dom/base/nsWindowMemoryReporter.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsWindowMemoryReporter.h"
   8 #include "nsWindowSizes.h"
   9 #include "nsGlobalWindow.h"
  10 #include "mozilla/dom/BrowsingContext.h"
  11 #include "mozilla/dom/Document.h"
  12 #include "mozilla/ClearOnShutdown.h"
  13 #include "mozilla/Preferences.h"
  14 #include "mozilla/Services.h"
  15 #include "mozilla/StaticPtr.h"
  16 #include "mozilla/Telemetry.h"
  17 #include "mozilla/ResultExtensions.h"
  18 #include "nsNetCID.h"
  19 #include "nsPrintfCString.h"
  20 #include "XPCJSMemoryReporter.h"
  21 #include "js/MemoryMetrics.h"
  22 #include "nsQueryObject.h"
  23 #include "nsServiceManagerUtils.h"
  24 #ifdef MOZ_XUL
  25 #  include "nsXULPrototypeCache.h"
  26 #endif
  27
  28 using namespace mozilla;
  29 using namespace mozilla::dom;
  30
  31 StaticRefPtr<nsWindowMemoryReporter> sWindowReporter;
  32
  33 /**
  34  * Don't trigger a ghost window check when a DOM window is detached if we've
  35  * run it this recently.
  36  */
  37 const int32_t kTimeBetweenChecks = 45; /* seconds */
  38
  39 nsWindowMemoryReporter::nsWindowMemoryReporter()
  40     : mLastCheckForGhostWindows(TimeStamp::NowLoRes()),
  41       mCycleCollectorIsRunning(false),
  42       mCheckTimerWaitingForCCEnd(false),
  43       mGhostWindowCount(0) {}
  44
  45 nsWindowMemoryReporter::~nsWindowMemoryReporter() { KillCheckTimer(); }
  46
  47 NS_IMPL_ISUPPORTS(nsWindowMemoryReporter, nsIMemoryReporter, nsIObserver,
  48                   nsISupportsWeakReference)
  49
  50 static nsresult AddNonJSSizeOfWindowAndItsDescendents(
  51     nsGlobalWindowOuter* aWindow, nsTabSizes* aSizes) {
  52   // Measure the window.
  53   SizeOfState state(moz_malloc_size_of);
  54   nsWindowSizes windowSizes(state);
  55   aWindow->AddSizeOfIncludingThis(windowSizes);
  56
  57   // Measure the inner window, if there is one.
  58   nsGlobalWindowInner* inner = aWindow->GetCurrentInnerWindowInternal();
  59   if (inner) {
  60     inner->AddSizeOfIncludingThis(windowSizes);
  61   }
  62
  63   windowSizes.addToTabSizes(aSizes);
  64
  65   BrowsingContext* bc = aWindow->GetBrowsingContext();
  66   if (!bc) {
  67     return NS_OK;
  68   }
  69
  70   // Measure this window's descendents.
  71   for (const auto& frame : bc->Children()) {
  72     if (auto* childWin = nsGlobalWindowOuter::Cast(frame->GetDOMWindow())) {
  73       MOZ_TRY(AddNonJSSizeOfWindowAndItsDescendents(childWin, aSizes));
  74     }
  75   }
  76   return NS_OK;
  77 }
  78
  79 static nsresult NonJSSizeOfTab(nsPIDOMWindowOuter* aWindow, size_t* aDomSize,
  80                                size_t* aStyleSize, size_t* aOtherSize) {
  81   nsGlobalWindowOuter* window = nsGlobalWindowOuter::Cast(aWindow);
  82
  83   nsTabSizes sizes;
  84   nsresult rv = AddNonJSSizeOfWindowAndItsDescendents(window, &sizes);
  85   NS_ENSURE_SUCCESS(rv, rv);
  86
  87   *aDomSize = sizes.mDom;
  88   *aStyleSize = sizes.mStyle;
  89   *aOtherSize = sizes.mOther;
  90   return NS_OK;
  91 }
  92
  93 /* static */
  94 void nsWindowMemoryReporter::Init() {
  95   MOZ_ASSERT(!sWindowReporter);
  96   sWindowReporter = new nsWindowMemoryReporter();
  97   ClearOnShutdown(&sWindowReporter);
  98   RegisterStrongMemoryReporter(sWindowReporter);
  99   RegisterNonJSSizeOfTab(NonJSSizeOfTab);
 100
 101   nsCOMPtr<nsIObserverService> os = services::GetObserverService();
 102   if (os) {
 103     os->AddObserver(sWindowReporter, "after-minimize-memory-usage",
 104                     /* weakRef = */ true);
 105     os->AddObserver(sWindowReporter, "cycle-collector-begin",
 106                     /* weakRef = */ true);
 107     os->AddObserver(sWindowReporter, "cycle-collector-end",
 108                     /* weakRef = */ true);
 109   }
 110
 111   RegisterGhostWindowsDistinguishedAmount(GhostWindowsDistinguishedAmount);
 112 }
 113
 114 /* static */
 115 nsWindowMemoryReporter* nsWindowMemoryReporter::Get() {
 116   return sWindowReporter;
 117 }
 118
 119 static nsCString GetWindowURISpec(nsGlobalWindowInner* aWindow) {
 120   NS_ENSURE_TRUE(aWindow, ""_ns);
 121
 122   nsCOMPtr<Document> doc = aWindow->GetExtantDoc();
 123   if (doc) {
 124     nsCOMPtr<nsIURI> uri;
 125     uri = doc->GetDocumentURI();
 126     return uri->GetSpecOrDefault();
 127   }
 128   nsCOMPtr<nsIScriptObjectPrincipal> scriptObjPrincipal =
 129       do_QueryObject(aWindow);
 130   NS_ENSURE_TRUE(scriptObjPrincipal, ""_ns);
 131
 132   // GetPrincipal() will print a warning if the window does not have an outer
 133   // window, so check here for an outer window first.  This code is
 134   // functionally correct if we leave out the GetOuterWindow() check, but we
 135   // end up printing a lot of warnings during debug mochitests.
