diff mbox

[v7,14/42] Return path: Send responses from destination to source

Message ID 1434450415-11339-15-git-send-email-dgilbert@redhat.com
State New
Headers show

Commit Message

Dr. David Alan Gilbert June 16, 2015, 10:26 a.m. UTC 
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Add migrate_send_rp_message to send a message from destination to source along the return path.
  (It uses a mutex to let it be called from multiple threads)
Add migrate_send_rp_shut to send a 'shut' message to indicate
  the destination is finished with the RP.
Add migrate_send_rp_ack to send a 'PONG' message in response to a PING
  Use it in the MSG_RP_PING handler

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 include/migration/migration.h | 17 ++++++++++++++++
 migration/migration.c         | 45 +++++++++++++++++++++++++++++++++++++++++++
 migration/savevm.c            |  2 +-
 trace-events                  |  1 +
 4 files changed, 64 insertions(+), 1 deletion(-)

Comments

Juan Quintela June 17, 2015, 4:30 p.m. UTC | #1 
"Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>
> Add migrate_send_rp_message to send a message from destination to source along the return path.
>   (It uses a mutex to let it be called from multiple threads)
> Add migrate_send_rp_shut to send a 'shut' message to indicate
>   the destination is finished with the RP.
> Add migrate_send_rp_ack to send a 'PONG' message in response to a PING
>   Use it in the MSG_RP_PING handler
>
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>  include/migration/migration.h | 17 ++++++++++++++++
>  migration/migration.c         | 45 +++++++++++++++++++++++++++++++++++++++++++
>  migration/savevm.c            |  2 +-
>  trace-events                  |  1 +
>  4 files changed, 64 insertions(+), 1 deletion(-)
>
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index 65fe5db..36caab9 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -42,12 +42,20 @@ struct MigrationParams {
>      bool shared;
>  };
>  
> +/* Messages sent on the return path from destination to source */
> +enum mig_rp_message_type {
> +    MIG_RP_MSG_INVALID = 0,  /* Must be 0 */
> +    MIG_RP_MSG_SHUT,         /* sibling will not send any more RP messages */
> +    MIG_RP_MSG_PONG,         /* Response to a PING; data (seq: be32 ) */
> +};
> +
>  typedef QLIST_HEAD(, LoadStateEntry) LoadStateEntry_Head;
>  /* State for the incoming migration */
>  struct MigrationIncomingState {
>      QEMUFile *file;
>  
>      QEMUFile *return_path;
> +    QemuMutex      rp_mutex;    /* We send replies from multiple threads */
>  
>      /* See savevm.c */
>      LoadStateEntry_Head loadvm_handlers;
> @@ -179,6 +187,15 @@ int migrate_compress_level(void);
>  int migrate_compress_threads(void);
>  int migrate_decompress_threads(void);
>  
> +/* Sending on the return path - generic and then for each message type */
> +void migrate_send_rp_message(MigrationIncomingState *mis,
> +                             enum mig_rp_message_type message_type,
> +                             uint16_t len, void *data);
> +void migrate_send_rp_shut(MigrationIncomingState *mis,
> +                          uint32_t value);
> +void migrate_send_rp_pong(MigrationIncomingState *mis,
> +                          uint32_t value);
> +
>  void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
>  void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
>  void ram_control_load_hook(QEMUFile *f, uint64_t flags);
> diff --git a/migration/migration.c b/migration/migration.c
> index 295f15a..afb19a1 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -85,6 +85,7 @@ MigrationIncomingState *migration_incoming_state_new(QEMUFile* f)
>      mis_current = g_malloc0(sizeof(MigrationIncomingState));
>      mis_current->file = f;
>      QLIST_INIT(&mis_current->loadvm_handlers);
> +    qemu_mutex_init(&mis_current->rp_mutex);
>  
>      return mis_current;
>  }
> @@ -182,6 +183,50 @@ void process_incoming_migration(QEMUFile *f)
>      qemu_coroutine_enter(co, f);
>  }
>  
> +/*
> + * Send a message on the return channel back to the source
> + * of the migration.
> + */
> +void migrate_send_rp_message(MigrationIncomingState *mis,
> +                             enum mig_rp_message_type message_type,
> +                             uint16_t len, void *data)
> +{
> +    trace_migrate_send_rp_message((int)message_type, len);
> +    qemu_mutex_lock(&mis->rp_mutex);
> +    qemu_put_be16(mis->return_path, (unsigned int)message_type);
> +    qemu_put_be16(mis->return_path, len);
if (len) {

> +    qemu_put_buffer(mis->return_path, data, len);
}


?

