mm: Enable Buddy allocation isolation for CDM nodes

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

This implements allocation isolation for CDM nodes in buddy allocator by
discarding CDM memory zones all the time except in the cases where the gfp
flag has got __GFP_THISNODE or the nodemask contains CDM nodes in cases
where it is non NULL (explicit allocation request in the kernel or user
process MPOL_BIND policy based requests).
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>

mm/page_alloc.c

@@ -3812,6 +3812,21 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
 		struct page *page;
 		unsigned long mark;
 
+		/*
+		 * CDM nodes get skipped if the requested gfp flag
+		 * does not have __GFP_THISNODE set or the nodemask
+		 * does not have any CDM nodes in case the nodemask
+		 * is non NULL (explicit allocation requests from
+		 * kernel or user process MPOL_BIND policy which has
+		 * CDM nodes).
+		 */
+		if (is_cdm_node(zone->zone_pgdat->node_id)) {
+			if (!(gfp_mask & __GFP_THISNODE)) {
+				if (!ac->nodemask)
+					continue;
+			}
+		}
+
 		if (cpusets_enabled() &&
 			(alloc_flags & ALLOC_CPUSET) &&
 			!__cpuset_zone_allowed(zone, gfp_mask))