lrdp: slab: read proper fields in page for allocated objects

ankban reported issue with slabsummary.txt showing wrong values in
ALLOCATED column. Read proper counter values from the slab page so that
values are reflected properly.

Change-Id: Id67d30f8e8af03785e35bb1ac2c0e440e841c0a6

linux-ramdump-parser-v2/parsers/slabsummary.py

@@ -31,7 +31,7 @@ class Slabinfo_summary(RamParser):
         if page == 0:
             return totalfree
         seen = []
-        mapcount = 0
+        count = 0
         total_objects = 0
         inuse = 0
         while page != start:
@@ -43,10 +43,14 @@ class Slabinfo_summary(RamParser):
                 return totalfree
             seen.append(page)
             page = page - slab_lru_offset
-            mapcount = self.ramdump.read_structure_field(
-                        page, 'struct page', '_mapcount')
-            inuse = mapcount & 0x0000FFFF
-            total_objects = (mapcount >> 16) & 0x00007FFF
+            if (self.ramdump.kernel_version <= (4, 14)):
+	            count = self.ramdump.read_structure_field(
+		                page, 'struct page', '_mapcount')
+	    else:
+	            count = self.ramdump.read_structure_field(
+		                page, 'struct page', 'counters')
+            inuse = count & 0x0000FFFF
+            total_objects = (count >> 16) & 0x00007FFF
             freeobj = total_objects - inuse
             totalfree = totalfree + freeobj
             page = self.ramdump.read_word(page + slab_lru_offset)