Re: [Qemu-devel] [PATCH V7 RESEND 04/17] COLO: integrate colo compare with colo frame

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Zhang Chen (zhangckid@gmail.com) wrote:
> For COLO FT, both the PVM and SVM run at the same time,
> only sync the state while it needs.
> 
> So here, let SVM runs while not doing checkpoint, change
> DEFAULT_MIGRATE_X_CHECKPOINT_DELAY to 200*100.
> 
> Besides, we forgot to release colo_checkpoint_semd and
> colo_delay_timer, fix them here.
> 
> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
> Signed-off-by: Zhang Chen <zhangckid@gmail.com>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>  migration/colo.c      | 42 ++++++++++++++++++++++++++++++++++++++++--
>  migration/migration.c |  4 ++--
>  2 files changed, 42 insertions(+), 4 deletions(-)
> 
> diff --git a/migration/colo.c b/migration/colo.c
> index 4381067ed4..081df1835f 100644
> --- a/migration/colo.c
> +++ b/migration/colo.c
> @@ -25,8 +25,11 @@
>  #include "qemu/error-report.h"
>  #include "migration/failover.h"
>  #include "replication.h"
> +#include "net/colo-compare.h"
> +#include "net/colo.h"
>  
>  static bool vmstate_loading;
> +static Notifier packets_compare_notifier;
>  
>  #define COLO_BUFFER_BASE_SIZE (4 * 1024 * 1024)
>  
> @@ -343,6 +346,11 @@ static int colo_do_checkpoint_transaction(MigrationState *s,
>          goto out;
>      }
>  
> +    colo_notify_compares_event(NULL, COLO_EVENT_CHECKPOINT, &local_err);
> +    if (local_err) {
> +        goto out;
> +    }
> +
>      /* Disable block migration */
>      migrate_set_block_enabled(false, &local_err);
>      qemu_savevm_state_header(fb);
> @@ -400,6 +408,11 @@ out:
>      return ret;
>  }
>  
> +static void colo_compare_notify_checkpoint(Notifier *notifier, void *data)
> +{
> +    colo_checkpoint_notify(data);
> +}
> +
>  static void colo_process_checkpoint(MigrationState *s)
>  {
>      QIOChannelBuffer *bioc;
> @@ -416,6 +429,9 @@ static void colo_process_checkpoint(MigrationState *s)
>          goto out;
>      }
>  
> +    packets_compare_notifier.notify = colo_compare_notify_checkpoint;
> +    colo_compare_register_notifier(&packets_compare_notifier);
> +
>      /*
>       * Wait for Secondary finish loading VM states and enter COLO
>       * restore.
> @@ -461,11 +477,21 @@ out:
>          qemu_fclose(fb);
>      }
>  
> -    timer_del(s->colo_delay_timer);
> -
>      /* Hope this not to be too long to wait here */
>      qemu_sem_wait(&s->colo_exit_sem);
>      qemu_sem_destroy(&s->colo_exit_sem);
> +
> +    /*
> +     * It is safe to unregister notifier after failover finished.
> +     * Besides, colo_delay_timer and colo_checkpoint_sem can't be
> +     * released befor unregister notifier, or there will be use-after-free
> +     * error.
> +     */
> +    colo_compare_unregister_notifier(&packets_compare_notifier);
> +    timer_del(s->colo_delay_timer);
> +    timer_free(s->colo_delay_timer);
> +    qemu_sem_destroy(&s->colo_checkpoint_sem);
> +
>      /*
>       * Must be called after failover BH is completed,
>       * Or the failover BH may shutdown the wrong fd that
> @@ -558,6 +584,11 @@ void *colo_process_incoming_thread(void *opaque)
>      fb = qemu_fopen_channel_input(QIO_CHANNEL(bioc));
>      object_unref(OBJECT(bioc));
>  
> +    qemu_mutex_lock_iothread();
> +    vm_start();
> +    trace_colo_vm_state_change("stop", "run");
> +    qemu_mutex_unlock_iothread();
> +
>      colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_READY,
>                        &local_err);
>      if (local_err) {
> @@ -577,6 +608,11 @@ void *colo_process_incoming_thread(void *opaque)
>              goto out;
>          }
>  
> +        qemu_mutex_lock_iothread();
> +        vm_stop_force_state(RUN_STATE_COLO);
> +        trace_colo_vm_state_change("run", "stop");
> +        qemu_mutex_unlock_iothread();
> +
>          /* FIXME: This is unnecessary for periodic checkpoint mode */
>          colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_REPLY,
>                       &local_err);
> @@ -630,6 +666,8 @@ void *colo_process_incoming_thread(void *opaque)
>          }
>  
>          vmstate_loading = false;
> +        vm_start();
> +        trace_colo_vm_state_change("stop", "run");
>          qemu_mutex_unlock_iothread();
>  
>          if (failover_get_state() == FAILOVER_STATUS_RELAUNCH) {
> diff --git a/migration/migration.c b/migration/migration.c
> index 35f2781b03..bca187275a 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -76,9 +76,9 @@
>  #define DEFAULT_MIGRATE_XBZRLE_CACHE_SIZE (64 * 1024 * 1024)
>  
>  /* The delay time (in ms) between two COLO checkpoints
> - * Note: Please change this default value to 10000 when we support hybrid mode.
> + * Note: Please change this default value to 20000 when we support hybrid mode.

You can remove that comment now?

Dave

>   */
> -#define DEFAULT_MIGRATE_X_CHECKPOINT_DELAY 200
> +#define DEFAULT_MIGRATE_X_CHECKPOINT_DELAY (200 * 100)
>  #define DEFAULT_MIGRATE_MULTIFD_CHANNELS 2
>  #define DEFAULT_MIGRATE_MULTIFD_PAGE_COUNT 16
>  
> -- 
> 2.17.0
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK