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gecko-dev/xpcom/base/nsMemoryImpl.cpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Netscape Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*/
#include "nsMemoryImpl.h"
#include "prmem.h"
#include "nsAlgorithm.h"
#include "nsIServiceManager.h"
#include "nsIObserverService.h"
#include "nsAutoLock.h"
#include "nsIThread.h"
#include "nsIEventQueueService.h"
#include "nsString.h"
#if defined(XP_WIN)
#include <windows.h>
#define NS_MEMORY_FLUSHER_THREAD
#elif defined(XP_MAC)
#include <MacMemory.h>
#define NS_MEMORY_FLUSHER_THREAD
#else
// Need to implement the nsIMemory::IsLowMemory() predicate
#undef NS_MEMORY_FLUSHER_THREAD
#endif
//----------------------------------------------------------------------
#if defined(XDEBUG_waterson)
#define NS_TEST_MEMORY_FLUSHER
#endif
/**
* A runnable that is used to periodically check the status
* of the system, determine if too much memory is in use,
* and if so, trigger a "memory flush".
*/
class MemoryFlusher : public nsIRunnable
{
protected:
nsMemoryImpl* mMemoryImpl; // WEAK, it owns us.
PRBool mRunning;
PRIntervalTime mTimeout;
PRLock* mLock;
PRCondVar* mCVar;
MemoryFlusher(nsMemoryImpl* aMemoryImpl);
virtual ~MemoryFlusher();
enum {
kInitialTimeout = 60 /*seconds*/
};
public:
/**
* Create a memory flusher.
* @param aResult the memory flusher
* @param aMemoryImpl the owning nsMemoryImpl object
* @return NS_OK if the memory flusher was created successfully
*/
static nsresult
Create(MemoryFlusher** aResult, nsMemoryImpl* aMemoryImpl);
NS_DECL_ISUPPORTS
NS_DECL_NSIRUNNABLE
/**
* Stop the memory flusher.
*/
nsresult Stop();
};
MemoryFlusher::MemoryFlusher(nsMemoryImpl* aMemoryImpl)
: mMemoryImpl(aMemoryImpl),
mRunning(PR_FALSE),
mTimeout(PR_SecondsToInterval(kInitialTimeout)),
mLock(nsnull),
mCVar(nsnull)
{
NS_INIT_REFCNT();
}
MemoryFlusher::~MemoryFlusher()
{
if (mLock)
PR_DestroyLock(mLock);
if (mCVar)
PR_DestroyCondVar(mCVar);
}
nsresult
MemoryFlusher::Create(MemoryFlusher** aResult, nsMemoryImpl* aMemoryImpl)
{
MemoryFlusher* result = new MemoryFlusher(aMemoryImpl);
if (! result)
return NS_ERROR_OUT_OF_MEMORY;
do {
if ((result->mLock = PR_NewLock()) == nsnull)
break;
if ((result->mCVar = PR_NewCondVar(result->mLock)) == nsnull)
break;
NS_ADDREF(*aResult = result);
return NS_OK;
} while (0);
// Something bad happened if we get here...
