DXGK_ALLOCATIONINFO structure (d3dkmddi.h)
The DXGK_ALLOCATIONINFO structure describes parameters for creating an allocation.
Syntax
typedef struct _DXGK_ALLOCATIONINFO {
VOID *pPrivateDriverData;
UINT PrivateDriverDataSize;
union {
UINT Alignment;
struct {
UINT16 MinimumPageSize;
UINT16 RecommendedPageSize;
};
};
SIZE_T Size;
SIZE_T PitchAlignedSize;
DXGK_SEGMENTBANKPREFERENCE HintedBank;
DXGK_SEGMENTPREFERENCE PreferredSegment;
union {
UINT SupportedReadSegmentSet;
UINT MmuSet;
};
UINT SupportedWriteSegmentSet;
UINT EvictionSegmentSet;
union {
UINT MaximumRenamingListLength;
UINT PhysicalAdapterIndex;
};
HANDLE hAllocation;
union {
DXGK_ALLOCATIONINFOFLAGS Flags;
DXGK_ALLOCATIONINFOFLAGS_WDDM2_0 FlagsWddm2;
};
DXGK_ALLOCATIONUSAGEHINT *pAllocationUsageHint;
UINT AllocationPriority;
DXGK_ALLOCATIONINFOFLAGS2 Flags2;
} DXGK_ALLOCATIONINFO;
Members
pPrivateDriverData
[in] A pointer to a block of private data. This data is for each allocation and is distinct from the pPrivateDriverData member in the DXGKARG_CREATEALLOCATION structure. The user-mode display driver (UMD) might pass this data to the kernel-mode display miniport driver (KMD). However, if Dxgkrnl passes this data to describe the shared primary or other lockable surface, the data is passed as the first element of the array in the pAllocationInfo member of DXGKARG_CREATEALLOCATION.
PrivateDriverDataSize
[in] The size, in bytes, of the block of private data in pPrivateDriverData.
Alignment
[out] The required alignment, in bytes, for the allocation.
MinimumPageSize
RecommendedPageSize
Size
[out] The size, in bytes, that is required for the allocation. The size value is expanded to a multiple of the native host page size (for example, 4 KB on the x86 architecture). The KMD specifies the allocation size to the video memory manager (VidMm).
PitchAlignedSize
[out] The size, in bytes, of the allocation when it is located in a pitch-aligned segment, which is specified by the PitchAlignment bit-field flag in the Flags member of the DXGK_SEGMENTDESCRIPTOR structure for the segment. If the allocation is not supported in a pitch-aligned segment (GPUs don't commonly support this type of segment), the driver should set the value in PitchAlignedSize to zero. If the driver specifies a nonzero value in PitchAlignedSize, the value must be greater than or equal to the value in the Size member.
HintedBank
[out] A DXGK_SEGMENTBANKPREFERENCE structure that specifies KMD's bank ordering preferences that VidMm use to page-in the allocation. If this member is specified, VidMm uses banking information about the most preferred segment, which is specified by the SegmentId0 member of the DXGK_SEGMENTPREFERENCE structure that the PreferredSegment member specifies.
PreferredSegment
[out] A DXGK_SEGMENTPREFERENCE structure that indicates preferred segments identifiers that the KMD requests that VidMm use to page-in the allocation.
SupportedReadSegmentSet
[out] Segment identifiers that the KMD can set in the PreferredSegment member for read operations. The segments that these identifiers indicate are segments that the KMD requests VidMm use to page-in the allocation for read operations, regardless of performance. Setting bit 0 indicates that the first segment is supported, setting bit 1 indicates that the second segment is supported, and so on.
The KMD can set preferences only for segments that are supported for read operations. VidMm asserts if the driver attempts to set preferences for unsupported segments in the PreferredSegment member.
MmuSet
SupportedWriteSegmentSet
[out] Segment identifiers that the KMD can set in the PreferredSegment member for write operations. The segments that these identifiers indicate are segments that the KMD requests that VidMm use to page-in the allocation for write operations, regardless of performance. Setting bit 0 indicates that the first segment is supported, setting bit 1 indicates that the second segment is supported, and so on.
The KMD can set preferences only for segments that are supported for write operations. VidMm asserts if the driver attempts to set preferences for unsupported segments in the PreferredSegment member.
EvictionSegmentSet
[out] Identifiers of segments that can be used for eviction. Setting bit 0 indicates that the first segment can be used for eviction, setting bit 1 indicates that the second segment can be used for eviction, and so on.
Only aperture segments can be specified by this member. If the driver specifies valid segments to be used for eviction, VidMm attempts to allocate resources in those aperture segments to accelerate the eviction process. If the driver specifies 0, VidMm calls the driver to transfer the content of an allocation directly to paged-locked system memory without mapping the underlying pages through an aperture segment.
MaximumRenamingListLength
[out] The maximum length of the renaming list for the allocation. For more information about the renaming list, see Requesting to Rename an Allocation.
Support for this member started with Windows 10 and the WDDM v2.
PhysicalAdapterIndex
[out] The index of the physical adapter.
Support for this member started with Windows 10 and the WDDM v2.
hAllocation
[out] A handle to the allocation. The KMD must set this member to a value that it can use to refer to its private tracking structure for the allocation.
Flags
[out] A DXGK_ALLOCATIONINFOFLAGS structure that identifies properties for an allocation in bit-field flags. These properties indicate the type of allocation to create. The KMD specifies these flags for VidMm. Drivers that target any WDDM version earlier than WDDM 2.0 should use Flags; drivers that target any WDDM version >= WDDM 2.0 should use FlagsWddm2.
FlagsWddm2
[out] A DXGK_ALLOCATIONINFOFLAGS_WDDM2_0 structure that identifies properties for an allocation in bit-field flags. These properties indicate the type of allocation to create. The KMD specifies these flags for VidMm. Drivers that target any WDDM version >= WDDM 2.0 should use FlagsWddm2; drivers that target any WDDM version earlier than WDDM 2.0 should use Flags.
pAllocationUsageHint
[out] A pointer to a DXGK_ALLOCATIONUSAGEHINT structure that the memory manager uses to determine how to use the allocation.
AllocationPriority
[out] A UINT value that specifies the starting priority level of the allocation.
The driver determines the appropriate priority level for each allocation. For more information about priority levels, see the Remarks section of the pfnSetPriorityCb function. If priority level for allocations is not an issue to the driver, the driver should set all priority levels to D3DDDI_ALLOCATIONPRIORITY_NORMAL. Note that 0 is an invalid initial allocation priority.
Flags2
[out] A DXGK_ALLOCATIONINFOFLAGS2 structure that contains additional properties for an allocation. Supported starting in Windows 11 (WDDM 3.0).
Remarks
With the WDDM v2, the DXGK_ALLOCATIONINFO structure has been changed so that the read and write segment set are no longer differentiated. During surface creation, VidMm will ignore the SupportedReadSegmentSet value and use only the segment set provide by SupportedWriteSegmentSet. Drivers should ensure that this value accurately represents the segment set that can be used by the allocation for its intended purpose.
Ignoring the supported read segment set doesn't mean that it is no longer supported, but simply that there should no longer be a difference between these sets, and VidMm will be allowed to choose an appropriate segment for any allocation from a single segment set.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista |
| Header | d3dkmddi.h (include D3dkmddi.h) |