ULONG
MiIsEntireRangeCommitted (
IN PVOID StartingAddress,
IN PVOID EndingAddress,
IN PMMVAD Vad,
IN PEPROCESS Process
)
/*++
Routine Description:
This routine examines the range of pages from the starting address
up to and including the ending address and returns TRUE if every
page in the range is committed, FALSE otherwise.
Arguments:
StartingAddress - Supplies the starting address of the range.
EndingAddress - Supplies the ending address of the range.
Vad - Supplies the virtual address descriptor which describes the range.
Process - Supplies the current process.
Return Value:
TRUE if the entire range is committed.
FALSE if any page within the range is not committed.
Environment:
Kernel mode, APCs disabled, WorkingSetMutex and AddressCreation mutexes
held.
--*/
{
PMMPTE PointerPte;
PMMPTE LastPte;
PMMPTE PointerPde;
PMMPTE PointerPpe;
PMMPTE PointerPxe;
ULONG FirstTime;
ULONG Waited;
PVOID Va;
PAGED_CODE();
FirstTime = TRUE;
PointerPde = MiGetPdeAddress (StartingAddress);
PointerPte = MiGetPteAddress (StartingAddress);
LastPte = MiGetPteAddress (EndingAddress);
//
// Set the Va to the starting address + 8, this solves problems
// associated with address 0 (NULL) being used as a valid virtual
// address and NULL in the VAD commitment field indicating no pages
// are committed.
//
Va = (PVOID)((PCHAR)StartingAddress + 8);
while (PointerPte <= LastPte) {
if (MiIsPteOnPdeBoundary(PointerPte) || (FirstTime)) {
//
// This may be a PXE/PPE/PDE boundary, check to see if all the
// PXE/PPE/PDE pages exist.
//
FirstTime = FALSE;
PointerPde = MiGetPteAddress (PointerPte);
PointerPpe = MiGetPteAddress (PointerPde);
PointerPxe = MiGetPteAddress (PointerPpe);
do {
#if (_MI_PAGING_LEVELS >= 4)
retry:
#endif
while (!MiDoesPxeExistAndMakeValid (PointerPxe, Process, MM_NOIRQL, &Waited)) {
//
// No PPE exists for the starting address, check the VAD
// to see if the pages are committed.
//
PointerPxe += 1;
PointerPpe = MiGetVirtualAddressMappedByPte (PointerPxe);
PointerPde = MiGetVirtualAddressMappedByPte (PointerPpe);
PointerPte = MiGetVirtualAddressMappedByPte (PointerPde);
Va = MiGetVirtualAddressMappedByPte (PointerPte);
if (PointerPte > LastPte) {
//
// Make sure the entire range is committed.
//
if (Vad->u.VadFlags.MemCommit == 0) {
//
// The entire range to be decommitted is not
// committed, return an error.
//
return FALSE;
}
return TRUE;
}
//
// Make sure the range thus far is committed.
//
if (Vad->u.VadFlags.MemCommit == 0) {
//
// The entire range to be decommitted is not committed,
// return an error.
//
return FALSE;
}
}
while (!MiDoesPpeExistAndMakeValid (PointerPpe, Process, MM_NOIRQL, &Waited)) {
//
// No PDE exists for the starting address, check the VAD
// to see if the pages are committed.
//
PointerPpe += 1;
PointerPde = MiGetVirtualAddressMappedByPte (PointerPpe);
PointerPte = MiGetVirtualAddressMappedByPte (PointerPde);
Va = MiGetVirtualAddressMappedByPte (PointerPte);
if (PointerPte > LastPte) {
//
// Make sure the entire range is committed.
//
if (Vad->u.VadFlags.MemCommit == 0) {
//
// The entire range to be decommitted is not
// committed, return an error.
//
return FALSE;
}
return TRUE;
}
//
// Make sure the range thus far is committed.
//
if (Vad->u.VadFlags.MemCommit == 0) {
//
// The entire range to be decommitted is not committed,
// return an error.