delete result;
return NS_ERROR_OUT_OF_MEMORY;
}
NS_IMPL_THREADSAFE_ISUPPORTS1(MemoryFlusher, nsIRunnable)
NS_IMETHODIMP
MemoryFlusher::Run()
{
nsresult rv;
mRunning = PR_TRUE;
while (1) {
PRStatus status;
{
nsAutoLock l(mLock);
if (! mRunning) {
rv = NS_OK;
break;
}
status = PR_WaitCondVar(mCVar, mTimeout);
}
if (status != PR_SUCCESS) {
rv = NS_ERROR_FAILURE;
break;
}
if (! mRunning) {
rv = NS_OK;
break;
}
PRBool isLowMemory;
rv = mMemoryImpl->IsLowMemory(&isLowMemory);
if (NS_FAILED(rv))
break;
#ifdef NS_TEST_MEMORY_FLUSHER
// Fire the flusher *every* time
isLowMemory = PR_TRUE;
#endif
if (isLowMemory) {
mMemoryImpl->FlushMemory(NS_MEMORY_PRESSURE_LOW_MEMORY, PR_FALSE);
}
}
mRunning = PR_FALSE;
return rv;
}
nsresult
MemoryFlusher::Stop()
{
if (mRunning) {
nsAutoLock l(mLock);
mRunning = PR_FALSE;
PR_NotifyCondVar(mCVar);
}
return NS_OK;
}
//----------------------------------------------------------------------
NS_IMPL_THREADSAFE_ISUPPORTS1(nsMemoryImpl, nsIMemory)
NS_METHOD
nsMemoryImpl::Create(nsISupports* outer, const nsIID& aIID, void* *aInstancePtr)
{
NS_ENSURE_ARG_POINTER(aInstancePtr);
NS_ENSURE_PROPER_AGGREGATION(outer, aIID);
nsMemoryImpl* mm = new nsMemoryImpl();
if (mm == NULL)
return NS_ERROR_OUT_OF_MEMORY;
nsresult rv;
do {
rv = mm->QueryInterface(aIID, aInstancePtr);
if (NS_FAILED(rv))
break;
rv = NS_ERROR_OUT_OF_MEMORY;
mm->mFlushLock = PR_NewLock();
if (! mm->mFlushLock)
break;
rv = NS_OK;
} while (0);
if (NS_FAILED(rv))
delete mm;
return rv;
}
nsMemoryImpl::nsMemoryImpl()
: mFlusher(nsnull),
mFlushLock(nsnull),
mIsFlushing(PR_FALSE)
{
NS_INIT_REFCNT();
}
nsMemoryImpl::~nsMemoryImpl()
{
if (mFlushLock)
PR_DestroyLock(mFlushLock);
}
////////////////////////////////////////////////////////////////////////////////
// Define NS_OUT_OF_MEMORY_TESTER if you want to force memory failures
#ifdef DEBUG_xwarren
#define NS_OUT_OF_MEMORY_TESTER
#endif
#ifdef NS_OUT_OF_MEMORY_TESTER
// flush memory one in this number of times:
#define NS_FLUSH_FREQUENCY 100000
// fail allocation one in this number of flushes:
#define NS_FAIL_FREQUENCY 10
PRUint32 gFlushFreq = 0;
PRUint32 gFailFreq = 0;
static void*
mallocator(PRSize size, PRUint32& counter, PRUint32 max)
{
if (counter++ >= max) {
counter = 0;
NS_ASSERTION(0, "about to fail allocation... watch out");
return nsnull;
}
return PR_Malloc(size);
}
static void*
reallocator(void* ptr, PRSize size, PRUint32& counter, PRUint32 max)
{
if (counter++ >= max) {
counter = 0;
NS_ASSERTION(0, "about to fail reallocation... watch out");
return nsnull;
}
return PR_Realloc(ptr, size);
}
#define MALLOC1(s) mallocator(s, gFlushFreq, NS_FLUSH_FREQUENCY)
#define REALLOC1(p, s) reallocator(p, s, gFlushFreq, NS_FLUSH_FREQUENCY)
#else
#define MALLOC1(s) PR_Malloc(s)
#define REALLOC1(p, s) PR_Realloc(p, s)
#endif // NS_OUT_OF_MEMORY_TESTER
////////////////////////////////////////////////////////////////////////////////
NS_IMETHODIMP_(void *)
nsMemoryImpl::Alloc(PRSize size)
{
void* result = MALLOC1(size);
if (! result) {
// Request an asynchronous flush
FlushMemory(NS_MEMORY_PRESSURE_ALLOC_FAILURE, PR_FALSE);
}
return result;
}
NS_IMETHODIMP_(void *)
nsMemoryImpl::Realloc(void * ptr, PRSize size)
{
void* result = REALLOC1(ptr, size);
if (! result) {
// Request an asynchronous flush
FlushMemory(NS_MEMORY_PRESSURE_ALLOC_FAILURE, PR_FALSE);
}
return result;
}
NS_IMETHODIMP_(void)
nsMemoryImpl::Free(void * ptr)
{
PR_Free(ptr);
}
NS_IMETHODIMP
nsMemoryImpl::HeapMinimize(PRBool aImmediate)
{
return FlushMemory(NS_MEMORY_PRESSURE_HEAP_MINIMIZE, aImmediate);
}
NS_IMETHODIMP
nsMemoryImpl::IsLowMemory(PRBool *result)
{
#if defined(XP_WIN)
MEMORYSTATUS stat;
GlobalMemoryStatus(&stat);
*result = ((float)stat.dwAvailPageFile / stat.dwTotalPageFile) < 0.1;
#elif defined(XP_MAC)
const long kReserveHeapFreeSpace = (256 * 1024);
const long kReserveHeapContigSpace = (128 * 1024);
long totalSpace, contiguousSpace;
// this call measures how much memory would be available if the OS
// purged. Despite the name, it does not purge (that happens
// automatically when heap space is low).
