* Hole in kernel virtual address space.
@ 2002-01-07 18:37 Raymond B. Jennings III
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From: Raymond B. Jennings III @ 2002-01-07 18:37 UTC (permalink / raw)
To: linux-mm
I've asked this question in the past but have yet to get any insight to
it.
Basically there appears to be a hole when HIGHMEM is turned on in the
kernel.
With HIGHMEM turned off:
VMALLOC_END = FIXADDR_START - 2*PAGE_SIZE
VMALLOC_END = (FFFFE000h - 4*PAGE_SIZE) - 2*PAGE_SIZE
(Pretty close to the 4GB boundary)
With HIGHMEM turned on:
VMALLOC_END = PKMAP_BASE - 2*PAGE_SIZE
I realize you need room for the pkmap_count array but the array only
allows for 1024 pages. If PKMAP_BASE = FE000000h then this fills the
address space upto
FE400000. What is being used in the remaining section of the address
space? Thanks.
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2002-01-07 18:37 Hole in kernel virtual address space Raymond B. Jennings III
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