from different sources, i seem to be reading conflicting explanations about what happens with "high memory" on an x86 -- the physical memory in the range 896M-1G. as i read it, the normal ranges are: ZONE_DMA: 0-16M ZONE_NORMAL: 16M-896M ZONE_HIGHMEM: 896M-1G now, what *exactly* does the kernel do with the 128M available in ZONE_HIGHMEM? one source tells me that that area is reserved exclusively for various kernel data structures, like memory map and page table info. but is that *all* it's used for? certainly, if the kernel needs to access any physical memory beyond 1G, it needs to be mapped into the kernel virtual address space first. but must that memory be mapped *only* into ZONE_NORMAL, or could it also be mapped into ZONE_HIGHMEM and share that area with the kernel data structures if there's room? rday p.s. where in the kernel is the beginning of ZONE_HIGHMEM defined anyway? is it configurable? thanks for any clarification. -- ======================================================================== Robert P. J. Day Linux Consulting, Training and Annoying Kernel Pedantry Waterloo, Ontario, CANADA http://fsdev.net/wiki/index.php?title=Main_Page ======================================================================== -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
