3848f6cd9973f8b3a7a907cf2519d52c24e5929f
[WebKit-https.git] / Source / WebCore / platform / mac / MemoryPressureHandlerMac.mm
1 /*
2  * Copyright (C) 2011, 2012 Apple Inc. All Rights Reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
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
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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         _cache_event_source = wkCreateVMPressureDispatchOnMainQueue();
74         if (_cache_event_source) {
75             dispatch_set_context(_cache_event_source, this);
76             dispatch_source_set_event_handler(_cache_event_source, ^{ memoryPressureHandler().respondToMemoryPressure();});
77             dispatch_resume(_cache_event_source);
78         }
79     });
80
81     notify_register_dispatch("org.WebKit.lowMemory", &_notifyToken,
82          dispatch_get_main_queue(), ^(int) { memoryPressureHandler().respondToMemoryPressure();});
83
84     m_installed = true;
85 }
86
87 void MemoryPressureHandler::uninstall()
88 {
89     if (!m_installed)
90         return;
91
92     dispatch_async(dispatch_get_main_queue(), ^{
93         if (_cache_event_source) {
94             dispatch_source_cancel(_cache_event_source);
95             dispatch_release(_cache_event_source);
96             _cache_event_source = 0;
97         }
98
99         if (_timer_event_source) {
100             dispatch_source_cancel(_timer_event_source);
101             dispatch_release(_timer_event_source);
102             _timer_event_source = 0;
103         }
104     });
105
106     m_installed = false;
107     
108     notify_cancel(_notifyToken);
109 }
110
111 void MemoryPressureHandler::holdOff(unsigned seconds)
112 {
113     dispatch_async(dispatch_get_main_queue(), ^{
114         _timer_event_source = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, dispatch_get_main_queue());
115         if (_timer_event_source) {
116             dispatch_set_context(_timer_event_source, this);
117             dispatch_source_set_timer(_timer_event_source, dispatch_time(DISPATCH_TIME_NOW, seconds * NSEC_PER_SEC), DISPATCH_TIME_FOREVER, 1 * s_minimumHoldOffTime);
118             dispatch_source_set_event_handler(_timer_event_source, ^{
119                 if (_timer_event_source) {
120                     dispatch_source_cancel(_timer_event_source);
121                     dispatch_release(_timer_event_source);
122                     _timer_event_source = 0;
123                 }
124                 memoryPressureHandler().install();
125             });
126             dispatch_resume(_timer_event_source);
127         }
128     });
129 }
130
131 void MemoryPressureHandler::respondToMemoryPressure()
132 {
133     uninstall();
134
135     double startTime = monotonicallyIncreasingTime();
136
137     m_lowMemoryHandler(false);
138
139     unsigned holdOffTime = (monotonicallyIncreasingTime() - startTime) * s_holdOffMultiplier;
140
141     holdOff(max(holdOffTime, s_minimumHoldOffTime));
142 }
143 #endif // !PLATFORM(IOS)
144
145 void MemoryPressureHandler::releaseMemory(bool)
146 {
147     int savedPageCacheCapacity = pageCache()->capacity();
148     pageCache()->setCapacity(0);
149     pageCache()->setCapacity(savedPageCacheCapacity);
150
151     NSURLCache *nsurlCache = [NSURLCache sharedURLCache];
152     NSUInteger savedNsurlCacheMemoryCapacity = [nsurlCache memoryCapacity];
153     [nsurlCache setMemoryCapacity:0];
154     [nsurlCache setMemoryCapacity:savedNsurlCacheMemoryCapacity];
155
156     fontCache()->purgeInactiveFontData();
157
158     memoryCache()->pruneToPercentage(0);
159
160     LayerPool::sharedPool()->drain();
161
162     cssValuePool().drain();
163
164     gcController().discardAllCompiledCode();
165
166     // FastMalloc has lock-free thread specific caches that can only be cleared from the thread itself.
167     StorageThread::releaseFastMallocFreeMemoryInAllThreads();
168 #if ENABLE(WORKERS)
169     WorkerThread::releaseFastMallocFreeMemoryInAllThreads();
170 #endif
171 #if ENABLE(THREADED_SCROLLING)
172     ScrollingThread::dispatch(bind(WTF::releaseFastMallocFreeMemory));
173 #endif
174     WTF::releaseFastMallocFreeMemory();
175 }
176 #endif
177
178 } // namespace WebCore