low vs high memory on x86 architecture ?

["Giuseppe G" <guisep4@xxxxxxxxx>]

Hello list,

 

On the x86 architecture, does kernel have distinction of low-

vs high- memory from the kalloc() point of view ?

Or the whole memory is flat and equally available for kernel allocation ?

And where is boundary between low/high memory exactly, if it exists ?

 

About DMA needing only low memory ... I see dma-related slabs in /proc/slabinfo

but I do not know  whether this DMA limitation actually applies to the x86 architecture ?

Does it ?

 

Thanks

Guiseppe