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@xxxxxxxxxx>
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