[Qemu-devel] [PATCH v12 03/21] migration: terminate_* can be called for other threads

[Juan Quintela]

Once there, make  count field to always be accessed with atomic
operations.  To make blocking operations, we need to know that the
thread is running, so create a bool to indicate that.

Signed-off-by: Juan Quintela <address@hidden>
Reviewed-by: Daniel P. Berrangé <address@hidden>

--

Once here, s/terminate_multifd_*-threads/multifd_*_terminate_threads/
This is consistente with every other function
---
 migration/ram.c | 44 ++++++++++++++++++++++++++++++--------------
 1 file changed, 30 insertions(+), 14 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index c3c330b0e0..c0ad6d8e9f 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -406,6 +406,7 @@ struct MultiFDSendParams {
     QemuThread thread;
     QemuSemaphore sem;
     QemuMutex mutex;
+    bool running;
     bool quit;
 };
 typedef struct MultiFDSendParams MultiFDSendParams;
@@ -416,7 +417,7 @@ struct {
     int count;
 } *multifd_send_state;
 
-static void terminate_multifd_send_threads(Error *err)
+static void multifd_send_terminate_threads(Error *err)
 {
     int i;
 
@@ -430,7 +431,7 @@ static void terminate_multifd_send_threads(Error *err)
         }
     }
 
-    for (i = 0; i < multifd_send_state->count; i++) {
+    for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
         qemu_mutex_lock(&p->mutex);
@@ -448,11 +449,13 @@ int multifd_save_cleanup(Error **errp)
     if (!migrate_use_multifd()) {
         return 0;
     }
-    terminate_multifd_send_threads(NULL);
-    for (i = 0; i < multifd_send_state->count; i++) {
+    multifd_send_terminate_threads(NULL);
+    for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
-        qemu_thread_join(&p->thread);
+        if (p->running) {
+            qemu_thread_join(&p->thread);
+        }
         qemu_mutex_destroy(&p->mutex);
         qemu_sem_destroy(&p->sem);
         g_free(p->name);
@@ -479,6 +482,10 @@ static void *multifd_send_thread(void *opaque)
         qemu_sem_wait(&p->sem);
     }
 
+    qemu_mutex_lock(&p->mutex);
+    p->running = false;
+    qemu_mutex_unlock(&p->mutex);
+
     return NULL;
 }
 
@@ -493,7 +500,7 @@ int multifd_save_setup(void)
     thread_count = migrate_multifd_channels();
     multifd_send_state = g_malloc0(sizeof(*multifd_send_state));
     multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
-    multifd_send_state->count = 0;
+    atomic_set(&multifd_send_state->count, 0);
     for (i = 0; i < thread_count; i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
@@ -502,10 +509,11 @@ int multifd_save_setup(void)
         p->quit = false;
         p->id = i;
         p->name = g_strdup_printf("multifdsend_%d", i);
+        p->running = true;
         qemu_thread_create(&p->thread, p->name, multifd_send_thread, p,
                            QEMU_THREAD_JOINABLE);
 
-        multifd_send_state->count++;
+        atomic_inc(&multifd_send_state->count);
     }
     return 0;
 }
@@ -516,6 +524,7 @@ struct MultiFDRecvParams {
     QemuThread thread;
     QemuSemaphore sem;
     QemuMutex mutex;
+    bool running;
     bool quit;
 };
 typedef struct MultiFDRecvParams MultiFDRecvParams;
@@ -526,7 +535,7 @@ struct {
     int count;
 } *multifd_recv_state;
 
-static void terminate_multifd_recv_threads(Error *err)
+static void multifd_recv_terminate_threads(Error *err)
 {
     int i;
 
@@ -540,7 +549,7 @@ static void terminate_multifd_recv_threads(Error *err)
         }
     }
 
-    for (i = 0; i < multifd_recv_state->count; i++) {
+    for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
         qemu_mutex_lock(&p->mutex);
@@ -558,11 +567,13 @@ int multifd_load_cleanup(Error **errp)
     if (!migrate_use_multifd()) {
         return 0;
     }
-    terminate_multifd_recv_threads(NULL);
-    for (i = 0; i < multifd_recv_state->count; i++) {
+    multifd_recv_terminate_threads(NULL);
+    for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
-        qemu_thread_join(&p->thread);
+        if (p->running) {
+            qemu_thread_join(&p->thread);
+        }
         qemu_mutex_destroy(&p->mutex);
         qemu_sem_destroy(&p->sem);
         g_free(p->name);
@@ -590,6 +601,10 @@ static void *multifd_recv_thread(void *opaque)
         qemu_sem_wait(&p->sem);
     }
 
+    qemu_mutex_lock(&p->mutex);
+    p->running = false;
+    qemu_mutex_unlock(&p->mutex);
+
     return NULL;
 }
 
@@ -604,7 +619,7 @@ int multifd_load_setup(void)
     thread_count = migrate_multifd_channels();
     multifd_recv_state = g_malloc0(sizeof(*multifd_recv_state));
     multifd_recv_state->params = g_new0(MultiFDRecvParams, thread_count);
-    multifd_recv_state->count = 0;
+    atomic_set(&multifd_recv_state->count, 0);
     for (i = 0; i < thread_count; i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];
 
@@ -613,9 +628,10 @@ int multifd_load_setup(void)
         p->quit = false;
         p->id = i;
         p->name = g_strdup_printf("multifdrecv_%d", i);
+        p->running = true;
         qemu_thread_create(&p->thread, p->name, multifd_recv_thread, p,
                            QEMU_THREAD_JOINABLE);
-        multifd_recv_state->count++;
+        atomic_inc(&multifd_recv_state->count);
     }
     return 0;
 }
-- 
2.17.0