Consider ZFS ARC shrinkable as cache on FreeBSD (#12879)

3 files changed, 17 insertions, 6 deletions

diff --git a/collectors/freebsd.plugin/freebsd_kstat_zfs.c b/collectors/freebsd.plugin/freebsd_kstat_zfs.c
index 8b5cc5799f..142fdb9744 100644
--- a/collectors/freebsd.plugin/freebsd_kstat_zfs.c
+++ b/collectors/freebsd.plugin/freebsd_kstat_zfs.c
@@ -5,6 +5,8 @@
 
 extern struct arcstats arcstats;
 
+unsigned long long zfs_arcstats_shrinkable_cache_size_bytes = 0;
+
 // --------------------------------------------------------------------------------------------------------------------
 // kstat.zfs.misc.arcstats
 
@@ -213,6 +215,12 @@ int do_kstat_zfs_misc_arcstats(int update_every, usec_t dt) {
     // missing mib: GETSYSCTL_SIMPLE("kstat.zfs.misc.arcstats.arc_need_free", mibs.arc_need_free, arcstats.arc_need_free);
     // missing mib: GETSYSCTL_SIMPLE("kstat.zfs.misc.arcstats.arc_sys_free", mibs.arc_sys_free, arcstats.arc_sys_free);
 
+    if (arcstats.size > arcstats.c_min) {
+        zfs_arcstats_shrinkable_cache_size_bytes = arcstats.size - arcstats.c_min;
+    } else {
+        zfs_arcstats_shrinkable_cache_size_bytes = 0;
+    }
+
     generate_charts_arcstats("freebsd.plugin", "zfs", show_zero_charts, update_every);
     generate_charts_arc_summary("freebsd.plugin", "zfs", show_zero_charts, update_every);
 
diff --git a/collectors/freebsd.plugin/freebsd_sysctl.c b/collectors/freebsd.plugin/freebsd_sysctl.c
index 3dc1fbfb16..eb339b23b8 100644
--- a/collectors/freebsd.plugin/freebsd_sysctl.c
+++ b/collectors/freebsd.plugin/freebsd_sysctl.c
@@ -1026,10 +1026,8 @@ int do_system_ram(int update_every, usec_t dt) {
             rd_free     = rrddim_add(st, "free",     NULL, system_pagesize, MEGA_FACTOR, RRD_ALGORITHM_ABSOLUTE);
             rd_active   = rrddim_add(st, "active",   NULL, system_pagesize, MEGA_FACTOR, RRD_ALGORITHM_ABSOLUTE);
             rd_inactive = rrddim_add(st, "inactive", NULL, system_pagesize, MEGA_FACTOR, RRD_ALGORITHM_ABSOLUTE);
-            rd_wired    = rrddim_add(st, "wired",    NULL, system_pagesize, MEGA_FACTOR, RRD_ALGORITHM_ABSOLUTE);
-#if __FreeBSD_version < 1200016
-            rd_cache    = rrddim_add(st, "cache",    NULL, system_pagesize, MEGA_FACTOR, RRD_ALGORITHM_ABSOLUTE);
-#endif
+            rd_wired    = rrddim_add(st, "wired",    NULL, 1, MEGA_FACTOR, RRD_ALGORITHM_ABSOLUTE);
+            rd_cache    = rrddim_add(st, "cache",    NULL, 1, MEGA_FACTOR, RRD_ALGORITHM_ABSOLUTE);
 #if defined(NETDATA_COLLECT_LAUNDRY)
             rd_laundry  = rrddim_add(st, "laundry",  NULL, system_pagesize, MEGA_FACTOR, RRD_ALGORITHM_ABSOLUTE);
 #endif
@@ -1040,9 +1038,11 @@ int do_system_ram(int update_every, usec_t dt) {
         rrddim_set_by_pointer(st, rd_free,     vmmeter_data.v_free_count);
         rrddim_set_by_pointer(st, rd_active,   vmmeter_data.v_active_count);
         rrddim_set_by_pointer(st, rd_inactive, vmmeter_data.v_inactive_count);
-        rrddim_set_by_pointer(st, rd_wired,    vmmeter_data.v_wire_count);
+        rrddim_set_by_pointer(st, rd_wired,    vmmeter_data.v_wire_count * system_pagesize - zfs_arcstats_shrinkable_cache_size_bytes);
 #if __FreeBSD_version < 1200016
-        rrddim_set_by_pointer(st, rd_cache,    vmmeter_data.v_cache_count);
+        rrddim_set_by_pointer(st, rd_cache,    vmmeter_data.v_cache_count * system_pagesize + zfs_arcstats_shrinkable_cache_size_bytes);
+#else
+        rrddim_set_by_pointer(st, rd_cache,    zfs_arcstats_shrinkable_cache_size_bytes);
 #endif
 #if defined(NETDATA_COLLECT_LAUNDRY)
         rrddim_set_by_pointer(st, rd_laundry,  vmmeter_data.v_laundry_count);
diff --git a/collectors/freebsd.plugin/plugin_freebsd.h b/collectors/freebsd.plugin/plugin_freebsd.h
index 26f76b6bf8..3a4ec13a7b 100644
--- a/collectors/freebsd.plugin/plugin_freebsd.h
+++ b/collectors/freebsd.plugin/plugin_freebsd.h
@@ -49,4 +49,7 @@ extern int do_kstat_zfs_misc_arcstats(int update_every, usec_t dt);
 extern int do_kstat_zfs_misc_zio_trim(int update_every, usec_t dt);
 extern int do_ipfw(int update_every, usec_t dt);
 
+// metrics that need to be shared among data collectors
+extern unsigned long long zfs_arcstats_shrinkable_cache_size_bytes;
+
 #endif /* NETDATA_PLUGIN_FREEBSD_H */