Re: [PATCH] mm, vmscan: Give up balancing node for high order allocations earlier

["Hillf Danton" <hillf.zj@alibaba-inc.com>]

> > To avoid excessive reclaim, we give up rebalancing for high order
> > allocations right after reclaiming enough pages.
> 
> hm.  What are the observed runtime effects of this change?  Any testing
> results?
> 
This work was based on Mel's work, Sir,
"[PATCH 00/27] Move LRU page reclaim from zones to nodes v7".

In "[PATCH 06/27] mm, vmscan: Make kswapd reclaim in terms of nodes", 
fragmentation detection is introduced to avoid excessive reclaim. We bail 
out of balancing for high-order allocations if the pages reclaimed at the 
__current__ reclaim priority are two times more than required.

In this work we give up reclaiming for high-order allocations if the 
__total__ number of pages reclaimed, from the first priority to the 
current priority, is more than needed, and in net result we reclaim less 
pages.

Given " [PATCH 00/34] Move LRU page reclaim from zones to nodes v9" 
is delivered, I will send this work if necessary, after Mel's work landing 
in the -mm tree.

thanks
Hillf