migration: Put thread names together with macros

Keep migration thread names together, so it's easier to see a list of all
possible migration threads.

Still two functional changes below besides the macro defintions:

  - There's one dirty rate thread that we overlooked before, now we add
  that too and name it as "mig/dirtyrate" following the old rules.

  - The old name "mig/src/rp-thr" has "-thr" but it may not be useful if
  it's a thread name anyway, while "rp" can be slightly hard to read.
  Taking this chance to rename it to "mig/src/return", hopefully a better
  name.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Acked-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Link: https://lore.kernel.org/r/20241011153652.517440-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>

migration/colo.c

@@ -935,7 +935,8 @@ void coroutine_fn colo_incoming_co(void)
     assert(bql_locked());
     assert(migration_incoming_colo_enabled());
 
-    qemu_thread_create(&th, "mig/dst/colo", colo_process_incoming_thread,
+    qemu_thread_create(&th, MIGRATION_THREAD_DST_COLO,
+                       colo_process_incoming_thread,
                        mis, QEMU_THREAD_JOINABLE);
 
     mis->colo_incoming_co = qemu_coroutine_self();

migration/dirtyrate.c

@@ -29,6 +29,7 @@
 #include "sysemu/runstate.h"
 #include "exec/memory.h"
 #include "qemu/xxhash.h"
+#include "migration.h"
 
 /*
  * total_dirty_pages is procted by BQL and is used
@@ -839,8 +840,9 @@ void qmp_calc_dirty_rate(int64_t calc_time,
 
     init_dirtyrate_stat(config);
 
-    qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread,
-                       (void *)&config, QEMU_THREAD_DETACHED);
+    qemu_thread_create(&thread, MIGRATION_THREAD_DIRTY_RATE,
+                       get_dirtyrate_thread, (void *)&config,
+                       QEMU_THREAD_DETACHED);
 }
 
 

migration/migration.c

@@ -2484,7 +2484,7 @@ static int open_return_path_on_source(MigrationState *ms)
 
     trace_open_return_path_on_source();
 
-    qemu_thread_create(&ms->rp_state.rp_thread, "mig/src/rp-thr",
+    qemu_thread_create(&ms->rp_state.rp_thread, MIGRATION_THREAD_SRC_RETURN,
                        source_return_path_thread, ms, QEMU_THREAD_JOINABLE);
     ms->rp_state.rp_thread_created = true;
 
@@ -3473,7 +3473,8 @@ static void *migration_thread(void *opaque)
     Error *local_err = NULL;
     int ret;
 
-    thread = migration_threads_add("live_migration", qemu_get_thread_id());
+    thread = migration_threads_add(MIGRATION_THREAD_SRC_MAIN,
+                                   qemu_get_thread_id());
 
     rcu_register_thread();
 
@@ -3823,10 +3824,10 @@ void migrate_fd_connect(MigrationState *s, Error *error_in)
     }
 
     if (migrate_background_snapshot()) {
-        qemu_thread_create(&s->thread, "mig/snapshot",
+        qemu_thread_create(&s->thread, MIGRATION_THREAD_SNAPSHOT,
                 bg_migration_thread, s, QEMU_THREAD_JOINABLE);
     } else {
-        qemu_thread_create(&s->thread, "mig/src/main",
+        qemu_thread_create(&s->thread, MIGRATION_THREAD_SRC_MAIN,
                 migration_thread, s, QEMU_THREAD_JOINABLE);
     }
     s->migration_thread_running = true;

migration/migration.h

@@ -28,6 +28,20 @@
 #include "sysemu/runstate.h"
 #include "migration/misc.h"
 
+#define  MIGRATION_THREAD_SNAPSHOT          "mig/snapshot"
+#define  MIGRATION_THREAD_DIRTY_RATE        "mig/dirtyrate"
+
+#define  MIGRATION_THREAD_SRC_MAIN          "mig/src/main"
+#define  MIGRATION_THREAD_SRC_MULTIFD       "mig/src/send_%d"
+#define  MIGRATION_THREAD_SRC_RETURN        "mig/src/return"
+#define  MIGRATION_THREAD_SRC_TLS           "mig/src/tls"
+
+#define  MIGRATION_THREAD_DST_COLO          "mig/dst/colo"
+#define  MIGRATION_THREAD_DST_MULTIFD       "mig/src/recv_%d"
+#define  MIGRATION_THREAD_DST_FAULT         "mig/dst/fault"
+#define  MIGRATION_THREAD_DST_LISTEN        "mig/dst/listen"
+#define  MIGRATION_THREAD_DST_PREEMPT       "mig/dst/preempt"
+
 struct PostcopyBlocktimeContext;
 
 #define  MIGRATION_RESUME_ACK_VALUE  (1)

migration/multifd.c

@@ -723,7 +723,7 @@ static bool multifd_tls_channel_connect(MultiFDSendParams *p,
     args->p = p;
 
     p->tls_thread_created = true;
-    qemu_thread_create(&p->tls_thread, "mig/src/tls",
+    qemu_thread_create(&p->tls_thread, MIGRATION_THREAD_SRC_TLS,
                        multifd_tls_handshake_thread, args,
                        QEMU_THREAD_JOINABLE);
     return true;
@@ -841,7 +841,7 @@ bool multifd_send_setup(void)
                           + sizeof(uint64_t) * page_count;
             p->packet = g_malloc0(p->packet_len);
         }
-        p->name = g_strdup_printf("mig/src/send_%d", i);
+        p->name = g_strdup_printf(MIGRATION_THREAD_SRC_MULTIFD, i);
         p->write_flags = 0;
 
         if (!multifd_new_send_channel_create(p, &local_err)) {
@@ -1259,7 +1259,7 @@ int multifd_recv_setup(Error **errp)
                 + sizeof(uint64_t) * page_count;
             p->packet = g_malloc0(p->packet_len);
         }
-        p->name = g_strdup_printf("mig/dst/recv_%d", i);
+        p->name = g_strdup_printf(MIGRATION_THREAD_DST_MULTIFD, i);
         p->normal = g_new0(ram_addr_t, page_count);
         p->zero = g_new0(ram_addr_t, page_count);
     }

migration/postcopy-ram.c

@@ -1230,7 +1230,8 @@ int postcopy_ram_incoming_setup(MigrationIncomingState *mis)
         return -1;
     }
 
-    postcopy_thread_create(mis, &mis->fault_thread, "mig/dst/fault",
+    postcopy_thread_create(mis, &mis->fault_thread,
+                           MIGRATION_THREAD_DST_FAULT,
                            postcopy_ram_fault_thread, QEMU_THREAD_JOINABLE);
     mis->have_fault_thread = true;
 
@@ -1250,7 +1251,8 @@ int postcopy_ram_incoming_setup(MigrationIncomingState *mis)
          * This thread needs to be created after the temp pages because
          * it'll fetch RAM_CHANNEL_POSTCOPY PostcopyTmpPage immediately.
          */
-        postcopy_thread_create(mis, &mis->postcopy_prio_thread, "mig/dst/preempt",
+        postcopy_thread_create(mis, &mis->postcopy_prio_thread,
+                               MIGRATION_THREAD_DST_PREEMPT,
                                postcopy_preempt_thread, QEMU_THREAD_JOINABLE);
         mis->preempt_thread_status = PREEMPT_THREAD_CREATED;
     }

migration/savevm.c

@@ -2131,7 +2131,8 @@ static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis)
     }
 
     mis->have_listen_thread = true;
-    postcopy_thread_create(mis, &mis->listen_thread, "mig/dst/listen",
+    postcopy_thread_create(mis, &mis->listen_thread,
+                           MIGRATION_THREAD_DST_LISTEN,
                            postcopy_ram_listen_thread, QEMU_THREAD_DETACHED);
     trace_loadvm_postcopy_handle_listen("return");