Let all FEATURE()s use the same Prometheus metric.

Without this change, every individual FEATURE() declaration would have
an individual metric in Prometheus. Though this wouldn't be harmful, it
would look very cluttered.

By letting it use a single metric with the name of the feature attached
as a label, it also becomes easier to search, as you can apply regex
matching, etc.

Reviewed by:	cem
Differential Revision:	https://reviews.freebsd.org/D8775

diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h
index 5f949f5a40c6919d5e66a3cb54c2691c909d7260..799e69ed6a75ca7126a13e018c284c78ef3490dc 100644 (file)
--- a/sys/sys/sysctl.h
+++ b/sys/sys/sysctl.h
@@ -796,9 +796,9 @@ TAILQ_HEAD(sysctl_ctx_list, sysctl_ctx_entry);
  * A macro to generate a read-only sysctl to indicate the presence of optional
  * kernel features.
  */
-#define        FEATURE(name, desc)                                             \
-       SYSCTL_INT(_kern_features, OID_AUTO, name, CTLFLAG_RD | CTLFLAG_CAPRD, \
-           SYSCTL_NULL_INT_PTR, 1, desc)
+#define        FEATURE(name, desc, label)                                      \
+       SYSCTL_INT_WITH_LABEL(_kern_features, OID_AUTO, name,           \
+           CTLFLAG_RD | CTLFLAG_CAPRD, SYSCTL_NULL_INT_PTR, 1, desc, "feature")
 
 #endif /* _KERNEL */