 136   if (!aWindow->GetOuterWindow()) {
 137     return ""_ns;
 138   }
 139   nsIPrincipal* principal = scriptObjPrincipal->GetPrincipal();
 140   if (!principal) {
 141     return ""_ns;
 142   }
 143   nsCString spec;
 144   principal->GetAsciiSpec(spec);
 145   return spec;
 146 }
 147
 148 static void AppendWindowURI(nsGlobalWindowInner* aWindow, nsACString& aStr,
 149                             bool aAnonymize) {
 150   nsCString spec = GetWindowURISpec(aWindow);
 151
 152   if (spec.IsEmpty()) {
 153     // If we're unable to find a URI, we're dealing with a chrome window with
 154     // no document in it (or somesuch), so we call this a "system window".
 155     aStr += "[system]"_ns;
 156     return;
 157   }
 158   if (aAnonymize && !aWindow->IsChromeWindow()) {
 159     aStr.AppendPrintf("<anonymized-%" PRIu64 ">", aWindow->WindowID());
 160     return;
 161   }
 162   // A hack: replace forward slashes with '\\' so they aren't
 163   // treated as path separators.  Users of the reporters
 164   // (such as about:memory) have to undo this change.
 165   spec.ReplaceChar('/', '\\');
 166   aStr += spec;
 167 }
 168
 169 MOZ_DEFINE_MALLOC_SIZE_OF(WindowsMallocSizeOf)
 170
 171 // The key is the window ID.
 172 typedef nsDataHashtable<nsUint64HashKey, nsCString> WindowPaths;
 173
 174 static void ReportAmount(const nsCString& aBasePath, const char* aPathTail,
 175                          size_t aAmount, const nsCString& aDescription,
 176                          uint32_t aKind, uint32_t aUnits,
 177                          nsIHandleReportCallback* aHandleReport,
 178                          nsISupports* aData) {
 179   if (aAmount == 0) {
 180     return;
 181   }
 182
 183   nsAutoCString path(aBasePath);
 184   path += aPathTail;
 185
 186   aHandleReport->Callback(EmptyCString(), path, aKind, aUnits, aAmount,
 187                           aDescription, aData);
 188 }
 189
 190 static void ReportSize(const nsCString& aBasePath, const char* aPathTail,
 191                        size_t aAmount, const nsCString& aDescription,
 192                        nsIHandleReportCallback* aHandleReport,
 193                        nsISupports* aData) {
 194   ReportAmount(aBasePath, aPathTail, aAmount, aDescription,
 195                nsIMemoryReporter::KIND_HEAP, nsIMemoryReporter::UNITS_BYTES,
 196                aHandleReport, aData);
 197 }
 198
 199 static void ReportCount(const nsCString& aBasePath, const char* aPathTail,
 200                         size_t aAmount, const nsCString& aDescription,
 201                         nsIHandleReportCallback* aHandleReport,
 202                         nsISupports* aData) {
 203   ReportAmount(aBasePath, aPathTail, aAmount, aDescription,
 204                nsIMemoryReporter::KIND_OTHER, nsIMemoryReporter::UNITS_COUNT,
 205                aHandleReport, aData);
 206 }
 207
 208 static void CollectWindowReports(nsGlobalWindowInner* aWindow,
 209                                  nsWindowSizes* aWindowTotalSizes,
 210                                  nsTHashtable<nsUint64HashKey>* aGhostWindowIDs,
 211                                  WindowPaths* aWindowPaths,
 212                                  WindowPaths* aTopWindowPaths,
 213                                  nsIHandleReportCallback* aHandleReport,
 214                                  nsISupports* aData, bool aAnonymize) {
 215   nsAutoCString windowPath("explicit/");
 216
 217   // Avoid calling aWindow->GetInProcessTop() if there's no outer window.  It
 218   // will work just fine, but will spew a lot of warnings.
 219   nsGlobalWindowOuter* top = nullptr;
 220   if (aWindow->GetOuterWindow()) {
 221     // Our window should have a null top iff it has a null docshell.
 222     MOZ_ASSERT(!!aWindow->GetInProcessTopInternal() ==
 223                !!aWindow->GetDocShell());
 224     top = aWindow->GetInProcessTopInternal();
 225   }
 226
 227   windowPath += "window-objects/"_ns;
 228
 229   if (top) {
 230     windowPath += "top("_ns;
 231     AppendWindowURI(top->GetCurrentInnerWindowInternal(), windowPath,
 232                     aAnonymize);
 233     windowPath.AppendPrintf(", id=%" PRIu64 ")", top->WindowID());
 234
 235     aTopWindowPaths->Put(aWindow->WindowID(), windowPath);
 236
 237     windowPath += aWindow->IsFrozen() ? "/cached/"_ns : "/active/"_ns;
 238   } else {
 239     if (aGhostWindowIDs->Contains(aWindow->WindowID())) {
 240       windowPath += "top(none)/ghost/"_ns;
 241     } else {
 242       windowPath += "top(none)/detached/"_ns;
 243     }
 244   }
 245
 246   windowPath += "window("_ns;
 247   AppendWindowURI(aWindow, windowPath, aAnonymize);
 248   windowPath += ")"_ns;
 249
 250   // Use |windowPath|, but replace "explicit/" with "event-counts/".