We check for zero sized command on control commands but not on
responses?

> +    qemu_fflush(mis->return_path);
> +    qemu_mutex_unlock(&mis->rp_mutex);
> +}
> +
> +/*
> + * Send a 'SHUT' message on the return channel with the given value
> + * to indicate that we've finished with the RP.  Non-0 value indicates
> + * error.
> + */
> +void migrate_send_rp_shut(MigrationIncomingState *mis,
> +                          uint32_t value)
> +{
> +    uint32_t buf;
> +
> +    buf = cpu_to_be32(value);
> +    migrate_send_rp_message(mis, MIG_RP_MSG_SHUT, sizeof(buf), &buf);
> +}
> +
> +/*
> + * Send a 'PONG' message on the return channel with the given value
> + * (normally in response to a 'PING')
> + */
> +void migrate_send_rp_pong(MigrationIncomingState *mis,
> +                          uint32_t value)
> +{
> +    uint32_t buf;
> +
> +    buf = cpu_to_be32(value);
> +    migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf);
> +}
> +
>  /* amount of nanoseconds we are willing to wait for migration to be down.
>   * the choice of nanoseconds is because it is the maximum resolution that
>   * get_clock() can achieve. It is an internal measure. All user-visible
> diff --git a/migration/savevm.c b/migration/savevm.c
> index a995014..d424c2a 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -1071,7 +1071,7 @@ static int loadvm_process_command(QEMUFile *f)
>                           tmp32);
>              return -1;
>          }
> -        /* migrate_send_rp_pong(mis, tmp32); TODO: gets added later */
> +        migrate_send_rp_pong(mis, tmp32);
>          break;
>  
>      default:
> diff --git a/trace-events b/trace-events
> index 5967fdf..5738e3f 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -1399,6 +1399,7 @@ migrate_fd_cleanup(void) ""
>  migrate_fd_error(void) ""
>  migrate_fd_cancel(void) ""
>  migrate_pending(uint64_t size, uint64_t max) "pending size %" PRIu64 " max %" PRIu64
> +migrate_send_rp_message(int msg_type, uint16_t len) "%d: len %d"
>  migrate_transferred(uint64_t tranferred, uint64_t time_spent, double bandwidth, uint64_t size) "transferred %" PRIu64 " time_spent %" PRIu64 " bandwidth %g max_size %" PRId64
>  
>  # migration/rdma.c
Dr. David Alan Gilbert June 19, 2015, 6:42 p.m. UTC | #2 
* Juan Quintela (quintela@redhat.com) wrote:
> "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote:
> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> >
> > Add migrate_send_rp_message to send a message from destination to source along the return path.
> >   (It uses a mutex to let it be called from multiple threads)
> > Add migrate_send_rp_shut to send a 'shut' message to indicate
> >   the destination is finished with the RP.
> > Add migrate_send_rp_ack to send a 'PONG' message in response to a PING
> >   Use it in the MSG_RP_PING handler
> >
> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > ---
> >  include/migration/migration.h | 17 ++++++++++++++++
> >  migration/migration.c         | 45 +++++++++++++++++++++++++++++++++++++++++++
> >  migration/savevm.c            |  2 +-
> >  trace-events                  |  1 +
> >  4 files changed, 64 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/migration/migration.h b/include/migration/migration.h
> > index 65fe5db..36caab9 100644
> > --- a/include/migration/migration.h
> > +++ b/include/migration/migration.h
> > @@ -42,12 +42,20 @@ struct MigrationParams {
> >      bool shared;
> >  };
> >  
> > +/* Messages sent on the return path from destination to source */
> > +enum mig_rp_message_type {
> > +    MIG_RP_MSG_INVALID = 0,  /* Must be 0 */
> > +    MIG_RP_MSG_SHUT,         /* sibling will not send any more RP messages */
> > +    MIG_RP_MSG_PONG,         /* Response to a PING; data (seq: be32 ) */
> > +};
> > +
> >  typedef QLIST_HEAD(, LoadStateEntry) LoadStateEntry_Head;
> >  /* State for the incoming migration */
> >  struct MigrationIncomingState {
> >      QEMUFile *file;
> >  
> >      QEMUFile *return_path;
> > +    QemuMutex      rp_mutex;    /* We send replies from multiple threads */
> >  
> >      /* See savevm.c */
> >      LoadStateEntry_Head loadvm_handlers;
> > @@ -179,6 +187,15 @@ int migrate_compress_level(void);
> >  int migrate_compress_threads(void);
> >  int migrate_decompress_threads(void);
> >  
> > +/* Sending on the return path - generic and then for each message type */
> > +void migrate_send_rp_message(MigrationIncomingState *mis,
> > +                             enum mig_rp_message_type message_type,
> > +                             uint16_t len, void *data);
> > +void migrate_send_rp_shut(MigrationIncomingState *mis,
> > +                          uint32_t value);
> > +void migrate_send_rp_pong(MigrationIncomingState *mis,
> > +                          uint32_t value);
> > +
> >  void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
> >  void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
> >  void ram_control_load_hook(QEMUFile *f, uint64_t flags);
> > diff --git a/migration/migration.c b/migration/migration.c
> > index 295f15a..afb19a1 100644
> > --- a/migration/migration.c
> > +++ b/migration/migration.c
> > @@ -85,6 +85,7 @@ MigrationIncomingState *migration_incoming_state_new(QEMUFile* f)
> >      mis_current = g_malloc0(sizeof(MigrationIncomingState));
> >      mis_current->file = f;
> >      QLIST_INIT(&mis_current->loadvm_handlers);
> > +    qemu_mutex_init(&mis_current->rp_mutex);
> >  
> >      return mis_current;
> >  }
> > @@ -182,6 +183,50 @@ void process_incoming_migration(QEMUFile *f)
> >      qemu_coroutine_enter(co, f);
> >  }
> >  
> > +/*
> > + * Send a message on the return channel back to the source
> > + * of the migration.
> > + */
> > +void migrate_send_rp_message(MigrationIncomingState *mis,
> > +                             enum mig_rp_message_type message_type,
> > +                             uint16_t len, void *data)
> > +{
> > +    trace_migrate_send_rp_message((int)message_type, len);
> > +    qemu_mutex_lock(&mis->rp_mutex);
> > +    qemu_put_be16(mis->return_path, (unsigned int)message_type);
> > +    qemu_put_be16(mis->return_path, len);
> if (len) {
> 
> > +    qemu_put_buffer(mis->return_path, data, len);
> }
> 
> 
> ?
> 
> We check for zero sized command on control commands but not on
> responses?

