On 03/14/2016 03:10 PM, Joonsoo Kim wrote:

2016-03-14 21:30 GMT+09:00 Vlastimil Babka [off-list ref]:

Now I see why this happen. I enabled CONFIG_DEBUG_PAGEALLOC
and it makes difference.

I tested on x86_64, gcc (Ubuntu 4.8.4-2ubuntu1~14.04.1) 4.8.4.

With CONFIG_CMA + CONFIG_DEBUG_PAGEALLOC
./scripts/bloat-o-meter page_alloc_base.o page_alloc_vlastimil_orig.o
add/remove: 0/0 grow/shrink: 2/0 up/down: 510/0 (510)
function                                     old     new   delta
free_one_page                               1050    1334    +284
free_pcppages_bulk                          1396    1622    +226

./scripts/bloat-o-meter page_alloc_base.o page_alloc_mine.o
add/remove: 0/0 grow/shrink: 2/0 up/down: 351/0 (351)
function                                     old     new   delta
free_one_page                               1050    1230    +180
free_pcppages_bulk                          1396    1567    +171


With CONFIG_CMA + !CONFIG_DEBUG_PAGEALLOC
(pa_b is base, pa_v is yours and pa_m is mine)

./scripts/bloat-o-meter pa_b.o pa_v.o
add/remove: 0/0 grow/shrink: 1/1 up/down: 88/-23 (65)
function                                     old     new   delta
free_one_page                                761     849     +88
free_pcppages_bulk                          1117    1094     -23

./scripts/bloat-o-meter pa_b.o pa_m.o
add/remove: 0/0 grow/shrink: 2/0 up/down: 329/0 (329)
function                                     old     new   delta
free_one_page                                761    1031    +270
free_pcppages_bulk                          1117    1176     +59

Still, it has difference but less than before.
Maybe, we are still using different configuration. Could you
check if CONFIG_DEBUG_VM is enabled or not? In my case, it's not

It's disabled here.

enabled. And, do you think this bloat isn't acceptable?

Well, it is quite significant. But given that Hanjun sees the errors 
still, it's not the biggest issue now :/

Thanks.