mm: Exclude CDM marked VMAs from auto NUMA

ascend inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4JMLR
CVE: NA
-------------------

Kernel cannot track device memory accesses behind VMAs containing CDM
memory. Hence all the VM_CDM marked VMAs should not be part of the auto
NUMA migration scheme. This patch also adds a new function is_cdm_vma()
to detect any VMA marked with flag VM_CDM.
Signed-off-by: NAnshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: NLijun Fang <fanglijun3@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/mempolicy.h

@@ -181,6 +181,20 @@ extern int mpol_parse_str(char *str, struct mempolicy **mpol);
 
 extern void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol);
 
+#ifdef CONFIG_COHERENT_DEVICE
+static inline bool is_cdm_vma(struct vm_area_struct *vma)
+{
+	if (vma->vm_flags & VM_CDM)
+		return true;
+	return false;
+}
+#else
+static inline bool is_cdm_vma(struct vm_area_struct *vma)
+{
+	return false;
+}
+#endif
+
 /* Check if a vma is migratable */
 extern bool vma_migratable(struct vm_area_struct *vma);
 

kernel/sched/fair.c

@@ -2836,7 +2836,8 @@ static void task_numa_work(struct callback_head *work)
 	}
 	for (; vma; vma = vma->vm_next) {
 		if (!vma_migratable(vma) || !vma_policy_mof(vma) ||
-			is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_MIXEDMAP)) {
+			is_vm_hugetlb_page(vma) || is_cdm_vma(vma) ||
+					(vma->vm_flags & VM_MIXEDMAP)) {
 			continue;
 		}