[Qemu-devel] [PULL 04/42] block: Add support for throttling burst max in QMP and the command line.

[Stefan Hajnoczi <stefanha@redhat.com>]

From: Benoît Canet <benoit@irqsave.net>

The max parameter of the leaky bucket throttling algorithm can be used to
allow the guest to do bursts.
The max value is a pool of I/O that the guest can use without being throttled
at all. Throttling is triggered once this pool is empty.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/qapi.c     | 26 ++++++++++++++++
 blockdev.c       | 94 ++++++++++++++++++++++++++++++++++++++++++++++----------
 hmp.c            | 32 +++++++++++++++++--
 qapi-schema.json | 34 ++++++++++++++++++--
 qemu-options.hx  |  5 ++-
 qmp-commands.hx  | 28 +++++++++++++++--
 6 files changed, 195 insertions(+), 24 deletions(-)

diff --git a/block/qapi.c b/block/qapi.c
index cac3919..b1edc66 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -232,6 +232,32 @@ void bdrv_query_info(BlockDriverState *bs,
             info->inserted->iops    = cfg.buckets[THROTTLE_OPS_TOTAL].avg;
             info->inserted->iops_rd = cfg.buckets[THROTTLE_OPS_READ].avg;
             info->inserted->iops_wr = cfg.buckets[THROTTLE_OPS_WRITE].avg;
+
+            info->inserted->has_bps_max     =
+                cfg.buckets[THROTTLE_BPS_TOTAL].max;
+            info->inserted->bps_max         =
+                cfg.buckets[THROTTLE_BPS_TOTAL].max;
+            info->inserted->has_bps_rd_max  =
+                cfg.buckets[THROTTLE_BPS_READ].max;
+            info->inserted->bps_rd_max      =
+                cfg.buckets[THROTTLE_BPS_READ].max;
+            info->inserted->has_bps_wr_max  =
+                cfg.buckets[THROTTLE_BPS_WRITE].max;
+            info->inserted->bps_wr_max      =
+                cfg.buckets[THROTTLE_BPS_WRITE].max;
+
+            info->inserted->has_iops_max    =
+                cfg.buckets[THROTTLE_OPS_TOTAL].max;
+            info->inserted->iops_max        =
+                cfg.buckets[THROTTLE_OPS_TOTAL].max;
+            info->inserted->has_iops_rd_max =
+                cfg.buckets[THROTTLE_OPS_READ].max;
+            info->inserted->iops_rd_max     =
+                cfg.buckets[THROTTLE_OPS_READ].max;
+            info->inserted->has_iops_wr_max =
+                cfg.buckets[THROTTLE_OPS_WRITE].max;
+            info->inserted->iops_wr_max     =
+                cfg.buckets[THROTTLE_OPS_WRITE].max;
         }
 
         bs0 = bs;
diff --git a/blockdev.c b/blockdev.c
index 5f5ba96..76e9308 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -494,13 +494,18 @@ static DriveInfo *blockdev_init(QemuOpts *all_opts,
     cfg.buckets[THROTTLE_OPS_WRITE].avg =
         qemu_opt_get_number(opts, "throttling.iops-write", 0);
 
-    cfg.buckets[THROTTLE_BPS_TOTAL].max = 0;
-    cfg.buckets[THROTTLE_BPS_READ].max  = 0;
-    cfg.buckets[THROTTLE_BPS_WRITE].max = 0;
-
-    cfg.buckets[THROTTLE_OPS_TOTAL].max = 0;
-    cfg.buckets[THROTTLE_OPS_READ].max  = 0;
-    cfg.buckets[THROTTLE_OPS_WRITE].max = 0;
+    cfg.buckets[THROTTLE_BPS_TOTAL].max =
+        qemu_opt_get_number(opts, "throttling.bps-total-max", 0);
+    cfg.buckets[THROTTLE_BPS_READ].max  =
+        qemu_opt_get_number(opts, "throttling.bps-read-max", 0);
+    cfg.buckets[THROTTLE_BPS_WRITE].max =
+        qemu_opt_get_number(opts, "throttling.bps-write-max", 0);
+    cfg.buckets[THROTTLE_OPS_TOTAL].max =
+        qemu_opt_get_number(opts, "throttling.iops-total-max", 0);
+    cfg.buckets[THROTTLE_OPS_READ].max =
+        qemu_opt_get_number(opts, "throttling.iops-read-max", 0);
+    cfg.buckets[THROTTLE_OPS_WRITE].max =
+        qemu_opt_get_number(opts, "throttling.iops-write-max", 0);
 
     cfg.op_size = 0;
 
