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 <khandual@xxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index afbd24d..40c942c 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>
@@ -2898,6 +2899,10 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
struct zoneref *z = ac->preferred_zoneref;
struct zone *zone;
struct pglist_data *last_pgdat_dirty_limit = NULL;
+ bool cpuset_fallback = false;
+
+ if (ac->nodemask != orig_mask)
+ cpuset_fallback = true;
/*
* Scan zonelist, looking for a zone with enough free.
@@ -2908,6 +2913,24 @@ 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 (cpuset_fallback)
+ continue;
+
+ if (!ac->nodemask)
+ continue;
+ }
+ }
+
if (cpusets_enabled() &&
(alloc_flags & ALLOC_CPUSET) &&
!__cpuset_zone_allowed(zone, gfp_mask))
--
2.9.3
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