gecko-dev/dom/ipc/PreallocatedProcessManager.cpp

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9.0 KiB
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/PreallocatedProcessManager.h"
#include "mozilla/ClearOnShutdown.h"
#include "mozilla/Preferences.h"
#include "mozilla/Unused.h"
#include "mozilla/dom/ContentParent.h"
#include "mozilla/dom/ScriptSettings.h"
#include "nsIPropertyBag2.h"
#include "ProcessPriorityManager.h"
#include "nsServiceManagerUtils.h"
// This number is fairly arbitrary ... the intention is to put off
// launching another app process until the last one has finished
// loading its content, to reduce CPU/memory/IO contention.
#define DEFAULT_ALLOCATE_DELAY 1000
using namespace mozilla;
using namespace mozilla::hal;
using namespace mozilla::dom;
namespace mozilla {
/**
* This singleton class implements the static methods on
* PreallocatedProcessManager.
*/
class PreallocatedProcessManagerImpl final
: public nsIObserver
{
public:
static PreallocatedProcessManagerImpl* Singleton();
NS_DECL_ISUPPORTS
NS_DECL_NSIOBSERVER
// See comments on PreallocatedProcessManager for these methods.
void AddBlocker(ContentParent* aParent);
void RemoveBlocker(ContentParent* aParent);
already_AddRefed<ContentParent> Take();
bool Provide(ContentParent* aParent);
void Disable();
private:
static mozilla::StaticRefPtr<PreallocatedProcessManagerImpl> sSingleton;
PreallocatedProcessManagerImpl();
~PreallocatedProcessManagerImpl() {}
DISALLOW_EVIL_CONSTRUCTORS(PreallocatedProcessManagerImpl);
void Init();
bool CanAllocate();
void AllocateAfterDelay();
void AllocateOnIdle();
void AllocateNow();
void RereadPrefs();
void Enable();
void CloseProcess();
void ObserveProcessShutdown(nsISupports* aSubject);
bool mEnabled;
bool mShutdown;
RefPtr<ContentParent> mPreallocatedProcess;
nsTHashtable<nsUint64HashKey> mBlockers;
};
/* static */ StaticRefPtr<PreallocatedProcessManagerImpl>
PreallocatedProcessManagerImpl::sSingleton;
/* static */ PreallocatedProcessManagerImpl*
PreallocatedProcessManagerImpl::Singleton()
{
MOZ_ASSERT(NS_IsMainThread());
if (!sSingleton) {
sSingleton = new PreallocatedProcessManagerImpl();
sSingleton->Init();
ClearOnShutdown(&sSingleton);
}
return sSingleton;
}
NS_IMPL_ISUPPORTS(PreallocatedProcessManagerImpl, nsIObserver)
PreallocatedProcessManagerImpl::PreallocatedProcessManagerImpl()
: mEnabled(false)
, mShutdown(false)
{}
void
PreallocatedProcessManagerImpl::Init()
{
Preferences::AddStrongObserver(this, "dom.ipc.processPrelaunch.enabled");
// We have to respect processCount at all time. This is especially important
// for testing.
Preferences::AddStrongObserver(this, "dom.ipc.processCount");
nsCOMPtr<nsIObserverService> os = services::GetObserverService();
if (os) {
os->AddObserver(this, "ipc:content-shutdown",
/* weakRef = */ false);
os->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID,
/* weakRef = */ false);
os->AddObserver(this, "profile-change-teardown",
/* weakRef = */ false);
}
RereadPrefs();
}
NS_IMETHODIMP
PreallocatedProcessManagerImpl::Observe(nsISupports* aSubject,
const char* aTopic,
const char16_t* aData)
{
if (!strcmp("ipc:content-shutdown", aTopic)) {
ObserveProcessShutdown(aSubject);
} else if (!strcmp("nsPref:changed", aTopic)) {
// The only other observer we registered was for our prefs.
RereadPrefs();
} else if (!strcmp(NS_XPCOM_SHUTDOWN_OBSERVER_ID, aTopic) ||
!strcmp("profile-change-teardown", aTopic)) {
Preferences::RemoveObserver(this, "dom.ipc.processPrelaunch.enabled");
Preferences::RemoveObserver(this, "dom.ipc.processCount");
nsCOMPtr<nsIObserverService> os = services::GetObserverService();
if (os) {
os->RemoveObserver(this, "ipc:content-shutdown");
os->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID);
os->RemoveObserver(this, "profile-change-teardown");
}
// Let's prevent any new preallocated processes from starting. ContentParent will
// handle the shutdown of the existing process and the mPreallocatedProcess reference
// will be cleared by the ClearOnShutdown of the manager singleton.
mShutdown = true;
} else {
MOZ_ASSERT(false);
}
return NS_OK;
}
void
PreallocatedProcessManagerImpl::RereadPrefs()
{
if (mozilla::BrowserTabsRemoteAutostart() &&
Preferences::GetBool("dom.ipc.processPrelaunch.enabled")) {
Enable();
} else {
Disable();
}
if (ContentParent::IsMaxProcessCountReached(NS_LITERAL_STRING(DEFAULT_REMOTE_TYPE))) {
CloseProcess();
}
}
already_AddRefed<ContentParent>
PreallocatedProcessManagerImpl::Take()
{
if (!mEnabled || mShutdown) {
return nullptr;
}
if (mPreallocatedProcess) {
// The preallocated process is taken. Let's try to start up a new one soon.
