From: "Raymond B. Jennings III" <raymondj@watson.ibm.com>
To: linux-mm@kvack.org
Subject: Hole in kernel virtual address space.
Date: Mon, 07 Jan 2002 13:37:05 -0500 [thread overview]
Message-ID: <3C39EAD1.20CDF9CE@watson.ibm.com> (raw)
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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reply other threads:[~2002-01-07 18:33 UTC|newest]
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