On Fri, Jul 19, 2013 at 5:34 AM, Naoya Horiguchi
<n-horiguchi@xxxxxxxxxxxxx> wrote:
> This patch extends check_range() to handle vma with VM_HUGETLB set.
> We will be able to migrate hugepage with migrate_pages(2) after
> applying the enablement patch which comes later in this series.
>
> Note that for larger hugepages (covered by pud entries, 1GB for
> x86_64 for example), we simply skip it now.
>
> Note that using pmd_huge/pud_huge assumes that hugepages are pointed to
> by pmd/pud. This is not true in some architectures implementing hugepage
> with other mechanisms like ia64, but it's OK because pmd_huge/pud_huge
> simply return 0 in such arch and page walker simply ignores such hugepages.
>
> ChangeLog v3:
> - revert introducing migrate_movable_pages
> - use isolate_huge_page
>
> ChangeLog v2:
> - remove unnecessary extern
> - fix page table lock in check_hugetlb_pmd_range
> - updated description and renamed patch title
>
> Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> ---
> mm/mempolicy.c | 39 ++++++++++++++++++++++++++++++++++-----
> 1 file changed, 34 insertions(+), 5 deletions(-)
>
> diff --git v3.11-rc1.orig/mm/mempolicy.c v3.11-rc1/mm/mempolicy.c
> index 7431001..f3b65c0 100644
> --- v3.11-rc1.orig/mm/mempolicy.c
> +++ v3.11-rc1/mm/mempolicy.c
> @@ -512,6 +512,27 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
> return addr != end;
> }
>
> +static void check_hugetlb_pmd_range(struct vm_area_struct *vma, pmd_t *pmd,
> + const nodemask_t *nodes, unsigned long flags,
> + void *private)
> +{
> +#ifdef CONFIG_HUGETLB_PAGE
> + int nid;
> + struct page *page;
> +
> + spin_lock(&vma->vm_mm->page_table_lock);
> + page = pte_page(huge_ptep_get((pte_t *)pmd));
> + nid = page_to_nid(page);
Can you please add a brief comment for the if block?
> + if (node_isset(nid, *nodes) != !!(flags & MPOL_MF_INVERT)
> + && ((flags & MPOL_MF_MOVE && page_mapcount(page) == 1)
> + || flags & MPOL_MF_MOVE_ALL))
> + isolate_huge_page(page, private);
> + spin_unlock(&vma->vm_mm->page_table_lock);
> +#else
> + BUG();
> +#endif
> +}
> +
> static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
> unsigned long addr, unsigned long end,
> const nodemask_t *nodes, unsigned long flags,
> @@ -523,6 +544,11 @@ static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
> pmd = pmd_offset(pud, addr);
> do {
> next = pmd_addr_end(addr, end);
> + if (pmd_huge(*pmd) && is_vm_hugetlb_page(vma)) {
> + check_hugetlb_pmd_range(vma, pmd, nodes,
> + flags, private);
> + continue;
> + }
> split_huge_page_pmd(vma, addr, pmd);
> if (pmd_none_or_trans_huge_or_clear_bad(pmd))
> continue;
> @@ -544,6 +570,8 @@ static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
> pud = pud_offset(pgd, addr);
> do {
> next = pud_addr_end(addr, end);
> + if (pud_huge(*pud) && is_vm_hugetlb_page(vma))
> + continue;
> if (pud_none_or_clear_bad(pud))
> continue;
> if (check_pmd_range(vma, pud, addr, next, nodes,
> @@ -635,9 +663,6 @@ check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
> return ERR_PTR(-EFAULT);
> }
>
> - if (is_vm_hugetlb_page(vma))
> - goto next;
> -
> if (flags & MPOL_MF_LAZY) {
> change_prot_numa(vma, start, endvma);
> goto next;
> @@ -986,7 +1011,11 @@ static void migrate_page_add(struct page *page, struct list_head *pagelist,
>
> static struct page *new_node_page(struct page *page, unsigned long node, int **x)
> {
> - return alloc_pages_exact_node(node, GFP_HIGHUSER_MOVABLE, 0);
> + if (PageHuge(page))
> + return alloc_huge_page_node(page_hstate(compound_head(page)),
> + node);
> + else
> + return alloc_pages_exact_node(node, GFP_HIGHUSER_MOVABLE, 0);
> }
>
> /*
> @@ -1016,7 +1045,7 @@ static int migrate_to_node(struct mm_struct *mm, int source, int dest,
> err = migrate_pages(&pagelist, new_node_page, dest,
> MIGRATE_SYNC, MR_SYSCALL);
> if (err)
> - putback_lru_pages(&pagelist);
> + putback_movable_pages(&pagelist);
> }
>
> return err;
> --
> 1.8.3.1
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>