 251   nsCString censusWindowPath(windowPath);
 252   censusWindowPath.ReplaceLiteral(0, strlen("explicit"), "event-counts");
 253
 254   // Remember the path for later.
 255   aWindowPaths->Put(aWindow->WindowID(), windowPath);
 256
 257 // Report the size from windowSizes and add to the appropriate total in
 258 // aWindowTotalSizes.
 259 #define REPORT_SIZE(_pathTail, _field, _desc)                \
 260   ReportSize(windowPath, _pathTail, windowSizes._field,      \
 261              nsLiteralCString(_desc), aHandleReport, aData); \
 262   aWindowTotalSizes->_field += windowSizes._field;
 263
 264 // Report the size, which is a sum of other sizes, and so doesn't require
 265 // updating aWindowTotalSizes.
 266 #define REPORT_SUM_SIZE(_pathTail, _amount, _desc)                    \
 267   ReportSize(windowPath, _pathTail, _amount, nsLiteralCString(_desc), \
 268              aHandleReport, aData);
 269
 270 // Like REPORT_SIZE, but for a count.
 271 #define REPORT_COUNT(_pathTail, _field, _desc)                 \
 272   ReportCount(censusWindowPath, _pathTail, windowSizes._field, \
 273               nsLiteralCString(_desc), aHandleReport, aData);  \
 274   aWindowTotalSizes->_field += windowSizes._field;
 275
 276   // This SizeOfState contains the SeenPtrs used for all memory reporting of
 277   // this window.
 278   SizeOfState state(WindowsMallocSizeOf);
 279   nsWindowSizes windowSizes(state);
 280   aWindow->AddSizeOfIncludingThis(windowSizes);
 281
 282   REPORT_SIZE("/dom/element-nodes", mDOMElementNodesSize,
 283               "Memory used by the element nodes in a window's DOM.");
 284
 285   REPORT_SIZE("/dom/text-nodes", mDOMTextNodesSize,
 286               "Memory used by the text nodes in a window's DOM.");
 287
 288   REPORT_SIZE("/dom/cdata-nodes", mDOMCDATANodesSize,
 289               "Memory used by the CDATA nodes in a window's DOM.");
 290
 291   REPORT_SIZE("/dom/comment-nodes", mDOMCommentNodesSize,
 292               "Memory used by the comment nodes in a window's DOM.");
 293
 294   REPORT_SIZE("/dom/event-targets", mDOMEventTargetsSize,
 295               "Memory used by the event targets table in a window's DOM, and "
 296               "the objects it points to, which include XHRs.");
 297
 298   REPORT_SIZE("/dom/performance/user-entries", mDOMPerformanceUserEntries,
 299               "Memory used for performance user entries.");
 300
 301   REPORT_SIZE("/dom/performance/resource-entries",
 302               mDOMPerformanceResourceEntries,
 303               "Memory used for performance resource entries.");
 304
 305   REPORT_SIZE("/dom/media-query-lists", mDOMMediaQueryLists,
 306               "Memory used by MediaQueryList objects for the window's "
 307               "document.");
 308
 309   REPORT_SIZE("/dom/resize-observers", mDOMResizeObserverControllerSize,
 310               "Memory used for resize observers.");
 311
 312   REPORT_SIZE("/dom/other", mDOMOtherSize,
 313               "Memory used by a window's DOM that isn't measured by the "
 314               "other 'dom/' numbers.");
 315
 316   REPORT_SIZE("/layout/style-sheets", mLayoutStyleSheetsSize,
 317               "Memory used by document style sheets within a window.");
 318
 319   REPORT_SIZE("/layout/svg-mapped-declarations", mLayoutSvgMappedDeclarations,
 320               "Memory used by mapped declarations of SVG elements");
 321
 322   REPORT_SIZE("/layout/shadow-dom/style-sheets",
 323               mLayoutShadowDomStyleSheetsSize,
 324               "Memory used by Shadow DOM style sheets within a window.");
 325
 326   // TODO(emilio): We might want to split this up between invalidation map /
 327   // element-and-pseudos / revalidation too just like the style set.
