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?
Thanks,
Ryo Tsuruta
> Regards,
> -Kame
>
>
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