On Mon, Mar 25, 2013 at 02:04:16PM +0100, Michal Hocko wrote:
> 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.
So we need arch-dependent helper functions. I'll try that, but it
might be better to start with enabling only x86_64 if it takes time
to implement this.
> > + 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?
I consider migrate_movable_pages() as a wrapper of migrate_pages(),
not the variant of migrate_pages().
We can find the same pattern in the callers like
if (!list_empty(&pagelist)) {
err = migrate_pages(...);
if (err)
putback_lru_pages(&pagelist);
}
, so it can be simplified by migrate_movable_pages().
Thanks,
Naoya
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