michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=8 sts=2 et sw=2 tw=80: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsWindowMemoryReporter_h__
michael@0: #define nsWindowMemoryReporter_h__
michael@0: 
michael@0: #include "nsIMemoryReporter.h"
michael@0: #include "nsIObserver.h"
michael@0: #include "nsITimer.h"
michael@0: #include "nsDataHashtable.h"
michael@0: #include "nsWeakReference.h"
michael@0: #include "nsAutoPtr.h"
michael@0: #include "mozilla/Attributes.h"
michael@0: #include "mozilla/Assertions.h"
michael@0: #include "mozilla/MemoryReporting.h"
michael@0: #include "mozilla/PodOperations.h"
michael@0: #include "mozilla/TimeStamp.h"
michael@0: #include "nsArenaMemoryStats.h"
michael@0: 
michael@0: class nsWindowSizes {
michael@0: #define FOR_EACH_SIZE(macro) \
michael@0:   macro(DOM,   mDOMElementNodesSize) \
michael@0:   macro(DOM,   mDOMTextNodesSize) \
michael@0:   macro(DOM,   mDOMCDATANodesSize) \
michael@0:   macro(DOM,   mDOMCommentNodesSize) \
michael@0:   macro(DOM,   mDOMEventTargetsSize) \
michael@0:   macro(DOM,   mDOMOtherSize) \
michael@0:   macro(Style, mStyleSheetsSize) \
michael@0:   macro(Other, mLayoutPresShellSize) \
michael@0:   macro(Style, mLayoutStyleSetsSize) \
michael@0:   macro(Other, mLayoutTextRunsSize) \
michael@0:   macro(Other, mLayoutPresContextSize) \
michael@0:   macro(Other, mPropertyTablesSize) \
michael@0: 
michael@0: public:
michael@0:   nsWindowSizes(mozilla::MallocSizeOf aMallocSizeOf)
michael@0:     :
michael@0:       #define ZERO_SIZE(kind, mSize)  mSize(0),
michael@0:       FOR_EACH_SIZE(ZERO_SIZE)
michael@0:       #undef ZERO_SIZE
michael@0:       mDOMEventTargetsCount(0),
michael@0:       mDOMEventListenersCount(0),
michael@0:       mArenaStats(),
michael@0:       mMallocSizeOf(aMallocSizeOf)
michael@0:   {}
michael@0: 
michael@0:   void addToTabSizes(nsTabSizes *sizes) const {
michael@0:     #define ADD_TO_TAB_SIZES(kind, mSize) sizes->add(nsTabSizes::kind, mSize);
michael@0:     FOR_EACH_SIZE(ADD_TO_TAB_SIZES)
michael@0:     #undef ADD_TO_TAB_SIZES
michael@0:     mArenaStats.addToTabSizes(sizes);
michael@0:   }
michael@0: 
michael@0:   #define DECL_SIZE(kind, mSize) size_t mSize;
michael@0:   FOR_EACH_SIZE(DECL_SIZE);
michael@0:   #undef DECL_SIZE
michael@0: 
michael@0:   uint32_t mDOMEventTargetsCount;
michael@0:   uint32_t mDOMEventListenersCount;
michael@0: 
michael@0:   nsArenaMemoryStats mArenaStats;
michael@0:   mozilla::MallocSizeOf mMallocSizeOf;
michael@0: 
michael@0: #undef FOR_EACH_SIZE
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * nsWindowMemoryReporter is responsible for the 'explicit/window-objects'
michael@0:  * memory reporter.
michael@0:  *
michael@0:  * We classify DOM window objects into one of three categories:
michael@0:  *
michael@0:  *   - "active" windows, which are displayed in a tab (as the top-level window
michael@0:  *     or an iframe),
michael@0:  *
michael@0:  *   - "cached" windows, which are in the fastback cache (aka the bfcache), and
michael@0:  *
michael@0:  *   - "detached" windows, which have a null docshell.  A window becomes
michael@0:  *     detached when its <iframe> or tab containing the window is destroyed --
michael@0:  *     i.e., when the window is no longer active or cached.