 328   REPORT_SIZE("/layout/shadow-dom/author-styles", mLayoutShadowDomAuthorStyles,
 329               "Memory used by Shadow DOM computed rule data within a window.");
 330
 331   REPORT_SIZE("/layout/pres-shell", mLayoutPresShellSize,
 332               "Memory used by layout's PresShell, along with any structures "
 333               "allocated in its arena and not measured elsewhere, "
 334               "within a window.");
 335
 336   REPORT_SIZE("/layout/display-list", mLayoutRetainedDisplayListSize,
 337               "Memory used by the retained display list data, "
 338               "along with any structures allocated in its arena and not "
 339               "measured elsewhere, within a window.");
 340
 341   REPORT_SIZE("/layout/style-sets/stylist/rule-tree",
 342               mLayoutStyleSetsStylistRuleTree,
 343               "Memory used by rule trees within style sets within a window.");
 344
 345   REPORT_SIZE("/layout/style-sets/stylist/element-and-pseudos-maps",
 346               mLayoutStyleSetsStylistElementAndPseudosMaps,
 347               "Memory used by element and pseudos maps within style "
 348               "sets within a window.");
 349
 350   REPORT_SIZE("/layout/style-sets/stylist/invalidation-map",
 351               mLayoutStyleSetsStylistInvalidationMap,
 352               "Memory used by invalidation maps within style sets "
 353               "within a window.");
 354
 355   REPORT_SIZE("/layout/style-sets/stylist/revalidation-selectors",
 356               mLayoutStyleSetsStylistRevalidationSelectors,
 357               "Memory used by selectors for cache revalidation within "
 358               "style sets within a window.");
 359
 360   REPORT_SIZE("/layout/style-sets/stylist/other", mLayoutStyleSetsStylistOther,
 361               "Memory used by other Stylist data within style sets "
 362               "within a window.");
 363
 364   REPORT_SIZE("/layout/style-sets/other", mLayoutStyleSetsOther,
 365               "Memory used by other parts of style sets within a window.");
 366
 367   REPORT_SIZE("/layout/element-data-objects", mLayoutElementDataObjects,
 368               "Memory used for ElementData objects, but not the things "
 369               "hanging off them.");
 370
 371   REPORT_SIZE("/layout/text-runs", mLayoutTextRunsSize,
 372               "Memory used for text-runs (glyph layout) in the PresShell's "
 373               "frame tree, within a window.");
 374
 375   REPORT_SIZE("/layout/pres-contexts", mLayoutPresContextSize,
 376               "Memory used for the PresContext in the PresShell's frame "
 377               "within a window.");
 378
 379   REPORT_SIZE("/layout/frame-properties", mLayoutFramePropertiesSize,
 380               "Memory used for frame properties attached to frames "
 381               "within a window.");
 382
 383   REPORT_SIZE("/layout/computed-values/dom", mLayoutComputedValuesDom,
 384               "Memory used by ComputedValues objects accessible from DOM "
 385               "elements.");
 386
 387   REPORT_SIZE("/layout/computed-values/non-dom", mLayoutComputedValuesNonDom,
 388               "Memory used by ComputedValues objects not accessible from DOM "
 389               "elements.");
 390
 391   REPORT_SIZE("/layout/computed-values/visited", mLayoutComputedValuesVisited,
 392               "Memory used by ComputedValues objects used for visited styles.");
 393
 394   REPORT_SIZE("/property-tables", mPropertyTablesSize,
 395               "Memory used for the property tables within a window.");
 396
 397   REPORT_SIZE("/bindings", mBindingsSize,
 398               "Memory used by bindings within a window.");
 399
 400   REPORT_COUNT("/dom/event-targets", mDOMEventTargetsCount,
 401                "Number of non-node event targets in the event targets table "
 402                "in a window's DOM, such as XHRs.");
 403
 404   REPORT_COUNT("/dom/event-listeners", mDOMEventListenersCount,
 405                "Number of event listeners in a window, including event "
 406                "listeners on nodes and other event targets.");
 407
 408   // There are many different kinds of frames, but it is very likely
 409   // that only a few matter.  Implement a cutoff so we don't bloat
 410   // about:memory with many uninteresting entries.
 411   const size_t ARENA_SUNDRIES_THRESHOLD =
 412       js::MemoryReportingSundriesThreshold();
 413
 414   size_t presArenaSundriesSize = 0;
 415 #define ARENA_OBJECT(name_, sundries_size_, prefix_)                    \
 416   {                                                                     \
 417     size_t size = windowSizes.mArenaSizes.NS_ARENA_SIZES_FIELD(name_);  \
 418     if (size < ARENA_SUNDRIES_THRESHOLD) {                              \
 419       sundries_size_ += size;                                           \
 420     } else {                                                            \
 421       REPORT_SUM_SIZE(prefix_ #name_, size,                             \
 422                       "Memory used by objects of type " #name_          \
 423                       " within a window.");                             \
 424     }                                                                   \
 425     aWindowTotalSizes->mArenaSizes.NS_ARENA_SIZES_FIELD(name_) += size; \
 426   }
 427 #define PRES_ARENA_OBJECT(name_) \
 428   ARENA_OBJECT(name_, presArenaSundriesSize, "/layout/pres-arena/")
 429 #include "nsPresArenaObjectList.h"
 430 #undef PRES_ARENA_OBJECT
 431
 432   if (presArenaSundriesSize > 0) {
 433     REPORT_SUM_SIZE(
 434         "/layout/pres-arena/sundries", presArenaSundriesSize,
 435         "The sum of all memory used by objects in the arena which were too "
 436         "small to be shown individually.");
 437   }
 438
 439   size_t displayListArenaSundriesSize = 0;
 440 #define DISPLAY_LIST_ARENA_OBJECT(name_)            \
 441   ARENA_OBJECT(name_, displayListArenaSundriesSize, \
 442                "/layout/display-list-arena/")
 443 #include "nsDisplayListArenaTypes.h"
 444 #undef DISPLAY_LIST_ARENA_OBJECT
 445
 446   if (displayListArenaSundriesSize > 0) {
 447     REPORT_SUM_SIZE(
 448         "/layout/display-list-arena/sundries", displayListArenaSundriesSize,
 449         "The sum of all memory used by objects in the DL arena which were too "
 450         "small to be shown individually.");
 451   }
 452
 453 #undef ARENA_OBJECT
 454
 455   // There are many different kinds of style structs, but it is likely that
 456   // only a few matter. Implement a cutoff so we don't bloat about:memory with
 457   // many uninteresting entries.
