block: convert ThrottleGroup to object with QOM

ThrottleGroup is converted to an object. This will allow the future
throttle block filter drive easy creation and configuration of throttle
groups in QMP and cli.

A new QAPI struct, ThrottleLimits, is introduced to provide a shared
struct for all throttle configuration needs in QMP.

ThrottleGroups can be created via CLI as
    -object throttle-group,id=foo,x-iops-total=100,x-..
where x-* are individual limit properties. Since we can't add non-scalar
properties in -object this interface must be used instead. However,
setting these properties must be disabled after initialization because
certain combinations of limits are forbidden and thus configuration
changes should be done in one transaction. The individual properties
will go away when support for non-scalar values in CLI is implemented
and thus are marked as experimental.

ThrottleGroup also has a `limits` property that uses the ThrottleLimits
struct.  It can be used to create ThrottleGroups or set the
configuration in existing groups as follows:

{ "execute": "object-add",
  "arguments": {
    "qom-type": "throttle-group",
    "id": "foo",
    "props" : {
      "limits": {
          "iops-total": 100
      }
    }
  }
}
{ "execute" : "qom-set",
    "arguments" : {
        "path" : "foo",
        "property" : "limits",
        "value" : {
            "iops-total" : 99
        }
    }
}

This also means a group's configuration can be fetched with qom-get.

Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

3 files changed, 46 insertions, 19 deletions

diff --git a/include/block/throttle-groups.h b/include/block/throttle-groups.h
index a0f27cac63..82f030523f 100644
--- a/include/block/throttle-groups.h
+++ b/include/block/throttle-groups.h
@@ -53,6 +53,9 @@ typedef struct ThrottleGroupMember {
 
 } ThrottleGroupMember;
 
+#define TYPE_THROTTLE_GROUP "throttle-group"
+#define THROTTLE_GROUP(obj) OBJECT_CHECK(ThrottleGroup, (obj), TYPE_THROTTLE_GROUP)
+
 const char *throttle_group_get_name(ThrottleGroupMember *tgm);
 
 ThrottleState *throttle_group_incref(const char *name);
diff --git a/include/qemu/throttle-options.h b/include/qemu/throttle-options.h
index 3133d1ca40..182b7896e1 100644
--- a/include/qemu/throttle-options.h
+++ b/include/qemu/throttle-options.h
@@ -10,81 +10,102 @@
 #ifndef THROTTLE_OPTIONS_H
 #define THROTTLE_OPTIONS_H
 
