[Qemu-devel] [PATCH v8 19/20] migration: Transfer pages over new channels

[Juan Quintela <quintela@redhat.com>]

We switch for sending the page number to send real pages.

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

--

Remove the HACK bit, now we have the function that calculates the size
of a page exported.
---
 migration/migration.c |  7 ++++++-
 migration/ram.c       | 39 +++++++++++----------------------------
 2 files changed, 17 insertions(+), 29 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 67f3375ddc..b26b987fe9 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2072,6 +2072,7 @@ static void *migration_thread(void *opaque)
      */
     int64_t threshold_size = 0;
     int64_t qemu_file_bytes = 0;
+    int64_t multifd_pages = 0;
     int64_t start_time = initial_time;
     int64_t end_time;
     bool old_vm_running = false;
@@ -2160,8 +2161,11 @@ static void *migration_thread(void *opaque)
         current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
         if (current_time >= initial_time + BUFFER_DELAY) {
             uint64_t qemu_file_bytes_now = qemu_ftell(s->to_dst_file);
+            uint64_t multifd_pages_now = ram_counters.multifd;
             uint64_t transferred_bytes =
-                qemu_file_bytes_now - qemu_file_bytes;
+                (qemu_file_bytes_now - qemu_file_bytes) +
+                (multifd_pages_now - multifd_pages) *
+                qemu_target_page_size();
             uint64_t time_spent = current_time - initial_time;
             double bandwidth = (double)transferred_bytes / time_spent;
             threshold_size = bandwidth * s->parameters.downtime_limit;
@@ -2181,6 +2185,7 @@ static void *migration_thread(void *opaque)
             qemu_file_reset_rate_limit(s->to_dst_file);
             initial_time = current_time;
             qemu_file_bytes = qemu_file_bytes_now;
+            multifd_pages = multifd_pages_now;
         }
         if (qemu_file_rate_limit(s->to_dst_file)) {
             /* usleep expects microseconds */
diff --git a/migration/ram.c b/migration/ram.c
index 1b1e346ae0..2d89d4e39f 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -498,21 +498,15 @@ static void *multifd_send_thread(void *opaque)
         if (p->pages.num) {
             Error *local_err = NULL;
             size_t ret;
-            int i;
             int num;
 
             num = p->pages.num;
             p->pages.num = 0;
             qemu_mutex_unlock(&p->mutex);
-
-            for (i = 0; i < num; i++) {
-                ret = qio_channel_write_all(p->c,
-                         (const char *)&p->pages.iov[i].iov_base,
-                         sizeof(uint8_t *), &local_err);
-                if (ret != 0) {
-                    terminate_multifd_send_threads(local_err);
-                    return NULL;
-                }
+            ret = qio_channel_writev_all(p->c, p->pages.iov, num, &local_err);
+            if (ret != 0) {
+                terminate_multifd_send_threads(local_err);
+                return NULL;
             }
             qemu_mutex_lock(&multifd_send_state->mutex);
             p->done = true;
@@ -695,7 +689,6 @@ int multifd_load_cleanup(Error **errp)
 static void *multifd_recv_thread(void *opaque)
 {
     MultiFDRecvParams *p = opaque;
-    uint8_t *recv_address;
 
     qemu_sem_post(&p->ready);
     while (true) {
@@ -707,27 +700,16 @@ static void *multifd_recv_thread(void *opaque)
         if (p->pages.num) {
             Error *local_err = NULL;
             size_t ret;
-            int i;
             int num;
 
             num = p->pages.num;
             p->pages.num = 0;
 
-            for (i = 0; i < num; i++) {
-                ret = qio_channel_read_all(p->c, (char *)&recv_address,
-                                           sizeof(uint8_t *), &local_err);
-                if (ret != 0) {
-                    terminate_multifd_recv_threads(local_err);
-                    return NULL;
-                }
-                if (recv_address != p->pages.iov[i].iov_base) {
-                    error_setg(&local_err, "received %p and expecting %p (%d)",
-                               recv_address, p->pages.iov[i].iov_base, i);
-                    terminate_multifd_recv_threads(local_err);
-                    return NULL;
-                }
+            ret = qio_channel_readv_all(p->c, p->pages.iov, num, &local_err);
+            if (ret != 0) {
+                terminate_multifd_recv_threads(local_err);
+                return NULL;
             }
-
             p->done = true;
             qemu_mutex_unlock(&p->mutex);
             qemu_sem_post(&p->ready);
@@ -1289,8 +1271,10 @@ static int ram_multifd_page(RAMState *rs, PageSearchStatus *pss,
                              offset | RAM_SAVE_FLAG_MULTIFD_PAGE);
         fd_num = multifd_send_page(p, rs->migration_dirty_pages == 1);
         qemu_put_be16(rs->f, fd_num);
+        if (fd_num != MULTIFD_CONTINUE) {
+            qemu_fflush(rs->f);
+        }
         ram_counters.transferred += 2; /* size of fd_num */
-        qemu_put_buffer(rs->f, p, TARGET_PAGE_SIZE);
         ram_counters.transferred += TARGET_PAGE_SIZE;
         pages = 1;
         ram_counters.normal++;
@@ -3153,7 +3137,6 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
         case RAM_SAVE_FLAG_MULTIFD_PAGE:
             fd_num = qemu_get_be16(f);
             multifd_recv_page(host, fd_num);
-            qemu_get_buffer(f, host, TARGET_PAGE_SIZE);
             break;
 
         case RAM_SAVE_FLAG_EOS:
-- 
2.13.5