Re: [RFC][PATCH 02/11] blkiocg async: The main part of iotrack

[Munehiro Ikeda]

KAMEZAWA Hiroyuki wrote, on 07/09/2010 03:38 AM:
> On Thu, 08 Jul 2010 23:15:30 -0400
> Munehiro Ikeda<m-ikeda@xxxxxxxxxxxxx>  wrote:
>
> > Signed-off-by: Hirokazu Takahashi<taka@xxxxxxxxxxxxx>
> > Signed-off-by: Ryo Tsuruta<ryov@xxxxxxxxxxxxx>
> > Signed-off-by: Andrea Righi<arighi@xxxxxxxxxxx>
> > Signed-off-by: Munehiro "Muuhh" Ikeda<m-ikeda@xxxxxxxxxxxxx>
> > ---
> >   block/Kconfig.iosched       |    8 +++
> >   block/Makefile              |    1 +
> >   block/blk-iotrack.c         |  129 +++++++++++++++++++++++++++++++++++++++++++
> >   include/linux/blk-iotrack.h |   62 +++++++++++++++++++++
> >   include/linux/page_cgroup.h |   25 ++++++++
> >   init/Kconfig                |    2 +-
> >   mm/page_cgroup.c            |   91 +++++++++++++++++++++++++++---
> >   7 files changed, 309 insertions(+), 9 deletions(-)
> >   create mode 100644 block/blk-iotrack.c
> >   create mode 100644 include/linux/blk-iotrack.h

(snip)

> > +/**
> > + * blk_iotrack_set_owner() - set the owner ID of a page.
> > + * @page:	the page we want to tag
> > + * @mm:		the mm_struct of a page owner
> > + *
> > + * Make a given page have the blkio-cgroup ID of the owner of this page.
> > + */
> > +int blk_iotrack_set_owner(struct page *page, struct mm_struct *mm)
> > +{
> > +	struct blkio_cgroup *blkcg;
> > +	unsigned short id = 0;	/* 0: default blkio_cgroup id */
> > +
> > +	if (blk_iotrack_disabled())
> > +		return 0;
> > +	if (!mm)
> > +		goto out;
> > +
> > +	rcu_read_lock();
> > +	blkcg = task_to_blkio_cgroup(rcu_dereference(mm->owner));
> > +	if (likely(blkcg))
> > +		id = css_id(&blkcg->css);
> > +	rcu_read_unlock();
> > +out:
> > +	return page_cgroup_set_owner(page, id);
> > +}
> > +
>
> I think this is bad. I/O should be charged against threads i.e. "current",
> because CFQ/blockio-cgroup provides per-thread control.
> mm->owner is not suitable, I think.

OK, thanks.


--
IKEDA, Munehiro
  NEC Corporation of America
    m-ikeda@xxxxxxxxxxxxx

--
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/