Commit 4886a1bc authored by Dr. David Alan Gilbert's avatar Dr. David Alan Gilbert Committed by Juan Quintela
Browse files

migrate_start_postcopy: Command to trigger transition to postcopy 



Once postcopy is enabled (with migrate_set_capability), the migration
will still start on precopy mode.  To cause a transition into postcopy
the:

  migrate_start_postcopy

command must be issued.  Postcopy will start sometime after this
(when it's next checked in the migration loop).

Issuing the command before migration has started will error,
and issuing after it has finished is ignored.

Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarJuan Quintela <quintela@redhat.com>
Reviewed-by: default avatarAmit Shah <amit.shah@redhat.com>
Signed-off-by: default avatarJuan Quintela <quintela@redhat.com>
parent eb59db53

hmp-commands.hx

+15 −0
Original line number Diff line number Diff line
@@ -1005,6 +1005,21 @@ STEXI 
@item migrate_set_parameter @var{parameter} @var{value}

@findex migrate_set_parameter

Set the parameter @var{parameter} for migration.

ETEXI



    {

        .name       = "migrate_start_postcopy",

        .args_type  = "",

        .params     = "",

        .help       = "Switch migration to postcopy mode",

        .mhandler.cmd = hmp_migrate_start_postcopy,

    },



STEXI

@item migrate_start_postcopy

@findex migrate_start_postcopy

Switch in-progress migration to postcopy mode. Ignored after the end of

migration (or once already in postcopy).

ETEXI



    {

hmp.c

+7 −0
Original line number Diff line number Diff line
@@ -1293,6 +1293,13 @@ void hmp_client_migrate_info(Monitor *mon, const QDict *qdict) 
    hmp_handle_error(mon, &err);

}



void hmp_migrate_start_postcopy(Monitor *mon, const QDict *qdict)

{

    Error *err = NULL;

    qmp_migrate_start_postcopy(&err);

    hmp_handle_error(mon, &err);

}



void hmp_set_password(Monitor *mon, const QDict *qdict)

{

    const char *protocol  = qdict_get_str(qdict, "protocol");

hmp.h

+1 −0
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ void hmp_migrate_set_capability(Monitor *mon, const QDict *qdict); 
void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict);

void hmp_migrate_set_cache_size(Monitor *mon, const QDict *qdict);

void hmp_client_migrate_info(Monitor *mon, const QDict *qdict);

void hmp_migrate_start_postcopy(Monitor *mon, const QDict *qdict);

void hmp_set_password(Monitor *mon, const QDict *qdict);

void hmp_expire_password(Monitor *mon, const QDict *qdict);

void hmp_eject(Monitor *mon, const QDict *qdict);

include/migration/migration.h

+3 −0
Original line number Diff line number Diff line
@@ -127,6 +127,9 @@ struct MigrationState 
    int64_t xbzrle_cache_size;

    int64_t setup_time;

    int64_t dirty_sync_count;



    /* Flag set once the migration has been asked to enter postcopy */

    bool start_postcopy;

};



void process_incoming_migration(QEMUFile *f);

migration/migration.c

+22 −0
Original line number Diff line number Diff line
@@ -668,6 +668,28 @@ void qmp_migrate_set_parameters(bool has_compress_level, 
    }

}



void qmp_migrate_start_postcopy(Error **errp)

{

    MigrationState *s = migrate_get_current();



    if (!migrate_postcopy_ram()) {

        error_setg(errp, "Enable postcopy with migration_set_capability before"

                         " the start of migration");

        return;

    }



    if (s->state == MIGRATION_STATUS_NONE) {

        error_setg(errp, "Postcopy must be started after migration has been"

                         " started");

        return;

    }

    /*

     * we don't error if migration has finished since that would be racy

     * with issuing this command.

     */

    atomic_set(&s->start_postcopy, true);

}



/* shared migration helpers */



static void migrate_set_state(MigrationState *s, int old_state, int new_state)