[Qemu-devel] [PATCH 11/13] migration: Create thread infrastructure for multifd recv side

[Juan Quintela <quintela@redhat.com>]

We make the locking and the transfer of information specific, even if we
are still receiving things through the main thread.

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/ram.c | 51 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 44 insertions(+), 7 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 47e208b..5507b1f 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -533,20 +533,37 @@ struct MultiFDRecvParams {
     QemuThread thread;
     QemuCond cond;
     QemuMutex mutex;
-    bool quit;
     int s;
+    /* proteced by param mutex */
+    bool quit;
+    uint8_t *address;
+    /* proteced by multifd mutex */
+    bool done;
 };
 typedef struct MultiFDRecvParams MultiFDRecvParams;

 static MultiFDRecvParams *multifd_recv;

+QemuMutex multifd_recv_mutex;
+QemuCond  multifd_recv_cond;
+
 static void *multifd_recv_thread(void *opaque)
 {
-    MultiFDSendParams *params = opaque;
+    MultiFDRecvParams *params = opaque;

     qemu_mutex_lock(&params->mutex);
     while (!params->quit){
-        qemu_cond_wait(&params->cond, &params->mutex);
+        if (params->address) {
+            params->address = 0;
+            qemu_mutex_unlock(&params->mutex);
+            qemu_mutex_lock(&multifd_recv_mutex);
+            params->done = true;
+            qemu_cond_signal(&multifd_recv_cond);
+            qemu_mutex_unlock(&multifd_recv_mutex);
+            qemu_mutex_lock(&params->mutex);
+        } else {
+            qemu_cond_wait(&params->cond, &params->mutex);
+        }
     }
     qemu_mutex_unlock(&params->mutex);

@@ -598,7 +615,9 @@ void migrate_multifd_recv_threads_create(void)
         qemu_mutex_init(&multifd_recv[i].mutex);
         qemu_cond_init(&multifd_recv[i].cond);
         multifd_recv[i].quit = false;
+        multifd_recv[i].done = true;
         multifd_recv[i].s = tcp_recv_channel_create();
+        multifd_recv[i].address = 0;

         if(multifd_recv[i].s < 0) {
             printf("Error creating a recv channel");
@@ -610,6 +629,27 @@ void migrate_multifd_recv_threads_create(void)
     }
 }

+static void multifd_recv_page(uint8_t *address, int fd_num)
+{
+    int thread_count;
+    MultiFDRecvParams *params;
+
+    thread_count = migrate_multifd_threads();
+    assert(fd_num < thread_count);
+    params = &multifd_recv[fd_num];
+
+    qemu_mutex_lock(&multifd_recv_mutex);
+    while (!params->done) {
+        qemu_cond_wait(&multifd_recv_cond, &multifd_recv_mutex);
+    }
+    params->done = false;
+    qemu_mutex_unlock(&multifd_recv_mutex);
+    qemu_mutex_lock(&params->mutex);
+    params->address = address;
+    qemu_cond_signal(&params->cond);
+    qemu_mutex_unlock(&params->mutex);
+}
+
 /**
  * save_page_header: Write page header to wire
  *
@@ -2785,10 +2825,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)

         case RAM_SAVE_FLAG_MULTIFD_PAGE:
             fd_num = qemu_get_be16(f);
-            if (fd_num == fd_num) {
-                /* this is yet an unused variable, changed later */
-                fd_num = 0;
-            }
+            multifd_recv_page(host, fd_num);
             qemu_get_buffer(f, host, TARGET_PAGE_SIZE);
             break;

-- 
2.5.5