Re: [Qemu-devel] [PATCH v3 6/8] migration: Make none operations into its own structure

[Wei Yang <richardw.yang@linux.intel.com>]

On Wed, May 15, 2019 at 02:15:42PM +0200, Juan Quintela wrote:
>+
>+MultifdMethods multifd_none_ops = {
>+    .send_prepare = none_send_prepare,
>+    .send_write = none_send_write,
>+    .recv_pages = none_recv_pages
>+};
>+
> static int multifd_send_initial_packet(MultiFDSendParams *p, Error **errp)
> {
>     MultiFDInit_t msg;
>@@ -904,6 +938,8 @@ struct {
>     uint64_t packet_num;
>     /* send channels ready */
>     QemuSemaphore channels_ready;
>+    /* multifd ops */
>+    MultifdMethods *ops;
> } *multifd_send_state;
> 
> /*
>@@ -1093,6 +1129,8 @@ static void *multifd_send_thread(void *opaque)
>     /* initial packet */
>     p->num_packets = 1;
> 
>+    multifd_send_state->ops = &multifd_none_ops;
>+

I am afraid it is not a good practice to assign ops when each thread starts
work.

>     while (true) {
>         qemu_sem_wait(&p->sem);
>         qemu_mutex_lock(&p->mutex);
>@@ -1102,7 +1140,12 @@ static void *multifd_send_thread(void *opaque)
>             uint64_t packet_num = p->packet_num;
>             uint32_t flags = p->flags;
> 
>-            p->next_packet_size = used * qemu_target_page_size();
>+            if (used) {
>+                ret = multifd_send_state->ops->send_prepare(p, used);
>+                if (ret != 0) {
>+                    break;
>+                }
>+            }
>             multifd_send_fill_packet(p);
>             p->flags = 0;
>             p->num_packets++;
>@@ -1120,8 +1163,7 @@ static void *multifd_send_thread(void *opaque)
>             }
> 
>             if (used) {
>-                ret = qio_channel_writev_all(p->c, p->pages->iov,
>-                                             used, &local_err);
>+                ret = multifd_send_state->ops->send_write(p, used, &local_err);
>                 if (ret != 0) {
>                     break;
>                 }
>@@ -1223,6 +1265,8 @@ struct {
>     QemuSemaphore sem_sync;
>     /* global number of generated multifd packets */
>     uint64_t packet_num;
>+    /* multifd ops */
>+    MultifdMethods *ops;
> } *multifd_recv_state;
> 
> static void multifd_recv_terminate_threads(Error *err)
>@@ -1324,6 +1368,7 @@ static void *multifd_recv_thread(void *opaque)
>     trace_multifd_recv_thread_start(p->id);
>     rcu_register_thread();
> 
>+    multifd_recv_state->ops = &multifd_none_ops;

same as here.

>     while (true) {
>         uint32_t used;
>         uint32_t flags;
>@@ -1353,8 +1398,7 @@ static void *multifd_recv_thread(void *opaque)
>         qemu_mutex_unlock(&p->mutex);
> 
>         if (used) {
>-            ret = qio_channel_readv_all(p->c, p->pages->iov,
>-                                        used, &local_err);
>+            ret = multifd_recv_state->ops->recv_pages(p, used, &local_err);
>             if (ret != 0) {
>                 break;
>             }
>-- 
>2.21.0
>

-- 
Wei Yang
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