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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 : #ifndef nsWindowMemoryReporter_h__
8 : #define nsWindowMemoryReporter_h__
9 :
10 : #include "nsGlobalWindow.h"
11 : #include "nsIMemoryReporter.h"
12 : #include "nsIObserver.h"
13 : #include "nsITimer.h"
14 : #include "nsDataHashtable.h"
15 : #include "nsWeakReference.h"
16 : #include "mozilla/Attributes.h"
17 : #include "mozilla/Assertions.h"
18 : #include "mozilla/MemoryReporting.h"
19 : #include "mozilla/PodOperations.h"
20 : #include "mozilla/TimeStamp.h"
21 : #include "nsArenaMemoryStats.h"
22 :
23 : class nsWindowSizes {
24 : #define FOR_EACH_SIZE(macro) \
25 : macro(DOM, mDOMElementNodesSize) \
26 : macro(DOM, mDOMTextNodesSize) \
27 : macro(DOM, mDOMCDATANodesSize) \
28 : macro(DOM, mDOMCommentNodesSize) \
29 : macro(DOM, mDOMEventTargetsSize) \
30 : macro(DOM, mDOMOtherSize) \
31 : macro(Style, mStyleSheetsSize) \
32 : macro(Other, mLayoutPresShellSize) \
33 : macro(Style, mLayoutStyleSetsSize) \
34 : macro(Other, mLayoutTextRunsSize) \
35 : macro(Other, mLayoutPresContextSize) \
36 : macro(Other, mLayoutFramePropertiesSize) \
37 : macro(Other, mPropertyTablesSize) \
38 :
39 : public:
40 21 : explicit nsWindowSizes(mozilla::MallocSizeOf aMallocSizeOf)
41 21 : :
42 : #define ZERO_SIZE(kind, mSize) mSize(0),
43 : FOR_EACH_SIZE(ZERO_SIZE)
44 : #undef ZERO_SIZE
45 : mDOMEventTargetsCount(0),
46 : mDOMEventListenersCount(0),
47 : mArenaStats(),
48 21 : mMallocSizeOf(aMallocSizeOf)
49 21 : {}
50 :
51 0 : void addToTabSizes(nsTabSizes *sizes) const {
52 : #define ADD_TO_TAB_SIZES(kind, mSize) sizes->add(nsTabSizes::kind, mSize);
53 0 : FOR_EACH_SIZE(ADD_TO_TAB_SIZES)
54 : #undef ADD_TO_TAB_SIZES
55 0 : mArenaStats.addToTabSizes(sizes);
56 0 : }
57 :
58 42 : size_t getTotalSize() const
59 : {
60 42 : size_t total = 0;
61 : #define ADD_TO_TOTAL_SIZE(kind, mSize) total += mSize;
62 42 : FOR_EACH_SIZE(ADD_TO_TOTAL_SIZE)
63 : #undef ADD_TO_TOTAL_SIZE
64 42 : total += mArenaStats.getTotalSize();
65 42 : return total;
66 : }
67 :
68 : #define DECL_SIZE(kind, mSize) size_t mSize;
69 : FOR_EACH_SIZE(DECL_SIZE);
70 : #undef DECL_SIZE
71 :
72 : uint32_t mDOMEventTargetsCount;
73 : uint32_t mDOMEventListenersCount;
74 :
75 : nsArenaMemoryStats mArenaStats;
76 : mozilla::MallocSizeOf mMallocSizeOf;
77 :
78 : #undef FOR_EACH_SIZE
79 : };
80 :
81 : /**
82 : * nsWindowMemoryReporter is responsible for the 'explicit/window-objects'
83 : * memory reporter.
84 : *
85 : * We classify DOM window objects into one of three categories:
86 : *
87 : * - "active" windows, which are displayed in a tab (as the top-level window
88 : * or an iframe),
89 : *
90 : * - "cached" windows, which are in the fastback cache (aka the bfcache), and
91 : *
92 : * - "detached" windows, which have a null docshell. A window becomes
93 : * detached when its <iframe> or tab containing the window is destroyed --
94 : * i.e., when the window is no longer active or cached.
95 : *
96 : * Additionally, we classify a subset of detached windows as "ghost" windows.
97 : * Although ghost windows can happen legitimately (a page can hold a reference
98 : * to a cross-domain window and then close its container), the presence of
99 : * ghost windows is often indicative of a memory leak.
100 : *
101 : * A window is a ghost if it meets the following three criteria:
102 : *
103 : * 1) The window is detached.
104 : *
105 : * 2) There exist no non-detached windows with the same base domain as
106 : * the window's principal. (For example, the base domain of
107 : * "wiki.mozilla.co.uk" is "mozilla.co.uk".) This criterion makes us less
108 : * likely to flag a legitimately held-alive detached window as a ghost.
109 : *
110 : * 3) The window has met criteria (1) and (2) above for at least
111 : * memory.ghost_window_timeout_seconds. This criterion is in place so we
112 : * don't immediately declare a window a ghost before the GC/CC has had a
113 : * chance to run.
