numastat: default NR_BOUNCE to 0

It was removed and defaulted to zero in 6.16. This allows us existing
code to continue working with compatibility for old kernels. The
"Bounce" field in meminfo will likely remain hard-coded to zero for a
long time anyway.

Signed-off-by: Stephen Brennan <[email protected]>

Author: brenns10

drgn_tools/meminfo.py

@@ -509,7 +509,9 @@ def get_all_meminfo(prog: Program) -> Dict[str, int]:
     stats["NFS_Unstable"] = 0
     if "NR_UNSTABLE_NFS" in global_stats:
         stats["NFS_Unstable"] = global_stats["NR_UNSTABLE_NFS"]
-    stats["Bounce"] = global_stats["NR_BOUNCE"]
+    # Since 194df9f66db8d ("mm: remove NR_BOUNCE zone stat") in v6.16, NR_BOUNCE
+    # is removed from stats and set to zero.
+    stats["Bounce"] = global_stats.get("NR_BOUNCE", 0)
     stats["WritebackTmp"] = global_stats["NR_WRITEBACK_TEMP"]
 
     stats["CommitLimit"] = get_vm_commit_limit(prog)

drgn_tools/numastat.py

@@ -89,7 +89,9 @@ def get_per_node_meminfo(prog: Program, node: Object) -> Dict[str, int]:
 
     totalram_pages = node_zone_stats["NR_MANAGED_PAGES"]
     freeram_pages = node_zone_stats["NR_FREE_PAGES"]
-    bounce_pages = node_zone_stats["NR_BOUNCE"]
+    # Since 194df9f66db8d ("mm: remove NR_BOUNCE zone stat") in v6.16, NR_BOUNCE
+    # is removed from stats and set to zero.
+    bounce_pages = node_zone_stats.get("NR_BOUNCE", 0)
     mlocked_pages = node_zone_stats["NR_MLOCK"]
 
     slab_reclaimable = node_zone_stats["NR_SLAB_RECLAIMABLE"]