michael@0:  *
michael@0:  * Additionally, we classify a subset of detached windows as "ghost" windows.
michael@0:  * Although ghost windows can happen legitimately (a page can hold a reference
michael@0:  * to a cross-domain window and then close its container), the presence of
michael@0:  * ghost windows is often indicative of a memory leak.
michael@0:  *
michael@0:  * A window is a ghost if it meets the following three criteria:
michael@0:  *
michael@0:  *   1) The window is detached.
michael@0:  *
michael@0:  *   2) There exist no non-detached windows with the same base domain as
michael@0:  *      the window's principal.  (For example, the base domain of
michael@0:  *      "wiki.mozilla.co.uk" is "mozilla.co.uk".)  This criterion makes us less
michael@0:  *      likely to flag a legitimately held-alive detached window as a ghost.
michael@0:  *
michael@0:  *   3) The window has met criteria (1) and (2) above for at least
michael@0:  *      memory.ghost_window_timeout_seconds.  This criterion is in place so we
michael@0:  *      don't immediately declare a window a ghost before the GC/CC has had a
michael@0:  *      chance to run.
michael@0:  *
michael@0:  * nsWindowMemoryReporter observes window detachment and uses mDetachedWindows
michael@0:  * to remember when a window first met criteria (1) and (2).  When we generate
michael@0:  * a memory report, we use this accounting to determine which windows are
michael@0:  * ghosts.
michael@0:  *
michael@0:  *
michael@0:  * We use the following memory reporter path for active and cached windows:
michael@0:  *
michael@0:  *   explicit/window-objects/top(<top-outer-uri>, id=<top-outer-id>)/<category>/window(<window-uri>)/...
michael@0:  *
michael@0:  * For detached and ghost windows, we use
michael@0:  *
michael@0:  *   explicit/window-objects/top(none)/<category>/window(<window-uri>)/...
michael@0:  *
michael@0:  * Where
michael@0:  *
michael@0:  * - <category> is "active", "cached", "detached", or "ghost", as described
michael@0:  *   above.
michael@0:  *
michael@0:  * - <top-outer-id> is the window id of the top outer window (i.e. the tab, or
michael@0:  *   the top level chrome window).  Exposing this ensures that each tab gets
michael@0:  *   its own sub-tree, even if multiple tabs are showing the same URI.
michael@0:  *
michael@0:  * - <top-uri> is the URI of the top window.  Excepting special windows (such
michael@0:  *   as browser.xul or hiddenWindow.html) it's what the address bar shows for
michael@0:  *   the tab.
michael@0:  *
michael@0:  */
michael@0: class nsWindowMemoryReporter MOZ_FINAL : public nsIMemoryReporter,
michael@0:                                          public nsIObserver,
michael@0:                                          public nsSupportsWeakReference
michael@0: {
michael@0: public:
michael@0:   NS_DECL_ISUPPORTS
michael@0:   NS_DECL_NSIMEMORYREPORTER
michael@0:   NS_DECL_NSIOBSERVER
michael@0: 
michael@0:   static void Init();
michael@0: 
michael@0:   ~nsWindowMemoryReporter();
michael@0: 
michael@0: #ifdef DEBUG
michael@0:   /**
michael@0:    * Unlink all known ghost windows, to enable investigating what caused them
michael@0:    * to become ghost windows in the first place.
michael@0:    */
michael@0:   static void UnlinkGhostWindows();
michael@0: #endif
michael@0: 
michael@0: private:
michael@0:   /**
michael@0:    * nsGhostWindowReporter generates the "ghost-windows" report, which counts
michael@0:    * the number of ghost windows present.