//
return FALSE;
}
#if (_MI_PAGING_LEVELS >= 4)
if (MiIsPteOnPdeBoundary (PointerPpe)) {
PointerPxe = MiGetPteAddress (PointerPpe);
goto retry;
}
#endif
}
Waited = 0;
while (!MiDoesPdeExistAndMakeValid (PointerPde, Process, MM_NOIRQL, &Waited)) {
//
// No PDE exists for the starting address, check the VAD
// to see if the pages are committed.
//
PointerPde += 1;
PointerPpe = MiGetPteAddress (PointerPde);
PointerPxe = MiGetPdeAddress (PointerPde);
PointerPte = MiGetVirtualAddressMappedByPte (PointerPde);
Va = MiGetVirtualAddressMappedByPte (PointerPte);
if (PointerPte > LastPte) {
//
// Make sure the entire range is committed.
//
if (Vad->u.VadFlags.MemCommit == 0) {
//
// The entire range to be decommitted is not committed,
// return an error.
//
return FALSE;
}
return TRUE;
}
//
// Make sure the range thus far is committed.
//
if (Vad->u.VadFlags.MemCommit == 0) {
//
// The entire range to be decommitted is not committed,
// return an error.
//
return FALSE;
}
#if (_MI_PAGING_LEVELS >= 3)
if (MiIsPteOnPdeBoundary (PointerPde)) {
PointerPpe = MiGetPteAddress (PointerPde);
#if (_MI_PAGING_LEVELS >= 4)
if (MiIsPteOnPpeBoundary (PointerPde)) {
PointerPxe = MiGetPdeAddress (PointerPde);
Waited = 1;
break;
}
#endif
Waited = 1;
break;
}
#endif
}
} while (Waited != 0);
}
//
// The page table page exists, check each PTE for commitment.
//
if (PointerPte->u.Long == 0) {
//
// This page has not been committed, check the VAD.
//
if (Vad->u.VadFlags.MemCommit == 0) {
//
// The entire range to be decommitted is not committed,
// return an error.
//
return FALSE;
}
}
else {
//
// Has this page been explicitly decommitted?
//
if (MiIsPteDecommittedPage (PointerPte)) {
//
// This page has been explicitly decommitted, return an error.
//
return FALSE;
}
}
PointerPte += 1;
Va = (PVOID)((PCHAR)(Va) + PAGE_SIZE);
}
return TRUE;
}
/*
* @implemented
*/
VOID
NTAPI
MmProbeAndLockPages(IN PMDL Mdl,
IN KPROCESSOR_MODE AccessMode,
IN LOCK_OPERATION Operation)
{
PPFN_NUMBER MdlPages;
PVOID Base, Address, LastAddress, StartAddress;
ULONG LockPages, TotalPages;
NTSTATUS Status = STATUS_SUCCESS;
PEPROCESS CurrentProcess;
NTSTATUS ProbeStatus;
PMMPTE PointerPte, LastPte;
PMMPDE PointerPde;
#if (_MI_PAGING_LEVELS >= 3)
PMMPDE PointerPpe;
#endif
#if (_MI_PAGING_LEVELS == 4)
PMMPDE PointerPxe;
#endif
PFN_NUMBER PageFrameIndex;
BOOLEAN UsePfnLock;
KIRQL OldIrql;
PMMPFN Pfn1;
DPRINT("Probing MDL: %p\n", Mdl);
//
// Sanity checks
//
ASSERT(Mdl->ByteCount != 0);
ASSERT(((ULONG)Mdl->ByteOffset & ~(PAGE_SIZE - 1)) == 0);
ASSERT(((ULONG_PTR)Mdl->StartVa & (PAGE_SIZE - 1)) == 0);
