RE: [11/14] vcompound: Fallbacks for order 1 stack allocations on

[Christoph Lameter <clameter@sgi.com>]

On Mon, 24 Mar 2008, Luck, Tony wrote:

> > I am familiar with that area and I am resonably sure that this 
> > is an issue on IA64 under some conditions (the processor decides to spill 
> > some registers either onto the stack or into the register backing store 
> > during tlb processing). Recursion (in the kernel context) still expects 
> > the stack and register backing store to be available. ccing linux-ia64 for 
> > any thoughts to the contrary.
> 
> Christoph is correct ... IA64 pins the TLB entry for the kernel stack
> (which covers both the normal C stack and the register backing store)
> so that it won't have to deal with a TLB miss on the stack while handling
> another TLB miss.

I thought the only pinned TLB entry was for the per cpu area? How does it 
pin the TLB? The expectation is that a single TLB covers the complete 
stack area? Is that a feature of fault handling?