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FsRtlIncrementCcFastMdlReadWait routine

The FsRtlIncrementCcFastMdlReadWait routine increments the cache manager's CcFastMdlReadWait performance counter member in a processor control block (PRCB) object.

Syntax


VOID FsRtlIncrementCcFastMdlReadWait(
  VOID 
);

Parameters

None

Return value

This routine does not return a value.

Remarks

FsRtlIncrementCcFastMdlReadWait increments the cache manager's CcFastMdlReadWait performance counter in the per-processor control block for the processor on which FsRtlIncrementCcFastMdlReadWait is called. This counter records the number of fast I/O MDL read operations (FsRtlMdlRead) serviced by a file system driver.

File system drivers should call this function to update the CcFastMdlReadWait performance counter if the driver chooses to override the default fast I/O MDL read handler.

The counter is only used to record fast I/O MDL read operations for a nonzero length. FsRtlIncrementCcFastMdlReadWait should not be called for a zero-length fast I/O MDL read.

File system drivers should not increment the CcFastMdlReadWait performance counter if their fast I/O MDL read handler returns FALSE due to IoGetTopLevelIrp returning a non-NULL value. The counter should only be incremented if the file system driver actually attempts to satisfy a nonzero-length fast I/O MDL read.

Requirements

Version

Available in Windows Vista and later versions of the Windows operating system.

Header

Ntifs.h (include FltKernel.h or Ntifs.h)

Library

Ntoskrnl.lib

IRQL

<= APC_LEVEL

See also

IoGetTopLevelIrp
MDL

 

 

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