AllocateOnIdle();
}
return mPreallocatedProcess.forget();
}
bool
PreallocatedProcessManagerImpl::Provide(ContentParent* aParent)
{
if (mEnabled && !mShutdown && !mPreallocatedProcess) {
mPreallocatedProcess = aParent;
}
// We might get a call from both NotifyTabDestroying and NotifyTabDestroyed with the same
// ContentParent. Returning true here for both calls is important to avoid the cached process
// to be destroyed.
return aParent == mPreallocatedProcess;
}
void
PreallocatedProcessManagerImpl::Enable()
{
if (mEnabled) {
return;
}
mEnabled = true;
AllocateAfterDelay();
}
void
PreallocatedProcessManagerImpl::AddBlocker(ContentParent* aParent)
{
uint64_t childID = aParent->ChildID();
MOZ_ASSERT(!mBlockers.Contains(childID));
mBlockers.PutEntry(childID);
}
void
PreallocatedProcessManagerImpl::RemoveBlocker(ContentParent* aParent)
{
uint64_t childID = aParent->ChildID();
MOZ_ASSERT(mBlockers.Contains(childID));
mBlockers.RemoveEntry(childID);
if (!mPreallocatedProcess && mBlockers.IsEmpty()) {
AllocateAfterDelay();
}
}
bool
PreallocatedProcessManagerImpl::CanAllocate()
{
return mEnabled &&
mBlockers.IsEmpty() &&
!mPreallocatedProcess &&
!mShutdown &&
!ContentParent::IsMaxProcessCountReached(NS_LITERAL_STRING(DEFAULT_REMOTE_TYPE));
}
void
PreallocatedProcessManagerImpl::AllocateAfterDelay()
{
if (!mEnabled) {
return;
}
NS_DelayedDispatchToCurrentThread(
NewRunnableMethod("PreallocatedProcessManagerImpl::AllocateOnIdle",
this,
&PreallocatedProcessManagerImpl::AllocateOnIdle),
Preferences::GetUint("dom.ipc.processPrelaunch.delayMs",
DEFAULT_ALLOCATE_DELAY));
}
void
PreallocatedProcessManagerImpl::AllocateOnIdle()
{
if (!mEnabled) {
return;
}
NS_IdleDispatchToCurrentThread(
NewRunnableMethod("PreallocatedProcessManagerImpl::AllocateNow",
this,
&PreallocatedProcessManagerImpl::AllocateNow));
}
void
PreallocatedProcessManagerImpl::AllocateNow()
{
if (!CanAllocate()) {
if (mEnabled && !mShutdown && !mPreallocatedProcess && !mBlockers.IsEmpty()) {
// If it's too early to allocate a process let's retry later.
AllocateAfterDelay();
}
return;
}
mPreallocatedProcess = ContentParent::PreallocateProcess();
}
void
PreallocatedProcessManagerImpl::Disable()
{
if (!mEnabled) {
return;
}
mEnabled = false;
CloseProcess();
}
void
PreallocatedProcessManagerImpl::CloseProcess()
{
if (mPreallocatedProcess) {
mPreallocatedProcess->ShutDownProcess(ContentParent::SEND_SHUTDOWN_MESSAGE);
mPreallocatedProcess = nullptr;
}
}
void
PreallocatedProcessManagerImpl::ObserveProcessShutdown(nsISupports* aSubject)
{
nsCOMPtr<nsIPropertyBag2> props = do_QueryInterface(aSubject);
NS_ENSURE_TRUE_VOID(props);
uint64_t childID = CONTENT_PROCESS_ID_UNKNOWN;
props->GetPropertyAsUint64(NS_LITERAL_STRING("childID"), &childID);
NS_ENSURE_TRUE_VOID(childID != CONTENT_PROCESS_ID_UNKNOWN);
if (mPreallocatedProcess && childID == mPreallocatedProcess->ChildID()) {
mPreallocatedProcess = nullptr;
}
mBlockers.RemoveEntry(childID);
}
inline PreallocatedProcessManagerImpl* GetPPMImpl()
{
return PreallocatedProcessManagerImpl::Singleton();
}
/* static */ void
PreallocatedProcessManager::AddBlocker(ContentParent* aParent)
{
GetPPMImpl()->AddBlocker(aParent);
}
/* static */ void
PreallocatedProcessManager::RemoveBlocker(ContentParent* aParent)
{
GetPPMImpl()->RemoveBlocker(aParent);
}
/* static */ already_AddRefed<ContentParent>
PreallocatedProcessManager::Take()
{
return GetPPMImpl()->Take();
}
/* static */ bool
PreallocatedProcessManager::Provide(ContentParent* aParent)
{
return GetPPMImpl()->Provide(aParent);
}
/* static */ void
PreallocatedProcessManager::Disable()
{
GetPPMImpl()->Disable();
}
} // namespace mozilla