Hi Subbu,

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

On Mon, Jun 25, 2012 at 1:00 PM, Mulyadi Santosa [off-list ref]
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
?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
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.

__pa should only be used on memory from PAGE_OFFSET through to (high_memory - 1)

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