hello,every one.
I have a question:
Why does linux choose 896MB to do a start point of ZONE_HIGHMEM and
the end point of ZONE_NORMAL. Just for experience?
What is the advantages?
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Hi Hayfeng,
On Tue, Apr 6, 2010 at 8:07 PM, hayfeng Lee teklife.ker...@gmail.com wrote:
hello,every one.
I have a question:
Why does linux choose 896MB to do a start point of ZONE_HIGHMEM and
the end point of ZONE_NORMAL. Just for experience?
What is the advantages?
This is not an advantage
Hi Peter,
On Wed, Apr 7, 2010 at 1:14 AM, H. Peter Anvin h...@zytor.com wrote:
On 04/06/2010 12:20 PM, Frank Hu wrote:
The ELF ABI specifies that user space has 3 GB available to it. That
leaves 1 GB for the kernel. The kernel, by default, uses 128 MB for I/O
mapping, vmalloc, and kmap
Joel,
To make things clear, 896 MB is not a hardware limitation. The 3GB:1GB split
can be configured during the kernel build but the split cannot be changed
dynamically.
you are correct that ZONE_* refers to grouping of physical memory but the
very concept of ZONES is logical and not physical.
Nice explanation, Venkatram,
Just one question pop up mind.
What if actual physical memory is only 256MB? How does kernel divide virtual
memory? Do we need to specify the region to kernel? Or will kernel itself
decide it automatically?
On Apr 6, 2010, at 3:28 PM, Venkatram Tummala
Hi...
On Wed, Apr 7, 2010 at 06:27, Youngwhan Song breadn...@gmail.com wrote:
What if actual physical memory is only 256MB? How does kernel divide virtual
memory?
Still the same as before, 3:1 vm split, 896 MB in ZONE_NORMAL and so
on. However, in this case there is no ZONE_HIGHMEM since all
Hey Xiao,
last 128MB is not used for highmem. last 128MB is used for data
structures(page tables etc.) to support highmem . Highmem is not something
which is INSIDE Kernel's Virtual Address space. Highmem refers to a region
of Physical memory which can be mapped into kernel's virtual address
On Wed, Apr 7, 2010 at 3:58 AM, Venkatram Tummala venkatram...@gmail.comwrote:
Joel,
To make things clear, 896 MB is not a hardware limitation. The 3GB:1GB
split can be configured during the kernel build but the split cannot be
changed dynamically.
you are correct that ZONE_* refers to
Greg,
My intention is to learn to write a SATA driver with the hardware
that I have. I have a SATA hard drive from Western Digital (MDL :
WD800JD-75MSAS)
and SATA controller (Intel 82801 GB/GR/GH ( ICH7 family ) for which the
drivers are already
present. I want to unload the drivers and
