panfrost: Introduce invisible pool
Whereas the main batch->pool is CPU read/write, the new
batch->invisible_pool is not. This enables GPU-internal structures that
the CPU must allocate from a pool dynamically but does not read,
corresponding to the BO_INVISIBLE create flag.
The use case is speeding up varying allocation by skipping the
CPU-side mmap/munmap.
We simultaneously half the pool's minimal allocation to avoid negatively
affecting memory usage.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6373>