+#define QEMU_OPT_IOPS_TOTAL "iops-total"
+#define QEMU_OPT_IOPS_TOTAL_MAX "iops-total-max"
+#define QEMU_OPT_IOPS_TOTAL_MAX_LENGTH "iops-total-max-length"
+#define QEMU_OPT_IOPS_READ "iops-read"
+#define QEMU_OPT_IOPS_READ_MAX "iops-read-max"
+#define QEMU_OPT_IOPS_READ_MAX_LENGTH "iops-read-max-length"
+#define QEMU_OPT_IOPS_WRITE "iops-write"
+#define QEMU_OPT_IOPS_WRITE_MAX "iops-write-max"
+#define QEMU_OPT_IOPS_WRITE_MAX_LENGTH "iops-write-max-length"
+#define QEMU_OPT_BPS_TOTAL "bps-total"
+#define QEMU_OPT_BPS_TOTAL_MAX "bps-total-max"
+#define QEMU_OPT_BPS_TOTAL_MAX_LENGTH "bps-total-max-length"
+#define QEMU_OPT_BPS_READ "bps-read"
+#define QEMU_OPT_BPS_READ_MAX "bps-read-max"
+#define QEMU_OPT_BPS_READ_MAX_LENGTH "bps-read-max-length"
+#define QEMU_OPT_BPS_WRITE "bps-write"
+#define QEMU_OPT_BPS_WRITE_MAX "bps-write-max"
+#define QEMU_OPT_BPS_WRITE_MAX_LENGTH "bps-write-max-length"
+#define QEMU_OPT_IOPS_SIZE "iops-size"
+
+#define THROTTLE_OPT_PREFIX "throttling."
 #define THROTTLE_OPTS \
           { \
-            .name = "throttling.iops-total",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_TOTAL,\
             .type = QEMU_OPT_NUMBER,\
             .help = "limit total I/O operations per second",\
         },{ \
-            .name = "throttling.iops-read",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_READ,\
             .type = QEMU_OPT_NUMBER,\
             .help = "limit read operations per second",\
         },{ \
-            .name = "throttling.iops-write",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_WRITE,\
             .type = QEMU_OPT_NUMBER,\
             .help = "limit write operations per second",\
         },{ \
-            .name = "throttling.bps-total",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_BPS_TOTAL,\
             .type = QEMU_OPT_NUMBER,\
             .help = "limit total bytes per second",\
         },{ \
-            .name = "throttling.bps-read",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_BPS_READ,\
             .type = QEMU_OPT_NUMBER,\
             .help = "limit read bytes per second",\
         },{ \
-            .name = "throttling.bps-write",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_BPS_WRITE,\
             .type = QEMU_OPT_NUMBER,\
             .help = "limit write bytes per second",\
         },{ \
-            .name = "throttling.iops-total-max",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_TOTAL_MAX,\
             .type = QEMU_OPT_NUMBER,\
             .help = "I/O operations burst",\
         },{ \
-            .name = "throttling.iops-read-max",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_READ_MAX,\
             .type = QEMU_OPT_NUMBER,\
             .help = "I/O operations read burst",\
         },{ \
-            .name = "throttling.iops-write-max",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_WRITE_MAX,\
             .type = QEMU_OPT_NUMBER,\
             .help = "I/O operations write burst",\
         },{ \
-            .name = "throttling.bps-total-max",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_BPS_TOTAL_MAX,\
             .type = QEMU_OPT_NUMBER,\
             .help = "total bytes burst",\
         },{ \
-            .name = "throttling.bps-read-max",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_BPS_READ_MAX,\
             .type = QEMU_OPT_NUMBER,\
             .help = "total bytes read burst",\
         },{ \
-            .name = "throttling.bps-write-max",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_BPS_WRITE_MAX,\
             .type = QEMU_OPT_NUMBER,\
             .help = "total bytes write burst",\
         },{ \
-            .name = "throttling.iops-total-max-length",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_TOTAL_MAX_LENGTH,\
             .type = QEMU_OPT_NUMBER,\
             .help = "length of the iops-total-max burst period, in seconds",\
         },{ \
-            .name = "throttling.iops-read-max-length",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_READ_MAX_LENGTH,\
             .type = QEMU_OPT_NUMBER,\
             .help = "length of the iops-read-max burst period, in seconds",\
         },{ \
-            .name = "throttling.iops-write-max-length",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_WRITE_MAX_LENGTH,\
             .type = QEMU_OPT_NUMBER,\
             .help = "length of the iops-write-max burst period, in seconds",\
         },{ \
-            .name = "throttling.bps-total-max-length",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_BPS_TOTAL_MAX_LENGTH,\
             .type = QEMU_OPT_NUMBER,\
             .help = "length of the bps-total-max burst period, in seconds",\
         },{ \
-            .name = "throttling.bps-read-max-length",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_BPS_READ_MAX_LENGTH,\
             .type = QEMU_OPT_NUMBER,\
             .help = "length of the bps-read-max burst period, in seconds",\
         },{ \
-            .name = "throttling.bps-write-max-length",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_BPS_WRITE_MAX_LENGTH,\
             .type = QEMU_OPT_NUMBER,\
             .help = "length of the bps-write-max burst period, in seconds",\
         },{ \
-            .name = "throttling.iops-size",\
+            .name = THROTTLE_OPT_PREFIX QEMU_OPT_IOPS_SIZE,\
             .type = QEMU_OPT_NUMBER,\
             .help = "when limiting by iops max size of an I/O in bytes",\
         }
diff --git a/include/qemu/throttle.h b/include/qemu/throttle.h
index 8e01885d29..8c93237866 100644
--- a/include/qemu/throttle.h
+++ b/include/qemu/throttle.h
@@ -152,5 +152,8 @@ bool throttle_schedule_timer(ThrottleState *ts,
                              bool is_write);
 
 void throttle_account(ThrottleState *ts, bool is_write, uint64_t size);
+void throttle_limits_to_config(ThrottleLimits *arg, ThrottleConfig *cfg,
+                               Error **errp);
+void throttle_config_to_limits(ThrottleConfig *cfg, ThrottleLimits *var);
 
 #endif