On Fri 16-03-12 23:09:28, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>
> hugepage_activelist will be used to track currently used HugeTLB pages.
> We need to find the in-use HugeTLB pages to support memcg removal.
> On memcg removal we update the page's memory cgroup to point to
> parent cgroup.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> ---
> include/linux/hugetlb.h | 1 +
> mm/hugetlb.c | 23 ++++++++++++++++++-----
> 2 files changed, 19 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index cbd8dc5..6919100 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
[...]
> @@ -2319,14 +2322,24 @@ void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
> page = pte_page(pte);
> if (pte_dirty(pte))
> set_page_dirty(page);
> - list_add(&page->lru, &page_list);
> +
> + spin_lock(&hugetlb_lock);
> + list_move(&page->lru, &page_list);
> + spin_unlock(&hugetlb_lock);
Why do we really need the spinlock here?
> }
> spin_unlock(&mm->page_table_lock);
> flush_tlb_range(vma, start, end);
> mmu_notifier_invalidate_range_end(mm, start, end);
> list_for_each_entry_safe(page, tmp, &page_list, lru) {
> page_remove_rmap(page);
> - list_del(&page->lru);
> + /*
> + * We need to move it back huge page active list. If we are
> + * holding the last reference, below put_page will move it
> + * back to free list.
> + */
> + spin_lock(&hugetlb_lock);
> + list_move(&page->lru, &h->hugepage_activelist);
> + spin_unlock(&hugetlb_lock);
This spinlock usage doesn't look nice but I guess we do not have many
other options.
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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