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      1 // Copyright (c) 2012 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/allocator/allocator_extension.h"
     10 #include "base/bind.h"
     11 #include "base/threading/thread.h"
     12 #include "chrome/browser/browser_process.h"
     13 #include "chrome/browser/history/history_service.h"
     14 #include "chrome/browser/history/history_service_factory.h"
     15 #include "chrome/browser/profiles/profile_manager.h"
     16 #include "chrome/browser/safe_browsing/database_manager.h"
     17 #include "chrome/browser/safe_browsing/safe_browsing_service.h"
     18 #include "chrome/browser/ui/browser_list.h"
     19 #include "chrome/browser/webdata/web_data_service.h"
     20 #include "chrome/browser/webdata/web_data_service_factory.h"
     21 #include "chrome/common/render_messages.h"
     22 #include "content/public/browser/render_process_host.h"
     23 #include "content/public/browser/render_widget_host.h"
     24 #include "content/public/browser/resource_context.h"
     25 #include "net/proxy/proxy_resolver.h"
     26 #include "net/proxy/proxy_service.h"
     27 #include "net/url_request/url_request_context.h"
     28 #include "net/url_request/url_request_context_getter.h"
     29 
     30 using content::BrowserContext;
     31 using content::BrowserThread;
     32 using content::ResourceContext;
     33 
     34 // PurgeMemoryHelper -----------------------------------------------------------
     35 
     36 // This is a small helper class used to ensure that the objects we want to use
     37 // on multiple threads are properly refed, so they don't get deleted out from
     38 // under us.
     39 class PurgeMemoryIOHelper
     40     : public base::RefCountedThreadSafe<PurgeMemoryIOHelper> {
     41  public:
     42   PurgeMemoryIOHelper() {
     43     safe_browsing_service_ = g_browser_process->safe_browsing_service();
     44   }
     45 
     46   void AddRequestContextGetter(
     47       scoped_refptr<net::URLRequestContextGetter> request_context_getter);
     48 
     49   void PurgeMemoryOnIOThread();
     50 
     51  private:
     52   friend class base::RefCountedThreadSafe<PurgeMemoryIOHelper>;
     53 
     54   virtual ~PurgeMemoryIOHelper() {}
     55 
     56   typedef scoped_refptr<net::URLRequestContextGetter> RequestContextGetter;
     57   std::vector<RequestContextGetter> request_context_getters_;
     58 
     59   scoped_refptr<SafeBrowsingService> safe_browsing_service_;
     60 
     61   DISALLOW_COPY_AND_ASSIGN(PurgeMemoryIOHelper);
     62 };
     63 
     64 void PurgeMemoryIOHelper::AddRequestContextGetter(
     65     scoped_refptr<net::URLRequestContextGetter> request_context_getter) {
     66   request_context_getters_.push_back(request_context_getter);
     67 }
     68 
     69 void PurgeMemoryIOHelper::PurgeMemoryOnIOThread() {
     70   // Ask ProxyServices to purge any memory they can (generally garbage in the
     71   // wrapped ProxyResolver's JS engine).
     72   for (size_t i = 0; i < request_context_getters_.size(); ++i) {
     73     request_context_getters_[i]->GetURLRequestContext()->proxy_service()->
     74         PurgeMemory();
     75   }
     76 
     77 #if defined(FULL_SAFE_BROWSING)
     78   safe_browsing_service_->database_manager()->PurgeMemory();
     79 #endif
     80 }
     81 
     82 // -----------------------------------------------------------------------------
     83 
     84 // static
     85 void MemoryPurger::PurgeAll() {
     86   PurgeBrowser();
     87   PurgeRenderers();
     88 
     89   // TODO(pkasting):
     90   // * Tell the plugin processes to release their free memory?  Other stuff?
     91   // * Enumerate what other processes exist and what to do for them.
     92 }
     93 
     94 // static
     95 void MemoryPurger::PurgeBrowser() {
     96   // Dump the backing stores.
     97   content::RenderWidgetHost::RemoveAllBackingStores();
     98 
     99   // Per-profile cleanup.
    100   scoped_refptr<PurgeMemoryIOHelper> purge_memory_io_helper(
    101       new PurgeMemoryIOHelper());
    102   ProfileManager* profile_manager = g_browser_process->profile_manager();
    103   std::vector<Profile*> profiles(profile_manager->GetLoadedProfiles());
    104   for (size_t i = 0; i < profiles.size(); ++i) {
    105     purge_memory_io_helper->AddRequestContextGetter(
    106         make_scoped_refptr(profiles[i]->GetRequestContext()));
    107 
    108     // NOTE: Some objects below may be duplicates across profiles.  We could
    109     // conceivably put all these in sets and then iterate over the sets.
    110 
    111     // Unload all history backends (freeing memory used to cache sqlite).
    112     // Spinning up the history service is expensive, so we avoid doing it if it
    113     // hasn't been done already.
    114     HistoryService* history_service =
    115         HistoryServiceFactory::GetForProfileWithoutCreating(profiles[i]);
    116     if (history_service)
    117       history_service->UnloadBackend();
    118 
    119     // Unload all web databases (freeing memory used to cache sqlite).
    120     WebDataServiceWrapper* wds_wrapper =
    121         WebDataServiceFactory::GetForProfileIfExists(
    122             profiles[i], Profile::EXPLICIT_ACCESS);
    123     if (wds_wrapper && wds_wrapper->GetWebData().get())
    124       wds_wrapper->GetWebData()->UnloadDatabase();
    125 
    126     BrowserContext::PurgeMemory(profiles[i]);
    127   }
    128 
    129   BrowserThread::PostTask(
    130       BrowserThread::IO, FROM_HERE,
    131       base::Bind(&PurgeMemoryIOHelper::PurgeMemoryOnIOThread,
    132                  purge_memory_io_helper.get()));
    133 
    134   // TODO(pkasting):
    135   // * Purge AppCache memory.  Not yet implemented sufficiently.
    136   // * Browser-side DatabaseTracker.  Not implemented sufficiently.
    137 
    138   // Tell our allocator to release any free pages it's still holding.
    139   //
    140   // TODO(pkasting): A lot of the above calls kick off actions on other threads.
    141   // Maybe we should find a way to avoid calling this until those actions
    142   // complete?
    143   base::allocator::ReleaseFreeMemory();
    144 }
    145 
    146 // static
    147 void MemoryPurger::PurgeRenderers() {
    148   // Direct all renderers to free everything they can.
    149   //
    150   // Concern: Telling a bunch of renderer processes to destroy their data may
    151   // cause them to page everything in to do it, which could take a lot of time/
    152   // cause jank.
    153   for (content::RenderProcessHost::iterator i(
    154           content::RenderProcessHost::AllHostsIterator());
    155        !i.IsAtEnd(); i.Advance())
    156     PurgeRendererForHost(i.GetCurrentValue());
    157 }
    158 
    159 // static
    160 void MemoryPurger::PurgeRendererForHost(content::RenderProcessHost* host) {
    161   // Direct the renderer to free everything it can.
    162   host->Send(new ChromeViewMsg_PurgeMemory());
    163 }
    164