On Tue, Feb 07, 2012 at 02:46:50PM +0000, carson bill wrote:

2012/2/7, Catalin Marinas [off-list ref]:

quoted

But if you avoid setting L_PTE_HPAGE_*, than we don't need the
masking for pte_pfn. In which case, we don't need to differentiate
between a normal and a huge pte in pte_pfn(), so no need for
L_PTE_HUGEPAGE. The set_huge_pte_at() function is only called with a
huge pte, so it doesn't need to check the L_PTE_HUGEPAGE bit either.

I understood what you mean now, and the original design is almost like
you said.  But the consequences of eliminating L_PTE_HUGEPAGE as well
as L_PTE_HPAGE_* only leave us with huge page size fixed at build
time, I mean boot time huge page size configuration feature like X86
will NOT be feasible anymore!

Yes it will :). Just store the page size in some variable that you check
at run-time. We won't support mixed huge page sizes though.

-- 
Catalin