Re: [Qemu-devel] [RFC PATCH v2 03/10] Colo-proxy: add colo-proxy framework

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

On 02/20/2016 03:57 AM, Dr. David Alan Gilbert wrote:
> * Zhang Chen (zhangchen.fnst@cn.fujitsu.com) wrote:
>> From: zhangchen <zhangchen.fnst@cn.fujitsu.com>
>>
>> +static void colo_proxy_setup(NetFilterState *nf, Error **errp)
>> +{
>> +    COLOProxyState *s = FILTER_COLO_PROXY(nf);
>> +
>> +    if (!s->addr) {
>> +        error_setg(errp, "filter colo_proxy needs 'addr' property set!");
>> +        return;
>> +    }
>> +
>> +    if (nf->direction != NET_FILTER_DIRECTION_ALL) {
>> +        error_setg(errp, "colo need queue all packet,"
>> +                        "please startup colo-proxy with queue=all\n");
>> +        return;
>> +    }
>> +
>> +    s->sockfd = -1;
>> +    s->hashtable_size = 0;
>> +    colo_do_checkpoint = false;
>> +    qemu_event_init(&s->need_compare_ev, false);
>> +
>> +    s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
> I found that I had to be careful that this queue got flushed.  If the packet
> can't be sent immediately, then the packet only gets sent if another
> packet is added to the queue later.  I added a state change notifier to
> flush it when the VM started running (this is more of a problem in my hybrid
> mode case).
>
> Note also that the queue is not protected by locks; so take care since packets
> are sent from both the comparison thread and the colo thread (when it flushes)
> and I think it's read by the main thread as well potentially as packets are sent.
>
> Dave
>

Hi, Dave.
Thanks for your review, I will pay attention to this problem in the 
following modules.
and We have split colo-proxy to filter-mirror, filter-redirector, 
filter-rewriter and
colo-compare about jason's comments. The detail please look at the 
discussion
about "[RFC PATCH v2 00/10] Add colo-proxy based on netfilter" . If you 
have time,
please review it.

Thanks
zhangchen

>> +    colo_conn_hash = g_hash_table_new_full(connection_key_hash,
>> +                                           connection_key_equal,
>> +                                           g_free,
>> +                                           connection_destroy);
>> +    g_queue_init(&s->conn_list);
>> +}
>> +
>> +static void colo_proxy_class_init(ObjectClass *oc, void *data)
>> +{
>> +    NetFilterClass *nfc = NETFILTER_CLASS(oc);
>> +
>> +    nfc->setup = colo_proxy_setup;
>> +    nfc->cleanup = colo_proxy_cleanup;
>> +    nfc->receive_iov = colo_proxy_receive_iov;
>> +}
>> +
>> +static int colo_proxy_get_mode(Object *obj, Error **errp)
>> +{
>> +    COLOProxyState *s = FILTER_COLO_PROXY(obj);
>> +
>> +    return s->colo_mode;
>> +}
>> +
>> +static void
>> +colo_proxy_set_mode(Object *obj, int mode, Error **errp)
>> +{
>> +    COLOProxyState *s = FILTER_COLO_PROXY(obj);
>> +
>> +    s->colo_mode = mode;
>> +}
>> +
>> +static char *colo_proxy_get_addr(Object *obj, Error **errp)
>> +{
>> +    COLOProxyState *s = FILTER_COLO_PROXY(obj);
>> +
>> +    return g_strdup(s->addr);
>> +}
>> +
>> +static void
>> +colo_proxy_set_addr(Object *obj, const char *value, Error **errp)
>> +{
>> +    COLOProxyState *s = FILTER_COLO_PROXY(obj);
>> +    g_free(s->addr);
>> +    s->addr = g_strdup(value);
>> +    if (!s->addr) {
>> +        error_setg(errp, "colo_proxy needs 'addr'"
>> +                     "property set!");
>> +        return;
>> +    }
>> +}
>> +
>> +static void colo_proxy_init(Object *obj)
>> +{
>> +    object_property_add_enum(obj, "mode", "COLOMode", COLOMode_lookup,
>> +                             colo_proxy_get_mode, colo_proxy_set_mode, NULL);
>> +    object_property_add_str(obj, "addr", colo_proxy_get_addr,
>> +                            colo_proxy_set_addr, NULL);
>> +}
>> +
>> +static void colo_proxy_fini(Object *obj)
>> +{
>> +    COLOProxyState *s = FILTER_COLO_PROXY(obj);
>> +    g_free(s->addr);
>> +}
>> +
>> +static const TypeInfo colo_proxy_info = {
>> +    .name = TYPE_FILTER_COLO_PROXY,
>> +    .parent = TYPE_NETFILTER,
>> +    .class_init = colo_proxy_class_init,
>> +    .instance_init = colo_proxy_init,
>> +    .instance_finalize = colo_proxy_fini,
>> +    .instance_size = sizeof(COLOProxyState),
>> +};
>> +
>> +static void register_types(void)
>> +{
>> +    type_register_static(&colo_proxy_info);
>> +}
>> +
>> +type_init(register_types);
>> diff --git a/net/colo-proxy.h b/net/colo-proxy.h
>> new file mode 100644
>> index 0000000..affc117
>> --- /dev/null
>> +++ b/net/colo-proxy.h
>> @@ -0,0 +1,24 @@
>> +/*
>> + * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
>> + * (a.k.a. Fault Tolerance or Continuous Replication)
>> + *
>> + * Copyright (c) 2015 HUAWEI TECHNOLOGIES CO., LTD.
>> + * Copyright (c) 2015 FUJITSU LIMITED
>> + * Copyright (c) 2015 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.
>> + */
>> +
>> +
>> +#ifndef QEMU_COLO_PROXY_H
>> +#define QEMU_COLO_PROXY_H
>> +
>> +int colo_proxy_start(int mode);
>> +void colo_proxy_stop(int mode);
>> +int colo_proxy_do_checkpoint(int mode);
>> +bool colo_proxy_query_checkpoint(void);
>> +
>> +#endif /* QEMU_COLO_PROXY_H */
>> -- 
>> 1.9.1
>>
>>
>>
>>
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>
>
> .
>

-- 
Thanks
zhangchen