Re: [RFC] Restrict size of page_cgroup->flags

From: Balbir Singh
Date: Wed Oct 06 2010 - 23:15:13 EST


* nishimura@xxxxxxxxxxxxxxxxx <nishimura@xxxxxxxxxxxxxxxxx> [2010-10-07 09:54:58]:

> On Wed, 6 Oct 2010 19:53:14 +0530
> Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
>
> > I propose restricting page_cgroup.flags to 16 bits. The patch for the
> > same is below. Comments?
> >
> >
> > Restrict the bits usage in page_cgroup.flags
> >
> > From: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
> >
> > Restricting the flags helps control growth of the flags unbound.
> > Restriciting it to 16 bits gives us the possibility of merging
> > cgroup id with flags (atomicity permitting) and saving a whole
> > long word in page_cgroup
> >
> I agree that reducing the size of page_cgroup would be good and important.
> But, wouldn't it be better to remove ->page, if possible ?
>

Without the page pointer, how do we go from pc to page for reclaim?

--
Three Cheers,
Balbir
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/