Or should I remove the check in the control commands case?
qemu_put_buffer looks like it's safe for size == 0

Dave

> 
> > +    qemu_fflush(mis->return_path);
> > +    qemu_mutex_unlock(&mis->rp_mutex);
> > +}
> > +
> > +/*
> > + * Send a 'SHUT' message on the return channel with the given value
> > + * to indicate that we've finished with the RP.  Non-0 value indicates
> > + * error.
> > + */
> > +void migrate_send_rp_shut(MigrationIncomingState *mis,
> > +                          uint32_t value)
> > +{
> > +    uint32_t buf;
> > +
> > +    buf = cpu_to_be32(value);
> > +    migrate_send_rp_message(mis, MIG_RP_MSG_SHUT, sizeof(buf), &buf);
> > +}
> > +
> > +/*
> > + * Send a 'PONG' message on the return channel with the given value
> > + * (normally in response to a 'PING')
> > + */
> > +void migrate_send_rp_pong(MigrationIncomingState *mis,
> > +                          uint32_t value)
> > +{
> > +    uint32_t buf;
> > +
> > +    buf = cpu_to_be32(value);
> > +    migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf);
> > +}
> > +
> >  /* amount of nanoseconds we are willing to wait for migration to be down.
> >   * the choice of nanoseconds is because it is the maximum resolution that
> >   * get_clock() can achieve. It is an internal measure. All user-visible
> > diff --git a/migration/savevm.c b/migration/savevm.c
> > index a995014..d424c2a 100644
> > --- a/migration/savevm.c
> > +++ b/migration/savevm.c
> > @@ -1071,7 +1071,7 @@ static int loadvm_process_command(QEMUFile *f)
> >                           tmp32);
> >              return -1;
> >          }
> > -        /* migrate_send_rp_pong(mis, tmp32); TODO: gets added later */
> > +        migrate_send_rp_pong(mis, tmp32);
> >          break;
> >  
> >      default:
> > diff --git a/trace-events b/trace-events
> > index 5967fdf..5738e3f 100644
> > --- a/trace-events
> > +++ b/trace-events
> > @@ -1399,6 +1399,7 @@ migrate_fd_cleanup(void) ""
> >  migrate_fd_error(void) ""
> >  migrate_fd_cancel(void) ""
> >  migrate_pending(uint64_t size, uint64_t max) "pending size %" PRIu64 " max %" PRIu64
> > +migrate_send_rp_message(int msg_type, uint16_t len) "%d: len %d"
> >  migrate_transferred(uint64_t tranferred, uint64_t time_spent, double bandwidth, uint64_t size) "transferred %" PRIu64 " time_spent %" PRIu64 " bandwidth %g max_size %" PRId64
> >  
> >  # migration/rdma.c
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
Juan Quintela July 1, 2015, 9:29 a.m. UTC | #3 
"Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:
> * Juan Quintela (quintela@redhat.com) wrote:
>> "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote:
>> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>> >
>> > Add migrate_send_rp_message to send a message from destination to source along the return path.
>> >   (It uses a mutex to let it be called from multiple threads)
>> > Add migrate_send_rp_shut to send a 'shut' message to indicate
>> >   the destination is finished with the RP.
>> > Add migrate_send_rp_ack to send a 'PONG' message in response to a PING
>> >   Use it in the MSG_RP_PING handler
>> >
>> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>> > ---
>> >  include/migration/migration.h | 17 ++++++++++++++++
>> >  migration/migration.c         | 45 +++++++++++++++++++++++++++++++++++++++++++
>> >  migration/savevm.c            |  2 +-
>> >  trace-events                  |  1 +
