On Fri 04-12-15 09:53:35, Huang, Ying wrote:
Mel Gorman <mgorman(a)techsingularity.net> writes:
[...]
> What is the result of the __GFP_HIGH patch to give it access to
> reserves?
Applied Michal's patch on v4.4-rc3 and tested again, now there is no
page allocation failure.
I still think this is just a coincidence and __GFP_HIGH just
papers over it (it still makes sense for other reasons though). It
would be better imho to log all allocations which do not include
___GFP_KSWAPD_RECLAIM. This might help us to pin point a caller which
was previously waking kswapd up but it doesn't do so anymore. There
would have to be a very specific pattern to trigger this because most
allocations would simply wake kswapd up. I am just wondering that
any debugging would simply alter the timing and/or allocation pattern
and we would see a different results so I am not sure this is worth
spending a lot of time on.
--
Michal Hocko
SUSE Labs