[RFC][PATCH] another swap controller for cgroup

[YAMAMOTO Takashi]

hi,

> Daisuke Nishimura wrote:
> > Hi, Yamamoto-san.
> > 
> > I'm reviewing and testing your patch now.
> > 
> 
> In building kernel infinitely(in a cgroup of
> memory.limit=64M and swap.limit=128M, with swappiness=100),
> almost all of the swap (1GB) is consumed as swap cache
> after a day or so.
> As a result, processes are occasionally OOM-killed even when
> the swap.usage of the group doesn't exceed the limit.
> 
> I don't know why the swap cache uses up swap space.
> I will test whether a similar issue happens without your patch.
> Do you have any thoughts?

my patch tends to yield more swap cache because it makes try_to_unmap
fail and shrink_page_list leaves swap cache in that case.
i'm not sure how it causes 1GB swap cache, tho.

YAMAMOTO Takashi

> 
> BTW, I think that it would be better, in the sence of
> isolating memory resource, if there is a framework
> to limit the usage of swap cache.
> 
> 
> Thanks,
> Daisuke Nishimura.