On Thu 21-02-13 14:41:44, Naoya Horiguchi wrote: > This patch extends check_range() to handle vma with VM_HUGETLB set. > With this changes, we can migrate hugepage with migrate_pages(2). > Note that for larger hugepages (covered by pud entries, 1GB for > x86_64 for example), we simply skip it now. > > Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> > --- > include/linux/hugetlb.h | 6 ++++-- > mm/hugetlb.c | 10 ++++++++++ > mm/mempolicy.c | 46 ++++++++++++++++++++++++++++++++++------------ > 3 files changed, 48 insertions(+), 14 deletions(-) > > diff --git v3.8.orig/include/linux/hugetlb.h v3.8/include/linux/hugetlb.h > index 8f87115..eb33df5 100644 > --- v3.8.orig/include/linux/hugetlb.h > +++ v3.8/include/linux/hugetlb.h > @@ -69,6 +69,7 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed); > int dequeue_hwpoisoned_huge_page(struct page *page); > void putback_active_hugepage(struct page *page); > void putback_active_hugepages(struct list_head *l); > +void migrate_hugepage_add(struct page *page, struct list_head *list); > void copy_huge_page(struct page *dst, struct page *src); > > extern unsigned long hugepages_treat_as_movable; > @@ -88,8 +89,8 @@ struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address, > pmd_t *pmd, int write); > struct page *follow_huge_pud(struct mm_struct *mm, unsigned long address, > pud_t *pud, int write); > -int pmd_huge(pmd_t pmd); > -int pud_huge(pud_t pmd); > +extern int pmd_huge(pmd_t pmd); > +extern int pud_huge(pud_t pmd); extern is not needed here. > unsigned long hugetlb_change_protection(struct vm_area_struct *vma, > unsigned long address, unsigned long end, pgprot_t newprot); > > @@ -134,6 +135,7 @@ static inline int dequeue_hwpoisoned_huge_page(struct page *page) > > #define putback_active_hugepage(p) 0 > #define putback_active_hugepages(l) 0 > +#define migrate_hugepage_add(p, l) 0 > static inline void copy_huge_page(struct page *dst, struct page *src) > { > } > diff --git v3.8.orig/mm/hugetlb.c v3.8/mm/hugetlb.c > index cb9d43b8..86ffcb7 100644 > --- v3.8.orig/mm/hugetlb.c > +++ v3.8/mm/hugetlb.c > @@ -3202,3 +3202,13 @@ void putback_active_hugepages(struct list_head *l) > list_for_each_entry_safe(page, page2, l, lru) > putback_active_hugepage(page); > } > + > +void migrate_hugepage_add(struct page *page, struct list_head *list) > +{ > + VM_BUG_ON(!PageHuge(page)); > + get_page(page); > + spin_lock(&hugetlb_lock); Why hugetlb_lock? Comment for this lock says that it protects hugepage_freelists, nr_huge_pages, and free_huge_pages. > + list_move_tail(&page->lru, list); > + spin_unlock(&hugetlb_lock); > + return; > +} > diff --git v3.8.orig/mm/mempolicy.c v3.8/mm/mempolicy.c > index e2df1c1..8627135 100644 > --- v3.8.orig/mm/mempolicy.c > +++ v3.8/mm/mempolicy.c > @@ -525,6 +525,27 @@ 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)); > + spin_unlock(&vma->vm_mm->page_table_lock); I am a bit confused why page_table_lock is used here and why it doesn't cover the page usage. > + nid = page_to_nid(page); > + if (node_isset(nid, *nodes) != !!(flags & MPOL_MF_INVERT) > + && ((flags & MPOL_MF_MOVE && page_mapcount(page) == 1) > + || flags & MPOL_MF_MOVE_ALL)) > + migrate_hugepage_add(page, private); > +#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, > @@ -536,6 +557,11 @@ 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)) { Why an explicit check for is_vm_hugetlb_page here? Isn't pmd_huge() sufficient? > + 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; [...] -- Michal Hocko SUSE Labs -- 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>