@@ -761,6 +766,14 @@ DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)
     qemu_opt_rename(all_opts, "bps_rd", "throttling.bps-read");
     qemu_opt_rename(all_opts, "bps_wr", "throttling.bps-write");
 
+    qemu_opt_rename(all_opts, "iops_max", "throttling.iops-total-max");
+    qemu_opt_rename(all_opts, "iops_rd_max", "throttling.iops-read-max");
+    qemu_opt_rename(all_opts, "iops_wr_max", "throttling.iops-write-max");
+
+    qemu_opt_rename(all_opts, "bps_max", "throttling.bps-total-max");
+    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, "readonly", "read-only");
 
     value = qemu_opt_get(all_opts, "cache");
@@ -1245,8 +1258,22 @@ void qmp_change_blockdev(const char *device, const char *filename,
 
 /* throttling disk I/O limits */
 void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
-                               int64_t bps_wr, int64_t iops, int64_t iops_rd,
-                               int64_t iops_wr, Error **errp)
+                               int64_t bps_wr,
+                               int64_t iops,
+                               int64_t iops_rd,
+                               int64_t iops_wr,
+                               bool has_bps_max,
+                               int64_t bps_max,
+                               bool has_bps_rd_max,
+                               int64_t bps_rd_max,
+                               bool has_bps_wr_max,
+                               int64_t bps_wr_max,
+                               bool has_iops_max,
+                               int64_t iops_max,
+                               bool has_iops_rd_max,
+                               int64_t iops_rd_max,
+                               bool has_iops_wr_max,
+                               int64_t iops_wr_max, Error **errp)
 {
     ThrottleConfig cfg;
     BlockDriverState *bs;
@@ -1266,13 +1293,24 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
     cfg.buckets[THROTTLE_OPS_READ].avg  = iops_rd;
     cfg.buckets[THROTTLE_OPS_WRITE].avg = iops_wr;
 
-    cfg.buckets[THROTTLE_BPS_TOTAL].max = 0;
-    cfg.buckets[THROTTLE_BPS_READ].max  = 0;
-    cfg.buckets[THROTTLE_BPS_WRITE].max = 0;
-
-    cfg.buckets[THROTTLE_OPS_TOTAL].max = 0;
-    cfg.buckets[THROTTLE_OPS_READ].max  = 0;
-    cfg.buckets[THROTTLE_OPS_WRITE].max = 0;
+    if (has_bps_max) {
+        cfg.buckets[THROTTLE_BPS_TOTAL].max = bps_max;
+    }
+    if (has_bps_rd_max) {
+        cfg.buckets[THROTTLE_BPS_READ].max = bps_rd_max;
+    }
+    if (has_bps_wr_max) {
+        cfg.buckets[THROTTLE_BPS_WRITE].max = bps_wr_max;
+    }
+    if (has_iops_max) {
+        cfg.buckets[THROTTLE_OPS_TOTAL].max = iops_max;
+    }
+    if (has_iops_rd_max) {
+        cfg.buckets[THROTTLE_OPS_READ].max = iops_rd_max;
+    }
+    if (has_iops_wr_max) {
+        cfg.buckets[THROTTLE_OPS_WRITE].max = iops_wr_max;
+    }
 
     cfg.op_size = 0;
 
