On Thu, 11 Mar 2010 09:39:13 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> > The performance overhead is not so huge in both solutions, but the impact on
> > performance is even more reduced using a complicated solution...
> >
> > Maybe we can go ahead with the simplest implementation for now and start to
> > think to an alternative implementation of the page_cgroup locking and
> > charge/uncharge of pages.
> >
>
> maybe. But in this 2 years, one of our biggest concerns was the performance.
> So, we do something complex in memcg. But complex-locking is , yes, complex.
> Hmm..I don't want to bet we can fix locking scheme without something complex.
>
But overall patch set seems good (to me.) And dirty_ratio and dirty_background_ratio
will give us much benefit (of performance) than we lose by small overheads.
IIUC, this series affects trgger for background-write-out.
Could you show some score which dirty_ratio give us benefit in the cases of
- copying a file in a memcg which hits limit
ex) copying a 100M file in 120MB limit. etc..
- kernel make performance in limited memcg.
ex) making a kernel in 100MB limit (too large ?)
etc....(when an application does many write and hits memcg's limit.)
But, please get enough ack for changes in generic codes of dirty_ratio.
Thank you for your work.
Regards,
-Kame
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