/*++
Copyright (c) 1989 Microsoft Corporation
Module Name:
zone.c
Abstract:
This module implements a simple zone buffer manager. The primary
consumer of this module is local LPC.
The zone package provides a fast and efficient memory allocator for
fixed-size 64-bit aligned blocks of storage. The zone package does
not provide any serialization over access to the zone header and
associated free list and segment list. It is the responsibility of
the caller to provide any necessary serialization.
The zone package views a zone as a set of fixed-size blocks of
storage. The block size of a zone is specified during zone
initialization. Storage is assigned to a zone during zone
initialization and when a zone is extended. In both of these cases,
a segment and length are specified.
The zone package uses the first ZONE_SEGMENT_HEADER portion of the
segment for zone overhead. The remainder of the segment is carved
up into fixed-size blocks and each block is added to the free list
maintained in the zone header.
As long as a block is on the free list, the first SINGLE_LIST_ENTRY
(32 bit) sized piece of the block is used as zone overhead. The
rest of the block is not used by the zone package and may be used by
applications to cache information. When a block is not on the free
list, its entire contents are available to the application.
Author:
Mark Lucovsky (markl) 13-May-1989
Revision History:
--*/
#include "exp.h"
NTSTATUS
ExInitializeZone(
IN PZONE_HEADER Zone,
IN ULONG BlockSize,
IN PVOID InitialSegment,
IN ULONG InitialSegmentSize
)
/*++
Routine Description:
This function initializes a zone header. Once successfully
initialized, blocks can be allocated and freed from the zone, and
the zone can be extended.
Arguments:
Zone - Supplies the address of a zone header to be initialized.
BlockSize - Supplies the block size of the allocatable unit within
the zone. The size must be larger that the size of the
initial segment, and must be 64-bit aligned.
InitialSegment - Supplies the address of a segment of storage. The
first ZONE_SEGMENT_HEADER-sized portion of the segment
is used by the zone allocator. The remainder of
the segment is carved up into fixed size
(BlockSize) blocks and is made available for
allocation and deallocation from the zone. The
address of the segment must be aligned on a 64-bit
boundary.
InitialSegmentSize - Supplies the size in bytes of the InitialSegment.
Return Value:
STATUS_UNSUCCESSFUL - BlockSize or InitialSegment was not aligned on
64-bit boundaries, or BlockSize was larger than
the initial segment size.
STATUS_SUCCESS - The zone was successfully initialized.
--*/
{
ULONG i;
PCH p;
if ( (BlockSize & 7) || ((ULONG)InitialSegment & 7) ||
(BlockSize > InitialSegmentSize) ) {
#if DBG
DbgPrint( "EX: ExInitializeZone( %x, %x, %x, %x ) - Invalid parameters.\n",
Zone, BlockSize, InitialSegment, InitialSegmentSize
);
DbgBreakPoint();
#endif
return STATUS_INVALID_PARAMETER;
}
Zone->BlockSize = BlockSize;
Zone->SegmentList.Next = &((PZONE_SEGMENT_HEADER) InitialSegment)->SegmentList;
((PZONE_SEGMENT_HEADER) InitialSegment)->SegmentList.Next = NULL;
((PZONE_SEGMENT_HEADER) InitialSegment)->Reserved = NULL;
Zone->FreeList.Next = NULL;
p = (PCH)InitialSegment + sizeof(ZONE_SEGMENT_HEADER);
for (i = sizeof(ZONE_SEGMENT_HEADER);
i <= InitialSegmentSize - BlockSize;
i += BlockSize
) {
((PSINGLE_LIST_ENTRY)p)->Next = Zone->FreeList.Next;
Zone->FreeList.Next = (PSINGLE_LIST_ENTRY)p;
p += BlockSize;
}
Zone->TotalSegmentSize = i;
#if 0
DbgPrint( "EX: ExInitializeZone( %lx, %lx, %lu, %lu, %lx )\n",
Zone, InitialSegment, InitialSegmentSize,
BlockSize, p
);
#endif
return STATUS_SUCCESS;
}
NTSTATUS
ExExtendZone(
IN PZONE_HEADER Zone,
IN PVOID Segment,
IN ULONG SegmentSize
)
/*++
Routine Description:
This function extends a zone by adding another segment's worth of
blocks to the zone.
Arguments:
Zone - Supplies the address of a zone header to be extended.
Segment - Supplies the address of a segment of storage. The first
ZONE_SEGMENT_HEADER-sized portion of the segment is used by the
zone allocator. The remainder of the segment is carved up
into fixed-size (BlockSize) blocks and is added to the
zone. The address of the segment must be aligned on a 64-
bit boundary.
SegmentSize - Supplies the size in bytes of Segment.
Return Value:
STATUS_UNSUCCESSFUL - BlockSize or Segment was not aligned on
64-bit boundaries, or BlockSize was larger than
the segment size.
STATUS_SUCCESS - The zone was successfully extended.
--*/
{
ULONG i;
PCH p;
if ( ((ULONG)Segment & 7) ||
(SegmentSize & 7) ||
(Zone->BlockSize > SegmentSize) ) {
return STATUS_UNSUCCESSFUL;
}
((PZONE_SEGMENT_HEADER) Segment)->SegmentList.Next = Zone->SegmentList.Next;
Zone->SegmentList.Next = &((PZONE_SEGMENT_HEADER) Segment)->SegmentList;
p = (PCH)Segment + sizeof(ZONE_SEGMENT_HEADER);
for (i = sizeof(ZONE_SEGMENT_HEADER);
i <= SegmentSize - Zone->BlockSize;
i += Zone->BlockSize
) {
((PSINGLE_LIST_ENTRY)p)->Next = Zone->FreeList.Next;
Zone->FreeList.Next = (PSINGLE_LIST_ENTRY)p;
p += Zone->BlockSize;
}
Zone->TotalSegmentSize += i;
#if 0
DbgPrint( "EX: ExExtendZone( %lx, %lx, %lu, %lu, %lx )\n",
Zone, Segment, SegmentSize, Zone->BlockSize, p
);
#endif
return STATUS_SUCCESS;
}
NTSTATUS
ExInterlockedExtendZone(
IN PZONE_HEADER Zone,
IN PVOID Segment,
IN ULONG SegmentSize,
IN PKSPIN_LOCK Lock
)
/*++
Routine Description:
This function extends a zone by adding another segment's worth of
blocks to the zone.
Arguments:
Zone - Supplies the address of a zone header to be extended.
Segment - Supplies the address of a segment of storage. The first
ZONE_SEGMENT_HEADER-sized portion of the segment is used by the
zone allocator. The remainder of the segment is carved up
into fixed-size (BlockSize) blocks and is added to the
zone. The address of the segment must be aligned on a 64-
bit boundary.
SegmentSize - Supplies the size in bytes of Segment.
Lock - pointer to spinlock to use
Return Value:
STATUS_UNSUCCESSFUL - BlockSize or Segment was not aligned on
64-bit boundaries, or BlockSize was larger than
the segment size.
STATUS_SUCCESS - The zone was successfully extended.
--*/
{
NTSTATUS Status;
KIRQL OldIrql;
ExAcquireSpinLock( Lock, &OldIrql );
Status = ExExtendZone( Zone, Segment, SegmentSize );
ExReleaseSpinLock( Lock, OldIrql );
return Status;
}
