| class TShPoolCreateInfo |
Specifies characteristics of the pool to be created.
| Public Member Functions | |
|---|---|
| TShPoolCreateInfo(TShPoolPageAlignedBuffers, TUint, TUint) | |
| TShPoolCreateInfo(TShPoolNonPageAlignedBuffers, TUint, TUint, TUint) | |
| IMPORT_C TInt | SetExclusive() |
| IMPORT_C TInt | SetGuardPages() |
| IMPORT_C TInt | SetSizingAttributes(TUint, TUint, TUint, TUint) |
| Private Member Functions | |
|---|---|
| TShPoolCreateInfo() | |
| Public Member Enumerations | |
|---|---|
| enum | TShPoolNonPageAlignedBuffers { ENonPageAlignedBuffer = EShPoolNonPageAlignedBuffer } |
| enum | TShPoolPageAlignedBuffers { EPageAlignedBuffer = EShPoolPageAlignedBuffer } |
| Private Attributes | |
|---|---|
| TShPoolInfo | iInfo |
| IMPORT_C | TShPoolCreateInfo | ( | TShPoolPageAlignedBuffers | aFlag, |
| TUint | aBufSize, | |||
| TUint | aInitialBufs | |||
| ) | ||||
Specifies the buffer size and initial number of committed buffers for a pool with page-aligned buffers.
| TShPoolPageAlignedBuffers aFlag | Page-aligned buffers |
| TUint aBufSize | Size in bytes of each buffer within the pool |
| TUint aInitialBufs | Initial number of buffers allocated to the pool |
| IMPORT_C | TShPoolCreateInfo | ( | TShPoolNonPageAlignedBuffers | aFlag, |
| TUint | aBufSize, | |||
| TUint | aInitialBufs, | |||
| TUint | aAlignment | |||
| ) | ||||
Specifies the buffer size, initial number of committed buffers, and buffer alignment for a pool with non-page-aligned buffers.
| TShPoolNonPageAlignedBuffers aFlag | Non-page aligned buffers |
| TUint aBufSize | Size in bytes of each buffer within the pool |
| TUint aInitialBufs | Initial number of buffers allocated to the pool |
| TUint aAlignment | Alignment of the start of each buffer in the pool (shift/log2 value) |
| IMPORT_C TInt | SetExclusive | ( | ) |
Ensures that each buffer is mapped into at most one process address space at a time.
If this is set for a non-page-aligned pool, the pool creation will fail.
| IMPORT_C TInt | SetGuardPages | ( | ) |
Specifies that unmapped guard pages are inserted between each buffer in a process's address space.
If this is set for a non-page-aligned pool, the pool creation will fail.
| IMPORT_C TInt | SetSizingAttributes | ( | TUint | aMaxBufs, |
| TUint | aGrowTriggerRatio, | |||
| TUint | aGrowByRatio, | |||
| TUint | aShrinkHysteresisRatio | |||
| ) | ||||
Sets the sizing attributes for the pool, allowing it to grow and shrink automatically.
If either aGrowTriggerRatio or aGrowByRatio is 0, no automatic growing or shrinking will be performed.
| TUint aMaxBufs | The maximum number of buffers that the pool can grow to. This value must not be less than aInitialBufs. |
| TUint aGrowTriggerRatio | This specifies when to grow the pool. When the proportion of free buffers in the pool drops below this value, the pool will be grown. This value is expressed as a 32-bit fixed-point number, where the binary point is defined to be between bits 7 and 8 (where the least-significant bit is defined as bit 0). (This format is also known as a Q8, or fx24.8 number, or alternatively as the value * 256.) It must represent a value < 1 (i.e. must be < 256). |
| TUint aGrowByRatio | The proportion to grow the pool by each time, expressed as a 32-bit fx24.8 fixed-point number, in the same way as aGrowTriggerRatio. |
| TUint aShrinkHysteresisRatio | The hysteresis value to ensure that a pool is not automatically shrunk immediately after it is grown. Automatic shrinking will only happen when there are (aGrowTriggerRatio + aGrowByRatio) * aShrinkHysteresisRatio * (total buffers in the pool) free buffers left in the pool. This is a 32-bit fx24.8 fixed-point number in the same way as aGrowTriggerRatio and aGrowByRatio. It must represent a value > 1 (i.e. must be > 256). |
Enumeration type to create a pool with non-page-aligned buffers.
The buffers in the pool do not have any size or alignment restrictions beyond the iAlignment specified in TShPoolInfo.
The whole pool will always mapped into a process's address space.
| ENonPageAlignedBuffer = EShPoolNonPageAlignedBuffer |
Enumeration type to create a pool with page-aligned buffers.
The buffers in the pool will be at least the size of an MMU page, aligned to an MMU page, and may be mapped in and out of a process's address space independently.
| EPageAlignedBuffer = EShPoolPageAlignedBuffer |
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