Source code of Windows XP (NT5)
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/*++
Copyright (c) 1999-2001 Microsoft Corporation
Module Name:
opaqueidp.h
Abstract:
This module contains declarations private to the opaque ID table. These
declarations are placed in a separate .H file to make it easier to access
them from within the kernel debugger extension DLL.
Author:
Keith Moore (keithmo) 10-Sep-1999
Revision History:
--*/
#ifndef _OPAQUEIDP_H_
#define _OPAQUEIDP_H_
#ifdef __cplusplus
extern "C" {
#endif
//
// The internal structure of an HTTP_OPAQUE_ID.
//
// N.B. This structure must be EXACTLY the same size as an HTTP_OPAQUE_ID!
//
#define PROCESSOR_BIT_WIDTH 6
#define FIRST_INDEX_BIT_WIDTH 18
#define SECOND_INDEX_BIT_WIDTH 8
#define OPAQUE_ID_CYCLIC_BIT_WIDTH 29
#define OPAQUE_ID_TYPE_BIT_WIDTH 3
typedef union _UL_OPAQUE_ID_INTERNAL
{
HTTP_OPAQUE_ID OpaqueId;
struct
{
union
{
ULONG Index;
struct
{
ULONG Processor : PROCESSOR_BIT_WIDTH;
ULONG FirstIndex : FIRST_INDEX_BIT_WIDTH;
ULONG SecondIndex : SECOND_INDEX_BIT_WIDTH;
};
};
union
{
ULONG Cyclic;
struct
{
ULONG OpaqueIdCyclic : OPAQUE_ID_CYCLIC_BIT_WIDTH;
ULONG OpaqueIdType : OPAQUE_ID_TYPE_BIT_WIDTH;
};
};
};
} UL_OPAQUE_ID_INTERNAL, *PUL_OPAQUE_ID_INTERNAL;
C_ASSERT( sizeof(HTTP_OPAQUE_ID) == sizeof(UL_OPAQUE_ID_INTERNAL) );
C_ASSERT( 8 * sizeof(HTTP_OPAQUE_ID) == (PROCESSOR_BIT_WIDTH + \
FIRST_INDEX_BIT_WIDTH + \
SECOND_INDEX_BIT_WIDTH + \
OPAQUE_ID_CYCLIC_BIT_WIDTH + \
OPAQUE_ID_TYPE_BIT_WIDTH \
));
C_ASSERT((1 << PROCESSOR_BIT_WIDTH) >= MAXIMUM_PROCESSORS);
//
// A per-entry opaque ID lock.
//
#define OPAQUE_ID_DPC
#ifdef OPAQUE_ID_DPC
typedef KSPIN_LOCK UL_OPAQUE_ID_LOCK, *PUL_OPAQUE_ID_LOCK;
__inline
VOID
FASTCALL
UlpInitializeOpaqueIdLock(
IN PUL_OPAQUE_ID_LOCK pLock
)
{
KeInitializeSpinLock( pLock );
}
__inline
VOID
FASTCALL
UlpAcquireOpaqueIdLock(
IN PUL_OPAQUE_ID_LOCK pLock,
OUT PKIRQL pOldIrql
)
{
KeAcquireSpinLock( pLock, pOldIrql );
}
__inline
VOID
FASTCALL
UlpReleaseOpaqueIdLock(
IN PUL_OPAQUE_ID_LOCK pLock,
IN KIRQL OldIrql
)
{
KeReleaseSpinLock( pLock, OldIrql );
}
#else
typedef volatile LONG UL_OPAQUE_ID_LOCK, *PUL_OPAQUE_ID_LOCK;
__inline
VOID
FASTCALL
UlpInitializeOpaqueIdLock(
IN PUL_OPAQUE_ID_LOCK pLock
)
{
*pLock = 0;
}
__inline
VOID
FASTCALL
UlpAcquireOpaqueIdLock(
IN PUL_OPAQUE_ID_LOCK pLock,
OUT PKIRQL pOldIrql
)
{
while (TRUE)
{
while (*pLock == 1)
{
PAUSE_PROCESSOR
}
if (0 == InterlockedCompareExchange( pLock, 1, 0 ))
{
break;
}
}
}
__inline
VOID
FASTCALL
UlpReleaseOpaqueIdLock(
IN PUL_OPAQUE_ID_LOCK pLock,
IN KIRQL OldIrql
)
{
ASSERT( *pLock == 1 );
InterlockedExchange( pLock, 0 );
}
#endif
//
// A second-level table entry.
//
// Note that FreeListEntry and pContext are in an anonymous
// union to save space; an entry is either on the free list or in use,
// so only one of these fields will be used at a time.
//
// Also note that Cyclic is in a second anonymous union. It's overlayed
// with FirstLevelIndex (which is basically the second-level table's
// index in the first-level table) and ID type (used to distinguish
// free entries from in-use entries).
//
#define SECOND_LEVEL_TABLE_SIZE 256
C_ASSERT( SECOND_LEVEL_TABLE_SIZE == 1 << SECOND_INDEX_BIT_WIDTH );
typedef struct _UL_OPAQUE_ID_TABLE_ENTRY
{
//
// NonPagedPool
//
union
{
//
// To ensure FreeListEntry is aligned on 8-byte boundary.
//
ULONGLONG Alignment;
struct
{
union
{
//
// An entry to the global ID table's free ID list.
//
SINGLE_LIST_ENTRY FreeListEntry;
//
// Context associated with the opaque ID.
