Re: [RFC][PATCH] prevent incorrect oom under split_lru

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

Hi Kim-san,

> >> So, if priority==0, We should try to reclaim all page for prevent OOM.
> >
> > You are absolutely right.  Good catch.
> 
> I have a concern about application latency.
> If lru list have many pages, it take a very long time to scan pages.
> More system have many ram, More many time to scan pages.

No problem.

priority==0 indicate emergency.
it doesn't happend on typical workload.


> Of course I know this is trade-off between memory efficiency VS latency.
> But In embedded, some application think latency is more important
> thing than memory efficiency.
> We need some mechanism to cut off scanning time.
> 
> I think Takenori Nagano's "memory reclaim more efficiently patch" is
> proper to reduce application latency in this case If we modify some
> code.

I think this is off-topic.

but Yes.
both my page reclaim throttle and nagano-san's patch provide 
reclaim cut off mechanism.


and more off-topic,
nagano-san's patch improve only priority==12.
So, typical embedded doesn't improve so big because 
embedded system does't have so large memory.