Re: [RFI] Shared accounting for memory resource controller

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Wed, 8 Apr 2009 13:18:09 +0530
Balbir Singh <balbir@linux.vnet.ibm.com> wrote:

> > > 3. Using the above, we can then try to (using an algorithm you
> > > proposed), try to do some work for figuring out the shared percentage.
> > > 
> > This is the point. At last. Why "# of shared pages" is important ?
> > 
> 
> I posted this in my motivation yesterday. # of shared pages can help
> plan the system better and the size of the cgroup. A cgroup might have
> small usage_in_bytes but large number of shared pages. We need a
> metric that can help figure out the fair usage of the cgroup.
> 
I don't fully understand but NR_FILE_MAPPED is an information in /proc/meminfo.
I personally think I want to support information in /proc/meminfo per memcg.

Hmm ? then, if you add a hook, it seems
== mm/rmap.c
 689 void page_add_file_rmap(struct page *page)
 690 {
 691         if (atomic_inc_and_test(&page->_mapcount))
 692                 __inc_zone_page_state(page, NR_FILE_MAPPED);
 693 }
==  page_remove_rmap(struct page *page)
 739                 __dec_zone_page_state(page,
 740                         PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED);
==

Is good place to go, maybe.

page->page_cgroup->mem_cgroup-> inc/dec counter ?

Maybe the patch itself will be simple, overhead is unknown..

Thanks,
-Kame

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