>> >  4 files changed, 64 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/include/migration/migration.h b/include/migration/migration.h
>> > index 65fe5db..36caab9 100644
>> > --- a/include/migration/migration.h
>> > +++ b/include/migration/migration.h
>> > @@ -42,12 +42,20 @@ struct MigrationParams {
>> >      bool shared;
>> >  };
>> >  
>> > +/* Messages sent on the return path from destination to source */
>> > +enum mig_rp_message_type {
>> > +    MIG_RP_MSG_INVALID = 0,  /* Must be 0 */
>> > +    MIG_RP_MSG_SHUT,         /* sibling will not send any more RP messages */
>> > +    MIG_RP_MSG_PONG,         /* Response to a PING; data (seq: be32 ) */
>> > +};
>> > +
>> >  typedef QLIST_HEAD(, LoadStateEntry) LoadStateEntry_Head;
>> >  /* State for the incoming migration */
>> >  struct MigrationIncomingState {
>> >      QEMUFile *file;
>> >  
>> >      QEMUFile *return_path;
>> > +    QemuMutex      rp_mutex;    /* We send replies from multiple threads */
>> >  
>> >      /* See savevm.c */
>> >      LoadStateEntry_Head loadvm_handlers;
>> > @@ -179,6 +187,15 @@ int migrate_compress_level(void);
>> >  int migrate_compress_threads(void);
>> >  int migrate_decompress_threads(void);
>> >  
>> > +/* Sending on the return path - generic and then for each message type */
>> > +void migrate_send_rp_message(MigrationIncomingState *mis,
>> > +                             enum mig_rp_message_type message_type,
>> > +                             uint16_t len, void *data);
>> > +void migrate_send_rp_shut(MigrationIncomingState *mis,
>> > +                          uint32_t value);
>> > +void migrate_send_rp_pong(MigrationIncomingState *mis,
>> > +                          uint32_t value);
>> > +
>> >  void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
>> >  void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
>> >  void ram_control_load_hook(QEMUFile *f, uint64_t flags);
>> > diff --git a/migration/migration.c b/migration/migration.c
>> > index 295f15a..afb19a1 100644
>> > --- a/migration/migration.c
>> > +++ b/migration/migration.c
>> > @@ -85,6 +85,7 @@ MigrationIncomingState *migration_incoming_state_new(QEMUFile* f)
>> >      mis_current = g_malloc0(sizeof(MigrationIncomingState));
>> >      mis_current->file = f;
>> >      QLIST_INIT(&mis_current->loadvm_handlers);
>> > +    qemu_mutex_init(&mis_current->rp_mutex);
>> >  
>> >      return mis_current;
>> >  }
>> > @@ -182,6 +183,50 @@ void process_incoming_migration(QEMUFile *f)
>> >      qemu_coroutine_enter(co, f);
>> >  }
>> >  
>> > +/*
>> > + * Send a message on the return channel back to the source
>> > + * of the migration.
>> > + */
>> > +void migrate_send_rp_message(MigrationIncomingState *mis,
>> > +                             enum mig_rp_message_type message_type,
>> > +                             uint16_t len, void *data)
>> > +{
>> > +    trace_migrate_send_rp_message((int)message_type, len);
>> > +    qemu_mutex_lock(&mis->rp_mutex);
>> > +    qemu_put_be16(mis->return_path, (unsigned int)message_type);
>> > +    qemu_put_be16(mis->return_path, len);
>> if (len) {
>> 
>> > +    qemu_put_buffer(mis->return_path, data, len);
>> }
>> 
>> 
>> ?
>> 
>> We check for zero sized command on control commands but not on
>> responses?
>
> Or should I remove the check in the control commands case?
> qemu_put_buffer looks like it's safe for size == 0

