--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/kernel/eka/memmodel/epoc/flexible/mmu/mpagecleaner.cpp	Tue May 11 17:28:22 2010 +0300
@@ -0,0 +1,244 @@
+// Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of the License "Eclipse Public License v1.0"
+// which accompanies this distribution, and is available
+// at the URL "http://www.eclipse.org/legal/epl-v10.html".
+//
+// Initial Contributors:
+// Nokia Corporation - initial contribution.
+//
+// Contributors:
+//
+// Description:
+//
+
+#include <kernel.h>
+#include "mpagecleaner.h"
+#include "mm.h"
+#include "mmu.h"
+#include "mpager.h"
+
+#ifdef __PAGING_PRE_CLEAN_DIRTY_PAGES
+
+inline void IgnorePrintf(...) { }
+
+#define PAGE_CLEANER_TRACE IgnorePrintf
+//#define PAGE_CLEANER_TRACE Kern::Printf
+
+_LIT(KThreadName, "PageCleaner");
+
+const TInt KThreadPriority = 25;
+
+/// The length of time the paging device is idle before we decide to use it for cleaning dirty
+/// pages, in milliseconds.
+const TInt KIdleDelayInMillis = 2;
+
+class DPageCleaner
+	{
+public:
+	DPageCleaner();
+	void Start();
+	void NotifyPagingDeviceIdle();
+	void NotifyPagingDeviceBusy();
+	void NotifyPagesToClean();
+
+private:
+	inline TBool IsRunning();
+	void UpdateBusyCount(TInt aChange);
+	void IdleTimerExpired(TUint aInitialNotificationCount);
+	void TryToClean();
+	
+private:
+	static void TimerDfcFn(TAny*);
+	static void CleanerDfcFn(TAny*);
+	
+private:
+	TInt iIdleDelayInTicks;
+	NTimer iDelayTimer;
+	TDfcQue iDfcQue;
+	TDfc iTimerDfc;
+	TDfc iCleanerDfc;
+	TBool iRunning;
+
+	// All state below is accessed with the MmuLock held.
+
+	/// Whether the paging device is currently idle.
+	TBool iPagingDeviceIdle;
+
+	/// Whether the paging device has been idle for longer than the wait period.
+	TBool iIdleForAWhile;
+	
+	/// Whether the page cleaner is currently running.
+	TBool iCleaningInProgress;	
+	};
+
+DPageCleaner ThePageCleaner;
+
+DPageCleaner::DPageCleaner() :
+	iTimerDfc(TimerDfcFn, NULL, 1),
+	iCleanerDfc(CleanerDfcFn, NULL, 1),
+	iRunning(EFalse),
+	iPagingDeviceIdle(ETrue),
+	iIdleForAWhile(ETrue),
+	iCleaningInProgress(EFalse)
+	{
+	}
+
+void DPageCleaner::Start()
+	{
+	TBool alreadyRunning = __e32_atomic_swp_ord32(&iRunning, ETrue);
+	if (alreadyRunning)
+		return;
+
+	iIdleDelayInTicks = NKern::TimerTicks(KIdleDelayInMillis);
+	
+	TInt r = Kern::DfcQInit(&iDfcQue, KThreadPriority, &KThreadName);
+	__NK_ASSERT_ALWAYS(r == KErrNone);
+	iTimerDfc.SetDfcQ(&iDfcQue);
+	iCleanerDfc.SetDfcQ(&iDfcQue);
+
+	PAGE_CLEANER_TRACE("PageCleaner started");
+	}
+
+FORCE_INLINE TBool DPageCleaner::IsRunning()
+	{
+	return __e32_atomic_load_acq32(&iRunning);
+	}
+
