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-rw-r--r--mm/mempolicy.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index b190cd456ace..58e3dfa2f83a 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1743,6 +1743,34 @@ COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
#endif /* CONFIG_COMPAT */
+bool vma_migratable(struct vm_area_struct *vma)
+{
+ if (vma->vm_flags & (VM_IO | VM_PFNMAP))
+ return false;
+
+ /*
+ * DAX device mappings require predictable access latency, so avoid
+ * incurring periodic faults.
+ */
+ if (vma_is_dax(vma))
+ return false;
+
+ if (is_vm_hugetlb_page(vma) &&
+ !hugepage_migration_supported(hstate_vma(vma)))
+ return false;
+
+ /*
+ * Migration allocates pages in the highest zone. If we cannot
+ * do so then migration (at least from node to node) is not
+ * possible.
+ */
+ if (vma->vm_file &&
+ gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
+ < policy_zone)
+ return false;
+ return true;
+}
+
struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
unsigned long addr)
{