 458   const size_t STYLE_SUNDRIES_THRESHOLD =
 459       js::MemoryReportingSundriesThreshold();
 460
 461   size_t styleSundriesSize = 0;
 462 #define STYLE_STRUCT(name_)                                             \
 463   {                                                                     \
 464     size_t size = windowSizes.mStyleSizes.NS_STYLE_SIZES_FIELD(name_);  \
 465     if (size < STYLE_SUNDRIES_THRESHOLD) {                              \
 466       styleSundriesSize += size;                                        \
 467     } else {                                                            \
 468       REPORT_SUM_SIZE("/layout/style-structs/" #name_, size,            \
 469                       "Memory used by the " #name_                      \
 470                       " style structs within a window.");               \
 471     }                                                                   \
 472     aWindowTotalSizes->mStyleSizes.NS_STYLE_SIZES_FIELD(name_) += size; \
 473   }
 474 #include "nsStyleStructList.h"
 475 #undef STYLE_STRUCT
 476
 477   if (styleSundriesSize > 0) {
 478     REPORT_SUM_SIZE(
 479         "/layout/style-structs/sundries", styleSundriesSize,
 480         "The sum of all memory used by style structs which were too "
 481         "small to be shown individually.");
 482   }
 483
 484 #undef REPORT_SIZE
 485 #undef REPORT_SUM_SIZE
 486 #undef REPORT_COUNT
 487 }
 488
 489 typedef nsTArray<RefPtr<nsGlobalWindowInner>> WindowArray;
 490
 491 NS_IMETHODIMP
 492 nsWindowMemoryReporter::CollectReports(nsIHandleReportCallback* aHandleReport,
 493                                        nsISupports* aData, bool aAnonymize) {
 494   nsGlobalWindowInner::InnerWindowByIdTable* windowsById =
 495       nsGlobalWindowInner::GetWindowsTable();
 496   NS_ENSURE_TRUE(windowsById, NS_OK);
 497
 498   // Hold on to every window in memory so that window objects can't be
 499   // destroyed while we're calling the memory reporter callback.
 500   WindowArray windows;
 501   for (auto iter = windowsById->Iter(); !iter.Done(); iter.Next()) {
 502     windows.AppendElement(iter.Data());
 503   }
 504
 505   // Get the IDs of all the "ghost" windows, and call aHandleReport->Callback()
 506   // for each one.
 507   nsTHashtable<nsUint64HashKey> ghostWindows;
 508   CheckForGhostWindows(&ghostWindows);
 509   for (auto iter = ghostWindows.ConstIter(); !iter.Done(); iter.Next()) {
 510     nsGlobalWindowInner::InnerWindowByIdTable* windowsById =
 511         nsGlobalWindowInner::GetWindowsTable();
 512     if (!windowsById) {
 513       NS_WARNING("Couldn't get window-by-id hashtable?");
 514       continue;
 515     }
 516
 517     nsGlobalWindowInner* window = windowsById->Get(iter.Get()->GetKey());
 518     if (!window) {
 519       NS_WARNING("Could not look up window?");
 520       continue;
 521     }
 522
 523     nsAutoCString path;
 524     path.AppendLiteral("ghost-windows/");
 525     AppendWindowURI(window, path, aAnonymize);
 526
 527     aHandleReport->Callback(
 528         /* process = */ EmptyCString(), path, nsIMemoryReporter::KIND_OTHER,
 529         nsIMemoryReporter::UNITS_COUNT,
 530         /* amount = */ 1,
 531         /* description = */ "A ghost window."_ns, aData);
 532   }
 533
 534   // clang-format off
 535   MOZ_COLLECT_REPORT(
 536     "ghost-windows", KIND_OTHER, UNITS_COUNT, ghostWindows.Count(),
 537 "The number of ghost windows present (the number of nodes underneath "
 538 "explicit/window-objects/top(none)/ghost, modulo race conditions).  A ghost "
 539 "window is not shown in any tab, is not in a browsing context group with any "
 540 "non-detached windows, and has met these criteria for at least "
 541 "memory.ghost_window_timeout_seconds, or has survived a round of "
 542 "about:memory's minimize memory usage button.\n\n"
 543 "Ghost windows can happen legitimately, but they are often indicative of "
 544 "leaks in the browser or add-ons.");
 545   // clang-format on
 546
 547   WindowPaths windowPaths;
 548   WindowPaths topWindowPaths;
 549
 550   // Collect window memory usage.
 551   SizeOfState fakeState(nullptr);  // this won't be used
 552   nsWindowSizes windowTotalSizes(fakeState);
 553   for (uint32_t i = 0; i < windows.Length(); i++) {
 554     CollectWindowReports(windows[i], &windowTotalSizes, &ghostWindows,
 555                          &windowPaths, &topWindowPaths, aHandleReport, aData,
 556                          aAnonymize);
 557   }
 558
 559   // Report JS memory usage.  We do this from here because the JS memory
 560   // reporter needs to be passed |windowPaths|.
