diff --git a/trace2/tr2_tls.h b/trace2/tr2_tls.h
index b1e327a928..a90bd639d4 100644
--- a/trace2/tr2_tls.h
+++ b/trace2/tr2_tls.h
@@ -11,8 +11,8 @@
 struct tr2tls_thread_ctx {
 	struct strbuf thread_name;
 	uint64_t *array_us_start;
-	int alloc;
-	int nr_open_regions; /* plays role of "nr" in ALLOC_GROW */
+	size_t alloc;
+	size_t nr_open_regions; /* plays role of "nr" in ALLOC_GROW */
 	int thread_id;
 };