When generating the zone stats make sure to handle the master zone

("UMA Zone") carefully, because it does not have pcpu caches allocated
at all.  In the UP case, we did not catch this because one pcpu cache
is always allocated with the zone, but for the MP case, we were getting
bogus stats for this zone.

Tested by: Lukas Ertl <le@univie.ac.at>

1 files changed, 7 insertions, 0 deletions

diff --git a/sys/vm/uma_core.c b/sys/vm/uma_core.c
index 1a585a7..fd15954 100644
--- a/sys/vm/uma_core.c
+++ b/sys/vm/uma_core.c
@@ -2119,6 +2119,13 @@ sysctl_vm_zone(SYSCTL_HANDLER_ARGS)
 				cachefree += cache->uc_freebucket->ub_ptr + 1;
 			CPU_UNLOCK(cpu);
 		}
+		/*
+		 * The "UMA Zones" zone (master zone) does not have pcpu
+		 * caches allocated for it, so the above computation is entirely
+		 * bogus.  Re-set cachefree to 0 in that case.
+		 */
+		if (z == zones)
+			cachefree = 0;
 		LIST_FOREACH(bucket, &z->uz_full_bucket, ub_link) {
 			cachefree += bucket->ub_ptr + 1;
 		}