ASSERT((Mdl->MdlFlags & (MDL_PAGES_LOCKED |
MDL_MAPPED_TO_SYSTEM_VA |
MDL_SOURCE_IS_NONPAGED_POOL |
MDL_PARTIAL |
MDL_IO_SPACE)) == 0);
//
// Get page and base information
//
MdlPages = (PPFN_NUMBER)(Mdl + 1);
Base = Mdl->StartVa;
//
// Get the addresses and how many pages we span (and need to lock)
//
Address = (PVOID)((ULONG_PTR)Base + Mdl->ByteOffset);
LastAddress = (PVOID)((ULONG_PTR)Address + Mdl->ByteCount);
LockPages = ADDRESS_AND_SIZE_TO_SPAN_PAGES(Address, Mdl->ByteCount);
ASSERT(LockPages != 0);
/* Block invalid access */
if ((AccessMode != KernelMode) &&
((LastAddress > (PVOID)MM_USER_PROBE_ADDRESS) || (Address >= LastAddress)))
{
/* Caller should be in SEH, raise the error */
*MdlPages = LIST_HEAD;
ExRaiseStatus(STATUS_ACCESS_VIOLATION);
}
//
// Get the process
//
if (Address <= MM_HIGHEST_USER_ADDRESS)
{
//
// Get the process
//
CurrentProcess = PsGetCurrentProcess();
}
else
{
//
// No process
//
CurrentProcess = NULL;
}
//
// Save the number of pages we'll have to lock, and the start address
//
TotalPages = LockPages;
StartAddress = Address;
/* Large pages not supported */
ASSERT(!MI_IS_PHYSICAL_ADDRESS(Address));
//
// Now probe them
//
ProbeStatus = STATUS_SUCCESS;
_SEH2_TRY
{
//
// Enter probe loop
//
do
{
//
// Assume failure
//
*MdlPages = LIST_HEAD;
//
// Read
//
*(volatile CHAR*)Address;
//
// Check if this is write access (only probe for user-mode)
//
if ((Operation != IoReadAccess) &&
(Address <= MM_HIGHEST_USER_ADDRESS))
{
//
// Probe for write too
//
ProbeForWriteChar(Address);
}
//
// Next address...
//
Address = PAGE_ALIGN((ULONG_PTR)Address + PAGE_SIZE);
//
// Next page...
//
LockPages--;
MdlPages++;
} while (Address < LastAddress);
//
// Reset back to the original page
//
ASSERT(LockPages == 0);
MdlPages = (PPFN_NUMBER)(Mdl + 1);
}
_SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
{
//
// Oops :(
//
ProbeStatus = _SEH2_GetExceptionCode();
}
_SEH2_END;
//
// So how did that go?
//
if (ProbeStatus != STATUS_SUCCESS)
{
//
// Fail
//
DPRINT1("MDL PROBE FAILED!\n");
Mdl->Process = NULL;
ExRaiseStatus(ProbeStatus);
}
//
// Get the PTE and PDE
//
PointerPte = MiAddressToPte(StartAddress);
PointerPde = MiAddressToPde(StartAddress);
#if (_MI_PAGING_LEVELS >= 3)
PointerPpe = MiAddressToPpe(StartAddress);
#endif
#if (_MI_PAGING_LEVELS == 4)
PointerPxe = MiAddressToPxe(StartAddress);
#endif
//
// Sanity check
//
ASSERT(MdlPages == (PPFN_NUMBER)(Mdl + 1));
//
// Check what kind of operation this is
//
if (Operation != IoReadAccess)
{
//
// Set the write flag
//
Mdl->MdlFlags |= MDL_WRITE_OPERATION;
}
