[dm-devel] Re: a room for blkio-cgroup in struct page_cgroup

[Ryo Tsuruta <ryov valinux co jp>]

Hi Kamezawa-san,

"KAMEZAWA Hiroyuki" <kamezawa hiroyu jp fujitsu com> wrote:
> Ryo Tsuruta wrote:
> > Hi Kamezawa-san,
> >
> > As you wrote before (http://lkml.org/lkml/2009/7/22/65)
> >> To be honest, what I expected in these days for people of blockio
> >> cgroup is like following for getting room for themselves.
> > <<snip>>
> >> --- mmotm-2.6.31-Jul16.orig/include/linux/page_cgroup.h
> >> +++ mmotm-2.6.31-Jul16/include/linux/page_cgroup.h
> >> @@ -13,7 +13,7 @@
> >>  struct page_cgroup {
> >>       unsigned long flags;
> >>       struct mem_cgroup *mem_cgroup;
> >> -     struct page *page;
> >> +     /* block io tracking will use extra unsigned long bytes */
> >>       struct list_head lru;       /* per cgroup LRU list */
> >> };
> >
> > Have you already added a room for blkio_cgroup in struct page_cgroup?
> No.
> 
> > If not, I would like you to apply the above change to mmotm.
> >
> Plz wait until October. We're deadly busy and some amount of more important
> patches are piled up in front of us. I have no objections if you add
> a pointer or id  because I know I can reduce 8(4)bytes later.
> Just add (a small) member for a while and ignore page_cgroup's size.
> I'll fix later.

Thank you very much, but I've already added unsigned long member in the
last posted patch...

> > The latest blkio-cgroup has reflected the comments you pointed out.
> > I would also like you to give me any comments on it and consider
> > merging blkio-cgroup to mmotm.
> >
> BTW, do you all have cosensus about implementation ?

Not yet, it is under discussion now.

Thanks,
Ryo Tsuruta