RE: [RFC] Variable Kernel Page size support

["Chen, Kenneth W" <kenneth.w.chen@intel.com>]

Christoph Lameter wrote on Thursday, October 12, 2006 5:33 PM
> IA64: Variable Kernel Page size support
> 
> This patch adds the capability to manage pages of varying sizes for the
> kernel in region 7. This is done by setting special bits in bits 54 to 60.
> 
> 54-59 Page size.
> 
> If set then the default pagesize of region 7 is overridden on a fault
> and a TLB of the requested size is inserted. This may be used to
> manually control the coverage of a single TLB. A macro SET_TLB_SIZE
> is provide that can be used upon a kernel address to encode the
> desired page size. Code must refer to the address range through
> this address in order to get the desired TLB size.
> 
> 60 Page table enable.

This is just getting better and better :-)) nifty!


> If set then a lookup is performed using the region7_pgdir table.
> That table is segmented into 8 section for the varying page
> sizes supported.

What is the reason to anchor these 8 sections with pgdir?  Can't we just
extract page size directly from the virtual address? Chop off bit 54 - 60,
that's the physical address, whola.  I don't see why it can't be done.