entries on each list at least kTargetTime | |
| 547 // hours. Each successive list on the enumeration has 2x the target time of | |
| 548 // the previous list. | |
| 549 Time used = Time::FromInternalValue(node->Data()->last_used); | |
| 550 int multiplier = 1 << list; | |
| 551 return (Time::Now() - used).InHours() > kTargetTime * multiplier; | |
| 552 } | |
| 553 | |
| 554 int Eviction::SelectListByLength(Rankings::ScopedRankingsBlock* next) { | |
| 555 int data_entries = header_->num_entries - | |
| 556 header_->lru.sizes[Rankings::DELETED]; | |
| 557 // Start by having each list to be roughly the same size. | |
| 558 if (header_->lru.sizes[0] > data_entries / 3) | |
| 559 return 0; | |
| 560 | |
| 561 int list = (header_->lru.sizes[1] > data_entries / 3) ? 1 : 2; | |
| 562 | |
| 563 // Make sure that frequently used items are kept for a minimum time; we know | |
| 564 // that this entry is not older than its current target, but it must be at | |
| 565 // least older than the target for list 0 (kTargetTime), as long as we don't | |
| 566 // exhaust list 0. | |
| 567 if (!NodeIsOldEnough(next[list].get(), 0) && | |
| 568 header_->lru.sizes[0] > data_entries / 10) | |
| 569 list = 0; | |
| 570 | |
| 571 return list; | |
| 572 } | |
| 573 | |
| 574 void Eviction::ReportListStats() { | |
| 575 if (!new_eviction_) | |
| 576 return; | |
| 577 | |
| 578 Rankings::ScopedRankingsBlock last1(rankings_, | |
| 579 rankings_->GetPrev(NULL, Rankings::NO_USE)); | |
| 580 Rankings::ScopedRankingsBlock last2(rankings_, | |
| 581 rankings_->GetPrev(NULL, Rankings::LOW_USE)); | |
| 582 Rankings::ScopedRankingsBlock last3(rankings_, | |
| 583 rankings_->GetPrev(NULL, Rankings::HIGH_USE)); | |
| 584 Rankings::ScopedRankingsBlock last4(rankings_, | |
| 585 rankings_->GetPrev(NULL, Rankings::DELETED)); | |
| 586 | |
| 587 if (last1.get()) | |
| 588 CACHE_UMA(AGE, "NoUseAge", 0, | |
| 589 Time::FromInternalValue(last1.get()->Data()->last_used)); | |
| 590 if (last2.get()) | |
| 591 CACHE_UMA(AGE, "LowUseAge", 0, | |
| 592 Time::FromInternalValue(last2.get()->Data()->last_used)); | |
| 593 if (last3.get()) | |
| 594 CACHE_UMA(AGE, "HighUseAge", 0, | |
| 595 Time::FromInternalValue(last3.get()->Data()->last_used)); | |
| 596 if (last4.get()) | |
| 597 CACHE_UMA(AGE, "DeletedAge", 0, | |
| 598 Time::FromInternalValue(last4.get()->Data()->last_used)); | |
| 599 } | |
| 600 | |
| 601 } // 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