Messages in this thread | | | Date | Tue, 27 Aug 2013 16:58:38 +0900 | From | Joonsoo Kim <> | Subject | Re: [PATCH v2 14/20] mm, hugetlb: call vma_needs_reservation before entering alloc_huge_page() |
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> >> @@ -2504,6 +2498,8 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, > >> struct hstate *h = hstate_vma(vma); > >> struct page *old_page, *new_page; > >> int outside_reserve = 0; > >> + long chg; > >> + bool use_reserve; > >> unsigned long mmun_start; /* For mmu_notifiers */ > >> unsigned long mmun_end; /* For mmu_notifiers */ > >> > >> @@ -2535,7 +2531,17 @@ retry_avoidcopy: > >> > >> /* Drop page_table_lock as buddy allocator may be called */ > >> spin_unlock(&mm->page_table_lock); > >> - new_page = alloc_huge_page(vma, address, outside_reserve); > >> + chg = vma_needs_reservation(h, vma, address); > >> + if (chg == -ENOMEM) { > > > > why not > > > > if (chg < 0) ? > > > > Should we try to unmap the page from child and avoid cow here ?. May be > > with outside_reserve = 1 we will never have vma_needs_reservation fail. > > Any how it would be nice to document why this error case is different > > from alloc_huge_page error case. > > > > I guess patch 16 address this . So if we do if (chg < 0) we are good > here.
Okay! I will change it.
> > Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Thanks.
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