Messages in this thread | | | Date | Tue, 26 Mar 2013 01:13:10 -0400 | From | Naoya Horiguchi <> | Subject | Re: [PATCH 05/10] migrate: add hugepage migration code to migrate_pages() |
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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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