block/throttle.c uses existing I/O throttle infrastructure inside a
block filter driver. I/O operations are intercepted in the filter's
read/write coroutines, and referred to block/throttle-groups.c
The driver can be used with the syntax
-drive driver=throttle,file.filename=foo.qcow2,throttle-group=bar
which registers the throttle filter node with the ThrottleGroup 'bar'. The
given group must be created beforehand with object-add or -object.
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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>
This patch removes the redundant throttle code that was present in
block and fsdev device files. Now the common code is moved
to a single file.
Signed-off-by: Pradeep Jagadeesh <pradeep.jagadeesh@huawei.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
(fix indent nit, Greg Kurz)
Signed-off-by: Greg Kurz <groug@kaod.org>
Manos Pitsidianakis
Pradeep Jagadeesh