I would go for this just for consistence?
Amit Shah July 15, 2015, 7:31 a.m. UTC | #4 
On (Tue) 16 Jun 2015 [11:26:27], Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> 
> Add migrate_send_rp_message to send a message from destination to source along the return path.
>   (It uses a mutex to let it be called from multiple threads)
> Add migrate_send_rp_shut to send a 'shut' message to indicate
>   the destination is finished with the RP.
> Add migrate_send_rp_ack to send a 'PONG' message in response to a PING
>   Use it in the MSG_RP_PING handler
> 
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Reviewed-by: Amit Shah <amit.shah@redhat.com>

		Amit
Dr. David Alan Gilbert Aug. 6, 2015, 12:18 p.m. UTC | #5 
* Juan Quintela (quintela@redhat.com) wrote:
> "Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:
> > * Juan Quintela (quintela@redhat.com) wrote:
> >> "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote:
> >> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> >> >
> >> > Add migrate_send_rp_message to send a message from destination to source along the return path.
> >> >   (It uses a mutex to let it be called from multiple threads)
> >> > Add migrate_send_rp_shut to send a 'shut' message to indicate
> >> >   the destination is finished with the RP.
> >> > Add migrate_send_rp_ack to send a 'PONG' message in response to a PING
> >> >   Use it in the MSG_RP_PING handler
> >> >
> >> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> >> > ---
> >> >  include/migration/migration.h | 17 ++++++++++++++++
> >> >  migration/migration.c         | 45 +++++++++++++++++++++++++++++++++++++++++++
> >> >  migration/savevm.c            |  2 +-
> >> >  trace-events                  |  1 +
> >> >  4 files changed, 64 insertions(+), 1 deletion(-)
> >> >
> >> > diff --git a/include/migration/migration.h b/include/migration/migration.h
> >> > index 65fe5db..36caab9 100644
> >> > --- a/include/migration/migration.h
> >> > +++ b/include/migration/migration.h
> >> > @@ -42,12 +42,20 @@ struct MigrationParams {
> >> >      bool shared;
> >> >  };
> >> >  
> >> > +/* Messages sent on the return path from destination to source */
> >> > +enum mig_rp_message_type {
> >> > +    MIG_RP_MSG_INVALID = 0,  /* Must be 0 */
> >> > +    MIG_RP_MSG_SHUT,         /* sibling will not send any more RP messages */
> >> > +    MIG_RP_MSG_PONG,         /* Response to a PING; data (seq: be32 ) */
> >> > +};
> >> > +
> >> >  typedef QLIST_HEAD(, LoadStateEntry) LoadStateEntry_Head;
> >> >  /* State for the incoming migration */
> >> >  struct MigrationIncomingState {
> >> >      QEMUFile *file;
> >> >  
> >> >      QEMUFile *return_path;
> >> > +    QemuMutex      rp_mutex;    /* We send replies from multiple threads */
> >> >  
> >> >      /* See savevm.c */
> >> >      LoadStateEntry_Head loadvm_handlers;
> >> > @@ -179,6 +187,15 @@ int migrate_compress_level(void);
> >> >  int migrate_compress_threads(void);
> >> >  int migrate_decompress_threads(void);
> >> >  
> >> > +/* Sending on the return path - generic and then for each message type */
> >> > +void migrate_send_rp_message(MigrationIncomingState *mis,
