Re: [patch 05/19] split LRU lists into anon & file sets

Balbir Singh
2008-01-10T03:27:03Z

* KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2008-01-10 11:36:18]:

> On Thu, 10 Jan 2008 07:51:33 +0530
> Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
>
> > > > #define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */
> > > > #define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */
> > > > +#define PAGE_CGROUP_FLAG_FILE (0x4) /* page is file system backed */
> > > >
> > >
> > > Now, we don't have control_type and a feature for accounting only CACHE.
> > > Balbir-san, do you have some new plan ?
> > >
> >
> > Hi, KAMEZAWA-San,
> >
> > The control_type feature is gone. We still have cached page
> > accounting, but we do not allow control of only RSS pages anymore. We
> > need to control both RSS+cached pages. I do not understand your
> > question about new plan? Is it about adding back control_type?
> >
> Ah, just wanted to confirm that we can drop PAGE_CGROUP_FLAG_CACHE
> if page_file_cache() function and split-LRU is introduced.
>

Earlier we would have had a problem, since we even accounted for swap
cache with PAGE_CGROUP_FLAG_CACHE and I think page_file_cache() does
not account swap cache pages with page_file_cache(). Our accounting
is based on mapped vs unmapped whereas the new code from Rik accounts
file vs anonymous. I suspect we could live a little while longer
with PAGE_CGROUP_FLAG_CACHE and then if we do not need it at all,
we can mark it down for removal. What do you think?

--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL