[Devel] Re: memrlimit controller merge to mainline

[KAMEZAWA Hiroyuki]

On Wed, 30 Jul 2008 12:11:15 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com> wrote:

> On Wed, 30 Jul 2008 11:52:26 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com> wrote:
> > mem+swap controller means a shrink to memory resource controller 
> > (try_to_free_mem_cgroup_pages()) should drop only file caches.
> > (Because kick-out-to-swap will never changes the usage.)
> > 
> > right ? only global-lru can make a swap.
> > maybe I can add optimization to do this. Hmm. I should see how OOM works
> > under some situation.
> > 
> (I'm sorry that I'm not a good writer of e-mail.)
> 
> A brief summary about changes to mem controller.
> 
>  - mem+swap controller which limits the # sum of pages and swap_entries.
>  - mem+swap controller just drops file caches when it reaches limit.
>  - under mem+swap controller, recaliming Anon pages make no sense.
>    Then,
>       - LRU for Anon is not necessary.
>       - LRU for tmpfs/shmem is not necessary.
>       just showing account is better.
>  - we should see try_to_free_mem_cgroup() again to avoid too much OOM.
>    Maybe Retries=5 is too small because we never do swap under us.
>    a problem like struck-into-ext3-journal can easily make file-cache reclaim
>    difficult.
>  - need some changes to documentation.
>  - Should we have on/off switch of taking swap into account ?
>    or should we implement mem+swap contoller in different name than
>    "memory" controller ?
>    If swap is not accounted, we need to do swap-out in memory reclaiming path,
>    again.
>    
Then, mem+swap controller finally means
 - under mem+swap controller, program works with no swap. Only global LRU
   may make pages swapped-out.
 - If swap-accounting-mode is off, swap can be used unlimitedly.

Hmm, sounds a bit differenct from what I want. How about others ?

Thanks,
-Kame



> 
> Thanks,
> -Kame
> 
> 

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