Re: [PATCH 05/10] migrate: add hugepage migration code tomigrate_pages()

From: Michal Hocko
Date: Mon Mar 25 2013 - 09:04:22 EST


On Fri 22-03-13 16:23:50, Naoya Horiguchi wrote:
[...]
> @@ -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);

I am afraid this has the same issue with other huge page sizes I have
mentioned earlier.

> + continue;
> + }
> split_huge_page_pmd(vma, addr, pmd);
> if (pmd_none_or_trans_huge_or_clear_bad(pmd))
> continue;
[...]
> @@ -1012,14 +1040,8 @@ static int migrate_to_node(struct mm_struct *mm, int source, int dest,
> check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask,
> flags | MPOL_MF_DISCONTIG_OK, &pagelist);
>
> - if (!list_empty(&pagelist)) {
> - err = migrate_pages(&pagelist, new_node_page, dest,
> + return migrate_movable_pages(&pagelist, new_node_page, dest,
> MIGRATE_SYNC, MR_SYSCALL);
> - if (err)
> - putback_lru_pages(&pagelist);
> - }
> -
> - return err;

This is really confusing. Why migrate_pages doesn't do putback cleanup
on its own but migrate_movable_pages does?
Please also move migrate_movable_pages definition to this patch.

> }
>
> /*
> --
> 1.7.11.7
>

--
Michal Hocko
SUSE Labs
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