[PATCH 4/4] Adding support for multi-FD connections dynamically

[Het Gala]

i) Dynamically decide appropriate source and destination ip pairs for the
   corresponding multi-FD channel to be connected.

ii) Removed the support for setting the number of multi-fd channels from qmp
    commands. As now all multiFD parameters will be passed via qmp: migrate
    command or incoming flag itself.

Suggested-by: Manish Mishra <manish.mishra@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
---
 migration/migration.c | 15 ---------------
 migration/migration.h |  1 -
 migration/multifd.c   | 42 +++++++++++++++++++++---------------------
 migration/socket.c    | 42 +++++++++++++++++++++++++++++++++---------
 migration/socket.h    |  4 +++-
 monitor/hmp-cmds.c    |  4 ----
 qapi/migration.json   |  6 ------
 7 files changed, 57 insertions(+), 57 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 9b0ad732e7..57dd4494b4 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1585,9 +1585,6 @@ static void 
migrate_params_test_apply(MigrateSetParameters *params,
     if (params->has_block_incremental) {
         dest->block_incremental = params->block_incremental;
     }
-    if (params->has_multifd_channels) {
-        dest->multifd_channels = params->multifd_channels;
-    }
     if (params->has_multifd_compression) {
         dest->multifd_compression = params->multifd_compression;
     }
@@ -1702,9 +1699,6 @@ static void migrate_params_apply(MigrateSetParameters 
*params, Error **errp)
     if (params->has_block_incremental) {
         s->parameters.block_incremental = params->block_incremental;
     }
-    if (params->has_multifd_channels) {
-        s->parameters.multifd_channels = params->multifd_channels;
-    }
     if (params->has_multifd_compression) {
         s->parameters.multifd_compression = params->multifd_compression;
     }
@@ -2686,15 +2680,6 @@ bool migrate_pause_before_switchover(void)
         MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER];
 }
 
-int migrate_multifd_channels(void)
-{
-    MigrationState *s;
-
-    s = migrate_get_current();
-
-    return s->parameters.multifd_channels;
-}
-
 MultiFDCompression migrate_multifd_compression(void)
 {
     MigrationState *s;
diff --git a/migration/migration.h b/migration/migration.h
index fa8717ec9e..9464de8ef7 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -372,7 +372,6 @@ bool migrate_validate_uuid(void);
 bool migrate_auto_converge(void);
 bool migrate_use_multifd(void);
 bool migrate_pause_before_switchover(void);
-int migrate_multifd_channels(void);
 MultiFDCompression migrate_multifd_compression(void);
 int migrate_multifd_zlib_level(void);
 int migrate_multifd_zstd_level(void);
diff --git a/migration/multifd.c b/migration/multifd.c
index 9282ab6aa4..ce017436fb 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -225,7 +225,7 @@ static int multifd_recv_initial_packet(QIOChannel *c, Error 
**errp)
         return -1;
     }
 
-    if (msg.id > migrate_multifd_channels()) {
+    if (msg.id > total_multifd_channels()) {
         error_setg(errp, "multifd: received channel version %u "
                    "expected %u", msg.version, MULTIFD_VERSION);
         return -1;
@@ -410,8 +410,8 @@ static int multifd_send_pages(QEMUFile *f)
      * using more channels, so ensure it doesn't overflow if the
      * limit is lower now.
      */
-    next_channel %= migrate_multifd_channels();
-    for (i = next_channel;; i = (i + 1) % migrate_multifd_channels()) {
+    next_channel %= total_multifd_channels();
+    for (i = next_channel;; i = (i + 1) % total_multifd_channels()) {
         p = &multifd_send_state->params[i];
 
         qemu_mutex_lock(&p->mutex);
@@ -422,7 +422,7 @@ static int multifd_send_pages(QEMUFile *f)
         }
         if (!p->pending_job) {
             p->pending_job++;
-            next_channel = (i + 1) % migrate_multifd_channels();
+            next_channel = (i + 1) % total_multifd_channels();
             break;
         }
         qemu_mutex_unlock(&p->mutex);
@@ -500,7 +500,7 @@ static void multifd_send_terminate_threads(Error *err)
         return;
     }
 