 561   xpc::JSReporter::CollectReports(&windowPaths, &topWindowPaths, aHandleReport,
 562                                   aData, aAnonymize);
 563
 564 #ifdef MOZ_XUL
 565   nsXULPrototypeCache::CollectMemoryReports(aHandleReport, aData);
 566 #endif
 567
 568 #define REPORT(_path, _amount, _desc)                                          \
 569   aHandleReport->Callback(EmptyCString(), nsLiteralCString(_path), KIND_OTHER, \
 570                           UNITS_BYTES, _amount, nsLiteralCString(_desc),       \
 571                           aData);
 572
 573   REPORT("window-objects/dom/element-nodes",
 574          windowTotalSizes.mDOMElementNodesSize,
 575          "This is the sum of all windows' 'dom/element-nodes' numbers.");
 576
 577   REPORT("window-objects/dom/text-nodes", windowTotalSizes.mDOMTextNodesSize,
 578          "This is the sum of all windows' 'dom/text-nodes' numbers.");
 579
 580   REPORT("window-objects/dom/cdata-nodes", windowTotalSizes.mDOMCDATANodesSize,
 581          "This is the sum of all windows' 'dom/cdata-nodes' numbers.");
 582
 583   REPORT("window-objects/dom/comment-nodes",
 584          windowTotalSizes.mDOMCommentNodesSize,
 585          "This is the sum of all windows' 'dom/comment-nodes' numbers.");
 586
 587   REPORT("window-objects/dom/event-targets",
 588          windowTotalSizes.mDOMEventTargetsSize,
 589          "This is the sum of all windows' 'dom/event-targets' numbers.");
 590
 591   REPORT("window-objects/dom/performance",
 592          windowTotalSizes.mDOMPerformanceUserEntries +
 593              windowTotalSizes.mDOMPerformanceResourceEntries,
 594          "This is the sum of all windows' 'dom/performance/' numbers.");
 595
 596   REPORT("window-objects/dom/other", windowTotalSizes.mDOMOtherSize,
 597          "This is the sum of all windows' 'dom/other' numbers.");
 598
 599   REPORT("window-objects/layout/style-sheets",
 600          windowTotalSizes.mLayoutStyleSheetsSize,
 601          "This is the sum of all windows' 'layout/style-sheets' numbers.");
 602
 603   REPORT("window-objects/layout/pres-shell",
 604          windowTotalSizes.mLayoutPresShellSize,
 605          "This is the sum of all windows' 'layout/arenas' numbers.");
 606
 607   REPORT("window-objects/layout/style-sets",
 608          windowTotalSizes.mLayoutStyleSetsStylistRuleTree +
 609              windowTotalSizes.mLayoutStyleSetsStylistElementAndPseudosMaps +
 610              windowTotalSizes.mLayoutStyleSetsStylistInvalidationMap +
 611              windowTotalSizes.mLayoutStyleSetsStylistRevalidationSelectors +
 612              windowTotalSizes.mLayoutStyleSetsStylistOther +
 613              windowTotalSizes.mLayoutStyleSetsOther,
 614          "This is the sum of all windows' 'layout/style-sets/' numbers.");
 615
 616   REPORT("window-objects/layout/element-data-objects",
 617          windowTotalSizes.mLayoutElementDataObjects,
 618          "This is the sum of all windows' 'layout/element-data-objects' "
 619          "numbers.");
 620
 621   REPORT("window-objects/layout/text-runs",
 622          windowTotalSizes.mLayoutTextRunsSize,
 623          "This is the sum of all windows' 'layout/text-runs' numbers.");
 624
 625   REPORT("window-objects/layout/pres-contexts",
 626          windowTotalSizes.mLayoutPresContextSize,
 627          "This is the sum of all windows' 'layout/pres-contexts' numbers.");
 628
 629   REPORT("window-objects/layout/frame-properties",
 630          windowTotalSizes.mLayoutFramePropertiesSize,
 631          "This is the sum of all windows' 'layout/frame-properties' numbers.");
 632
 633   REPORT("window-objects/layout/computed-values",
 634          windowTotalSizes.mLayoutComputedValuesDom +
 635              windowTotalSizes.mLayoutComputedValuesNonDom +
 636              windowTotalSizes.mLayoutComputedValuesVisited,
 637          "This is the sum of all windows' 'layout/computed-values/' numbers.");
 638
 639   REPORT("window-objects/property-tables", windowTotalSizes.mPropertyTablesSize,
 640          "This is the sum of all windows' 'property-tables' numbers.");
 641
 642   size_t presArenaTotal = 0;
 643 #define PRES_ARENA_OBJECT(name_) \
 644   presArenaTotal += windowTotalSizes.mArenaSizes.NS_ARENA_SIZES_FIELD(name_);
 645 #include "nsPresArenaObjectList.h"
 646 #undef PRES_ARENA_OBJECT
 647
 648   REPORT("window-objects/layout/pres-arena", presArenaTotal,
 649          "Memory used for the pres arena within windows. "
 650          "This is the sum of all windows' 'layout/pres-arena/' numbers.");
 651
 652   size_t displayListArenaTotal = 0;
 653 #define DISPLAY_LIST_ARENA_OBJECT(name_) \
 654   displayListArenaTotal +=               \
 655       windowTotalSizes.mArenaSizes.NS_ARENA_SIZES_FIELD(name_);
 656 #include "nsDisplayListArenaTypes.h"
 657 #undef DISPLAY_LIST_ARENA_OBJECT
 658
 659   REPORT("window-objects/layout/display-list-arena", displayListArenaTotal,
 660          "Memory used for the display list arena within windows. This is the "
 661          "sum of all windows' 'layout/display-list-arena/' numbers.");
 662
 663   size_t styleTotal = 0;
 664 #define STYLE_STRUCT(name_) \
