On Mon, Jun 25, 2012 at 3:00 PM, Dave Hylands [off-list ref] wrote:

Hi Subbu,

On Mon, Jun 25, 2012 at 11:18 AM, Subramaniam Appadodharana
[off-list ref] wrote:

quoted

On Mon, Jun 25, 2012 at 1:00 PM, Mulyadi Santosa <

mulyadi.santosa at gmail.com>

quoted

wrote:

quoted

Hi.... :)

On Sun, Jun 24, 2012 at 1:32 AM, Subramaniam Appadodharana
[off-list ref] wrote:

quoted

Hi All,
I am trying to understand how vmalloc memory is reserved in kernel. In
3.4+
latest kernel, the default vmalloc size is 240MB.

vmalloc reserved address range, you meant?

quoted

Is this a carveout from
the 1GiB memory that kernel has?

Yup....

quoted

In other words can I do a __pa(VMALLOC_START) or __pa(VMALLOC_END)
or __pa(highmemory) irrespective of the vmalloc size that I request,

say

quoted

quoted

quoted

 doing vmalloc=1G?

uhm....not sure....vmalloc-ed is not physically contigous. Also, it is
set up far after identity mapping setup. So, the value you get from
__pa() IMHO would be likely invalid or has no meaning.

I thought that, as log as we know that the address is within  the 1GiB,

we

quoted

could get the
pa of the virtual address using __pa(). Is this not the case?

__pa only works on kernel direct addresses.

__pa doesn't work on the addresses from vmalloc

Using __pa on VMALLOC_START or VMALLOC_END doesn't really make sense.
If there were any physical memory there, it would be highmem.

Okay, but my intention was to just print out the pa for the VMALLOC_START

and END, just to know where they are.
And I thought they will work. no?

__pa should only be used on memory from PAGE_OFFSET through to (high_memory

- 1)

--
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com

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