[Qemu-devel] [PATCH v5 07/17] migration: Create multifd migration threads

[Juan Quintela <quintela@redhat.com>]

Creation of the threads, nothing inside yet.

Signed-off-by: Juan Quintela <quintela@redhat.com>

--

Use pointers instead of long array names
Move to use semaphores instead of conditions as paolo suggestion

Put all the state inside one struct.
Use a counter for the number of threads created.  Needed during cancellation.

Add error return to thread creation

Add id field

Rename functions to multifd_save/load_setup/cleanup
---
 migration/migration.c |  14 ++++
 migration/ram.c       | 192 ++++++++++++++++++++++++++++++++++++++++++++++++++
 migration/ram.h       |   5 ++
 3 files changed, 211 insertions(+)

diff --git a/migration/migration.c b/migration/migration.c
index ff3fc9d..5a82c1c 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -288,6 +288,7 @@ static void process_incoming_migration_bh(void *opaque)
     } else {
         runstate_set(global_state_get_runstate());
     }
+    multifd_load_cleanup();
     /*
      * This must happen after any state changes since as soon as an external
      * observer sees this event they might start to prod at the VM assuming
@@ -348,6 +349,7 @@ static void process_incoming_migration_co(void *opaque)
         migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
                           MIGRATION_STATUS_FAILED);
         error_report("load of migration failed: %s", strerror(-ret));
+        multifd_load_cleanup();
         exit(EXIT_FAILURE);
     }
     mis->bh = qemu_bh_new(process_incoming_migration_bh, mis);
@@ -358,6 +360,11 @@ void migration_fd_process_incoming(QEMUFile *f)
 {
     Coroutine *co = qemu_coroutine_create(process_incoming_migration_co, f);
 
+    if (multifd_load_setup() != 0) {
+        /* We haven't been able to create multifd threads
+           nothing better to do */
+        exit(EXIT_FAILURE);
+    }
     qemu_file_set_blocking(f, false);
     qemu_coroutine_enter(co);
 }
@@ -860,6 +867,7 @@ static void migrate_fd_cleanup(void *opaque)
         }
         qemu_mutex_lock_iothread();
 
+        multifd_save_cleanup();
         qemu_fclose(s->to_dst_file);
         s->to_dst_file = NULL;
     }
@@ -2049,6 +2057,12 @@ void migrate_fd_connect(MigrationState *s)
         }
     }
 
+    if (multifd_save_setup() != 0) {
+        migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
+                          MIGRATION_STATUS_FAILED);
+        migrate_fd_cleanup(s);
+        return;
+    }
     qemu_thread_create(&s->thread, "live_migration", migration_thread, s,
                        QEMU_THREAD_JOINABLE);
     s->migration_thread_running = true;
diff --git a/migration/ram.c b/migration/ram.c
index 1b08296..8e87533 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -356,6 +356,198 @@ static void compress_threads_save_setup(void)
     }
 }
 
+/* Multiple fd's */
+
+struct MultiFDSendParams {
+    uint8_t id;
+    QemuThread thread;
+    QemuSemaphore sem;
+    QemuMutex mutex;
+    bool quit;
+};
+typedef struct MultiFDSendParams MultiFDSendParams;
+
+struct {
+    MultiFDSendParams *params;
+    /* number of created threads */
+    int count;
+} *multifd_send_state;
+
+static void terminate_multifd_send_threads(void)
+{
+    int i;
+
+    for (i = 0; i < multifd_send_state->count; i++) {
+        MultiFDSendParams *p = &multifd_send_state->params[i];
+
+        qemu_mutex_lock(&p->mutex);
+        p->quit = true;
+        qemu_sem_post(&p->sem);
+        qemu_mutex_unlock(&p->mutex);
+    }
+}
+
+void multifd_save_cleanup(void)
+{
+    int i;
+
+    if (!migrate_use_multifd()) {
+        return;
+    }
+    terminate_multifd_send_threads();
+    for (i = 0; i < multifd_send_state->count; i++) {
+        MultiFDSendParams *p = &multifd_send_state->params[i];
+
+        qemu_thread_join(&p->thread);
+        qemu_mutex_destroy(&p->mutex);
+        qemu_sem_destroy(&p->sem);
+    }
+    g_free(multifd_send_state->params);
+    multifd_send_state->params = NULL;
+    g_free(multifd_send_state);
+    multifd_send_state = NULL;
+}
+
+static void *multifd_send_thread(void *opaque)
+{
+    MultiFDSendParams *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_save_setup(void)
+{
+    int thread_count;
+    uint8_t i;
+
+    if (!migrate_use_multifd()) {
+        return 0;
+    }
+    thread_count = migrate_multifd_threads();
+    multifd_send_state = g_malloc0(sizeof(*multifd_send_state));
+    multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
+    multifd_send_state->count = 0;
+    for (i = 0; i < thread_count; i++) {
+        char thread_name[16];
+        MultiFDSendParams *p = &multifd_send_state->params[i];
+
+        qemu_mutex_init(&p->mutex);
+        qemu_sem_init(&p->sem, 0);
+        p->quit = false;
+        p->id = i;
+        snprintf(thread_name, sizeof(thread_name), "multifdsend_%d", i);
+        qemu_thread_create(&p->thread, thread_name, multifd_send_thread, p,
+                           QEMU_THREAD_JOINABLE);
+        multifd_send_state->count++;
+    }
+    return 0;
+}
+
+struct MultiFDRecvParams {
+    uint8_t id;
+    QemuThread thread;
+    QemuSemaphore sem;
+    QemuMutex mutex;
+    bool quit;
+};
+typedef struct MultiFDRecvParams MultiFDRecvParams;
+
+struct {
+    MultiFDRecvParams *params;
+    /* number of created threads */
+    int count;
+} *multifd_recv_state;
+
+static void terminate_multifd_recv_threads(void)
+{
+    int i;
+
+    for (i = 0; i < multifd_recv_state->count; i++) {
+        MultiFDRecvParams *p = &multifd_recv_state->params[i];
+
+        qemu_mutex_lock(&p->mutex);
+        p->quit = true;
+        qemu_sem_post(&p->sem);
+        qemu_mutex_unlock(&p->mutex);
+    }
+}
+
+void multifd_load_cleanup(void)
+{
+    int i;
+
+    if (!migrate_use_multifd()) {
+        return;
+    }
+    terminate_multifd_recv_threads();
+    for (i = 0; i < multifd_recv_state->count; i++) {
+        MultiFDRecvParams *p = &multifd_recv_state->params[i];
+
+        qemu_thread_join(&p->thread);
+        qemu_mutex_destroy(&p->mutex);
+        qemu_sem_destroy(&p->sem);
+    }
+    g_free(multifd_recv_state->params);
+    multifd_recv_state->params = NULL;
+    g_free(multifd_recv_state);
+    multifd_recv_state = NULL;
+}
+
+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;
+    }
+    thread_count = migrate_multifd_threads();
+    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++) {
+        char thread_name[16];
+        MultiFDRecvParams *p = &multifd_recv_state->params[i];
+
+        qemu_mutex_init(&p->mutex);
+        qemu_sem_init(&p->sem, 0);
+        p->quit = false;
+        p->id = i;
+        snprintf(thread_name, sizeof(thread_name), "multifdrecv_%d", i);
+        qemu_thread_create(&p->thread, thread_name, multifd_recv_thread, p,
+                           QEMU_THREAD_JOINABLE);
+        multifd_recv_state->count++;
+    }
+    return 0;
+}
+
 /**
  * save_page_header: write page header to wire
  *
diff --git a/migration/ram.h b/migration/ram.h
index c081fde..93c2bb4 100644
--- a/migration/ram.h
+++ b/migration/ram.h
@@ -39,6 +39,11 @@ int64_t xbzrle_cache_resize(int64_t new_size);
 uint64_t ram_bytes_remaining(void);
 uint64_t ram_bytes_total(void);
 
+int multifd_save_setup(void);
+void multifd_save_cleanup(void);
+int multifd_load_setup(void);
+void multifd_load_cleanup(void);
+
 uint64_t ram_pagesize_summary(void);
 int ram_save_queue_pages(const char *rbname, ram_addr_t start, ram_addr_t len);
 void acct_update_position(QEMUFile *f, size_t size, bool zero);
-- 
2.9.4