[kernelreadfans] ZONE NORMAL size?

  • From: "oyk" <oyk@xxxxxxxxxxx>
  • To: kernelreadfans <kernelreadfans@xxxxxxxxxxxxx>
  • Date: Fri, 6 Jun 2003 18:4:40 +0800

 对于Understanding VM的5.1节最后一段话
 The region required for vmalloc(), kmap() and the fixed virtual address 
mapping is what limits the size of ZONE_NORMAL. As 
the running kernel needs these functions, a region of at least VMALLOC_RESERVE 
will be reserved at the top of the address 
space. VMALLOC_RESERVE is architecture specific but on the x86, it is defined 
as 128MiB. This is why ZONE_NORMAL is 
generally referred to being only 896MiB in size; it is the 1GiB of the upper 
potion of the linear address space minus the 
minimum 128MiB that is reserved for the vmalloc region.

Best Regards
  Ouyang Kai

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