114 : *
115 : * nsWindowMemoryReporter observes window detachment and uses mDetachedWindows
116 : * to remember when a window first met criteria (1) and (2). When we generate
117 : * a memory report, we use this accounting to determine which windows are
118 : * ghosts.
119 : *
120 : *
121 : * We use the following memory reporter path for active and cached windows:
122 : *
123 : * explicit/window-objects/top(<top-outer-uri>, id=<top-outer-id>)/<category>/window(<window-uri>)/...
124 : *
125 : * For detached and ghost windows, we use
126 : *
127 : * explicit/window-objects/top(none)/<category>/window(<window-uri>)/...
128 : *
129 : * Where
130 : *
131 : * - <category> is "active", "cached", "detached", or "ghost", as described
132 : * above.
133 : *
134 : * - <top-outer-id> is the window id of the top outer window (i.e. the tab, or
135 : * the top level chrome window). Exposing this ensures that each tab gets
136 : * its own sub-tree, even if multiple tabs are showing the same URI.
137 : *
138 : * - <top-uri> is the URI of the top window. Excepting special windows (such
139 : * as browser.xul or hiddenWindow.html) it's what the address bar shows for
140 : * the tab.
141 : *
142 : */
143 : class nsWindowMemoryReporter final : public nsIMemoryReporter,
144 : public nsIObserver,
145 : public nsSupportsWeakReference
146 : {
147 : public:
148 : NS_DECL_ISUPPORTS
149 : NS_DECL_NSIMEMORYREPORTER
150 : NS_DECL_NSIOBSERVER
151 :
152 : static void Init();
153 :
154 : #ifdef DEBUG
155 : /**
156 : * Unlink all known ghost windows, to enable investigating what caused them
157 : * to become ghost windows in the first place.
158 : */
159 : static void UnlinkGhostWindows();
160 : #endif
161 :
162 : static nsWindowMemoryReporter* Get();
163 : void ObserveDOMWindowDetached(nsGlobalWindow* aWindow);
164 :
165 : static int64_t GhostWindowsDistinguishedAmount();
166 :
167 : private:
168 : ~nsWindowMemoryReporter();
169 :
170 : // Protect ctor, use Init() instead.
171 : nsWindowMemoryReporter();
172 :
173 : /**
174 : * Get the number of seconds for which a window must satisfy ghost criteria
175 : * (1) and (2) before we deem that it satisfies criterion (3).
176 : */
177 : uint32_t GetGhostTimeout();
178 :
179 : void ObserveAfterMinimizeMemoryUsage();
180 :
181 : /**
182 : * Iterate over all weak window pointers in mDetachedWindows and update our
183 : * accounting of which windows meet ghost criterion (2).
184 : *
185 : * This method also cleans up mDetachedWindows, removing entries for windows
186 : * which have been destroyed or are no longer detached.
187 : *
188 : * If aOutGhostIDs is non-null, we populate it with the Window IDs of the
189 : * ghost windows.
190 : *
191 : * This is called asynchronously after we observe a DOM window being detached
192 : * from its docshell, and also right before we generate a memory report.
193 : */
194 : void CheckForGhostWindows(nsTHashtable<nsUint64HashKey> *aOutGhostIDs = nullptr);
195 :
196 : /**
197 : * Eventually do a check for ghost windows, if we haven't done one recently
198 : * and we aren't already planning to do one soon.
199 : */
200 : void AsyncCheckForGhostWindows();
201 :
202 : /**
203 : * Kill the check timer, if it exists.
204 : */
205 : void KillCheckTimer();
206 :
207 : static void CheckTimerFired(nsITimer* aTimer, void* aClosure);
208 :
209 : /**
210 : * Maps a weak reference to a detached window (nsIWeakReference) to the time
211 : * when we observed that the window met ghost criterion (2) above.
212 : *
213 : * If the window has not yet met criterion (2) it maps to the null timestamp.
214 : *
215 : * (Although windows are not added to this table until they're detached, it's
216 : * possible for a detached window to become non-detached, and we won't
217 : * remove it from the table until CheckForGhostWindows runs.)
218 : */
219 : nsDataHashtable<nsISupportsHashKey, mozilla::TimeStamp> mDetachedWindows;
220 :
221 : /**
222 : * Track the last time we ran CheckForGhostWindows(), to avoid running it
223 : * too often after a DOM window is detached.
224 : */
225 : mozilla::TimeStamp mLastCheckForGhostWindows;
226 :
227 : nsCOMPtr<nsITimer> mCheckTimer;
228 :
229 : bool mCycleCollectorIsRunning;
230 :
231 : bool mCheckTimerWaitingForCCEnd;
232 :
233 : int64_t mGhostWindowCount;
234 : };
235 :
236 : #endif // nsWindowMemoryReporter_h__
237 :
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