Re: [Qemu-devel] [PATCH v6 18/19] migration: Transfer pages over new channels

["Daniel P. Berrange" <berrange@redhat.com>]

On Tue, Aug 08, 2017 at 06:26:28PM +0200, Juan Quintela wrote:
> 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       | 59 +++++++++++++++++----------------------------------
>  2 files changed, 25 insertions(+), 41 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 974ff92..aac3cdc 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -2051,6 +2051,7 @@ 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;
> @@ -2139,8 +2140,11 @@ 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;
> @@ -2160,6 +2164,7 @@ 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 42ad126..f337360 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -479,25 +479,21 @@ static void *multifd_send_thread(void *opaque)
>              break;
>          }
>          if (p->pages.num) {
> -            int i;
>              int num;
>  
>              num = p->pages.num;
>              p->pages.num = 0;
>              qemu_mutex_unlock(&p->mutex);
>  
> -            for (i = 0; i < num; i++) {
> -                if (qio_channel_write(p->c,
> -                                      (const char *)&p->pages.iov[i].iov_base,
> -                                      sizeof(uint8_t *), &error_abort)
> -                    != sizeof(uint8_t *)) {
> -                    MigrationState *s = migrate_get_current();
> +            if (qio_channel_writev_all(p->c, p->pages.iov,
> +                                       num, &error_abort)
> +                != num * TARGET_PAGE_SIZE) {

Again, should not be using error_abort - the error should be captured
so it cna be reported in any query-migrate QMP call.

> +                MigrationState *s = migrate_get_current();
>  
> -                    migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
> -                                      MIGRATION_STATUS_FAILED);
> -                    terminate_multifd_send_threads();
> -                    return NULL;
> -                }
> +                migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
> +                                  MIGRATION_STATUS_FAILED);
> +                terminate_multifd_send_threads();
> +                return NULL;
>              }
>              qemu_mutex_lock(&multifd_send_state->mutex);
>              p->done = true;
> @@ -658,7 +654,6 @@ void multifd_load_cleanup(void)
>  static void *multifd_recv_thread(void *opaque)
>  {
>      MultiFDRecvParams *p = opaque;
> -    uint8_t *recv_address;
>  
>      qemu_sem_post(&p->ready);
>      while (true) {
> @@ -668,38 +663,21 @@ static void *multifd_recv_thread(void *opaque)
>              break;
>          }
>          if (p->pages.num) {
> -            int i;
>              int num;
>  
>              num = p->pages.num;
>              p->pages.num = 0;
>  
> -            for (i = 0; i < num; i++) {
> -                if (qio_channel_read(p->c,
> -                                     (char *)&recv_address,
> -                                     sizeof(uint8_t *), &error_abort)
> -                    != sizeof(uint8_t *)) {
> -                    MigrationState *s = migrate_get_current();
> +            if (qio_channel_readv_all(p->c, p->pages.iov,
> +                                      num, &error_abort)
> +                != num * TARGET_PAGE_SIZE) {

Same note about error_abort usage.


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|