[PATCH v7 09/14] xen/page_alloc: introduce page flag to stop buddy merging

[Carlo Nonato <carlo.nonato@minervasys.tech>]

Add a new PGC_no_buddy_merge flag that prevents the buddy algorithm in
free_heap_pages() from merging pages that have it set. As of now, only
PGC_static has this feature, but future work can extend it easier than
before.

Signed-off-by: Carlo Nonato <carlo.nonato@minervasys.tech>
---
v7:
- new patch
---
 xen/common/page_alloc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 6a98d9013f..3adea713b7 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -159,6 +159,7 @@
 #endif
 
 #define PGC_preserved (PGC_extra | PGC_static)
+#define PGC_no_buddy_merge PGC_static
 
 #ifndef PGT_TYPE_INFO_INITIALIZER
 #define PGT_TYPE_INFO_INITIALIZER 0
@@ -1504,7 +1505,7 @@ static void free_heap_pages(
             /* Merge with predecessor block? */
             if ( !mfn_valid(page_to_mfn(predecessor)) ||
                  !page_state_is(predecessor, free) ||
-                 (predecessor->count_info & PGC_static) ||
+                 (predecessor->count_info & PGC_no_buddy_merge) ||
                  (PFN_ORDER(predecessor) != order) ||
                  (page_to_nid(predecessor) != node) )
                 break;
@@ -1528,7 +1529,7 @@ static void free_heap_pages(
             /* Merge with successor block? */
             if ( !mfn_valid(page_to_mfn(successor)) ||
                  !page_state_is(successor, free) ||
-                 (successor->count_info & PGC_static) ||
+                 (successor->count_info & PGC_no_buddy_merge) ||
                  (PFN_ORDER(successor) != order) ||
                  (page_to_nid(successor) != node) )
                 break;
-- 
2.34.1