else
{
//
// Remove the write flag
//
Mdl->MdlFlags &= ~(MDL_WRITE_OPERATION);
}
//
// Mark the MDL as locked *now*
//
Mdl->MdlFlags |= MDL_PAGES_LOCKED;
//
// Check if this came from kernel mode
//
if (Base > MM_HIGHEST_USER_ADDRESS)
{
//
// We should not have a process
//
ASSERT(CurrentProcess == NULL);
Mdl->Process = NULL;
//
// In kernel mode, we don't need to check for write access
//
Operation = IoReadAccess;
//
// Use the PFN lock
//
UsePfnLock = TRUE;
OldIrql = KeAcquireQueuedSpinLock(LockQueuePfnLock);
}
else
{
//
// Sanity checks
//
ASSERT(TotalPages != 0);
ASSERT(CurrentProcess == PsGetCurrentProcess());
//
// Track locked pages
//
InterlockedExchangeAddSizeT(&CurrentProcess->NumberOfLockedPages,
TotalPages);
//
// Save the process
//
Mdl->Process = CurrentProcess;
/* Lock the process working set */
MiLockProcessWorkingSet(CurrentProcess, PsGetCurrentThread());
UsePfnLock = FALSE;
OldIrql = MM_NOIRQL;
}
//
// Get the last PTE
//
LastPte = MiAddressToPte((PVOID)((ULONG_PTR)LastAddress - 1));
//
// Loop the pages
//
do
{
//
// Assume failure and check for non-mapped pages
//
*MdlPages = LIST_HEAD;
while (
#if (_MI_PAGING_LEVELS == 4)
(PointerPxe->u.Hard.Valid == 0) ||
#endif
#if (_MI_PAGING_LEVELS >= 3)
(PointerPpe->u.Hard.Valid == 0) ||
#endif
(PointerPde->u.Hard.Valid == 0) ||
(PointerPte->u.Hard.Valid == 0))
{
//
// What kind of lock were we using?
//
if (UsePfnLock)
{
//
// Release PFN lock
//
KeReleaseQueuedSpinLock(LockQueuePfnLock, OldIrql);
}
else
{
/* Release process working set */
MiUnlockProcessWorkingSet(CurrentProcess, PsGetCurrentThread());
}
//
// Access the page
//
Address = MiPteToAddress(PointerPte);
//HACK: Pass a placeholder TrapInformation so the fault handler knows we're unlocked
Status = MmAccessFault(FALSE, Address, KernelMode, (PVOID)0xBADBADA3);
if (!NT_SUCCESS(Status))
{
//
// Fail
//
DPRINT1("Access fault failed\n");
goto Cleanup;
}
//
// What lock should we use?
//
if (UsePfnLock)
{
//
// Grab the PFN lock
//
OldIrql = KeAcquireQueuedSpinLock(LockQueuePfnLock);
}
else
{
/* Lock the process working set */
MiLockProcessWorkingSet(CurrentProcess, PsGetCurrentThread());
}
}
//
// Check if this was a write or modify
//
if (Operation != IoReadAccess)
{
//
// Check if the PTE is not writable
//
if (MI_IS_PAGE_WRITEABLE(PointerPte) == FALSE)
{
//
// Check if it's copy on write
//
if (MI_IS_PAGE_COPY_ON_WRITE(PointerPte))
{
//
// Get the base address and allow a change for user-mode
//
Address = MiPteToAddress(PointerPte);
if (Address <= MM_HIGHEST_USER_ADDRESS)
{
//
// What kind of lock were we using?
