Merge "memtrack: Update AIDL memtrack hal documentation" into sc-dev

 * accounting for stride, bit depth, rounding up to page size, etc.

 *

 * The following getMemory() categories are important for memory accounting in

 * `dumpsys meminfo` and should be reported as described below:

 * Android frameworks (e.g. `dumpsys meminfo`) and should be reported as described

 * below:

 *

 * - MemtrackType::GRAPHICS and MemtrackRecord::FLAG_SMAPS_UNACCOUNTED

 *     This should report the PSS of all DMA buffers mapped by the process

 *     with the specified PID. This PSS can be calculated using ReadDmaBufPss()

 *     form libdmabufinfo.

 *     This should report the PSS of all CPU-Mapped DMA-BUFs (buffers mapped into

 *     the process address space) and all GPU-Mapped DMA-BUFs (buffers mapped into

 *     the GPU device address space on behalf of the process), removing any overlap

 *     between the CPU-mapped and GPU-mapped sets.

 *

 * - MemtrackType::GL and MemtrackRecord::FLAG_SMAPS_UNACCOUNTED

 *     This category should report all GPU private allocations for the specified

 *     Any other memory not accounted for in /proc/<pid>/smaps if any, otherwise

 *     this should return 0.

 *

 * SMAPS_UNACCOUNTED memory should also include memory that is mapped with

 * VM_PFNMAP flag set. For these mappings PSS and RSS are reported as 0 in smaps.

 * Such mappings have no backing page structs from which PSS/RSS can be calculated.

 *

 * Constructor for the interface should be used to perform memtrack management

 * setup actions and must be called once before any calls to getMemory().

 */