-    for (i = 0; i < migrate_multifd_channels(); i++) {
+    for (i = 0; i < total_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
         qemu_mutex_lock(&p->mutex);
@@ -521,14 +521,14 @@ void multifd_save_cleanup(void)
         return;
     }
     multifd_send_terminate_threads(NULL);
-    for (i = 0; i < migrate_multifd_channels(); i++) {
+    for (i = 0; i < total_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
         if (p->running) {
             qemu_thread_join(&p->thread);
         }
     }
-    for (i = 0; i < migrate_multifd_channels(); i++) {
+    for (i = 0; i < total_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
         Error *local_err = NULL;
 
@@ -594,7 +594,7 @@ int multifd_send_sync_main(QEMUFile *f)
 
     flush_zero_copy = migrate_use_zero_copy_send();
 
-    for (i = 0; i < migrate_multifd_channels(); i++) {
+    for (i = 0; i < total_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
         trace_multifd_send_sync_main_signal(p->id);
@@ -627,7 +627,7 @@ int multifd_send_sync_main(QEMUFile *f)
             }
         }
     }
-    for (i = 0; i < migrate_multifd_channels(); i++) {
+    for (i = 0; i < total_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
         trace_multifd_send_sync_main_wait(p->id);
@@ -903,7 +903,7 @@ int multifd_save_setup(Error **errp)
     int thread_count;
     uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
     uint8_t i;
-
+    int idx;
     if (!migrate_use_multifd()) {
         return 0;
     }
@@ -912,7 +912,7 @@ int multifd_save_setup(Error **errp)
         return -1;
     }
 
-    thread_count = migrate_multifd_channels();
+    thread_count = total_multifd_channels();
     multifd_send_state = g_malloc0(sizeof(*multifd_send_state));
     multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
     multifd_send_state->pages = multifd_pages_init(page_count);
@@ -945,8 +945,8 @@ int multifd_save_setup(Error **errp)
         } else {
             p->write_flags = 0;
         }
-
-        socket_send_channel_create(multifd_new_send_channel_async, p);
+        idx = multifd_index(i);
+        socket_send_channel_create(multifd_new_send_channel_async, p, idx);
     }
 
     for (i = 0; i < thread_count; i++) {
@@ -991,7 +991,7 @@ static void multifd_recv_terminate_threads(Error *err)
         }
     }
 
-    for (i = 0; i < migrate_multifd_channels(); i++) {
+    for (i = 0; i < total_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
         qemu_mutex_lock(&p->mutex);
@@ -1017,7 +1017,7 @@ int multifd_load_cleanup(Error **errp)
         return 0;
     }
     multifd_recv_terminate_threads(NULL);
-    for (i = 0; i < migrate_multifd_channels(); i++) {
+    for (i = 0; i < total_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
         if (p->running) {
@@ -1030,7 +1030,7 @@ int multifd_load_cleanup(Error **errp)
             qemu_thread_join(&p->thread);
         }
     }
-    for (i = 0; i < migrate_multifd_channels(); i++) {
+    for (i = 0; i < total_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
         migration_ioc_unregister_yank(p->c);
@@ -1065,13 +1065,13 @@ void multifd_recv_sync_main(void)
     if (!migrate_use_multifd()) {
         return;
     }
-    for (i = 0; i < migrate_multifd_channels(); i++) {
+    for (i = 0; i < total_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
         trace_multifd_recv_sync_main_wait(p->id);
         qemu_sem_wait(&multifd_recv_state->sem_sync);
     }
-    for (i = 0; i < migrate_multifd_channels(); i++) {
+    for (i = 0; i < total_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
         WITH_QEMU_LOCK_GUARD(&p->mutex) {
@@ -1166,7 +1166,7 @@ int multifd_load_setup(Error **errp)
         error_setg(errp, "multifd is not supported by current protocol");
         return -1;
     }
-    thread_count = migrate_multifd_channels();
+    thread_count = total_multifd_channels();
     multifd_recv_state = g_malloc0(sizeof(*multifd_recv_state));
     multifd_recv_state->params = g_new0(MultiFDRecvParams, thread_count);
     qatomic_set(&multifd_recv_state->count, 0);
@@ -1204,7 +1204,7 @@ int multifd_load_setup(Error **errp)
 
 bool multifd_recv_all_channels_created(void)
 {
-    int thread_count = migrate_multifd_channels();
+    int thread_count = total_multifd_channels();
 
     if (!migrate_use_multifd()) {
         return true;
@@ -1259,5 +1259,5 @@ bool multifd_recv_new_channel(QIOChannel *ioc, Error 
**errp)
                        QEMU_THREAD_JOINABLE);
     qatomic_inc(&multifd_recv_state->count);
     return qatomic_read(&multifd_recv_state->count) ==
-           migrate_multifd_channels();
+           total_multifd_channels();
 }
diff --git a/migration/socket.c b/migration/socket.c
index d0cb7cc6a6..c0ac6dbbe2 100644
--- a/migration/socket.c
+++ b/migration/socket.c
@@ -28,9 +28,6 @@
 #include "trace.h"
 