//
if (UsePfnLock)
{
//
// Release PFN lock
//
KeReleaseQueuedSpinLock(LockQueuePfnLock, OldIrql);
}
else
{
/* Release process working set */
MiUnlockProcessWorkingSet(CurrentProcess, PsGetCurrentThread());
}
//
// Access the page
//
//HACK: Pass a placeholder TrapInformation so the fault handler knows we're unlocked
Status = MmAccessFault(TRUE, Address, KernelMode, (PVOID)0xBADBADA3);
if (!NT_SUCCESS(Status))
{
//
// Fail
//
DPRINT1("Access fault failed\n");
goto Cleanup;
}
//
// Re-acquire the lock
//
if (UsePfnLock)
{
//
// Grab the PFN lock
//
OldIrql = KeAcquireQueuedSpinLock(LockQueuePfnLock);
}
else
{
/* Lock the process working set */
MiLockProcessWorkingSet(CurrentProcess, PsGetCurrentThread());
}
//
// Start over
//
continue;
}
}
//
// Fail, since we won't allow this
//
Status = STATUS_ACCESS_VIOLATION;
goto CleanupWithLock;
}
}
//
// Grab the PFN
//
PageFrameIndex = PFN_FROM_PTE(PointerPte);
Pfn1 = MiGetPfnEntry(PageFrameIndex);
if (Pfn1)
{
/* Either this is for kernel-mode, or the working set is held */
ASSERT((CurrentProcess == NULL) || (UsePfnLock == FALSE));
/* No Physical VADs supported yet */
if (CurrentProcess) ASSERT(CurrentProcess->PhysicalVadRoot == NULL);
/* This address should already exist and be fully valid */
MiReferenceProbedPageAndBumpLockCount(Pfn1);
}
else
{
//
// For I/O addresses, just remember this
//
Mdl->MdlFlags |= MDL_IO_SPACE;
}
//
// Write the page and move on
//
*MdlPages++ = PageFrameIndex;
PointerPte++;
/* Check if we're on a PDE boundary */
if (MiIsPteOnPdeBoundary(PointerPte)) PointerPde++;
#if (_MI_PAGING_LEVELS >= 3)
if (MiIsPteOnPpeBoundary(PointerPte)) PointerPpe++;
#endif
#if (_MI_PAGING_LEVELS == 4)
if (MiIsPteOnPxeBoundary(PointerPte)) PointerPxe++;
#endif
} while (PointerPte <= LastPte);
//
// What kind of lock were we using?
//
if (UsePfnLock)
{
//
// Release PFN lock
//
KeReleaseQueuedSpinLock(LockQueuePfnLock, OldIrql);
}
else
{
/* Release process working set */
MiUnlockProcessWorkingSet(CurrentProcess, PsGetCurrentThread());
}
//
// Sanity check
//
ASSERT((Mdl->MdlFlags & MDL_DESCRIBES_AWE) == 0);
return;
CleanupWithLock:
//
// This is the failure path
//
ASSERT(!NT_SUCCESS(Status));
//
// What kind of lock were we using?
//
if (UsePfnLock)
{
//
// Release PFN lock
//
KeReleaseQueuedSpinLock(LockQueuePfnLock, OldIrql);
}
else
{
/* Release process working set */
MiUnlockProcessWorkingSet(CurrentProcess, PsGetCurrentThread());
}
Cleanup:
//
// Pages must be locked so MmUnlock can work
//
ASSERT(Mdl->MdlFlags & MDL_PAGES_LOCKED);
MmUnlockPages(Mdl);
//
// Raise the error
//
ExRaiseStatus(Status);
}
ULONG
MiDecommitPages (
IN PVOID StartingAddress,
IN PMMPTE EndingPte,
IN PEPROCESS Process,
IN PMMVAD_SHORT Vad
)
/*++
Routine Description:
This routine decommits the specified range of pages.
Arguments:
StartingAddress - Supplies the starting address of the range.
EndingPte - Supplies the ending PTE of the range.
Process - Supplies the current process.
Vad - Supplies the virtual address descriptor which describes the range.
Return Value:
Value to reduce commitment by for the VAD.
Environment:
Kernel mode, APCs disabled, AddressCreation mutex held.
