Re: [Qemu-devel] [RFC PATCH V5 1/4] colo-compare: introduce colo compare initialization

[Zhang Chen <zhangchen.fnst@cn.fujitsu.com>]

On 07/08/2016 05:12 PM, Jason Wang wrote:
>
>
> On 2016年07月08日 16:21, Zhang Chen wrote:
>>
>>
>> On 07/08/2016 11:40 AM, Jason Wang wrote:
>>>
>>>
>>> On 2016年06月23日 19:34, Zhang Chen wrote:
>>>> Packets coming from the primary char indev will be sent to outdev
>>>> Packets coming from the secondary char dev will be dropped
>>>>
>>>> usage:
>>>>
>>>> primary:
>>>> -netdev 
>>>> tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
>>>> -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
>>>> -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
>>>> -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
>>>> -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
>>>> -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
>>>> -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
>>>> -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
>>>> -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
>>>> -object 
>>>> filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
>>>> -object 
>>>> filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
>>>> -object 
>>>> colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0
>>>>
>>>> secondary:
>>>> -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down 
>>>> script=/etc/qemu-ifdown
>>>> -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
>>>> -chardev socket,id=red0,host=3.3.3.3,port=9003
>>>> -chardev socket,id=red1,host=3.3.3.3,port=9004
>>>> -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
>>>> -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
>>>
>>> Consider we finally want a non-rfc patch, it's better to have a some 
>>> explanations on the above configurations since it was not easy to 
>>> for starters at first glance.Maybe you can use either a ascii figure 
>>> or a paragraph. Also need to explain the parameter of colo-compare 
>>> in detail.
>>
>> Make sense,I will add a ascii figure and some comments to explain it.
>>
>>>
>>>>
>>>> Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
>>>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
>>>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>>>> ---
>>>>   net/Makefile.objs  |   1 +
>>>>   net/colo-compare.c | 231 
>>>> +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>   qemu-options.hx    |  34 ++++++++
>>>>   vl.c               |   3 +-
>>>>   4 files changed, 268 insertions(+), 1 deletion(-)
>>>>   create mode 100644 net/colo-compare.c
>>>>
>>>> diff --git a/net/Makefile.objs b/net/Makefile.objs
>>>> index b7c22fd..ba92f73 100644
>>>> --- a/net/Makefile.objs
>>>> +++ b/net/Makefile.objs
>>>> @@ -16,3 +16,4 @@ common-obj-$(CONFIG_NETMAP) += netmap.o
>>>>   common-obj-y += filter.o
>>>>   common-obj-y += filter-buffer.o
>>>>   common-obj-y += filter-mirror.o
>>>> +common-obj-y += colo-compare.o
>>>> diff --git a/net/colo-compare.c b/net/colo-compare.c
>>>> new file mode 100644
>>>> index 0000000..a3e1456
>>>> --- /dev/null
>>>> +++ b/net/colo-compare.c
>>>> @@ -0,0 +1,231 @@
>>>> +/*
>>>> + * COarse-grain LOck-stepping Virtual Machines for Non-stop 
>>>> Service (COLO)
>>>> + * (a.k.a. Fault Tolerance or Continuous Replication)
>>>> + *
>>>> + * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
>>>> + * Copyright (c) 2016 FUJITSU LIMITED
>>>> + * Copyright (c) 2016 Intel Corporation
>>>> + *
>>>> + * Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
>>>> + *
>>>> + * This work is licensed under the terms of the GNU GPL, version 2 or
>>>> + * later.  See the COPYING file in the top-level directory.
>>>> + */
>>>> +
>>>> +#include "qemu/osdep.h"
