reactos/ntoskrnl/cc/lazywrite.c

405 lines
11 KiB
C
Raw Normal View History

/*
* COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS kernel
* FILE: ntoskrnl/cc/lazywrite.c
* PURPOSE: Cache manager
*
* PROGRAMMERS: Pierre Schweitzer (pierre@reactos.org)
*/
/* INCLUDES *****************************************************************/
#include <ntoskrnl.h>
#define NDEBUG
#include <debug.h>
/* Counters:
* - Amount of pages flushed by lazy writer
* - Number of times lazy writer ran
*/
ULONG CcLazyWritePages = 0;
ULONG CcLazyWriteIos = 0;
/* Internal vars (MS):
* - Lazy writer status structure
* - Lookaside list where to allocate work items
* - Queue for high priority work items (read ahead)
* - Queue for regular work items
* - Available worker threads
* - Queue for stuff to be queued after lazy writer is done
* - Marker for throttling queues
* - Number of ongoing workers
* - Three seconds delay for lazy writer
* - One second delay for lazy writer
* - Zero delay for lazy writer
* - Number of worker threads
*/
LAZY_WRITER LazyWriter;
NPAGED_LOOKASIDE_LIST CcTwilightLookasideList;
LIST_ENTRY CcExpressWorkQueue;
LIST_ENTRY CcRegularWorkQueue;
LIST_ENTRY CcIdleWorkerThreadList;
LIST_ENTRY CcPostTickWorkQueue;
BOOLEAN CcQueueThrottle = FALSE;
ULONG CcNumberActiveWorkerThreads = 0;
LARGE_INTEGER CcFirstDelay = RTL_CONSTANT_LARGE_INTEGER((LONGLONG)-1*3000*1000*10);
LARGE_INTEGER CcIdleDelay = RTL_CONSTANT_LARGE_INTEGER((LONGLONG)-1*1000*1000*10);
LARGE_INTEGER CcNoDelay = RTL_CONSTANT_LARGE_INTEGER((LONGLONG)0);
ULONG CcNumberWorkerThreads;
/* FUNCTIONS *****************************************************************/
VOID
CcPostWorkQueue(
IN PWORK_QUEUE_ENTRY WorkItem,
IN PLIST_ENTRY WorkQueue)
{
KIRQL OldIrql;
PWORK_QUEUE_ITEM ThreadToSpawn;
/* First of all, insert the item in the queue */
OldIrql = KeAcquireQueuedSpinLock(LockQueueWorkQueueLock);
InsertTailList(WorkQueue, &WorkItem->WorkQueueLinks);
/* Now, define whether we have to spawn a new work thread
* We will spawn a new one if:
* - There's no throttle in action
* - There's still at least one idle thread
*/
ThreadToSpawn = NULL;
if (!CcQueueThrottle && !IsListEmpty(&CcIdleWorkerThreadList))
{
PLIST_ENTRY ListEntry;
/* Get the idle thread */
ListEntry = RemoveHeadList(&CcIdleWorkerThreadList);
ThreadToSpawn = CONTAINING_RECORD(ListEntry, WORK_QUEUE_ITEM, List);
/* We're going to have one more! */
CcNumberActiveWorkerThreads += 1;
}
KeReleaseQueuedSpinLock(LockQueueWorkQueueLock, OldIrql);
/* If we have a thread to spawn, do it! */
if (ThreadToSpawn != NULL)
{
/* We NULLify it to be consistent with initialization */
ThreadToSpawn->List.Flink = NULL;
ExQueueWorkItem(ThreadToSpawn, CriticalWorkQueue);
}
}
VOID
NTAPI
CcScanDpc(
IN PKDPC Dpc,
IN PVOID DeferredContext,
IN PVOID SystemArgument1,
IN PVOID SystemArgument2)
{
PWORK_QUEUE_ENTRY WorkItem;
/* Allocate a work item */
WorkItem = ExAllocateFromNPagedLookasideList(&CcTwilightLookasideList);
if (WorkItem == NULL)
{
LazyWriter.ScanActive = FALSE;
return;
}
/* And post it, it will be for lazy write */