 
-struct SocketOutgoingArgs {
-    SocketAddress *saddr;
-} outgoing_args;
 
 struct SocketArgs {
     struct SrcDestAddr data;
@@ -43,20 +40,47 @@ struct OutgoingMigrateParams {
     uint64_t total_multifd_channel;
 } outgoing_migrate_params;
 
-void socket_send_channel_create(QIOTaskFunc f, void *data)
+
+int total_multifd_channels(void)
+{
+    return outgoing_migrate_params.total_multifd_channel;
+}
+
+int multifd_index(int i)
+{
+    int length = outgoing_migrate_params.length;
+    int j = 0;
+    int runn_sum = 0;
+    while (j < length) {
+        runn_sum += outgoing_migrate_params.socket_args[j].multifd_channels;
+        if (i >= runn_sum) {
+            j++;
+        } else {
+            break;
+        }
+    }
+    return j;
+}
+
+void socket_send_channel_create(QIOTaskFunc f, void *data, int idx)
 {
     QIOChannelSocket *sioc = qio_channel_socket_new();
-    qio_channel_socket_connect_async(sioc, outgoing_args.saddr,
-                                     f, data, NULL, NULL, NULL);
+    qio_channel_socket_connect_async(sioc,
+                       outgoing_migrate_params.socket_args[idx].data.dst_addr,
+                       f, data, NULL, NULL,
+                       outgoing_migrate_params.socket_args[idx].data.src_addr);
 }
 
 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;
+    if (outgoing_migrate_params.socket_args != NULL) {
+        g_free(outgoing_migrate_params.socket_args);
+        outgoing_migrate_params.socket_args = NULL;
+    }
+    if (outgoing_migrate_params.length) {
+        outgoing_migrate_params.length = 0;
     }
 
     if (outgoing_migrate_params.socket_args != NULL) {
diff --git a/migration/socket.h b/migration/socket.h
index b9e3699167..c8b9252384 100644
--- a/migration/socket.h
+++ b/migration/socket.h
@@ -27,7 +27,9 @@ struct SrcDestAddr {
     SocketAddress *src_addr;
 };
 
-void socket_send_channel_create(QIOTaskFunc f, void *data);
+int total_multifd_channels(void);
+int multifd_index(int i);
+void socket_send_channel_create(QIOTaskFunc f, void *data, int idx);
 int socket_send_channel_destroy(QIOChannel *send);
 
 void socket_start_incoming_migration(const char *str, uint8_t number,
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index 32a6b67d5f..9a3d76d6ba 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -1281,10 +1281,6 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict 
*qdict)
         p->has_block_incremental = true;
         visit_type_bool(v, param, &p->block_incremental, &err);
         break;
-    case MIGRATION_PARAMETER_MULTIFD_CHANNELS:
-        p->has_multifd_channels = true;
-        visit_type_uint8(v, param, &p->multifd_channels, &err);
-        break;
     case MIGRATION_PARAMETER_MULTIFD_COMPRESSION:
         p->has_multifd_compression = true;
         visit_type_MultiFDCompression(v, param, &p->multifd_compression,
diff --git a/qapi/migration.json b/qapi/migration.json
index 62a7b22d19..1b1c6d01d3 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -877,11 +877,6 @@
 #                     migrated and the destination must already have access to 
the
 #                     same backing chain as was used on the source.  (since 
2.10)
 #
-# @multifd-channels: Number of channels used to migrate data in
-#                    parallel. This is the same number that the
-#                    number of sockets used for migration.  The
-#                    default value is 2 (since 4.0)
-#
 # @xbzrle-cache-size: cache size to be used by XBZRLE migration.  It
 #                     needs to be a multiple of the target page size
 #                     and a power of 2
@@ -965,7 +960,6 @@
             '*x-checkpoint-delay': { 'type': 'uint32',
                                      'features': [ 'unstable' ] },
             '*block-incremental': 'bool',
-            '*multifd-channels': 'uint8',
             '*xbzrle-cache-size': 'size',
             '*max-postcopy-bandwidth': 'size',
             '*max-cpu-throttle': 'uint8',
-- 
2.22.3