Re: Suspicious error for CMA stress test

[Joonsoo Kim]

On Mon, Mar 14, 2016 at 08:06:16AM +0100, Vlastimil Babka wrote:
> On 03/14/2016 07:49 AM, Joonsoo Kim wrote:
> >On Fri, Mar 11, 2016 at 06:07:40PM +0100, Vlastimil Babka wrote:
> >>On 03/11/2016 04:00 PM, Joonsoo Kim wrote:
> >>
> >>How about something like this? Just and idea, probably buggy (off-by-one etc.).
> >>Should keep away cost from <pageblock_order iterations at the expense of the
> >>relatively fewer >pageblock_order iterations.
> >
> >Hmm... I tested this and found that it's code size is a little bit
> >larger than mine. I'm not sure why this happens exactly but I guess it would be
> >related to compiler optimization. In this case, I'm in favor of my
> >implementation because it looks like well abstraction. It adds one
> >unlikely branch to the merge loop but compiler would optimize it to
> >check it once.
> 
> I would be surprised if compiler optimized that to check it once, as
> order increases with each loop iteration. But maybe it's smart
> enough to do something like I did by hand? Guess I'll check the
> disassembly.

Okay. I used following slightly optimized version and I need to
add 'max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1)'
to yours. Please consider it, too.

Thanks.

------------------------>8------------------------