Messages in this thread | | | Date | Wed, 28 Mar 2012 15:58:46 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH -V4 08/10] hugetlbfs: Add a list for tracking in-use HugeTLB pages |
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On Fri 16-03-12 23:09:28, Aneesh Kumar K.V wrote: > From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> > > 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@linux.vnet.ibm.com> > --- > 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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