Source/WebCore: Update low memory handler to use new memory pressure notifications...
[WebKit-https.git] / Source / WebCore / platform / mac / MemoryPressureHandlerMac.mm
1 /*
2  * Copyright (C) 2011, 2012 Apple Inc. All Rights Reserved.
3  *
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5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
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23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25
26 #import "config.h"
27 #import "MemoryPressureHandler.h"
28
29 #import <WebCore/CSSValuePool.h>
30 #import <WebCore/GCController.h>
31 #import <WebCore/FontCache.h>
32 #import <WebCore/MemoryCache.h>
33 #import <WebCore/PageCache.h>
34 #import <WebCore/LayerPool.h>
35 #import <WebCore/ScrollingThread.h>
36 #import <WebCore/StorageThread.h>
37 #import <WebCore/WorkerThread.h>
38 #import <wtf/CurrentTime.h>
39 #import <wtf/FastMalloc.h>
40 #import <wtf/Functional.h>
41
42 #if !PLATFORM(IOS) && __MAC_OS_X_VERSION_MIN_REQUIRED >= 1070
43 #import "WebCoreSystemInterface.h"
44 #import <notify.h>
45 #endif
46
47 using std::max;
48
49 namespace WebCore {
50
51 #if PLATFORM(IOS) || __MAC_OS_X_VERSION_MIN_REQUIRED >= 1070
52
53 #if !PLATFORM(IOS)
54 static dispatch_source_t _cache_event_source = 0;
55 static dispatch_source_t _timer_event_source = 0;
56 static int _notifyToken;
57
58 // Disable memory event reception for a minimum of s_minimumHoldOffTime
59 // seconds after receiving an event.  Don't let events fire any sooner than
60 // s_holdOffMultiplier times the last cleanup processing time.  Effectively 
61 // this is 1 / s_holdOffMultiplier percent of the time.
62 // These value seems reasonable and testing verifies that it throttles frequent
63 // low memory events, greatly reducing CPU usage.
64 static const unsigned s_minimumHoldOffTime = 5;
65 static const unsigned s_holdOffMultiplier = 20;
66
67 void MemoryPressureHandler::install()
68 {
69     if (m_installed || _timer_event_source)
70         return;
71
72     dispatch_async(dispatch_get_main_queue(), ^{
73 #if MAC_OS_X_VERSION_MIN_REQUIRED >= 1090
74         _cache_event_source = wkCreateMemoryStatusPressureCriticalDispatchOnMainQueue();
75 #else
76         _cache_event_source = wkCreateVMPressureDispatchOnMainQueue();
77 #endif
78         if (_cache_event_source) {
79             dispatch_set_context(_cache_event_source, this);
80             dispatch_source_set_event_handler(_cache_event_source, ^{ memoryPressureHandler().respondToMemoryPressure();});
81             dispatch_resume(_cache_event_source);
82         }
83     });
84
85     notify_register_dispatch("org.WebKit.lowMemory", &_notifyToken,
86          dispatch_get_main_queue(), ^(int) { memoryPressureHandler().respondToMemoryPressure();});
87
88     m_installed = true;
89 }
90
91 void MemoryPressureHandler::uninstall()
92 {
93     if (!m_installed)
94         return;
95
96     dispatch_async(dispatch_get_main_queue(), ^{
97         if (_cache_event_source) {
98             dispatch_source_cancel(_cache_event_source);
99             dispatch_release(_cache_event_source);
100             _cache_event_source = 0;
101         }
102
103         if (_timer_event_source) {
104             dispatch_source_cancel(_timer_event_source);
105             dispatch_release(_timer_event_source);
106             _timer_event_source = 0;
107         }
108     });
109
110     m_installed = false;
111     
112     notify_cancel(_notifyToken);
113 }
114
115 void MemoryPressureHandler::holdOff(unsigned seconds)
116 {
117     dispatch_async(dispatch_get_main_queue(), ^{
118         _timer_event_source = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, dispatch_get_main_queue());
119         if (_timer_event_source) {
120             dispatch_set_context(_timer_event_source, this);
121             dispatch_source_set_timer(_timer_event_source, dispatch_time(DISPATCH_TIME_NOW, seconds * NSEC_PER_SEC), DISPATCH_TIME_FOREVER, 1 * s_minimumHoldOffTime);
122             dispatch_source_set_event_handler(_timer_event_source, ^{
123                 if (_timer_event_source) {
124                     dispatch_source_cancel(_timer_event_source);
125                     dispatch_release(_timer_event_source);
126                     _timer_event_source = 0;
127                 }
128                 memoryPressureHandler().install();
129             });
130             dispatch_resume(_timer_event_source);
131         }
132     });
133 }
134
135 void MemoryPressureHandler::respondToMemoryPressure()
136 {
137     uninstall();
138
139     double startTime = monotonicallyIncreasingTime();
140
141     m_lowMemoryHandler(false);
142
143     unsigned holdOffTime = (monotonicallyIncreasingTime() - startTime) * s_holdOffMultiplier;
144
145     holdOff(max(holdOffTime, s_minimumHoldOffTime));
146 }
147 #endif // !PLATFORM(IOS)
148
149 void MemoryPressureHandler::releaseMemory(bool)
150 {
151     int savedPageCacheCapacity = pageCache()->capacity();
152     pageCache()->setCapacity(0);
153     pageCache()->setCapacity(savedPageCacheCapacity);
154
155     NSURLCache *nsurlCache = [NSURLCache sharedURLCache];
156     NSUInteger savedNsurlCacheMemoryCapacity = [nsurlCache memoryCapacity];
157     [nsurlCache setMemoryCapacity:0];
158     [nsurlCache setMemoryCapacity:savedNsurlCacheMemoryCapacity];
159
160     fontCache()->purgeInactiveFontData();
161
162     memoryCache()->pruneToPercentage(0);
163
164     LayerPool::sharedPool()->drain();
165
166     cssValuePool().drain();
167
168     gcController().discardAllCompiledCode();
169
170     // FastMalloc has lock-free thread specific caches that can only be cleared from the thread itself.
171     StorageThread::releaseFastMallocFreeMemoryInAllThreads();
172 #if ENABLE(WORKERS)
173     WorkerThread::releaseFastMallocFreeMemoryInAllThreads();
174 #endif
175 #if ENABLE(THREADED_SCROLLING)
176     ScrollingThread::dispatch(bind(WTF::releaseFastMallocFreeMemory));
177 #endif
178     WTF::releaseFastMallocFreeMemory();
179 }
180 #endif
181
182 } // namespace WebCore