mm: numa: Do not group on RO pages

[mirror_ubuntu-artful-kernel.git] / mm / huge_memory.c

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index becf92ca54f3891930f47edb6c8c70462598270d..7ab4e32afe12b4798d625c97ec22d14067b89991 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1285,6 +1285,7 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
        int target_nid, last_cpupid = -1;
        bool page_locked;
        bool migrated = false;
+       int flags = 0;
 
        spin_lock(&mm->page_table_lock);
        if (unlikely(!pmd_same(pmd, *pmdp)))
@@ -1298,6 +1299,14 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
        if (page_nid == this_nid)
                count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
 
+       /*
+        * Avoid grouping on DSO/COW pages in specific and RO pages
+        * in general, RO pages shouldn't hurt as much anyway since
+        * they can be in shared cache state.
+        */
+       if (!pmd_write(pmd))
+               flags |= TNF_NO_GROUP;
+
        /*
         * Acquire the page lock to serialise THP migrations but avoid dropping
         * page_table_lock if at all possible
@@ -1343,8 +1352,10 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
        spin_unlock(&mm->page_table_lock);
        migrated = migrate_misplaced_transhuge_page(mm, vma,
                                pmdp, pmd, addr, page, target_nid);
-       if (migrated)
+       if (migrated) {
+               flags |= TNF_MIGRATED;
                page_nid = target_nid;
+       }
 
        goto out;
 clear_pmdnuma:
@@ -1362,7 +1373,7 @@ out:
                page_unlock_anon_vma_read(anon_vma);
 
        if (page_nid != -1)
-               task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, migrated);
+               task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, flags);
 
        return 0;
 }