--*/
{
PMMPTE PointerPde;
PMMPTE PointerPte;
PVOID Va;
ULONG CommitReduction;
PMMPTE CommitLimitPte;
KIRQL OldIrql;
PMMPTE ValidPteList[MM_VALID_PTE_SIZE];
ULONG count;
WSLE_NUMBER WorkingSetIndex;
PMMPFN Pfn1;
PMMPFN Pfn2;
WSLE_NUMBER Entry;
MMWSLENTRY Locked;
MMPTE PteContents;
PFN_NUMBER PageTableFrameIndex;
PVOID UsedPageTableHandle;
PETHREAD CurrentThread;
count = 0;
CommitReduction = 0;
if (Vad->u.VadFlags.MemCommit) {
CommitLimitPte = MiGetPteAddress (MI_VPN_TO_VA (Vad->EndingVpn));
}
else {
CommitLimitPte = NULL;
}
//
// Decommit each page by setting the PTE to be explicitly
// decommitted. The PTEs cannot be deleted all at once as
// this would set the PTEs to zero which would auto-evaluate
// as committed if referenced by another thread when a page
// table page is being in-paged.
//
PointerPde = MiGetPdeAddress (StartingAddress);
PointerPte = MiGetPteAddress (StartingAddress);
Va = StartingAddress;
//
// Loop through all the PDEs which map this region and ensure that
// they exist. If they don't exist create them by touching a
// PTE mapped by the PDE.
//
CurrentThread = PsGetCurrentThread ();
LOCK_WS_UNSAFE (CurrentThread, Process);
MiMakePdeExistAndMakeValid (PointerPde, Process, MM_NOIRQL);
while (PointerPte <= EndingPte) {
if (MiIsPteOnPdeBoundary (PointerPte)) {
PointerPde = MiGetPdeAddress (Va);
if (count != 0) {
MiProcessValidPteList (&ValidPteList[0], count);
count = 0;
}
MiMakePdeExistAndMakeValid (PointerPde, Process, MM_NOIRQL);
}
//
// The working set lock is held. No PTEs can go from
// invalid to valid or valid to invalid. Transition
// PTEs can go from transition to pagefile.
//
PteContents = *PointerPte;
if (PteContents.u.Long != 0) {
if (PointerPte->u.Long == MmDecommittedPte.u.Long) {
//
// This PTE is already decommitted.
//
CommitReduction += 1;
}
else {
Process->NumberOfPrivatePages -= 1;
if (PteContents.u.Hard.Valid == 1) {
//
// Make sure this is not a forked PTE.
//
Pfn1 = MI_PFN_ELEMENT (PteContents.u.Hard.PageFrameNumber);
if (Pfn1->u3.e1.PrototypePte) {
//
// MiDeletePte may release both the working set pushlock
// and the PFN lock so the valid PTE list must be
// processed now.
//
if (count != 0) {
MiProcessValidPteList (&ValidPteList[0], count);
count = 0;
}
LOCK_PFN (OldIrql);
MiDeletePte (PointerPte,
Va,
FALSE,
Process,
NULL,
NULL,
OldIrql);
UNLOCK_PFN (OldIrql);
Process->NumberOfPrivatePages += 1;
MI_WRITE_INVALID_PTE (PointerPte, MmDecommittedPte);
}
else {
//
// PTE is valid, process later when PFN lock is held.
//
if (count == MM_VALID_PTE_SIZE) {
MiProcessValidPteList (&ValidPteList[0], count);
count = 0;
}
ValidPteList[count] = PointerPte;
count += 1;
//
// Remove address from working set list.
//
WorkingSetIndex = Pfn1->u1.WsIndex;
ASSERT (PAGE_ALIGN(MmWsle[WorkingSetIndex].u1.Long) ==
Va);
//
// Check to see if this entry is locked in the
// working set or locked in memory.
//
Locked = MmWsle[WorkingSetIndex].u1.e1;
MiRemoveWsle (WorkingSetIndex, MmWorkingSetList);
//
// Add this entry to the list of free working set
// entries and adjust the working set count.
//
MiReleaseWsle (WorkingSetIndex, &Process->Vm);
if ((Locked.LockedInWs == 1) || (Locked.LockedInMemory == 1)) {
//
// This entry is locked.