WorkItem->Function = LazyScan;
CcPostWorkQueue(WorkItem, &CcRegularWorkQueue);
}
VOID
CcWriteBehind(VOID)
{
ULONG Target, Count;
Target = CcTotalDirtyPages / 8;
if (Target != 0)
{
/* Flush! */
DPRINT("Lazy writer starting (%d)\n", Target);
CcRosFlushDirtyPages(Target, &Count, FALSE, TRUE);
/* And update stats */
CcLazyWritePages += Count;
++CcLazyWriteIos;
DPRINT("Lazy writer done (%d)\n", Count);
}
}
VOID
CcLazyWriteScan(VOID)
{
ULONG Target;
KIRQL OldIrql;
PLIST_ENTRY ListEntry;
LIST_ENTRY ToPost;
PWORK_QUEUE_ENTRY WorkItem;
/* Do we have entries to queue after we're done? */
InitializeListHead(&ToPost);
OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
if (LazyWriter.OtherWork)
{
while (!IsListEmpty(&CcPostTickWorkQueue))
{
ListEntry = RemoveHeadList(&CcPostTickWorkQueue);
WorkItem = CONTAINING_RECORD(ListEntry, WORK_QUEUE_ENTRY, WorkQueueLinks);
InsertTailList(&ToPost, &WorkItem->WorkQueueLinks);
}
LazyWriter.OtherWork = FALSE;
}
KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
/* Our target is one-eighth of the dirty pages */
Target = CcTotalDirtyPages / 8;
if (Target != 0)
{
/* There is stuff to flush, schedule a write-behind operation */
/* Allocate a work item */
WorkItem = ExAllocateFromNPagedLookasideList(&CcTwilightLookasideList);
if (WorkItem != NULL)
{
WorkItem->Function = WriteBehind;
CcPostWorkQueue(WorkItem, &CcRegularWorkQueue);
}
}
/* Post items that were due for end of run */
while (!IsListEmpty(&ToPost))
{
ListEntry = RemoveHeadList(&ToPost);
WorkItem = CONTAINING_RECORD(ListEntry, WORK_QUEUE_ENTRY, WorkQueueLinks);
CcPostWorkQueue(WorkItem, &CcRegularWorkQueue);
}
/* If we have deferred writes, try them now! */
if (!IsListEmpty(&CcDeferredWrites))
{
CcPostDeferredWrites();
/* Reschedule immediately a lazy writer run
* Keep us active to have short idle delay
*/
CcScheduleLazyWriteScan(FALSE);
}
else
{
/* We're no longer active */
OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
LazyWriter.ScanActive = FALSE;
KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
}
}
VOID CcScheduleLazyWriteScan(
IN BOOLEAN NoDelay)
{
/* If no delay, immediately start lazy writer,
* no matter it was already started
*/
if (NoDelay)
{
LazyWriter.ScanActive = TRUE;
KeSetTimer(&LazyWriter.ScanTimer, CcNoDelay, &LazyWriter.ScanDpc);
}
/* Otherwise, if it's not running, just wait three seconds to start it */
else if (!LazyWriter.ScanActive)
{
LazyWriter.ScanActive = TRUE;
KeSetTimer(&LazyWriter.ScanTimer, CcFirstDelay, &LazyWriter.ScanDpc);
}
/* Finally, already running, so queue for the next second */
else
{
KeSetTimer(&LazyWriter.ScanTimer, CcIdleDelay, &LazyWriter.ScanDpc);
}
}
VOID
NTAPI
CcWorkerThread(
IN PVOID Parameter)
{
KIRQL OldIrql;
BOOLEAN DropThrottle, WritePerformed;
PWORK_QUEUE_ITEM Item;
#if DBG
PIRP TopLevel;
#endif
/* Get back our thread item */
Item = Parameter;
/* And by default, don't touch throttle */
DropThrottle = FALSE;
/* No write performed */
WritePerformed = FALSE;
#if DBG
/* Top level IRP should be clean when started
* Save it to catch buggy drivers (or bugs!)
