Re: [patch 2] mm: speculative get_page

William Lee Irwin III
2005-06-28T04:06:08Z

William Lee Irwin III wrote:
>> tmpfs

On Tue, Jun 28, 2005 at 11:42:16AM +1000, Nick Piggin wrote:
> Well it switches between page and swap cache, but it seems to just
> use the normal pagecache / swapcache functions for that. It could be
> that I've got a big hole somewhere, but so far I don't think you've
> pointed oen out.

Its radix tree movement bypasses the page allocator.

William Lee Irwin III wrote:
>> hugetlbfs

On Tue, Jun 28, 2005 at 11:42:16AM +1000, Nick Piggin wrote:
> Well what's the trouble with it?

hugetlb reallocation doesn't go through the page allocator either.

William Lee Irwin III wrote:
>> Someone else deal with this (paulus? anton? other arch maintainers?).

On Tue, Jun 28, 2005 at 11:42:16AM +1000, Nick Piggin wrote:
> I know what a memory barrier is and does, so you said the
> necessary memory barriers aren't in place, so can you deal
> with it?

spin_unlock() does not imply a memory barrier.

William Lee Irwin III wrote:
>> The above is as much as I wanted to go into it. I need to direct my
>> capacity for the grunt work of devising adversary arguments elsewhere.

On Tue, Jun 28, 2005 at 11:42:16AM +1000, Nick Piggin wrote:
> I don't think there is anything wrong with it. I would be very
> keen to see real adversary arguments elsewhere though.

They take time to construct.

William Lee Irwin III wrote:
>> You requested comments. I made some.

On Tue, Jun 28, 2005 at 11:42:16AM +1000, Nick Piggin wrote:
> Well yeah thanks, you did point out a thinko I made, and that was very
> helpful and I value any time you spend looking at it. But just saying
> "this is wrong, that won't work, that's crap, ergo the concept is
> useless" without finding anything specifically wrong is not very
> constructive.

I said nothing of that kind, and I did point out specific things.

The limitation of time/effort is directly related to the nature of the
responses.

-- wli