@@ -1976,6 +2014,30 @@ QemuOptsList qemu_common_drive_opts = {
             .type = QEMU_OPT_NUMBER,
             .help = "limit write bytes per second",
         },{
+            .name = "throttling.iops-total-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "I/O operations burst",
+        },{
+            .name = "throttling.iops-read-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "I/O operations read burst",
+        },{
+            .name = "throttling.iops-write-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "I/O operations write burst",
+        },{
+            .name = "throttling.bps-total-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "total bytes burst",
+        },{
+            .name = "throttling.bps-read-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "total bytes read burst",
+        },{
+            .name = "throttling.bps-write-max",
+            .type = QEMU_OPT_NUMBER,
+            .help = "total bytes write burst",
+        },{
             .name = "copy-on-read",
             .type = QEMU_OPT_BOOL,
             .help = "copy read data from backing file into image file",
diff --git a/hmp.c b/hmp.c
index fcca6ae..85a6c16 100644
--- a/hmp.c
+++ b/hmp.c
@@ -344,14 +344,28 @@ void hmp_info_block(Monitor *mon, const QDict *qdict)
         {
             monitor_printf(mon, "    I/O throttling:   bps=%" PRId64
                             " bps_rd=%" PRId64  " bps_wr=%" PRId64
+                            " bps_max=%" PRId64
+                            " bps_rd_max=%" PRId64
+                            " bps_wr_max=%" PRId64
                             " iops=%" PRId64 " iops_rd=%" PRId64
-                            " iops_wr=%" PRId64 "\n",
+                            " iops_wr=%" PRId64
+                            " iops_max=%" PRId64
+                            " iops_rd_max=%" PRId64
+                            " iops_wr_max=%" PRId64 "\n",
                             info->value->inserted->bps,
                             info->value->inserted->bps_rd,
                             info->value->inserted->bps_wr,
+                            info->value->inserted->bps_max,
+                            info->value->inserted->bps_rd_max,
+                            info->value->inserted->bps_wr_max,
                             info->value->inserted->iops,
                             info->value->inserted->iops_rd,
-                            info->value->inserted->iops_wr);
+                            info->value->inserted->iops_wr,
+                            info->value->inserted->iops_max,
+                            info->value->inserted->iops_rd_max,
+                            info->value->inserted->iops_wr_max);
+        } else {
+            monitor_printf(mon, " [not inserted]");
         }
 
         if (verbose) {
@@ -1098,7 +1112,19 @@ void hmp_block_set_io_throttle(Monitor *mon, const QDict *qdict)
                               qdict_get_int(qdict, "bps_wr"),
                               qdict_get_int(qdict, "iops"),
                               qdict_get_int(qdict, "iops_rd"),
-                              qdict_get_int(qdict, "iops_wr"), &err);
+                              qdict_get_int(qdict, "iops_wr"),
+                              false, /* no burst max via HMP */
+                              0,
+                              false,
+                              0,
+                              false,
+                              0,
+                              false,
+                              0,
+                              false,
+                              0,
+                              false,
+                              0, &err);
     hmp_handle_error(mon, &err);
 }
 
diff --git a/qapi-schema.json b/qapi-schema.json
index a51f7d2..6a9b8ca 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -785,6 +785,18 @@
 #
 # @image: the info of image used (since: 1.6)
 #
+# @bps_max: #optional total max in bytes (Since 1.7)
+#
+# @bps_rd_max: #optional read max in bytes (Since 1.7)
+#
+# @bps_wr_max: #optional write max in bytes (Since 1.7)
+#
+# @iops_max: #optional total I/O operations max (Since 1.7)
+#
+# @iops_rd_max: #optional read I/O operations max (Since 1.7)
+#
+# @iops_wr_max: #optional write I/O operations max (Since 1.7)
+#
 # Since: 0.14.0
 #
 # Notes: This interface is only found in @BlockInfo.
@@ -795,7 +807,10 @@
             'encrypted': 'bool', 'encryption_key_missing': 'bool',
             'bps': 'int', 'bps_rd': 'int', 'bps_wr': 'int',
             'iops': 'int', 'iops_rd': 'int', 'iops_wr': 'int',
-            'image': 'ImageInfo' } }
+            'image': 'ImageInfo',
+            '*bps_max': 'int', '*bps_rd_max': 'int',
+            '*bps_wr_max': 'int', '*iops_max': 'int',
+            '*iops_rd_max': 'int', '*iops_wr_max': 'int' } }
 
