Re: [Qemu-devel] [PATCH v4 3/5] net/announce: Add optional ID

[Jason Wang <jasowang@redhat.com>]

On 2019/6/13 下午5:59, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>
> Previously there was a single instance of the timer used by
> monitor triggered announces, that's OK, but when combined with the
> previous change that lets you have announces for subsets of interfaces
> it's a bit restrictive if you want to do different things to different
> interfaces.
>
> Add an 'id' field to the announce, and maintain a list of the
> timers based on id.
>
> This allows you to for example:
>      a) Start an announce going on interface eth0 for a long time
>      b) Start an announce going on interface eth1 for a long time
>      c) Kill the announce on eth0 while leaving eth1 going.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>   hw/net/virtio-net.c    |  4 ++--
>   include/net/announce.h |  8 ++++++--
>   net/announce.c         | 46 +++++++++++++++++++++++++++++++++++-------
>   net/trace-events       |  3 ++-
>   qapi/net.json          |  9 +++++++--
>   5 files changed, 56 insertions(+), 14 deletions(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index c3f5fccfd1..b9e1cd71cf 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -2360,7 +2360,7 @@ static int virtio_net_post_load_device(void *opaque, int version_id)
>               timer_mod(n->announce_timer.tm,
>                         qemu_clock_get_ms(n->announce_timer.type));
>           } else {
> -            qemu_announce_timer_del(&n->announce_timer);
> +            qemu_announce_timer_del(&n->announce_timer, false);
>           }
>       }
>   
> @@ -2784,7 +2784,7 @@ static void virtio_net_device_unrealize(DeviceState *dev, Error **errp)
>           virtio_net_del_queue(n, i);
>       }
>   
> -    qemu_announce_timer_del(&n->announce_timer);
> +    qemu_announce_timer_del(&n->announce_timer, false);
>       g_free(n->vqs);
>       qemu_del_nic(n->nic);
>       virtio_net_rsc_cleanup(n);
> diff --git a/include/net/announce.h b/include/net/announce.h
> index 773470428b..3d90c83c23 100644
> --- a/include/net/announce.h
> +++ b/include/net/announce.h
> @@ -22,8 +22,12 @@ struct AnnounceTimer {
>   /* Returns: update the timer to the next time point */
>   int64_t qemu_announce_timer_step(AnnounceTimer *timer);
>   
> -/* Delete the underlying timer and other data */
> -void qemu_announce_timer_del(AnnounceTimer *timer);
> +/*
> + * Delete the underlying timer and other data
> + * If 'free_named' true and the timer is a named timer, then remove
> + * it from the list of named timers and free the AnnounceTimer itself.
> + */
> +void qemu_announce_timer_del(AnnounceTimer *timer, bool free_named);
>   
>   /*
>    * Under BQL/main thread
> diff --git a/net/announce.c b/net/announce.c
> index 1ce42b571d..4d4e2c22a1 100644
> --- a/net/announce.c
> +++ b/net/announce.c
> @@ -15,6 +15,8 @@
>   #include "qapi/qapi-commands-net.h"
>   #include "trace.h"
>   
> +static GData *named_timers;
> +
>   int64_t qemu_announce_timer_step(AnnounceTimer *timer)
>   {
>       int64_t step;
> @@ -31,8 +33,13 @@ int64_t qemu_announce_timer_step(AnnounceTimer *timer)
>       return step;
>   }
>   
> -void qemu_announce_timer_del(AnnounceTimer *timer)
> +/*
> + * If 'free_named' is true, then remove the timer from the list
> + * and free the timer itself.
> + */
> +void qemu_announce_timer_del(AnnounceTimer *timer, bool free_named)
>   {
> +    bool free_timer = false;
>       if (timer->tm) {
>           timer_del(timer->tm);
>           timer_free(timer->tm);
> @@ -40,6 +47,18 @@ void qemu_announce_timer_del(AnnounceTimer *timer)
>       }
>       qapi_free_strList(timer->params.interfaces);
>       timer->params.interfaces = NULL;
> +    if (free_named && timer->params.has_id) {
> +        free_timer = timer ==
> +                     g_datalist_get_data(&named_timers, timer->params.id);


Any chance that the timer get from datalist is different from the one 
that caller passed to us?

Thanks


> +        g_datalist_remove_data(&named_timers, timer->params.id);
> +    }
> +    trace_qemu_announce_timer_del(free_named, free_timer, timer->params.id);
> +    g_free(timer->params.id);
> +    timer->params.id = NULL;
> +
> +    if (free_timer) {
> +        g_free(timer);
> +    }
>   }
>   
>   /*
> @@ -56,7 +75,7 @@ void qemu_announce_timer_reset(AnnounceTimer *timer,
>        * We're under the BQL, so the current timer can't
>        * be firing, so we should be able to delete it.
>        */
> -    qemu_announce_timer_del(timer);
> +    qemu_announce_timer_del(timer, false);
>   
>       QAPI_CLONE_MEMBERS(AnnounceParameters, &timer->params, params);
>       timer->round = params->rounds;
> @@ -120,7 +139,8 @@ static void qemu_announce_self_iter(NICState *nic, void *opaque)
>           skip = false;
>       }
>   
> -    trace_qemu_announce_self_iter(nic->ncs->name,
> +    trace_qemu_announce_self_iter(timer->params.has_id ? timer->params.id : "_",
> +                                  nic->ncs->name,
>                                     qemu_ether_ntoa(&nic->conf->macaddr), skip);
>   
>       if (!skip) {
> @@ -143,7 +163,7 @@ static void qemu_announce_self_once(void *opaque)
>       if (--timer->round) {
>           qemu_announce_timer_step(timer);
>       } else {
> -        qemu_announce_timer_del(timer);
> +        qemu_announce_timer_del(timer, true);
>       }
>   }
>   
> @@ -154,12 +174,24 @@ void qemu_announce_self(AnnounceTimer *timer, AnnounceParameters *params)
>       if (params->rounds) {
>           qemu_announce_self_once(timer);
>       } else {
> -        qemu_announce_timer_del(timer);
> +        qemu_announce_timer_del(timer, true);
>       }
>   }
>   
>   void qmp_announce_self(AnnounceParameters *params, Error **errp)
>   {
> -    static AnnounceTimer announce_timer;
> -    qemu_announce_self(&announce_timer, params);
> +    AnnounceTimer *named_timer;
> +    if (!params->has_id) {
> +        params->id = g_strdup("");
> +        params->has_id = true;
> +    }
> +
> +    named_timer = g_datalist_get_data(&named_timers, params->id);
> +
> +    if (!named_timer) {
> +        named_timer = g_new0(AnnounceTimer, 1);
> +        g_datalist_set_data(&named_timers, params->id, named_timer);
> +    }
> +
> +    qemu_announce_self(named_timer, params);
>   }
> diff --git a/net/trace-events b/net/trace-events
> index 875ef2a0f3..ac57056497 100644
> --- a/net/trace-events
> +++ b/net/trace-events
> @@ -1,7 +1,8 @@
>   # See docs/devel/tracing.txt for syntax documentation.
>   
>   # announce.c
> -qemu_announce_self_iter(const char *name, const char *mac, int skip) "%s:%s skip: %d"
> +qemu_announce_self_iter(const char *id, const char *name, const char *mac, int skip) "%s:%s:%s skip: %d"
> +qemu_announce_timer_del(bool free_named, bool free_timer, char *id) "free named: %d free timer: %d id: %s"
>   
>   # vhost-user.c
>   vhost_user_event(const char *chr, int event) "chr: %s got event: %d"
> diff --git a/qapi/net.json b/qapi/net.json
> index 6f2cd4f530..728990f4fb 100644
> --- a/qapi/net.json
> +++ b/qapi/net.json
> @@ -702,6 +702,10 @@
>   # @interfaces: An optional list of interface names, which restricts the
>   #        announcement to the listed interfaces. (Since 4.1)
>   #
> +# @id: A name to be used to identify an instance of announce-timers
> +#        and to allow it to modified later.  Not for use as
> +#        part of the migration parameters. (Since 4.1)
> +#
>   # Since: 4.0
>   ##
>   
> @@ -710,7 +714,8 @@
>               'max': 'int',
>               'rounds': 'int',
>               'step': 'int',
> -            '*interfaces': ['str'] } }
> +            '*interfaces': ['str'],
> +            '*id' : 'str' } }
>   
>   ##
>   # @announce-self:
> @@ -725,7 +730,7 @@
>   # -> { "execute": "announce-self",
>   #      "arguments": {
>   #          "initial": 50, "max": 550, "rounds": 10, "step": 50,
> -#          "interfaces": ["vn2", "vn3"] } }
> +#          "interfaces": ["vn2", "vn3"], "id": "bob" } }
>   # <- { "return": {} }
>   #
>   # Since: 4.0