+void DPageCleaner::NotifyPagingDeviceIdle()
+	{
+	__NK_ASSERT_DEBUG(MmuLock::IsHeld());
+	if (IsRunning())
+		{
+		iPagingDeviceIdle = ETrue;
+		if (!iDelayTimer.IsPending())
+			iDelayTimer.OneShot(iIdleDelayInTicks, iTimerDfc);
+		}
+	}
+
+void DPageCleaner::NotifyPagingDeviceBusy()
+	{
+	__NK_ASSERT_DEBUG(MmuLock::IsHeld());
+	if (IsRunning())
+		{
+		iDelayTimer.Cancel();
+		iPagingDeviceIdle = EFalse;
+		iIdleForAWhile = EFalse;
+		}		
+	}
+
+void DPageCleaner::NotifyPagesToClean()
+	{
+	__NK_ASSERT_DEBUG(MmuLock::IsHeld());
+	if (IsRunning())
+		{
+		if (!iCleaningInProgress && iIdleForAWhile)
+			iCleanerDfc.Enque();
+		}
+	}
+
+void DPageCleaner::TimerDfcFn(TAny* aPtr)
+	{
+	ThePageCleaner.IdleTimerExpired((TUint)aPtr);	
+	}
+
+void DPageCleaner::IdleTimerExpired(TUint aInitialNotificationCount)
+	{
+	MmuLock::Lock();	
+	if (iPagingDeviceIdle)
+		{
+		iIdleForAWhile = ETrue;
+		if (!iCleaningInProgress && ThePager.HasPagesToClean())
+			iCleanerDfc.Enque();
+		}
+	MmuLock::Unlock();
+	}
+
+void DPageCleaner::CleanerDfcFn(TAny*)
+	{
+	ThePageCleaner.TryToClean();
+	}
+
+void DPageCleaner::TryToClean()
+	{
+	MmuLock::Lock();
+	TBool workToDo = iIdleForAWhile && ThePager.HasPagesToClean();
+	iCleaningInProgress = workToDo;
+	MmuLock::Unlock();
+	
+	if (!workToDo)
+		{
+		PAGE_CLEANER_TRACE("PageCleaner - started but no work to do");
+		return;
+		}
+
+	for (;;)
+		{
+		PageCleaningLock::Lock();
+		MmuLock::Lock();
+		if (!iIdleForAWhile)
+			break;
+		TInt attempted = ThePager.CleanSomePages(ETrue);
+		if (attempted == 0)
+			break;
+		PAGE_CLEANER_TRACE("PageCleaner - attempted to clean %d pages", attempted);
+		MmuLock::Unlock();
+		PageCleaningLock::Unlock();
+		}
+	
+	if (iIdleForAWhile)
+		PAGE_CLEANER_TRACE("PageCleaner - no more pages to clean");
+	else
+		PAGE_CLEANER_TRACE("PageCleaner - device now busy");
+	
+	iCleaningInProgress = EFalse;
+	MmuLock::Unlock();
+	PageCleaningLock::Unlock();
+	}
+
+void PageCleaner::Start()
+	{
+	ThePageCleaner.Start();
+	}
+
+void PageCleaner::NotifyPagesToClean()
+	{
+	ThePageCleaner.NotifyPagesToClean();
+	}
+
+EXPORT_C void DPagingDevice::NotifyIdle()
+	{
+	ThePageCleaner.NotifyPagingDeviceIdle();
+	}
+
+EXPORT_C void DPagingDevice::NotifyBusy()
+	{
+	ThePageCleaner.NotifyPagingDeviceBusy();
+	}
+
+#else  // __PAGING_PRE_CLEAN_DIRTY_PAGES not defined
+
+void PageCleaner::Start()
+	{
+	}
+
+void PageCleaner::NotifyPagesToClean()
+	{
+	}
+
+EXPORT_C void DPagingDevice::NotifyIdle()
+	{
+	}
+
+EXPORT_C void DPagingDevice::NotifyBusy()
+	{
+	}
+
+#endif
+
+EXPORT_C NFastMutex* DPagingDevice::NotificationLock()
+	{
+	// use the MmuLock
+	return &MmuLock::iLock;
+	}