*/
TopLevel = IoGetTopLevelIrp();
if (TopLevel != NULL)
{
DPRINT1("(%p) TopLevel IRP for this thread: %p\n", PsGetCurrentThread(), TopLevel);
}
#endif
/* Loop till we have jobs */
while (TRUE)
{
PWORK_QUEUE_ENTRY WorkItem;
/* Lock queues */
OldIrql = KeAcquireQueuedSpinLock(LockQueueWorkQueueLock);
/* If we have to touch throttle, reset it now! */
if (DropThrottle)
{
CcQueueThrottle = FALSE;
DropThrottle = FALSE;
}
/* Check first if we have read ahead to do */
if (IsListEmpty(&CcExpressWorkQueue))
{
/* If not, check regular queue */
if (IsListEmpty(&CcRegularWorkQueue))
{
break;
}
else
{
WorkItem = CONTAINING_RECORD(CcRegularWorkQueue.Flink, WORK_QUEUE_ENTRY, WorkQueueLinks);
}
}
else
{
WorkItem = CONTAINING_RECORD(CcExpressWorkQueue.Flink, WORK_QUEUE_ENTRY, WorkQueueLinks);
}
/* Get our work item, if someone is waiting for us to finish
* and we're not the only thread in queue
* then, quit running to let the others do
* and throttle so that noone starts till current activity is over
*/
if (WorkItem->Function == SetDone && CcNumberActiveWorkerThreads > 1)
{
CcQueueThrottle = TRUE;
break;
}
/* Otherwise, remove current entry */
RemoveEntryList(&WorkItem->WorkQueueLinks);
KeReleaseQueuedSpinLock(LockQueueWorkQueueLock, OldIrql);
/* And handle it */
switch (WorkItem->Function)
{
case ReadAhead:
CcPerformReadAhead(WorkItem->Parameters.Read.FileObject);
break;
case WriteBehind:
PsGetCurrentThread()->MemoryMaker = 1;
CcWriteBehind();
PsGetCurrentThread()->MemoryMaker = 0;
WritePerformed = TRUE;
break;
case LazyScan:
CcLazyWriteScan();
break;
case SetDone:
KeSetEvent(WorkItem->Parameters.Event.Event, IO_NO_INCREMENT, FALSE);
DropThrottle = TRUE;
break;
default:
DPRINT1("Ignored item: %p (%d)\n", WorkItem, WorkItem->Function);
break;
}
/* And release the item */
ExFreeToNPagedLookasideList(&CcTwilightLookasideList, WorkItem);
}
/* Our thread is available again */
InsertTailList(&CcIdleWorkerThreadList, &Item->List);
/* One less worker */
--CcNumberActiveWorkerThreads;
KeReleaseQueuedSpinLock(LockQueueWorkQueueLock, OldIrql);
/* If there are pending write openations and we have at least 20 dirty pages */
if (!IsListEmpty(&CcDeferredWrites) && CcTotalDirtyPages >= 20)
{
/* And if we performed a write operation previously, then
* stress the system a bit and reschedule a scan to find
* stuff to write
*/
if (WritePerformed)
{
CcLazyWriteScan();
}
}
#if DBG
/* Top level shouldn't have changed */
if (TopLevel != IoGetTopLevelIrp())
{
DPRINT1("(%p) Mismatching TopLevel: %p, %p\n", PsGetCurrentThread(), TopLevel, IoGetTopLevelIrp());
}
#endif
}
/*
* @implemented
*/
NTSTATUS
NTAPI
CcWaitForCurrentLazyWriterActivity (
VOID)
{
KIRQL OldIrql;
KEVENT WaitEvent;
PWORK_QUEUE_ENTRY WorkItem;
/* Allocate a work item */
WorkItem = ExAllocateFromNPagedLookasideList(&CcTwilightLookasideList);
if (WorkItem == NULL)
{
return STATUS_INSUFFICIENT_RESOURCES;
}
/* We want lazy writer to set our event */
WorkItem->Function = SetDone;
KeInitializeEvent(&WaitEvent, NotificationEvent, FALSE);
WorkItem->Parameters.Event.Event = &WaitEvent;
/* Use the post tick queue */
OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
InsertTailList(&CcPostTickWorkQueue, &WorkItem->WorkQueueLinks);
/* Inform the lazy writer it will have to handle the post tick queue */
LazyWriter.OtherWork = TRUE;
/* And if it's not running, queue a lazy writer run
* And start it NOW, we want the response now
*/
if (!LazyWriter.ScanActive)
{
CcScheduleLazyWriteScan(TRUE);
}
KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
/* And now, wait until lazy writer replies */
return KeWaitForSingleObject(&WaitEvent, Executive, KernelMode, FALSE, NULL);
}