memory_purger.cc revision c407dc5cd9bdc5668497f21b26b09d988ab439de 
1// Copyright (c) 2009 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "chrome/browser/memory_purger.h"
6
7#include <set>
8
9#include "base/thread.h"
10#include "chrome/browser/browser_list.h"
11#include "chrome/browser/browser_process.h"
12#include "chrome/browser/history/history.h"
13#include "chrome/browser/in_process_webkit/webkit_context.h"
14#include "chrome/browser/profile_manager.h"
15#include "chrome/browser/renderer_host/backing_store_manager.h"
16#include "chrome/browser/renderer_host/render_process_host.h"
17#include "chrome/browser/renderer_host/resource_dispatcher_host.h"
18#include "chrome/browser/safe_browsing/safe_browsing_service.h"
19#include "chrome/browser/webdata/web_data_service.h"
20#include "chrome/common/net/url_request_context_getter.h"
21#include "chrome/common/notification_service.h"
22#include "chrome/common/render_messages.h"
23#include "net/proxy/proxy_resolver.h"
24#include "net/url_request/url_request_context.h"
25#include "third_party/tcmalloc/chromium/src/google/malloc_extension.h"
26#include "v8/include/v8.h"
27
28// PurgeMemoryHelper -----------------------------------------------------------
29
30// This is a small helper class used to ensure that the objects we want to use
31// on multiple threads are properly refed, so they don't get deleted out from
32// under us.
33class PurgeMemoryIOHelper
34    : public base::RefCountedThreadSafe<PurgeMemoryIOHelper> {
35 public:
36  explicit PurgeMemoryIOHelper(SafeBrowsingService* safe_browsing_service)
37      : safe_browsing_service_(safe_browsing_service) {
38  }
39
40  void AddRequestContextGetter(URLRequestContextGetter* request_context_getter);
41
42  void PurgeMemoryOnIOThread();
43
44 private:
45  typedef scoped_refptr<URLRequestContextGetter> RequestContextGetter;
46  typedef std::set<RequestContextGetter> RequestContextGetters;
47
48  RequestContextGetters request_context_getters_;
49  scoped_refptr<SafeBrowsingService> safe_browsing_service_;
50
51  DISALLOW_COPY_AND_ASSIGN(PurgeMemoryIOHelper);
52};
53
54void PurgeMemoryIOHelper::AddRequestContextGetter(
55    URLRequestContextGetter* request_context_getter) {
56  if (!request_context_getters_.count(request_context_getter)) {
57    request_context_getters_.insert(
58        RequestContextGetter(request_context_getter));
59  }
60}
61
62void PurgeMemoryIOHelper::PurgeMemoryOnIOThread() {
63  // Ask ProxyServices to purge any memory they can (generally garbage in the
64  // wrapped ProxyResolver's JS engine).
65  for (RequestContextGetters::const_iterator i(
66           request_context_getters_.begin());
67       i != request_context_getters_.end(); ++i)
68    (*i)->GetURLRequestContext()->proxy_service()->PurgeMemory();
69
70  // Close the Safe Browsing database, freeing memory used to cache sqlite as
71  // well as a number of in-memory structures.
72  safe_browsing_service_->CloseDatabase();
73
74  // The appcache service listens for this notification.
75  NotificationService::current()->Notify(
76      NotificationType::PURGE_MEMORY,
77      Source<void>(NULL),
78      NotificationService::NoDetails());
79}
80
81// -----------------------------------------------------------------------------
82
83// static
84void MemoryPurger::PurgeAll() {
85  PurgeBrowser();
86  PurgeRenderers();
87
88  // TODO(pkasting):
89  // * Tell the plugin processes to release their free memory?  Other stuff?
90  // * Enumerate what other processes exist and what to do for them.
91}
92
93// static
94void MemoryPurger::PurgeBrowser() {
95  // Dump the backing stores.
96  BackingStoreManager::RemoveAllBackingStores();
97
98  // Per-profile cleanup.
99  scoped_refptr<PurgeMemoryIOHelper> purge_memory_io_helper(
100      new PurgeMemoryIOHelper(g_browser_process->resource_dispatcher_host()->
101          safe_browsing_service()));
102  ProfileManager* profile_manager = g_browser_process->profile_manager();
103  for (ProfileManager::iterator i(profile_manager->begin());
104       i != profile_manager->end(); ++i) {
105    Profile* profile = *i;
106    purge_memory_io_helper->AddRequestContextGetter(
107        profile->GetRequestContext());
108
109    // NOTE: Some objects below may be duplicates across profiles.  We could
110    // conceivably put all these in sets and then iterate over the sets.
111
112    // Unload all history backends (freeing memory used to cache sqlite).
113    // Spinning up the history service is expensive, so we avoid doing it if it
114    // hasn't been done already.
115    HistoryService* history_service =
116        profile->GetHistoryServiceWithoutCreating();
117    if (history_service)
118      history_service->UnloadBackend();
119
120    // Unload all web databases (freeing memory used to cache sqlite).
121    WebDataService* web_data_service =
122        profile->GetWebDataServiceWithoutCreating();
123    if (web_data_service)
124      web_data_service->UnloadDatabase();
125
126    // Ask all WebKitContexts to purge memory (freeing memory used to cache
127    // the LocalStorage sqlite DB).  WebKitContext creation is basically free so
128    // we don't bother with a "...WithoutCreating()" function.
129    profile->GetWebKitContext()->PurgeMemory();
130  }
131
132  ChromeThread::PostTask(ChromeThread::IO, FROM_HERE,
133      NewRunnableMethod(purge_memory_io_helper.get(),
134                        &PurgeMemoryIOHelper::PurgeMemoryOnIOThread));
135
136  // TODO(pkasting):
137  // * Purge AppCache memory.  Not yet implemented sufficiently.
138  // * Browser-side DatabaseTracker.  Not implemented sufficiently.
139
140#if (defined(OS_WIN) || defined(OS_LINUX)) && defined(USE_TCMALLOC)
141  // Tell tcmalloc to release any free pages it's still holding.
142  //
143  // TODO(pkasting): A lot of the above calls kick off actions on other threads.
144  // Maybe we should find a way to avoid calling this until those actions
145  // complete?
146  MallocExtension::instance()->ReleaseFreeMemory();
147#endif
148}
149
150// static
151void MemoryPurger::PurgeRenderers() {
152  // Direct all renderers to free everything they can.
153  //
154  // Concern: Telling a bunch of renderer processes to destroy their data may
155  // cause them to page everything in to do it, which could take a lot of time/
156  // cause jank.
157  for (RenderProcessHost::iterator i(RenderProcessHost::AllHostsIterator());
158       !i.IsAtEnd(); i.Advance())
159    PurgeRendererForHost(i.GetCurrentValue());
160}
161
162// static
163void MemoryPurger::PurgeRendererForHost(RenderProcessHost* host) {
164  // Direct the renderer to free everything it can.
165  host->Send(new ViewMsg_PurgeMemory());
166}
167