::PurgeSpace(&totalSpace, &contiguousSpace);
if (totalSpace < kReserveHeapFreeSpace || contiguousSpace < kReserveHeapContigSpace)
{
NS_WARNING("Found that heap mem is low");
*result = PR_TRUE;
return NS_OK;
}
// see how much temp mem is available (since our allocators allocate 1Mb chunks
// in temp mem. We don't use TempMaxMem() (to get contig space) here, because it
// compacts the application heap, so can be slow.
const long kReserveTempFreeSpace = (2 * 1024 * 1024); // 2Mb
long totalTempSpace = ::TempFreeMem();
if (totalTempSpace < kReserveTempFreeSpace)
{
NS_WARNING("Found that temp mem is low");
*result = PR_TRUE;
return NS_OK;
}
*result = PR_FALSE;
#else
*result = PR_FALSE;
#endif
return NS_OK;
}
nsresult
nsMemoryImpl::FlushMemory(const PRUnichar* aReason, PRBool aImmediate)
{
nsresult rv;
if (aImmediate) {
// They've asked us to run the flusher *immediately*. We've
// got to be on the UI main thread for us to be able to do
// that...are we?
PRBool isOnUIThread = PR_FALSE;
nsCOMPtr<nsIThread> main;
rv = nsIThread::GetMainThread(getter_AddRefs(main));
if (NS_SUCCEEDED(rv)) {
nsCOMPtr<nsIThread> current;
rv = nsIThread::GetCurrent(getter_AddRefs(current));
if (NS_SUCCEEDED(rv)) {
if (current == main)
isOnUIThread = PR_TRUE;
}
}
if (! isOnUIThread) {
NS_ERROR("can't synchronously flush memory: not on UI thread");
return NS_ERROR_FAILURE;
}
}
{
// Are we already flushing?
nsAutoLock l(mFlushLock);
if (mIsFlushing)
return NS_OK;
// Well, we are now!
mIsFlushing = PR_TRUE;
}
// Run the flushers immediately if we can; otherwise, proxy to the
// UI thread an run 'em asynchronously.
