mm: mempolicy: Use _PAGE_NUMA to migrate pages

Note: Based on "mm/mpol: Use special PROT_NONE to migrate pages" but
	sufficiently different that the signed-off-bys were dropped

Combine our previous _PAGE_NUMA, mpol_misplaced and migrate_misplaced_page()
pieces into an effective migrate on fault scheme.

Note that (on x86) we rely on PROT_NONE pages being !present and avoid
the TLB flush from try_to_unmap(TTU_MIGRATION). This greatly improves the
page-migration performance.

Based-on-work-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>

1 files changed, 5 insertions, 4 deletions

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index a1d26a98c655..dabb5108d6c0 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -160,8 +160,8 @@ static inline struct page *compound_trans_head(struct page *page)
         return page;
 }
 
-extern int do_huge_pmd_numa_page(struct mm_struct *mm, unsigned long addr,
-                                  pmd_t pmd, pmd_t *pmdp);
+extern int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
+                                unsigned long addr, pmd_t pmd, pmd_t *pmdp);
 
 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
@@ -200,9 +200,10 @@ static inline int pmd_trans_huge_lock(pmd_t *pmd,
         return 0;
 }
 
-static inline int do_huge_pmd_numa_page(struct mm_struct *mm, unsigned long addr,
-                                        pmd_t pmd, pmd_t *pmdp)
+static inline int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
+                                        unsigned long addr, pmd_t pmd, pmd_t *pmdp)
 {
+        return 0;
 }
 
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */