linux - linux内核内存管理：ZONE_DMA ,ZONE_NORMAL 大小变化

Question

在Linux内核中分配内存区域的任何固定比率（如ZONE_DMA）应该在0-16MB之间，ZONE_NORMAL在16-896 MB之间，或者我们可以根据我们的需求进行更改，如果是的话，如何？

Answer 1

Those memory zones are defined based on hardware limitations. Even if recompile the kernel with a larger ZONE_DMA then devices which do 16-bit DMA will just fail. Same for DMA32 on 64bit.

In theory perhaps you could shrink some of the zones, but I'm not sure you have a reason for it. AFAIK normal allocations can automatically overflow into the DMA zone.

If you want more than 1G kernel memory then you need to change some top-level config options, not sure which.