//
MmWorkingSetList->FirstDynamic -= 1;
if (WorkingSetIndex != MmWorkingSetList->FirstDynamic) {
Entry = MmWorkingSetList->FirstDynamic;
ASSERT (MmWsle[Entry].u1.e1.Valid);
MiSwapWslEntries (Entry,
WorkingSetIndex,
&Process->Vm,
FALSE);
}
}
MI_SET_PTE_IN_WORKING_SET (PointerPte, 0);
}
}
else if (PteContents.u.Soft.Prototype) {
//
// This is a forked PTE, just delete it.
//
// MiDeletePte may release both the working set pushlock
// and the PFN lock so the valid PTE list must be
// processed now.
//
if (count != 0) {
MiProcessValidPteList (&ValidPteList[0], count);
count = 0;
}
LOCK_PFN (OldIrql);
MiDeletePte (PointerPte,
Va,
FALSE,
Process,
NULL,
NULL,
OldIrql);
UNLOCK_PFN (OldIrql);
Process->NumberOfPrivatePages += 1;
MI_WRITE_INVALID_PTE (PointerPte, MmDecommittedPte);
}
else if (PteContents.u.Soft.Transition == 1) {
//
// Transition PTE, get the PFN database lock
// and reprocess this one.
//
LOCK_PFN (OldIrql);
PteContents = *PointerPte;
if (PteContents.u.Soft.Transition == 1) {
//
// PTE is still in transition, delete it.
//
Pfn1 = MI_PFN_ELEMENT (PteContents.u.Trans.PageFrameNumber);
MI_SET_PFN_DELETED (Pfn1);
PageTableFrameIndex = Pfn1->u4.PteFrame;
Pfn2 = MI_PFN_ELEMENT (PageTableFrameIndex);
MiDecrementShareCountInline (Pfn2, PageTableFrameIndex);
//
// Check the reference count for the page, if the
// reference count is zero, move the page to the
// free list, if the reference count is not zero,
// ignore this page. When the reference count
// goes to zero, it will be placed on the free list.
//
if (Pfn1->u3.e2.ReferenceCount == 0) {
MiUnlinkPageFromList (Pfn1);
MiReleasePageFileSpace (Pfn1->OriginalPte);
MiInsertPageInFreeList (MI_GET_PAGE_FRAME_FROM_TRANSITION_PTE(&PteContents));
}
}
else {
//
// Page MUST be in page file format!
//
ASSERT (PteContents.u.Soft.Valid == 0);
ASSERT (PteContents.u.Soft.Prototype == 0);
ASSERT (PteContents.u.Soft.PageFileHigh != 0);
MiReleasePageFileSpace (PteContents);
}
MI_WRITE_INVALID_PTE (PointerPte, MmDecommittedPte);
UNLOCK_PFN (OldIrql);
}
else {
//
// Must be demand zero or paging file format.
//
if (PteContents.u.Soft.PageFileHigh != 0) {
LOCK_PFN (OldIrql);
MiReleasePageFileSpace (PteContents);
UNLOCK_PFN (OldIrql);
}
else {
//
// Don't subtract out the private page count for
// a demand zero page.
//
Process->NumberOfPrivatePages += 1;
}
MI_WRITE_INVALID_PTE (PointerPte, MmDecommittedPte);
}
}
}
else {
//
// The PTE is already zero.
//
//
// Increment the count of non-zero page table entries for this
// page table and the number of private pages for the process.
//
UsedPageTableHandle = MI_GET_USED_PTES_HANDLE (Va);
MI_INCREMENT_USED_PTES_BY_HANDLE (UsedPageTableHandle);
if (PointerPte > CommitLimitPte) {
//
// PTE is not committed.
//
CommitReduction += 1;
}
MI_WRITE_INVALID_PTE (PointerPte, MmDecommittedPte);
}
PointerPte += 1;
Va = (PVOID)((PCHAR)Va + PAGE_SIZE);
}
if (count != 0) {
MiProcessValidPteList (&ValidPteList[0], count);
}
UNLOCK_WS_UNSAFE (CurrentThread, Process);
return CommitReduction;
}
