Re: [PATCH 2/2] page table iterators

[Nick Piggin <nickpiggin@yahoo.com.au>]

Hugh Dickins wrote:
> On Thu, 24 Feb 2005, Nick Piggin wrote:
> 
>>pud_addr_end?
> 
> 
> 		next = pud_addr_end(addr, end);
> 
> Hmm, yes, I'll go with that, thanks (unless a better idea follows).
> 
> Something I do intend on top of what I sent before, is another set
> of three macros, like
> 
> 		if (pud_none_or_clear_bad(pud))
> 			continue;
> 
> to replace all the p??_none, p??_bad clauses: not to save space,
> but just for clarity, those loops now seeming dominated by the
> unlikeliest of cases.
> 
> Has anyone _ever_ seen a p??_ERROR message?  I'm inclined to just
> put three functions into mm/memory.c to do the p??_ERROR and p??_clear,
> but that way the __FILE__ and __LINE__ will always come out the same.
> I think if it ever proves a problem, we'd just add in a dump_stack.
> 

I think a function is the most sensible. And a good idea, it should
reduce the icache pressure in the loops (although gcc does seem to
do a pretty good job of moving unlikely()s away from the fastpath).

I think at the point these things get detected, there is little use
for having a dump_stack. But we may as well add one anyway if it is
an out of line function?

Nick