 665   styleTotal += windowTotalSizes.mStyleSizes.NS_STYLE_SIZES_FIELD(name_);
 666 #include "nsStyleStructList.h"
 667 #undef STYLE_STRUCT
 668
 669   REPORT("window-objects/layout/style-structs", styleTotal,
 670          "Memory used for style structs within windows. This is the sum of "
 671          "all windows' 'layout/style-structs/' numbers.");
 672
 673 #undef REPORT
 674
 675   return NS_OK;
 676 }
 677
 678 uint32_t nsWindowMemoryReporter::GetGhostTimeout() {
 679   return Preferences::GetUint("memory.ghost_window_timeout_seconds", 60);
 680 }
 681
 682 NS_IMETHODIMP
 683 nsWindowMemoryReporter::Observe(nsISupports* aSubject, const char* aTopic,
 684                                 const char16_t* aData) {
 685   if (!strcmp(aTopic, "after-minimize-memory-usage")) {
 686     ObserveAfterMinimizeMemoryUsage();
 687   } else if (!strcmp(aTopic, "cycle-collector-begin")) {
 688     if (mCheckTimer) {
 689       mCheckTimerWaitingForCCEnd = true;
 690       KillCheckTimer();
 691     }
 692     mCycleCollectorIsRunning = true;
 693   } else if (!strcmp(aTopic, "cycle-collector-end")) {
 694     mCycleCollectorIsRunning = false;
 695     if (mCheckTimerWaitingForCCEnd) {
 696       mCheckTimerWaitingForCCEnd = false;
 697       AsyncCheckForGhostWindows();
 698     }
 699   } else {
 700     MOZ_ASSERT(false);
 701   }
 702
 703   return NS_OK;
 704 }
 705
 706 void nsWindowMemoryReporter::ObserveDOMWindowDetached(
 707     nsGlobalWindowInner* aWindow) {
 708   nsWeakPtr weakWindow = do_GetWeakReference(aWindow);
 709   if (!weakWindow) {
 710     NS_WARNING("Couldn't take weak reference to a window?");
 711     return;
 712   }
 713
 714   mDetachedWindows.Put(weakWindow, TimeStamp());
 715
 716   AsyncCheckForGhostWindows();
 717 }
 718
 719 // static
 720 void nsWindowMemoryReporter::CheckTimerFired(nsITimer* aTimer, void* aData) {
 721   if (sWindowReporter) {
 722     MOZ_ASSERT(!sWindowReporter->mCycleCollectorIsRunning);
 723     sWindowReporter->CheckForGhostWindows();
 724   }
 725 }
 726
 727 void nsWindowMemoryReporter::AsyncCheckForGhostWindows() {
 728   if (mCheckTimer) {
 729     return;
 730   }
 731
 732   if (mCycleCollectorIsRunning) {
 733     mCheckTimerWaitingForCCEnd = true;
 734     return;
 735   }
 736
 737   // If more than kTimeBetweenChecks seconds have elapsed since the last check,
 738   // timerDelay is 0.  Otherwise, it is kTimeBetweenChecks, reduced by the time
 739   // since the last check.  Reducing the delay by the time since the last check
 740   // prevents the timer from being completely starved if it is repeatedly killed
 741   // and restarted.
 742   int32_t timeSinceLastCheck =
 743       (TimeStamp::NowLoRes() - mLastCheckForGhostWindows).ToSeconds();
 744   int32_t timerDelay =
 745       (kTimeBetweenChecks - std::min(timeSinceLastCheck, kTimeBetweenChecks)) *
 746       PR_MSEC_PER_SEC;
 747
 748   NS_NewTimerWithFuncCallback(
 749       getter_AddRefs(mCheckTimer), CheckTimerFired, nullptr, timerDelay,
 750       nsITimer::TYPE_ONE_SHOT,
 751       "nsWindowMemoryReporter::AsyncCheckForGhostWindows_timer");
 752 }
 753
 754 void nsWindowMemoryReporter::ObserveAfterMinimizeMemoryUsage() {
 755   // Someone claims they've done enough GC/CCs so that all eligible windows
 756   // have been free'd.  So we deem that any windows which satisfy ghost
 757   // criteria (1) and (2) now satisfy criterion (3) as well.
 758   //
 759   // To effect this change, we'll backdate some of our timestamps.
 760
 761   TimeStamp minTimeStamp =
 762       TimeStamp::Now() - TimeDuration::FromSeconds(GetGhostTimeout());
 763
 764   for (auto iter = mDetachedWindows.Iter(); !iter.Done(); iter.Next()) {
 765     TimeStamp& timeStamp = iter.Data();
 766     if (!timeStamp.IsNull() && timeStamp > minTimeStamp) {
 767       timeStamp = minTimeStamp;
 768     }
 769   }
 770 }
 771
 772 /**
 773  * Iterate over mDetachedWindows and update it to reflect the current state of
 774  * the world.  In particular:
 775  *
 776  *   - Remove weak refs to windows which no longer exist.
 777  *
 778  *   - Remove references to windows which are no longer detached.
 779  *
 780  *   - Reset the timestamp on detached windows which share a domain with a
 781  *     non-detached window (they no longer meet ghost criterion (2)).
 782  *
 783  *   - If a window now meets ghost criterion (2) but didn't before, set its
 784  *     timestamp to now.
 785  *
 786  * Additionally, if aOutGhostIDs is not null, fill it with the window IDs of
 787  * all ghost windows we found.
 788  */
 789 void nsWindowMemoryReporter::CheckForGhostWindows(
 790     nsTHashtable<nsUint64HashKey>* aOutGhostIDs /* = nullptr */) {
 791   nsGlobalWindowInner::InnerWindowByIdTable* windowsById =
 792       nsGlobalWindowInner::GetWindowsTable();
 793   if (!windowsById) {
 794     NS_WARNING("GetWindowsTable returned null");
 795     return;
 796   }
 797
 798   mLastCheckForGhostWindows = TimeStamp::NowLoRes();
 799   KillCheckTimer();
 800
 801   nsTHashtable<nsPtrHashKey<BrowsingContextGroup>>
 802       nonDetachedBrowsingContextGroups;
 803
 804   // Populate nonDetachedBrowsingContextGroups.
