Messages in this thread | | | Date | Tue, 22 Feb 2011 14:35:20 +0100 | From | Andrea Arcangeli <> | Subject | Re: [PATCH 4/5] teach smaps_pte_range() about THP pmds |
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On Mon, Feb 21, 2011 at 05:53:43PM -0800, Dave Hansen wrote: > @@ -385,8 +387,25 @@ static int smaps_pte_range(pmd_t *pmd, u > pte_t *pte; > spinlock_t *ptl; > > - split_huge_page_pmd(walk->mm, pmd); > - > + spin_lock(&walk->mm->page_table_lock); > + if (pmd_trans_huge(*pmd)) { > + if (pmd_trans_splitting(*pmd)) { > + spin_unlock(&walk->mm->page_table_lock); > + wait_split_huge_page(vma->anon_vma, pmd); > + } else { > + smaps_pte_entry(*(pte_t *)pmd, addr, > + HPAGE_PMD_SIZE, walk); > + spin_unlock(&walk->mm->page_table_lock); > + return 0; > + } > + } else { > + spin_unlock(&walk->mm->page_table_lock); > + } > + /* > + * The mmap_sem held all the way back in m_start() is what > + * keeps khugepaged out of here and from collapsing things > + * in here. > + */
This time the locking is right and HPAGE_PMD_SIZE is used instead of HPAGE_SIZE, thanks! I think all 5 patches can go in -mm and upstream anytime (not mandatory for 2.6.38 but definitely we want this for 2.6.39).
BTW, Andi in his NUMA THP improvement series added a THP_SPLIT vmstat per-cpu counter so that part removed from his series, is taken care by him.
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
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