michael@0:    */
michael@0:   class GhostWindowsReporter MOZ_FINAL : public nsIMemoryReporter
michael@0:   {
michael@0:   public:
michael@0:     NS_DECL_ISUPPORTS
michael@0: 
michael@0:     static int64_t DistinguishedAmount();
michael@0: 
michael@0:     NS_IMETHOD
michael@0:     CollectReports(nsIHandleReportCallback* aHandleReport, nsISupports* aData)
michael@0:     {
michael@0:       return MOZ_COLLECT_REPORT(
michael@0:         "ghost-windows", KIND_OTHER, UNITS_COUNT, DistinguishedAmount(),
michael@0: "The number of ghost windows present (the number of nodes underneath "
michael@0: "explicit/window-objects/top(none)/ghost, modulo race conditions).  A ghost "
michael@0: "window is not shown in any tab, does not share a domain with any non-detached "
michael@0: "windows, and has met these criteria for at least "
michael@0: "memory.ghost_window_timeout_seconds, or has survived a round of "
michael@0: "about:memory's minimize memory usage button.\n\n"
michael@0: "Ghost windows can happen legitimately, but they are often indicative of "
michael@0: "leaks in the browser or add-ons.");
michael@0:     }
michael@0:   };
michael@0: 
michael@0:   // Protect ctor, use Init() instead.
michael@0:   nsWindowMemoryReporter();
michael@0: 
michael@0:   /**
michael@0:    * Get the number of seconds for which a window must satisfy ghost criteria
michael@0:    * (1) and (2) before we deem that it satisfies criterion (3).
michael@0:    */
michael@0:   uint32_t GetGhostTimeout();
michael@0: 
michael@0:   void ObserveDOMWindowDetached(nsISupports* aWindow);
michael@0:   void ObserveAfterMinimizeMemoryUsage();
michael@0: 
michael@0:   /**
michael@0:    * Iterate over all weak window pointers in mDetachedWindows and update our
michael@0:    * accounting of which windows meet ghost criterion (2).
michael@0:    *
michael@0:    * This method also cleans up mDetachedWindows, removing entries for windows
michael@0:    * which have been destroyed or are no longer detached.
michael@0:    *
michael@0:    * If aOutGhostIDs is non-null, we populate it with the Window IDs of the
michael@0:    * ghost windows.
michael@0:    *
michael@0:    * This is called asynchronously after we observe a DOM window being detached
michael@0:    * from its docshell, and also right before we generate a memory report.
michael@0:    */
michael@0:   void CheckForGhostWindows(nsTHashtable<nsUint64HashKey> *aOutGhostIDs = nullptr);
michael@0: 
michael@0:   /**
michael@0:    * Eventually do a check for ghost windows, if we haven't done one recently
michael@0:    * and we aren't already planning to do one soon.
michael@0:    */
michael@0:   void AsyncCheckForGhostWindows();
michael@0: 
michael@0:   /**
michael@0:    * Kill the check timer, if it exists.
michael@0:    */
michael@0:   void KillCheckTimer();
michael@0: 
michael@0:   static void CheckTimerFired(nsITimer* aTimer, void* aClosure);
michael@0: 
michael@0:   /**
michael@0:    * Maps a weak reference to a detached window (nsIWeakReference) to the time
michael@0:    * when we observed that the window met ghost criterion (2) above.
michael@0:    *
michael@0:    * If the window has not yet met criterion (2) it maps to the null timestamp.
michael@0:    *
michael@0:    * (Although windows are not added to this table until they're detached, it's
michael@0:    * possible for a detached window to become non-detached, and we won't
michael@0:    * remove it from the table until CheckForGhostWindows runs.)
michael@0:    */
michael@0:   nsDataHashtable<nsISupportsHashKey, mozilla::TimeStamp> mDetachedWindows;
michael@0: 
michael@0:   /**
michael@0:    * Track the last time we ran CheckForGhostWindows(), to avoid running it
michael@0:    * too often after a DOM window is detached.
michael@0:    */
michael@0:   mozilla::TimeStamp mLastCheckForGhostWindows;
michael@0: 
michael@0:   nsCOMPtr<nsITimer> mCheckTimer;
michael@0: 
michael@0:   bool mCycleCollectorIsRunning;
michael@0: 
michael@0:   bool mCheckTimerWaitingForCCEnd;
michael@0: };
michael@0: 
michael@0: #endif // nsWindowMemoryReporter_h__
michael@0: