block: Add iops_size to do the iops accounting for a given io size.

This feature can be used in case where users are avoiding the iops limit by
doing jumbo I/Os hammering the storage backend.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

block/qapi.c

@@ -258,6 +258,9 @@ void bdrv_query_info(BlockDriverState *bs,
                 cfg.buckets[THROTTLE_OPS_WRITE].max;
             info->inserted->iops_wr_max     =
                 cfg.buckets[THROTTLE_OPS_WRITE].max;
+
+            info->inserted->has_iops_size = cfg.op_size;
+            info->inserted->iops_size = cfg.op_size;
         }
 
         bs0 = bs;

blockdev.c

@@ -507,7 +507,7 @@ static DriveInfo *blockdev_init(QemuOpts *all_opts,
     cfg.buckets[THROTTLE_OPS_WRITE].max =
         qemu_opt_get_number(opts, "throttling.iops-write-max", 0);
 
-    cfg.op_size = 0;
+    cfg.op_size = qemu_opt_get_number(opts, "throttling.iops-size", 0);
 
     if (!check_throttle_config(&cfg, &error)) {
         error_report("%s", error_get_pretty(error));
@@ -774,6 +774,9 @@ DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)
     qemu_opt_rename(all_opts, "bps_rd_max", "throttling.bps-read-max");
     qemu_opt_rename(all_opts, "bps_wr_max", "throttling.bps-write-max");
 
+    qemu_opt_rename(all_opts,
+                    "iops_size", "throttling.iops-size");
+
     qemu_opt_rename(all_opts, "readonly", "read-only");
 
     value = qemu_opt_get(all_opts, "cache");
@@ -1273,7 +1276,9 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
                                bool has_iops_rd_max,
                                int64_t iops_rd_max,
                                bool has_iops_wr_max,
-                               int64_t iops_wr_max, Error **errp)
+                               int64_t iops_wr_max,
+                               bool has_iops_size,
+                               int64_t iops_size, Error **errp)
 {
     ThrottleConfig cfg;
     BlockDriverState *bs;
@@ -1312,7 +1317,9 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
         cfg.buckets[THROTTLE_OPS_WRITE].max = iops_wr_max;
     }
 
-    cfg.op_size = 0;
+    if (has_iops_size) {
+        cfg.op_size = iops_size;
+    }
 
     if (!check_throttle_config(&cfg, errp)) {
         return;
@@ -2037,6 +2044,10 @@ QemuOptsList qemu_common_drive_opts = {
             .name = "throttling.bps-write-max",
             .type = QEMU_OPT_NUMBER,
             .help = "total bytes write burst",
+        },{
+            .name = "throttling.iops-size",
+            .type = QEMU_OPT_NUMBER,
+            .help = "when limiting by iops max size of an I/O in bytes",
         },{
             .name = "copy-on-read",
             .type = QEMU_OPT_BOOL,

hmp.c

@@ -351,7 +351,8 @@ void hmp_info_block(Monitor *mon, const QDict *qdict)
                             " iops_wr=%" PRId64
                             " iops_max=%" PRId64
                             " iops_rd_max=%" PRId64
-                            " iops_wr_max=%" PRId64 "\n",
+                            " iops_wr_max=%" PRId64
+                            " iops_size=%" PRId64 "\n",
                             info->value->inserted->bps,
                             info->value->inserted->bps_rd,
                             info->value->inserted->bps_wr,
@@ -363,7 +364,8 @@ void hmp_info_block(Monitor *mon, const QDict *qdict)
                             info->value->inserted->iops_wr,
                             info->value->inserted->iops_max,
                             info->value->inserted->iops_rd_max,
-                            info->value->inserted->iops_wr_max);
+                            info->value->inserted->iops_wr_max,
+                            info->value->inserted->iops_size);
         } else {
             monitor_printf(mon, " [not inserted]");
         }
@@ -1124,6 +1126,8 @@ void hmp_block_set_io_throttle(Monitor *mon, const QDict *qdict)
                               false,
                               0,
                               false,
+                              0,
+                              false, /* No default I/O size */
                               0, &err);
     hmp_handle_error(mon, &err);
 }

qapi-schema.json

@@ -797,6 +797,8 @@
 #
 # @iops_wr_max: #optional write I/O operations max (Since 1.7)
 #
+# @iops_size: #optional an I/O size in bytes (Since 1.7)
+#
 # Since: 0.14.0
 #
 # Notes: This interface is only found in @BlockInfo.
@@ -810,7 +812,8 @@
             'image': 'ImageInfo',
             '*bps_max': 'int', '*bps_rd_max': 'int',
             '*bps_wr_max': 'int', '*iops_max': 'int',
-            '*iops_rd_max': 'int', '*iops_wr_max': 'int' } }
+            '*iops_rd_max': 'int', '*iops_wr_max': 'int',
+            '*iops_size': 'int' } }
 
 ##
 # @BlockDeviceIoStatus:
@@ -2201,6 +2204,8 @@
 #
 # @iops_wr_max: #optional write I/O operations max (Since 1.7)
 #
+# @iops_size: #optional an I/O size in bytes (Since 1.7)
+#
 # Returns: Nothing on success
 #          If @device is not a valid block device, DeviceNotFound
 #
@@ -2211,7 +2216,8 @@
             'iops': 'int', 'iops_rd': 'int', 'iops_wr': 'int',
             '*bps_max': 'int', '*bps_rd_max': 'int',
             '*bps_wr_max': 'int', '*iops_max': 'int',
-            '*iops_rd_max': 'int', '*iops_wr_max': 'int' } }
+            '*iops_rd_max': 'int', '*iops_wr_max': 'int',
+            '*iops_size': 'int' } }
 
 ##
 # @block-stream:

qemu-options.hx

@@ -413,6 +413,7 @@ DEF("drive", HAS_ARG, QEMU_OPTION_drive,
     "       [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n"
     "       [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n"
     "       [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n"
+    "       [[,iops_size=is]]\n"
     "                use 'file' as a drive image\n", QEMU_ARCH_ALL)
 STEXI
 @item -drive @var{option}[,@var{option}[,@var{option}[,...]]]

qmp-commands.hx

@@ -1389,7 +1389,7 @@ EQMP
 
     {
         .name       = "block_set_io_throttle",
-        .args_type  = "device:B,bps:l,bps_rd:l,bps_wr:l,iops:l,iops_rd:l,iops_wr:l,bps_max:l?,bps_rd_max:l?,bps_wr_max:l?,iops_max:l?,iops_rd_max:l?,iops_wr_max:l?",
+        .args_type  = "device:B,bps:l,bps_rd:l,bps_wr:l,iops:l,iops_rd:l,iops_wr:l,bps_max:l?,bps_rd_max:l?,bps_wr_max:l?,iops_max:l?,iops_rd_max:l?,iops_wr_max:l?,iops_size:l?",
         .mhandler.cmd_new = qmp_marshal_input_block_set_io_throttle,
     },
 
@@ -1414,6 +1414,7 @@ Arguments:
 - "iops_max":  total I/O operations max (json-int)
 - "iops_rd_max":  read I/O operations max (json-int)
 - "iops_wr_max":  write I/O operations max (json-int)
+- "iops_size":  I/O size in bytes when limiting (json-int)
 
 Example:
 
@@ -1429,7 +1430,8 @@ Example:
                                                "bps_wr_max": 0,
                                                "iops_max": 0,
                                                "iops_rd_max": 0,
-                                               "iops_wr_max": 0 } }
+                                               "iops_wr_max": 0,
+                                               "iops_size": 0 } }
 <- { "return": {} }
 
 EQMP
@@ -1776,6 +1778,7 @@ Each json-object contain the following:
          - "iops_max":  total I/O operations max (json-int)
          - "iops_rd_max":  read I/O operations max (json-int)
          - "iops_wr_max":  write I/O operations max (json-int)
+         - "iops_size": I/O size when limiting by iops (json-int)
          - "image": the detail of the image, it is a json-object containing
             the following:
              - "filename": image file name (json-string)
@@ -1851,6 +1854,7 @@ Example:
                "iops_max": 0,
                "iops_rd_max": 0,
                "iops_wr_max": 0,
+               "iops_size": 0,
                "image":{
                   "filename":"disks/test.qcow2",
                   "format":"qcow2",