> >> > +                             enum mig_rp_message_type message_type,
> >> > +                             uint16_t len, void *data);
> >> > +void migrate_send_rp_shut(MigrationIncomingState *mis,
> >> > +                          uint32_t value);
> >> > +void migrate_send_rp_pong(MigrationIncomingState *mis,
> >> > +                          uint32_t value);
> >> > +
> >> >  void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
> >> >  void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
> >> >  void ram_control_load_hook(QEMUFile *f, uint64_t flags);
> >> > diff --git a/migration/migration.c b/migration/migration.c
> >> > index 295f15a..afb19a1 100644
> >> > --- a/migration/migration.c
> >> > +++ b/migration/migration.c
> >> > @@ -85,6 +85,7 @@ MigrationIncomingState *migration_incoming_state_new(QEMUFile* f)
> >> >      mis_current = g_malloc0(sizeof(MigrationIncomingState));
> >> >      mis_current->file = f;
> >> >      QLIST_INIT(&mis_current->loadvm_handlers);
> >> > +    qemu_mutex_init(&mis_current->rp_mutex);
> >> >  
> >> >      return mis_current;
> >> >  }
> >> > @@ -182,6 +183,50 @@ void process_incoming_migration(QEMUFile *f)
> >> >      qemu_coroutine_enter(co, f);
> >> >  }
> >> >  
> >> > +/*
> >> > + * Send a message on the return channel back to the source
> >> > + * of the migration.
> >> > + */
> >> > +void migrate_send_rp_message(MigrationIncomingState *mis,
> >> > +                             enum mig_rp_message_type message_type,
> >> > +                             uint16_t len, void *data)
> >> > +{
> >> > +    trace_migrate_send_rp_message((int)message_type, len);
> >> > +    qemu_mutex_lock(&mis->rp_mutex);
> >> > +    qemu_put_be16(mis->return_path, (unsigned int)message_type);
> >> > +    qemu_put_be16(mis->return_path, len);
> >> if (len) {
> >> 
> >> > +    qemu_put_buffer(mis->return_path, data, len);
> >> }
> >> 
> >> 
> >> ?
> >> 
> >> We check for zero sized command on control commands but not on
> >> responses?
> >
> > Or should I remove the check in the control commands case?
> > qemu_put_buffer looks like it's safe for size == 0
> 
> I would go for this just for consistence?

OK, check removed in both cases.

Dave

(Resend: I dropped the list off the first message)
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
diff mbox

Patch

diff --git a/include/migration/migration.h b/include/migration/migration.h
index 65fe5db..36caab9 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -42,12 +42,20 @@  struct MigrationParams {
     bool shared;
 };
 
+/* Messages sent on the return path from destination to source */
+enum mig_rp_message_type {
+    MIG_RP_MSG_INVALID = 0,  /* Must be 0 */
+    MIG_RP_MSG_SHUT,         /* sibling will not send any more RP messages */
+    MIG_RP_MSG_PONG,         /* Response to a PING; data (seq: be32 ) */
+};
+
 typedef QLIST_HEAD(, LoadStateEntry) LoadStateEntry_Head;
 /* State for the incoming migration */
 struct MigrationIncomingState {
     QEMUFile *file;
 
     QEMUFile *return_path;
+    QemuMutex      rp_mutex;    /* We send replies from multiple threads */
 
