Alloc fail

[ZR233]

The current palloc bitmap-alloc implementation can only manage the first memory segment; all other segments are directly added to balloc. However, in real-world development board environments, the system typically consists of multiple physical memory segments, with the first segment usually being the smallest. Since critical structures such as page tables directly allocate memory via palloc, this frequently leads to insufficient memory. Moreover, palloc cannot preferentially select larger memory segments located at higher addresses, because DMA memory must also be allocated through palloc — and DMA is restricted to using low-address memory regions.