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: Anshuman Khandual <khand...@linux.vnet.ibm.com>
---
 mm/page_alloc.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 84d61bb..392c24a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -64,6 +64,7 @@
 #include <linux/page_owner.h>
 #include <linux/kthread.h>
 #include <linux/memcontrol.h>
+#include <linux/node.h>
 
 #include <asm/sections.h>
 #include <asm/tlbflush.h>
@@ -2908,6 +2909,21 @@ 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))
-- 
2.9.3

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