 ##
 # @BlockDeviceIoStatus:
@@ -2174,6 +2189,18 @@
 #
 # @iops_wr: write I/O operations per second
 #
+# @bps_max: #optional total max in bytes (Since 1.7)
+#
+# @bps_rd_max: #optional read max in bytes (Since 1.7)
+#
+# @bps_wr_max: #optional write max in bytes (Since 1.7)
+#
+# @iops_max: #optional total I/O operations max (Since 1.7)
+#
+# @iops_rd_max: #optional read I/O operations max (Since 1.7)
+#
+# @iops_wr_max: #optional write I/O operations max (Since 1.7)
+#
 # Returns: Nothing on success
 #          If @device is not a valid block device, DeviceNotFound
 #
@@ -2181,7 +2208,10 @@
 ##
 { 'command': 'block_set_io_throttle',
   'data': { 'device': 'str', 'bps': 'int', 'bps_rd': 'int', 'bps_wr': 'int',
-            'iops': 'int', 'iops_rd': 'int', 'iops_wr': 'int' } }
+            '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' } }
 
 ##
 # @block-stream:
diff --git a/qemu-options.hx b/qemu-options.hx
index d15338e..d3760df 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -409,7 +409,10 @@ DEF("drive", HAS_ARG, QEMU_OPTION_drive,
     "       [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
     "       [,serial=s][,addr=A][,id=name][,aio=threads|native]\n"
     "       [,readonly=on|off][,copy-on-read=on|off]\n"
-    "       [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]][[,iops=i]|[[,iops_rd=r][,iops_wr=w]]\n"
+    "       [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n"
+    "       [[,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"
     "                use 'file' as a drive image\n", QEMU_ARCH_ALL)
 STEXI
 @item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 8a8f342..7c9667b 100644
--- a/qmp-commands.hx
+++ b/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",
+        .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?",
         .mhandler.cmd_new = qmp_marshal_input_block_set_io_throttle,
     },
 
@@ -1408,6 +1408,12 @@ Arguments:
 - "iops": total I/O operations per second (json-int)
 - "iops_rd": read I/O operations per second (json-int)
 - "iops_wr": write I/O operations per second (json-int)
+- "bps_max":  total max in bytes (json-int)
+- "bps_rd_max":  read max in bytes (json-int)
+- "bps_wr_max":  write max in bytes (json-int)
+- "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)
 
 Example:
 
@@ -1417,7 +1423,13 @@ Example:
                                                "bps_wr": 0,
                                                "iops": 0,
                                                "iops_rd": 0,
-                                               "iops_wr": 0 } }
+                                               "iops_wr": 0,
+                                               "bps_max": 8000000,
+                                               "bps_rd_max": 0,
+                                               "bps_wr_max": 0,
+                                               "iops_max": 0,
+                                               "iops_rd_max": 0,
+                                               "iops_wr_max": 0 } }
 <- { "return": {} }
 
 EQMP
@@ -1758,6 +1770,12 @@ Each json-object contain the following:
          - "iops": limit total I/O operations per second (json-int)
          - "iops_rd": limit read operations per second (json-int)
          - "iops_wr": limit write operations per second (json-int)
+         - "bps_max":  total max in bytes (json-int)
+         - "bps_rd_max":  read max in bytes (json-int)
+         - "bps_wr_max":  write max in bytes (json-int)
+         - "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)
          - "image": the detail of the image, it is a json-object containing
             the following:
              - "filename": image file name (json-string)
@@ -1827,6 +1845,12 @@ Example:
                "iops":1000000,
                "iops_rd":0,
                "iops_wr":0,
+               "bps_max": 8000000,
+               "bps_rd_max": 0,
+               "bps_wr_max": 0,
+               "iops_max": 0,
+               "iops_rd_max": 0,
+               "iops_wr_max": 0,
                "image":{
                   "filename":"disks/test.qcow2",
                   "format":"qcow2",
-- 
1.8.3.1