if (aImmediate) {
rv = RunFlushers(this, aReason);
}
else {
nsCOMPtr<nsIEventQueueService> eqs = do_GetService(NS_EVENTQUEUESERVICE_CONTRACTID, &rv);
if (eqs) {
nsCOMPtr<nsIEventQueue> eq;
rv = eqs->GetThreadEventQueue(NS_UI_THREAD, getter_AddRefs(eq));
if (NS_SUCCEEDED(rv)) {
PL_InitEvent(&mFlushEvent.mEvent, this, HandleFlushEvent, DestroyFlushEvent);
mFlushEvent.mReason = aReason;
rv = eq->PostEvent(NS_REINTERPRET_CAST(PLEvent*, &mFlushEvent));
}
}
}
return rv;
}
nsresult
nsMemoryImpl::RunFlushers(nsMemoryImpl* aSelf, const PRUnichar* aReason)
{
nsCOMPtr<nsIObserverService> os = do_GetService(NS_OBSERVERSERVICE_CONTRACTID);
if (os) {
os->Notify(aSelf, NS_MEMORY_PRESSURE_TOPIC, aReason);
}
{
// Done flushing
nsAutoLock l(aSelf->mFlushLock);
aSelf->mIsFlushing = PR_FALSE;
}
return NS_OK;
}
void*
nsMemoryImpl::HandleFlushEvent(PLEvent* aEvent)
{
nsMemoryImpl* self = NS_STATIC_CAST(nsMemoryImpl*, PL_GetEventOwner(aEvent));
FlushEvent* event = NS_REINTERPRET_CAST(FlushEvent*, aEvent);
RunFlushers(self, event->mReason);
return 0;
}
void
nsMemoryImpl::DestroyFlushEvent(PLEvent* aEvent)
{
// no-op, since mEvent is a member of nsMemoryImpl
}
nsMemoryImpl* gMemory = nsnull;
static void
EnsureGlobalMemoryService()
{
if (gMemory) return;
nsresult rv = nsMemoryImpl::Create(nsnull, NS_GET_IID(nsIMemory), (void**)&gMemory);
NS_ASSERTION(NS_SUCCEEDED(rv), "nsMemoryImpl::Create failed");
NS_ASSERTION(gMemory, "improper xpcom initialization");
}
nsresult
nsMemoryImpl::Startup()
{
EnsureGlobalMemoryService();
if (! gMemory)
return NS_ERROR_FAILURE;
#ifdef NS_MEMORY_FLUSHER_THREAD
nsresult rv;
// Create and start a memory flusher thread
rv = MemoryFlusher::Create(&gMemory->mFlusher, gMemory);
if (NS_FAILED(rv)) return rv;
rv = NS_NewThread(getter_AddRefs(gMemory->mFlusherThread),
gMemory->mFlusher,
0, /* XXX use default stack size? */
PR_JOINABLE_THREAD);
if (NS_FAILED(rv)) return rv;
#endif
return NS_OK;
}
nsresult
nsMemoryImpl::Shutdown()
{
if (gMemory) {
#ifdef NS_MEMORY_FLUSHER_THREAD
if (gMemory->mFlusher) {
// Stop the runnable...
gMemory->mFlusher->Stop();
NS_RELEASE(gMemory->mFlusher);
// ...and wait for the thread to exit
if (gMemory->mFlusherThread)
gMemory->mFlusherThread->Join();
}
#endif
NS_RELEASE(gMemory);
gMemory = nsnull;
}
return NS_OK;
}
////////////////////////////////////////////////////////////////////////////////
// nsMemory static helper routines
NS_EXPORT void*
nsMemory::Alloc(PRSize size)
{
if (gMemory == nsnull) {
EnsureGlobalMemoryService();
}
return gMemory->Alloc(size);
}
NS_EXPORT void*
nsMemory::Realloc(void* ptr, PRSize size)
{
if (gMemory == nsnull) {
EnsureGlobalMemoryService();
}
return gMemory->Realloc(ptr, size);
}
NS_EXPORT void
nsMemory::Free(void* ptr)
{
if (gMemory == nsnull) {
EnsureGlobalMemoryService();
}
gMemory->Free(ptr);
}
NS_EXPORT nsresult
nsMemory::HeapMinimize(PRBool aImmediate)
{
if (gMemory == nsnull) {
EnsureGlobalMemoryService();
}
return gMemory->HeapMinimize(aImmediate);
}
NS_EXPORT void*
nsMemory::Clone(const void* ptr, PRSize size)
{
if (gMemory == nsnull) {
EnsureGlobalMemoryService();
}
void* newPtr = gMemory->Alloc(size);
if (newPtr)
memcpy(newPtr, ptr, size);
return newPtr;
}
NS_EXPORT nsIMemory*
nsMemory::GetGlobalMemoryService()
{
if (gMemory == nsnull) {
EnsureGlobalMemoryService();
}
NS_ADDREF(gMemory);
return gMemory;
}
//----------------------------------------------------------------------
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