Re: [PATCH 03/10] soft-offline: use migrate_pages() instead ofmigrate_huge_page()

[Michal Hocko]

On Fri 29-03-13 10:56:00, Aneesh Kumar K.V wrote:
> Michal Hocko <mhocko@xxxxxxx> writes:
[...]
> > Little bit offtopic:
> > Btw. hugetlb migration breaks to charging even before this patchset
> > AFAICS. The above put_page should remove the last reference and then it
> > will uncharge it but I do not see anything that would charge a new page.
> > This is all because regula LRU pages are uncharged when they are
> > unmapped. But this a different story not related to this series.
> 
> 
> But when we call that put_page, we would have alreayd move the cgroup
> information to the new page. We have
> 
> 	h_cg = hugetlb_cgroup_from_page(oldhpage);
> 	set_hugetlb_cgroup(oldhpage, NULL);
> 
> 	/* move the h_cg details to new cgroup */
> 	set_hugetlb_cgroup(newhpage, h_cg);
> 
> 
> in hugetlb_cgroup_migrate

Yes but the res counter charge would be missing for the newpage after
put_page

-- 
Michal Hocko
SUSE Labs
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