 805   for (auto iter = windowsById->Iter(); !iter.Done(); iter.Next()) {
 806     // Null outer window implies null top, but calling GetInProcessTop() when
 807     // there's no outer window causes us to spew debug warnings.
 808     nsGlobalWindowInner* window = iter.UserData();
 809     if (!window->GetOuterWindow() || !window->GetInProcessTopInternal() ||
 810         !window->GetBrowsingContextGroup()) {
 811       // This window is detached, so we don't care about its browsing
 812       // context group.
 813       continue;
 814     }
 815
 816     nonDetachedBrowsingContextGroups.PutEntry(
 817         window->GetBrowsingContextGroup());
 818   }
 819
 820   // Update mDetachedWindows and write the ghost window IDs into aOutGhostIDs,
 821   // if it's not null.
 822   uint32_t ghostTimeout = GetGhostTimeout();
 823   TimeStamp now = mLastCheckForGhostWindows;
 824   mGhostWindowCount = 0;
 825   for (auto iter = mDetachedWindows.Iter(); !iter.Done(); iter.Next()) {
 826     nsWeakPtr weakKey = do_QueryInterface(iter.Key());
 827     nsCOMPtr<mozIDOMWindow> iwindow = do_QueryReferent(weakKey);
 828     if (!iwindow) {
 829       // The window object has been destroyed.  Stop tracking its weak ref in
 830       // our hashtable.
 831       iter.Remove();
 832       continue;
 833     }
 834
 835     nsPIDOMWindowInner* window = nsPIDOMWindowInner::From(iwindow);
 836
 837     // Avoid calling GetInProcessTop() if we have no outer window.  Nothing
 838     // will break if we do, but it will spew debug output, which can cause our
 839     // test logs to overflow.
 840     nsCOMPtr<nsPIDOMWindowOuter> top;
 841     if (window->GetOuterWindow()) {
 842       top = window->GetOuterWindow()->GetInProcessTop();
 843     }
 844
 845     if (top) {
 846       // The window is no longer detached, so we no longer want to track it.
 847       iter.Remove();
 848       continue;
 849     }
 850
 851     TimeStamp& timeStamp = iter.Data();
 852     BrowsingContextGroup* browsingContextGroup =
 853         window->GetBrowsingContextGroup();
 854     if (browsingContextGroup &&
 855         nonDetachedBrowsingContextGroups.GetEntry(browsingContextGroup)) {
 856       // This window is in the same browsing context group as a non-detached
 857       // window, so reset its clock.
 858       timeStamp = TimeStamp();
 859     } else {
 860       // This window is not in the same browsing context group as a non-detached
 861       // window, so it meets ghost criterion (2).
 862       if (timeStamp.IsNull()) {
 863         // This may become a ghost window later; start its clock.
 864         timeStamp = now;
 865       } else if ((now - timeStamp).ToSeconds() > ghostTimeout) {
 866         // This definitely is a ghost window, so add it to aOutGhostIDs, if
 867         // that is not null.
 868         mGhostWindowCount++;
 869         if (aOutGhostIDs && window) {
 870           aOutGhostIDs->PutEntry(window->WindowID());
 871         }
 872       }
 873     }
 874   }
 875
 876   Telemetry::ScalarSetMaximum(
 877       Telemetry::ScalarID::MEMORYREPORTER_MAX_GHOST_WINDOWS, mGhostWindowCount);
 878 }
 879
 880 /* static */
 881 int64_t nsWindowMemoryReporter::GhostWindowsDistinguishedAmount() {
 882   return sWindowReporter->mGhostWindowCount;
 883 }
 884
 885 void nsWindowMemoryReporter::KillCheckTimer() {
 886   if (mCheckTimer) {
 887     mCheckTimer->Cancel();
 888     mCheckTimer = nullptr;
 889   }
 890 }
 891
 892 #ifdef DEBUG
 893 /* static */
 894 void nsWindowMemoryReporter::UnlinkGhostWindows() {
 895   if (!sWindowReporter) {
 896     return;
 897   }
 898
 899   nsGlobalWindowInner::InnerWindowByIdTable* windowsById =
 900       nsGlobalWindowInner::GetWindowsTable();
 901   if (!windowsById) {
 902     return;
 903   }
 904
 905   // Hold on to every window in memory so that window objects can't be
 906   // destroyed while we're calling the UnlinkGhostWindows callback.
 907   WindowArray windows;
 908   for (auto iter = windowsById->Iter(); !iter.Done(); iter.Next()) {
 909     windows.AppendElement(iter.Data());
 910   }
 911
 912   // Get the IDs of all the "ghost" windows, and unlink them all.
 913   nsTHashtable<nsUint64HashKey> ghostWindows;
 914   sWindowReporter->CheckForGhostWindows(&ghostWindows);
 915   for (auto iter = ghostWindows.ConstIter(); !iter.Done(); iter.Next()) {
 916     nsGlobalWindowInner::InnerWindowByIdTable* windowsById =
 917         nsGlobalWindowInner::GetWindowsTable();
 918     if (!windowsById) {
 919       continue;
 920     }
 921
 922     RefPtr<nsGlobalWindowInner> window = windowsById->Get(iter.Get()->GetKey());
 923     if (window) {
 924       window->RiskyUnlink();
 925     }
 926   }
 927 }
 928 #endif