Re: [PATCH 4/4] Memory controller soft limit reclaim on contention (v6)

[Balbir Singh <balbir@linux.vnet.ibm.com>]

* KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2009-03-17 15:30:46]:

> On Tue, 17 Mar 2009 11:52:05 +0530
> Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
> 
> > * KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2009-03-17 15:00:58]:
> > 
> > > On Tue, 17 Mar 2009 11:25:06 +0530
> > > Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
> > > 
> > > > * KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2009-03-17 14:17:14]:
> > > > > > That is not true..we don't track them to default cgroup unless
> > > > > > memory.use_hiearchy is enabled in the root cgroup. 
> > > > > What I want to say is "the task which is not attached to user's cgroup is
> > > > > also under defaut cgroup, so we don't need additional hook"
> > > > > Not talking about hierarchy.
> > > > >
> > > > 
> > > > Since all the user pages are tracked in one or the other cgroup, the
> > > > total accounting is equal to total_lru_pages across all zones/nodes.
> > > > Your suggestion boils down to if total_lru_pages reaches a threshold,
> > > > do soft limit reclaim, instead of doing reclaim when there is
> > > > contention.. right?
> > > >  
> > > Yes.
> > >
> > 
> > May I suggest that we first do the reclaim on contention and then
> > later on enhance it to add sysctl vm.soft_limit_ratio. I am not
> > proposing the soft limit patches for 2.6.30, but I would like to get
> > them in -mm for wider testing. If in that process the sysctl seems
> > more useful and applicable, we can consider adding it. Adding it right
> > now makes the reclaim logic more complex, having to check if we hit
> > the vm ratio quite often. Do you agree?
> >  
> If you can fix zone issues and can answer all Kosaki's request.
> But you said "this all is not for memory shortage but for softlimit".
> It seems strange for me to modify memory reclaim path.
>

Kame, the reason for modifying those paths is just to invoke the soft
limit reclaimer. At some point we need to make a decision on the soft
limit reclaim and where to invoke it from.

-- 
	Balbir

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