     /* See savevm.c */
     LoadStateEntry_Head loadvm_handlers;
@@ -179,6 +187,15 @@  int migrate_compress_level(void);
 int migrate_compress_threads(void);
 int migrate_decompress_threads(void);
 
+/* Sending on the return path - generic and then for each message type */
+void migrate_send_rp_message(MigrationIncomingState *mis,
+                             enum mig_rp_message_type message_type,
+                             uint16_t len, void *data);
+void migrate_send_rp_shut(MigrationIncomingState *mis,
+                          uint32_t value);
+void migrate_send_rp_pong(MigrationIncomingState *mis,
+                          uint32_t value);
+
 void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
 void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
 void ram_control_load_hook(QEMUFile *f, uint64_t flags);
diff --git a/migration/migration.c b/migration/migration.c
index 295f15a..afb19a1 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -85,6 +85,7 @@  MigrationIncomingState *migration_incoming_state_new(QEMUFile* f)
     mis_current = g_malloc0(sizeof(MigrationIncomingState));
     mis_current->file = f;
     QLIST_INIT(&mis_current->loadvm_handlers);
+    qemu_mutex_init(&mis_current->rp_mutex);
 
     return mis_current;
 }
@@ -182,6 +183,50 @@  void process_incoming_migration(QEMUFile *f)
     qemu_coroutine_enter(co, f);
 }
 
+/*
+ * Send a message on the return channel back to the source
+ * of the migration.
+ */
+void migrate_send_rp_message(MigrationIncomingState *mis,
+                             enum mig_rp_message_type message_type,
+                             uint16_t len, void *data)
+{
+    trace_migrate_send_rp_message((int)message_type, len);
+    qemu_mutex_lock(&mis->rp_mutex);
+    qemu_put_be16(mis->return_path, (unsigned int)message_type);
+    qemu_put_be16(mis->return_path, len);
+    qemu_put_buffer(mis->return_path, data, len);
+    qemu_fflush(mis->return_path);
+    qemu_mutex_unlock(&mis->rp_mutex);
+}
+
+/*
+ * Send a 'SHUT' message on the return channel with the given value
+ * to indicate that we've finished with the RP.  Non-0 value indicates
+ * error.
+ */
+void migrate_send_rp_shut(MigrationIncomingState *mis,
+                          uint32_t value)
+{
+    uint32_t buf;
+
+    buf = cpu_to_be32(value);
+    migrate_send_rp_message(mis, MIG_RP_MSG_SHUT, sizeof(buf), &buf);
+}
+
+/*
+ * Send a 'PONG' message on the return channel with the given value
+ * (normally in response to a 'PING')
+ */
+void migrate_send_rp_pong(MigrationIncomingState *mis,
+                          uint32_t value)
+{
+    uint32_t buf;
+
+    buf = cpu_to_be32(value);
+    migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf);
+}
+
 /* amount of nanoseconds we are willing to wait for migration to be down.
  * the choice of nanoseconds is because it is the maximum resolution that
  * get_clock() can achieve. It is an internal measure. All user-visible
diff --git a/migration/savevm.c b/migration/savevm.c
index a995014..d424c2a 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1071,7 +1071,7 @@  static int loadvm_process_command(QEMUFile *f)
                          tmp32);
             return -1;
         }
-        /* migrate_send_rp_pong(mis, tmp32); TODO: gets added later */
+        migrate_send_rp_pong(mis, tmp32);
         break;
 
     default:
diff --git a/trace-events b/trace-events
index 5967fdf..5738e3f 100644
--- a/trace-events
+++ b/trace-events
@@ -1399,6 +1399,7 @@  migrate_fd_cleanup(void) ""
 migrate_fd_error(void) ""
 migrate_fd_cancel(void) ""
 migrate_pending(uint64_t size, uint64_t max) "pending size %" PRIu64 " max %" PRIu64
+migrate_send_rp_message(int msg_type, uint16_t len) "%d: len %d"
 migrate_transferred(uint64_t tranferred, uint64_t time_spent, double bandwidth, uint64_t size) "transferred %" PRIu64 " time_spent %" PRIu64 " bandwidth %g max_size %" PRId64
 
 # migration/rdma.c