On 2016/3/14 15:18, Joonsoo Kim wrote: > 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. Hmm, this one is not work, I still can see the bug is there after applying this patch, did I miss something? Thanks Hanjun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>