>>>> +#include "qemu/error-report.h"
>>>> +#include "qemu-common.h"
>>>> +#include "qapi/qmp/qerror.h"
>>>> +#include "qapi/error.h"
>>>> +#include "net/net.h"
>>>> +#include "net/vhost_net.h"
>>>> +#include "qom/object_interfaces.h"
>>>> +#include "qemu/iov.h"
>>>> +#include "qom/object.h"
>>>> +#include "qemu/typedefs.h"
>>>> +#include "net/queue.h"
>>>> +#include "sysemu/char.h"
>>>> +#include "qemu/sockets.h"
>>>> +#include "qapi-visit.h"
>>>> +#include "trace.h"
>>>
>>> Looks like trace were not really used in the patch, you can delay 
>>> the inclusion until is was really used.
>>
>> OK~~~
>>
>>>
>>>> +
>>>> +#define TYPE_COLO_COMPARE "colo-compare"
>>>> +#define COLO_COMPARE(obj) \
>>>> +    OBJECT_CHECK(CompareState, (obj), TYPE_COLO_COMPARE)
>>>> +
>>>> +#define COMPARE_READ_LEN_MAX NET_BUFSIZE
>>>> +
>>>> +static QTAILQ_HEAD(, CompareState) net_compares =
>>>> +       QTAILQ_HEAD_INITIALIZER(net_compares);
>>>
>>> What's the usage of this? A comment would be better.
>>
>> If we need compare more than one netdev,we should use
>> more than one colo-compare. we do checkpoint should flush
>> all enqueued packet in colo-compare when work with colo-frame.
>> we use this queue to find all colo-compare.
>> So, look like no need here, I will move it to after patch.
>
> Yes unless you want a single colo comparing threads to do comparing 
> for all netdevs. (But I agree, looks not need).
>
>>
>>
>>>
>>>> +
>>>> +typedef struct CompareState {
>>>> +    Object parent;
>>>> +
>>>> +    char *pri_indev;
>>>> +    char *sec_indev;
>>>> +    char *outdev;
>>>> +    CharDriverState *chr_pri_in;
>>>> +    CharDriverState *chr_sec_in;
>>>> +    CharDriverState *chr_out;
>>>> +    QTAILQ_ENTRY(CompareState) next;
>>>> +    SocketReadState pri_rs;
>>>> +    SocketReadState sec_rs;
>>>> +} CompareState;
>>>> +
>>>> +typedef struct CompareClass {
>>>> +    ObjectClass parent_class;
>>>> +} CompareClass;
>>>> +
>>>> +static char *compare_get_pri_indev(Object *obj, Error **errp)
>>>> +{
>>>> +    CompareState *s = COLO_COMPARE(obj);
>>>> +
>>>> +    return g_strdup(s->pri_indev);
>>>> +}
>>>> +
>>>> +static void compare_set_pri_indev(Object *obj, const char *value, 
>>>> Error **errp)
>>>> +{
>>>> +    CompareState *s = COLO_COMPARE(obj);
>>>> +
>>>> +    g_free(s->pri_indev);
>>>> +    s->pri_indev = g_strdup(value);
>>>
>>> I think we need do something more than this, e.g release the orig 
>>> dev and get the new one? Or just forbid setting this property.
>>>
>>
>> Do you means that:
>> qemu_chr_fe_release(s->chr_pri_in);
>>
>> If yes,in here we just get/set char* pri_indev(chardev's name).
>> We don't get or set CharDriverState, so I think we needn't do more.
>
> Maybe I miss something, but is there any usage for just changing 
> chardev's name here?

Yes, colo-compare get the name of chardev and save it.
like primary_in=xxx, secondary_in=xxxx,outdev=xxxxx.

>
>>
>>
>>> And looks like we have similar issues for sec_indev and outdev.
>>>
>>>> +}
>>>> +
>>>>
>
> [...]
>
>>>> +
>>>> +static void colo_compare_finalize(Object *obj)
>>>> +{
>>>> +    CompareState *s = COLO_COMPARE(obj);
>>>> +
>>>> +    if (s->chr_pri_in) {
>>>> +        qemu_chr_add_handlers(s->chr_pri_in, NULL, NULL, NULL, NULL);
>>>
>>> Why need do this?
>>
>> more safty before do qemu_chr_fe_release() for chardev
>> like backends/rng-egd.c
>
> Ok, but looks like we don't set any handlers in the patch, so I don't 
> get why need to clear it.
>
> For the things of eng-egd, I think we need fail if it was not a socket 
> chardev. Vhost-use did similar check in net_vhost_chardev_opts() which 
> maybe useful for here (we probably need this for mirror/redirector too).
>
> [...]
>
>
> .
>

-- 
Thanks
zhangchen