Re: [Xen-ia64-devel] Re: [PATCH]: ptc.ga for SMP-g

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

Hi Kevin. Thank you for clarification.


On Fri, Mar 31, 2006 at 01:41:51PM +0800, Tian, Kevin wrote:
> Let's make some clarification here:
> 
> For IA64 linux, KERNEL_START records start of kernel image which is in 
> region 5 for 2.6 kernel while in region 7 for 2.4 kernel. PAGE_OFFSET is 
> start of region 7 which never changes with kernel versions.
> 
> First [KERNEL_START, KERNEL_START + KERNEL_TR_PAGE_SIZE - 
> 1] is definitely covered by TR.

[PAGE_OFFSET, PAGE_OFFSET + KERNEL_TR_PAGE_SIZE] may not be covered
by {d, i}tr[IA64_TR_KERNEL].
It's my misunderstanding. Sorry.


> The IA64_GRANULE_SIZE (16M/64M) area covering current kernel stack 
> is also mapped by TR. Except for init_task, all kernel stacks are 
> dynamically allocated from identity mapping area. So if stack of current 
> running task happens to reside within [PAGE_OFFSET, PAGE_OFFSET 
> + IA64_GRANULE_SIZE - 1], then that area is mapped by TR. Then once 
> stack of next task is outside of that range, TR will be purged and 
> re-inserted upon new area.
> 
> So I think Isaku is only taking [PAGE_OFFSET, PAGE_OFFSET+64M] as 
> an example to explain the issue, with assumption that area doesn't 
> contain current kernel stack. :-)

Exactly.


-- 
yamahata

_______________________________________________
Xen-ia64-devel mailing list
Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ia64-devel