Excerpt:
"Storage Profile buffer pool selection policy"
"The setting of a configuration bit (BP) associated with the second pool in effect configures the buffer selection policy for the profile as either "best fit" or "back-up only".
- Best fit: With each allocation FDMA tries to use the first buffer pool (which for this policy must contain smaller buffers than the second). If the smaller buffers of the first pool can be used to store the full/remaining data then it will be used. If not, then the second buffer pool is used. Both buffer pool must have their BP bit cleared to be in this mode.
- Backup Pool Only: With each allocation first buffer pool is used unless it is exhausted.
Otherwise the second buffer pool will be used. To be in this mode, the first buffer pool must have BP cleared and the second buffer pool must have BP set. This mode could be used for high performance when the first buffer pool is using PEB and the second buffer pool is using external system memory buffers."
There is no variant to autonomously(by the HW directly through an automatic selection mechanism -e.g based on QOS) transfer a buffer from a pool to another Software must explicitly do this: you can look at the code of create_frame.
Basically, when you receive a frame you will acquire a buffer from another storage profile and store the frame in a buffer pool from that storage profile