croup: expose IO accounting data per unit

This was the last kind of accounting still not exposed on for each unit.
Let's fix that.

Note that this is a relatively simplistic approach: we don't expose
per-device stats, but sum them all up, much like cgtop does. This kind
of metric is probably the most interesting for most usecases, and covers
the "systemctl status" output best. If we want per-device stats one day
we can of course always add that eventually.

1 files changed, 34 insertions, 0 deletions

diff --git a/src/core/dbus-unit.c b/src/core/dbus-unit.c
index d34833f4ff..1d73e0d46d 100644
--- a/src/core/dbus-unit.c
+++ b/src/core/dbus-unit.c
@@ -1051,6 +1051,36 @@ static int property_get_ip_counter(
         return sd_bus_message_append(reply, "t", value);
 }
 
+static int property_get_io_counter(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *property,
+                sd_bus_message *reply,
+                void *userdata,
+                sd_bus_error *error) {
+
+        static const char *const table[_CGROUP_IO_ACCOUNTING_METRIC_MAX] = {
+                [CGROUP_IO_READ_BYTES]       = "IOReadBytes",
+                [CGROUP_IO_WRITE_BYTES]      = "IOWriteBytes",
+                [CGROUP_IO_READ_OPERATIONS]  = "IOReadOperations",
+                [CGROUP_IO_WRITE_OPERATIONS] = "IOWriteOperations",
+        };
+
+        uint64_t value = UINT64_MAX;
+        Unit *u = userdata;
+        ssize_t metric;
+
+        assert(bus);
+        assert(reply);
+        assert(property);
+        assert(u);
+
+        assert_se((metric = string_table_lookup(table, ELEMENTSOF(table), property)) >= 0);
+        (void) unit_get_io_accounting(u, metric, false, &value);
+        return sd_bus_message_append(reply, "t", value);
+}
+
 int bus_unit_method_attach_processes(sd_bus_message *message, void *userdata, sd_bus_error *error) {
 
         _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
@@ -1174,6 +1204,10 @@ const sd_bus_vtable bus_unit_cgroup_vtable[] = {
         SD_BUS_PROPERTY("IPIngressPackets", "t", property_get_ip_counter, 0, 0),
         SD_BUS_PROPERTY("IPEgressBytes", "t", property_get_ip_counter, 0, 0),
         SD_BUS_PROPERTY("IPEgressPackets", "t", property_get_ip_counter, 0, 0),
+        SD_BUS_PROPERTY("IOReadBytes", "t", property_get_io_counter, 0, 0),
+        SD_BUS_PROPERTY("IOReadOperations", "t", property_get_io_counter, 0, 0),
+        SD_BUS_PROPERTY("IOWriteBytes", "t", property_get_io_counter, 0, 0),
+        SD_BUS_PROPERTY("IOWriteOperations", "t", property_get_io_counter, 0, 0),
         SD_BUS_METHOD("GetProcesses", NULL, "a(sus)", bus_unit_method_get_processes, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("AttachProcesses", "sau", NULL, bus_unit_method_attach_processes, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_VTABLE_END