Re: Query regarding adding physical memory after uvm_page_physload

[Masao Uebayashi <uebayasi%gmail.com@localhost>]

On Sun, Jun 26, 2011 at 5:05 PM, Bharat Joshi <bharat.josh%gmail.com@localhost> 
wrote:
> Hi,
>
>       I am currently uing NetBSD 2.0 (plan to move to new one in some
> time). I need to add more physical memory after it has already been
> initialized once using uvm_page_physload.
>
>       When I tried to call uvm_page_physload again with this new RAM
> area, it paniced. I then found out that a flag 'VM_PHYSSEG_NOADD' in
> vmparam.h for mips needs to be disabled. I removed this flag and then
> things seems to have worked as expected.
>
>       I want expert's opinion on whether this method of adding new
> physical memory in UVM is the right (may be the only) way in NetBSD
> 2.0. Please do let me know.

That would work to some extent.  Limitations:

- Data structures are not protected with locks.

- Metadata (vm_page array) is allocated in somewhere by malloc(), not
in the newly added physseg.

So, if it works for you on NetBSD 2.0, I'd say it's OK for you. ;)

>
> Regards,
> Bharat
>