Re: [RFC][PATCH 0/4] Memory controller soft limit patches (v2)

[KAMEZAWA Hiroyuki]

On Tue, 17 Feb 2009 13:03:52 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:

> > > 2. I don't like to change usual direct-memory-reclaim path. It will be obstacles
> > >    for VM-maintaners to improve memory reclaim. memcg's LRU is designed for
> > >    shrinking memory usage and not for avoiding memory shortage. IOW, it's slow routine
> > >    for reclaiming memory for memory shortage.
> > 
> > I don't think I agree here. Direct reclaim is the first indication of
> > shortage and if order 0 pages are short, memcg's above their soft
> > limit can be targetted first.
> > 
> My "slow" means "the overhead seems to be big". The latency will increase.
> 
> About 0-order
> In patch 4/4
> +	did_some_progress = mem_cgroup_soft_limit_reclaim(gfp_mask);
> +	/*
> should be
>         if (!order)
>             did_some_progress = mem....
above is wrong.

if (!order && (gfp_mask & GFP_MOVABLE)) ....Hmm, but this is not correct.
I have no good idea to avoid unnecessary works.

BTW,  why don't you call soft_limit_reclaim from kswapd's path ?

-Kame

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