[dm-devel] Re: [PATCH 5/9] blkio-cgroup-v9: The body of blkio-cgroup

[KAMEZAWA Hiroyuki <kamezawa hiroyu jp fujitsu com>]

On Tue, 21 Jul 2009 23:14:05 +0900 (JST)
Ryo Tsuruta <ryov valinux co jp> wrote:

> The body of blkio-cgroup.
> + * blkio_cgroup_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.
> + */
> +void blkio_cgroup_set_owner(struct page *page, struct mm_struct *mm)


> + * blkio_cgroup_reset_owner() - reset the owner ID of a page
> + * @page:	the page we want to tag
> + * @mm:		the mm_struct of a page owner
> + *
> + * Change the owner of a given page if necessary.
> + */
> +void blkio_cgroup_reset_owner(struct page *page, struct mm_struct *mm)
> +{
> +	blkio_cgroup_set_owner(page, mm);
> +}


> +void blkio_cgroup_reset_owner_pagedirty(struct page *page, struct mm_struct *mm)
> +{
> +	if (!page_is_file_cache(page))
> +		return;
> +	if (current->flags & PF_MEMALLOC)
> +		return;
> +
> +	blkio_cgroup_reset_owner(page, mm);
> +}
> +

Hmm, why pass "mm" not "thread" ? Do we need to take care of mm->ownder ?
Why "current" is bad ?

Thanks,
-Kame