WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] Re: [PATCH 3/9] blkio-cgroup-v9: The new page_cgroup framewo

* Ryo Tsuruta <ryov@xxxxxxxxxxxxx> [2009-07-22 17:28:43]:

> KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> > > > > Index: linux-2.6.31-rc3/include/linux/page_cgroup.h
> > > > > ===================================================================
> > > > > --- linux-2.6.31-rc3.orig/include/linux/page_cgroup.h
> > > > > +++ linux-2.6.31-rc3/include/linux/page_cgroup.h
> > > > > @@ -1,7 +1,7 @@
> > > > >  #ifndef __LINUX_PAGE_CGROUP_H
> > > > >  #define __LINUX_PAGE_CGROUP_H
> > > > > 
> > > > > -#ifdef CONFIG_CGROUP_MEM_RES_CTLR
> > > > > +#ifdef CONFIG_CGROUP_PAGE
> > > > >  #include <linux/bit_spinlock.h>
> > > > >  /*
> > > > >   * Page Cgroup can be considered as an extended mem_map.
> > > > > @@ -12,9 +12,11 @@
> > > > >   */
> > > > >  struct page_cgroup {
> > > > >       unsigned long flags;
> > > > > -     struct mem_cgroup *mem_cgroup;
> > > > >       struct page *page;
> > > > > +#ifdef CONFIG_CGROUP_MEM_RES_CTLR
> > > > > +     struct mem_cgroup *mem_cgroup;
> > > > >       struct list_head lru;           /* per cgroup LRU list */
> > > > > +#endif
> > > > >  };
> > > > 
> > > > If CONFIG_CGROUP_MEM_RES_CTLR is not enabled and CGROUP_PAGE is
> > > > (assuming that the depends on below is refactored), what would this
> > > > change buy us? What is page_cgroup helping us track, the mem_cgroup is
> > > > factored out, so we are interested in the flags only?
> > > > 
> > > plz remove CONFIG. This jsut makes code complicated.
> > > or plz use your own infrastructure, not depends on page_cgroup.
> 
> Thanks for reviewing the patch.
> Do you mean that remove only CONFIG_CGROUP_MEM_RES_CTR in struct
> page_cgroup? Is it OK to define CONFIG_CGROUP_PAGE?
> 
> > BTW, you can't modify page_cgroup->flags bit without cmpxchg.
> > Then, patch [5/9] is completely broken, now because new bit is used
> > with atomic bit ops but without lock_page_cgroup(). (see mmotm)
> > 
> > Why struct page's flags bit can includes zone id etc...is just because
> > it's initalized before using. Anyway, this is "flags" bit. If you want
> > to modify multiple bit at once, plz use cmpxchg.
> > Then, I buy patch [8/9] and just skip this patch.
> 
> O.K. I'll use cmpxchg.
> 
> > But, following is more straightforward. (and what you do is not different
> > from this.)
> > ==
> > struct page {
> >     .....
> > #ifdef CONFIG_BLOCKIO_CGROUP
> >     void *blockio_cgroup;
> > #endif
> > }
> > ==
> 
> This increases the size of struct page. Could I get a consensus on
> this approach?
>


This defeats the entire purpose of page_cgroup, IMHO. You need to add
the cgroup pointer to page_cgroup or use css id's there.
 
> Thanks,
> Ryo Tsuruta
> 
> > Regards,
> > -Kame
> > 
> > 

-- 
        Balbir

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel