[Qemu-devel] [PATCH v10 04/14] migration: Start of multiple fd work

[Juan Quintela]

We create new channels for each new thread created. We send through
them in a packed struct.  This way we can check we connect the right
channels in both sides.

Signed-off-by: Juan Quintela <address@hidden>

--
Split SocketArgs into incoming and outgoing args

Use UUID's on the initial message, so we are sure we are connecting to
the right channel.

Remove init semaphore.  Now that we use uuids on the init message, we
know that this is our channel.

Fix recv socket destwroy, we were destroying send channels.
This was very interesting, because we were using an unreferred object
without problems.

Move to struct of pointers
init channel sooner.
split recv thread creation.
listen on main thread
We count the number of created threads to know when we need to stop listening
Use g_strdup_printf
report channel id on errors
Add name parameter
Use local_err
Add Error * parameter to socket_send_channel_create()
Use qio_channel_*_all
Use asynchronous connect
Use an struct to send all fields
Use default uuid
Fix local_err = NULL (dave)
Make lines 80 lines long (checkpatch)
Move multifd_new_channel() and multifd_recv_thread() to later patches
when used.
Add __attribute__(packad)
Use UUIDs are opaques isntead of the ASCII represantation
rename migrate_new_channel_async to migrate_new_send_channel_async
rename recv_channel_destroy to _unref.  And create the pairing _ref.
---
 migration/migration.c |   7 +++-
 migration/ram.c       | 114 +++++++++++++++++++++++++++++++++++---------------
 migration/ram.h       |   3 ++
 migration/socket.c    |  39 ++++++++++++++++-
 migration/socket.h    |  10 +++++
 5 files changed, 137 insertions(+), 36 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index e506b9c2c6..77fc17f723 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -426,7 +426,7 @@ void migration_ioc_process_incoming(QIOChannel *ioc)
         QEMUFile *f = qemu_fopen_channel_input(ioc);
         migration_fd_process_incoming(f);
     }
-    /* We still only have a single channel.  Nothing to do here yet */
+    multifd_recv_new_channel(ioc);
 }
 
 /**
@@ -437,6 +437,11 @@ void migration_ioc_process_incoming(QIOChannel *ioc)
  */
 bool migration_has_all_channels(void)
 {
+    if (migrate_use_multifd()) {
+        int thread_count = migrate_multifd_channels();
+
+        return thread_count == multifd_created_channels();
+    }
     return true;
 }
 
diff --git a/migration/ram.c b/migration/ram.c
index 5a109efeda..aef5a323f3 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -36,6 +36,7 @@
 #include "xbzrle.h"
 #include "ram.h"
 #include "migration.h"
+#include "socket.h"
 #include "migration/register.h"
 #include "migration/misc.h"
 #include "qemu-file.h"
@@ -49,6 +50,8 @@
 #include "qemu/rcu_queue.h"
 #include "migration/colo.h"
 #include "migration/block.h"
+#include "sysemu/sysemu.h"
+#include "qemu/uuid.h"
 
 /***********************************************************/
 /* ram save/restore */
@@ -396,6 +399,7 @@ struct MultiFDSendParams {
     uint8_t id;
     char *name;
     QemuThread thread;
+    QIOChannel *c;
     QemuSemaphore sem;
     QemuMutex mutex;
     bool quit;
@@ -412,6 +416,15 @@ static void terminate_multifd_send_threads(Error *errp)
 {
     int i;
 
+    if (errp) {
+        MigrationState *s = migrate_get_current();
+        migrate_set_error(s, errp);
+        if (s->state == MIGRATION_STATUS_SETUP ||
+            s->state == MIGRATION_STATUS_ACTIVE) {
+            migrate_set_state(&s->state, s->state,
+                              MIGRATION_STATUS_FAILED);
+        }
+    }
     for (i = 0; i < multifd_send_state->count; i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
@@ -437,6 +450,7 @@ int multifd_save_cleanup(Error **errp)
         qemu_thread_join(&p->thread);
         qemu_mutex_destroy(&p->mutex);
         qemu_sem_destroy(&p->sem);
+        socket_send_channel_destroy(p->c);
         g_free(p->name);
         p->name = NULL;
     }
@@ -447,9 +461,27 @@ int multifd_save_cleanup(Error **errp)
     return ret;
 }
 
+typedef struct {
+    uint32_t version;
+    unsigned char uuid[16]; /* QemuUUID */
+    uint8_t id;
+} __attribute__((packed)) MultiFDInit_t;
+
 static void *multifd_send_thread(void *opaque)
 {
     MultiFDSendParams *p = opaque;
+    MultiFDInit_t msg;
+    Error *local_err = NULL;
+    size_t ret;
+
+    msg.version = 1;
+    msg.id = p->id;
+    memcpy(msg.uuid, &qemu_uuid.data, sizeof(msg.uuid));
+    ret = qio_channel_write_all(p->c, (char *)&msg, sizeof(msg), &local_err);
+    if (ret != 0) {
+        terminate_multifd_send_threads(local_err);
+        return NULL;
+    }
 
     while (true) {
         qemu_mutex_lock(&p->mutex);
@@ -464,6 +496,27 @@ static void *multifd_send_thread(void *opaque)
     return NULL;
 }
 
+static void multifd_new_send_channel_async(QIOTask *task, gpointer opaque)
+{
+    MultiFDSendParams *p = opaque;
+    QIOChannel *sioc = QIO_CHANNEL(qio_task_get_source(task));
+    Error *local_err = NULL;
+
+    if (qio_task_propagate_error(task, &local_err)) {
+        if (multifd_save_cleanup(&local_err) != 0) {
+            migrate_set_error(migrate_get_current(), local_err);
+        }
+    } else {
+        p->c = QIO_CHANNEL(sioc);
+        qio_channel_set_delay(p->c, false);
+
+        qemu_thread_create(&p->thread, p->name, multifd_send_thread, p,
+                           QEMU_THREAD_JOINABLE);
+
+        multifd_send_state->count++;
+    }
+}
+
 int multifd_save_setup(void)
 {
     int thread_count;
@@ -484,10 +537,7 @@ int multifd_save_setup(void)
         p->quit = false;
         p->id = i;
         p->name = g_strdup_printf("multifdsend_%d", i);
-        qemu_thread_create(&p->thread, p->name, multifd_send_thread, p,
-                           QEMU_THREAD_JOINABLE);
-
-        multifd_send_state->count++;
+        socket_send_channel_create(multifd_new_send_channel_async, p);
     }
     return 0;
 }
@@ -496,6 +546,7 @@ struct MultiFDRecvParams {
     uint8_t id;
     char *name;
     QemuThread thread;
+    QIOChannel *c;
     QemuSemaphore sem;
     QemuMutex mutex;
     bool quit;
@@ -506,12 +557,25 @@ struct {
     MultiFDRecvParams *params;
     /* number of created threads */
     int count;
+    /* Should we finish */
+    bool quit;
 } *multifd_recv_state;
 
 static void terminate_multifd_recv_threads(Error *errp)
 {
     int i;
 
+    if (errp) {
+        MigrationState *s = migrate_get_current();
+        migrate_set_error(s, errp);
+        if (s->state == MIGRATION_STATUS_SETUP ||
+            s->state == MIGRATION_STATUS_ACTIVE) {
+            migrate_set_state(&s->state, s->state,
+                              MIGRATION_STATUS_FAILED);
+        }
+    }
+    multifd_recv_state->quit = true;
+
     for (i = 0; i < multifd_recv_state->count; i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
@@ -537,6 +601,7 @@ int multifd_load_cleanup(Error **errp)
         qemu_thread_join(&p->thread);
         qemu_mutex_destroy(&p->mutex);
         qemu_sem_destroy(&p->sem);
+        socket_recv_channel_unref(p->c);
         g_free(p->name);
         p->name = NULL;
     }
@@ -548,27 +613,9 @@ int multifd_load_cleanup(Error **errp)
     return ret;
 }
 
-static void *multifd_recv_thread(void *opaque)
-{
-    MultiFDRecvParams *p = opaque;
-
-    while (true) {
-        qemu_mutex_lock(&p->mutex);
-        if (p->quit) {
-            qemu_mutex_unlock(&p->mutex);
-            break;
-        }
-        qemu_mutex_unlock(&p->mutex);
-        qemu_sem_wait(&p->sem);
-    }
-
-    return NULL;
-}
-
 int multifd_load_setup(void)
 {
     int thread_count;
-    uint8_t i;
 
     if (!migrate_use_multifd()) {
         return 0;
@@ -577,21 +624,20 @@ int multifd_load_setup(void)
     multifd_recv_state = g_malloc0(sizeof(*multifd_recv_state));
     multifd_recv_state->params = g_new0(MultiFDRecvParams, thread_count);
     multifd_recv_state->count = 0;
-    for (i = 0; i < thread_count; i++) {
-        MultiFDRecvParams *p = &multifd_recv_state->params[i];
-
-        qemu_mutex_init(&p->mutex);
-        qemu_sem_init(&p->sem, 0);
-        p->quit = false;
-        p->id = i;
-        p->name = g_strdup_printf("multifdrecv_%d", i);
-        qemu_thread_create(&p->thread, p->name, multifd_recv_thread, p,
-                           QEMU_THREAD_JOINABLE);
-        multifd_recv_state->count++;
-    }
+    multifd_recv_state->quit = false;
     return 0;
 }
 
+int multifd_created_channels(void)
+{
+    return multifd_recv_state->count;
+}
+
+void multifd_recv_new_channel(QIOChannel *ioc)
+{
+    socket_recv_channel_unref(ioc);
+}
+
 /**
  * save_page_header: write page header to wire
  *
diff --git a/migration/ram.h b/migration/ram.h
index 64d81e9f1d..be7d09d0ec 100644
--- a/migration/ram.h
+++ b/migration/ram.h
@@ -31,6 +31,7 @@
 
 #include "qemu-common.h"
 #include "exec/cpu-common.h"
+#include "io/channel.h"
 
 extern MigrationStats ram_counters;
 extern XBZRLECacheStats xbzrle_counters;
@@ -43,6 +44,8 @@ int multifd_save_setup(void);
 int multifd_save_cleanup(Error **errp);
 int multifd_load_setup(void);
 int multifd_load_cleanup(Error **errp);
+int multifd_created_channels(void);
+void multifd_recv_new_channel(QIOChannel *ioc);
 
 uint64_t ram_pagesize_summary(void);
 int ram_save_queue_pages(const char *rbname, ram_addr_t start, ram_addr_t len);
diff --git a/migration/socket.c b/migration/socket.c
index 6d49903978..aedabee8a1 100644
--- a/migration/socket.c
+++ b/migration/socket.c
@@ -27,6 +27,39 @@
 #include "io/channel-socket.h"
 #include "trace.h"
 
+int socket_recv_channel_ref(QIOChannel *recv)
+{
+    object_ref(OBJECT(recv));
+    return 0;
+}
+
+int socket_recv_channel_unref(QIOChannel *recv)
+{
+    object_unref(OBJECT(recv));
+    return 0;
+}
+
+struct SocketOutgoingArgs {
+    SocketAddress *saddr;
+} outgoing_args;
+
+void socket_send_channel_create(void (*f)(QIOTask *, gpointer), void *data)
+{
+    QIOChannelSocket *sioc = qio_channel_socket_new();
+    qio_channel_socket_connect_async(sioc, outgoing_args.saddr,
+                                     f, data, NULL);
+}
+
+int socket_send_channel_destroy(QIOChannel *send)
+{
+    /* Remove channel */
+    object_unref(OBJECT(send));
+    if (outgoing_args.saddr) {
+        qapi_free_SocketAddress(outgoing_args.saddr);
+        outgoing_args.saddr = NULL;
+    }
+    return 0;
+}
 
 static SocketAddress *tcp_build_address(const char *host_port, Error **errp)
 {
@@ -96,6 +129,11 @@ static void socket_start_outgoing_migration(MigrationState 
*s,
     struct SocketConnectData *data = g_new0(struct SocketConnectData, 1);
 
     data->s = s;
+
+    /* in case previous migration leaked it */
+    qapi_free_SocketAddress(outgoing_args.saddr);
+    outgoing_args.saddr = saddr;
+
     if (saddr->type == SOCKET_ADDRESS_TYPE_INET) {
         data->hostname = g_strdup(saddr->u.inet.host);
     }
@@ -106,7 +144,6 @@ static void socket_start_outgoing_migration(MigrationState 
*s,
                                      socket_outgoing_migration,
                                      data,
                                      socket_connect_data_free);
-    qapi_free_SocketAddress(saddr);
 }
 
 void tcp_start_outgoing_migration(MigrationState *s,
diff --git a/migration/socket.h b/migration/socket.h
index 6b91e9db38..cbdb8d64c3 100644
--- a/migration/socket.h
+++ b/migration/socket.h
@@ -16,6 +16,16 @@
 
 #ifndef QEMU_MIGRATION_SOCKET_H
 #define QEMU_MIGRATION_SOCKET_H
+
+#include "io/channel.h"
+#include "io/task.h"
+
+int socket_recv_channel_ref(QIOChannel *recv);
+int socket_recv_channel_unref(QIOChannel *recv);
+
+void socket_send_channel_create(void (*f)(QIOTask *, gpointer), void *data);
+int socket_send_channel_destroy(QIOChannel *send);
+
 void tcp_start_incoming_migration(const char *host_port, Error **errp);
 
 void tcp_start_outgoing_migration(MigrationState *s, const char *host_port,
-- 
2.14.3