//
PVOID pContext;
};
//
// A per-entry ID cyclic that guarantees we can generate
// 2 ^ OPAQUE_ID_CYCLIC_BIT_WIDTH of opaque IDs from the
// current entry without repeating. This gives us extra
// protection than using a global ID cyclic.
//
ULONG EntryOpaqueIdCyclic;
};
};
//
// A per-entry lock that protects the entry.
//
UL_OPAQUE_ID_LOCK Lock;
//
// The ID index for the opaque ID when the entry is free or the cyclic
// when the entry is in use.
//
union
{
union
{
ULONG Index;
struct
{
ULONG Processor : PROCESSOR_BIT_WIDTH;
ULONG FirstIndex : FIRST_INDEX_BIT_WIDTH;
ULONG Reserved : SECOND_INDEX_BIT_WIDTH;
};
};
union
{
ULONG Cyclic;
struct
{
ULONG OpaqueIdCyclic : OPAQUE_ID_CYCLIC_BIT_WIDTH;
ULONG OpaqueIdType : OPAQUE_ID_TYPE_BIT_WIDTH;
};
};
};
} UL_OPAQUE_ID_TABLE_ENTRY, *PUL_OPAQUE_ID_TABLE_ENTRY;
//
// We keep a per-processor first-level ID tables. A single table is a
// major scalability bottleneck on SMP machines. The size of the first-level
// table is controlled by a registry setting.
//
#if DBG
#define OPAQUE_ID_INSTRUMENTATION
#endif
typedef struct _UL_OPAQUE_ID_TABLE
{
//
// A list of free IDs available on this table.
//
SLIST_HEADER FreeOpaqueIdSListHead;
//
// An arrary of second-level ID table entries.
//
PUL_OPAQUE_ID_TABLE_ENTRY *FirstLevelTable;
//
// The corresponding CPU this table represents.
//
UCHAR Processor;
//
// The lock really only protects FirstLevelTableInUse.
//
UL_SPIN_LOCK Lock;
//
// The current number of first-level tables allocated.
//
ULONG FirstLevelTableInUse;
//
// The maximum size we can grow for the first-level tables.
//
ULONG FirstLevelTableSize;
#ifdef OPAQUE_ID_INSTRUMENTATION
LONGLONG NumberOfAllocations;
LONGLONG NumberOfFrees;
LONGLONG NumberOfTotalGets;
LONGLONG NumberOfSuccessfulGets;
#endif
} UL_OPAQUE_ID_TABLE, *PUL_OPAQUE_ID_TABLE;
//
// Necessary to ensure our array of UL_OPAQUE_ID_TABLE structures is
// cache aligned.
//
typedef union _UL_ALIGNED_OPAQUE_ID_TABLE
{
UL_OPAQUE_ID_TABLE OpaqueIdTable;
UCHAR CacheAlignment[(sizeof(UL_OPAQUE_ID_TABLE) + UL_CACHE_LINE - 1) & ~(UL_CACHE_LINE - 1)];
} UL_ALIGNED_OPAQUE_ID_TABLE, *PUL_ALIGINED_OPAQUE_ID_TABLE;
//
// An inline function that maps a specified HTTP_OPAQUE_ID to the
// corresponding ID table entry.
//
extern UL_ALIGNED_OPAQUE_ID_TABLE g_UlOpaqueIdTable[];
__inline
BOOLEAN
FASTCALL
UlpExtractIndexFromOpaqueId(
IN HTTP_OPAQUE_ID OpaqueId,
OUT PULONG pProcessor,
OUT PULONG pFirstIndex,
OUT PULONG pSecondIndex
)
{
UL_OPAQUE_ID_INTERNAL InternalId;
PUL_OPAQUE_ID_TABLE pOpaqueIdTable;
InternalId.OpaqueId = OpaqueId;
//
// Verify the processor portion of the index.
//
*pProcessor = InternalId.Processor;
if (*pProcessor >= g_UlNumberOfProcessors)
{
return FALSE;
}
//
// Verify the first-level index.
//
pOpaqueIdTable = &g_UlOpaqueIdTable[*pProcessor].OpaqueIdTable;
*pFirstIndex = InternalId.FirstIndex;
if (*pFirstIndex >= pOpaqueIdTable->FirstLevelTableInUse)
{
return FALSE;
}
//
// Second-level index is always valid since we only allocated 8-bits.
//
ASSERT( InternalId.SecondIndex < SECOND_LEVEL_TABLE_SIZE );
*pSecondIndex = InternalId.SecondIndex;
return TRUE;
}
__inline
PUL_OPAQUE_ID_TABLE_ENTRY
FASTCALL
UlpMapOpaqueIdToTableEntry(
IN HTTP_OPAQUE_ID OpaqueId
)
{
PUL_OPAQUE_ID_TABLE pOpaqueIdTable;
ULONG Processor;
ULONG FirstIndex;
ULONG SecondIndex;
if (UlpExtractIndexFromOpaqueId(
OpaqueId,
&Processor,
&FirstIndex,
&SecondIndex
))
{
pOpaqueIdTable = &g_UlOpaqueIdTable[Processor].OpaqueIdTable;
return pOpaqueIdTable->FirstLevelTable[FirstIndex] + SecondIndex;
}
else
{
return NULL;
}
}
//
// Private prototypes.
//
NTSTATUS
UlpExpandOpaqueIdTable(
IN PUL_OPAQUE_ID_TABLE pOpaqueIdTable,
IN LONG CapturedFirstTableInUse
);
#ifdef __cplusplus
}; // extern "C"
#endif
#endif // _OPAQUEIDP_H_