Re: [Qemu-devel] [PATCH 4/7] migration-local: implementation of outgoing part

[Anthony Liguori <aliguori@us.ibm.com>]

Lei Li <lilei@linux.vnet.ibm.com> writes:

> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
> ---
>  Makefile.objs                 |    1 +
>  include/migration/migration.h |   15 +++++
>  migration-local.c             |  116 +++++++++++++++++++++++++++++++++++++++++
>  migration-unix.c              |   13 +++++
>  qapi-schema.json              |   14 +++++
>  qmp-commands.hx               |   22 ++++++++
>  6 files changed, 181 insertions(+), 0 deletions(-)
>  create mode 100644 migration-local.c
>
> diff --git a/Makefile.objs b/Makefile.objs
> index 5b288ba..2a3d9a5 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -53,6 +53,7 @@ common-obj-$(CONFIG_LINUX) += fsdev/
>  common-obj-y += migration.o migration-tcp.o
>  common-obj-y += qemu-char.o #aio.o
>  common-obj-y += block-migration.o
> +common-obj-y += migration-local.o
>  common-obj-y += page_cache.o xbzrle.o
>  
>  common-obj-$(CONFIG_POSIX) += migration-exec.o migration-unix.o migration-fd.o
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index 9cc5285..12c75cf 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -58,6 +58,17 @@ struct MigrationState
>      int64_t xbzrle_cache_size;
>  };
>  
> +
> +typedef struct LocalMigState LocalMigState;
> +
> +struct LocalMigState
> +{
> +    int fd;
> +    int state;
> +    QEMUFile *file;
> +    QemuThread thread;
> +};
> +
>  void process_incoming_migration(QEMUFile *f);
>  
>  void qemu_start_incoming_migration(const char *uri, Error **errp);
> @@ -80,6 +91,8 @@ void unix_start_incoming_migration(const char *path, Error **errp);
>  
>  void unix_start_outgoing_migration(MigrationState *s, const char *path, Error **errp);
>  
> +void unix_start_local_outgoing_migration(LocalMigState *s, const char *path, Error **errp);
> +
>  void fd_start_incoming_migration(const char *path, Error **errp);
>  
>  void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp);
> @@ -90,6 +103,8 @@ void migrate_fd_connect(MigrationState *s);
>  
>  int migrate_fd_close(MigrationState *s);
>  
> +void migrate_fd_connect_local(LocalMigState *s);
> +
>  void add_migration_state_change_notifier(Notifier *notify);
>  void remove_migration_state_change_notifier(Notifier *notify);
>  bool migration_is_active(MigrationState *);
> diff --git a/migration-local.c b/migration-local.c
> new file mode 100644
> index 0000000..a97dd3a
> --- /dev/null
> +++ b/migration-local.c
> @@ -0,0 +1,116 @@
> +/*
> + * QEMU localhost live migration
> + *
> + * Copyright IBM, Corp. 2013
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + *
> + * Contributions are licensed under the terms of the GNU GPL, version 2
> + * or (at your option) any later version.

You can just add the "or later" clause to the first paragraph.

> + */
> +
> +#include "qemu-common.h"
> +#include "migration/migration.h"
> +#include "monitor/monitor.h"
> +#include "migration/qemu-file.h"
> +#include "sysemu/sysemu.h"
> +#include "block/block.h"
> +#include "qemu/sockets.h"
> +#include "migration/block.h"
> +#include "qemu/thread.h"
> +#include "qmp-commands.h"
> +#include "exec/memory.h"
> +#include "trace.h"
> +#include "qemu/osdep.h"
> +
> +//#define DEBUG_MIGRATION_LOCAL
> +
> +#ifdef DEBUG_MIGRATION_LOCAL
> +#define DPRINTF(fmt, ...) \
> +    do { printf("migration-local: " fmt, ## __VA_ARGS__); } while (0)
> +#else
> +#define DPRINTF(fmt, ...) \
> +    do { } while (0)
> +#endif
> +
> +
> +/************************************************************************
> + * Outgoing part
> + */
> +
> +static void *migration_local_thread(void *opaque)
> +{
> +    LocalMigState *s = opaque;
> +    int ret;
> +    ram_addr_t size;
> +
> +    DPRINTF("Beginning savevm\n");
> +
> +    /* This will be replaced by new function qemu_save_local_state(). */
> +    ret = qemu_save_device_state(s->file);
> +    qemu_fclose(s->file);
> +
> +    if (ret < 0) {
> +        s->state = MIG_STATE_ERROR;
> +        return NULL;
> +    } else {
> +        /* XXX: The logic will be changed, need more work here. */
> +        s->state = MIG_STATE_COMPLETED;
> +
> +        size = ram_bytes_total();
> +        ram_madvise_free(size);
> +    }
> +
> +    return NULL;
> +}
> +
> +void migrate_fd_connect_local(LocalMigState *s)
> +{
> +    s->state = MIG_STATE_ACTIVE;
> +    trace_migrate_set_state(MIG_STATE_ACTIVE);
> +
> +    qemu_thread_create(&s->thread, migration_local_thread, s,
> +                       QEMU_THREAD_JOINABLE);
> +}
> +
> +void qmp_localhost_migrate(const char *uri, Error **errp)
> +{
> +    const char *path;
> +    Error *local_err = NULL;
> +    int is_vm_running;
> +    LocalMigState *s;
> +
> +    is_vm_running = runstate_is_running();
> +
> +    /* Stop the VM first */
> +    if (is_vm_running) {
> +        vm_stop(RUN_STATE_SAVE_VM);
> +    }
> +
> +    bdrv_flush_all();
> +
> +    s = g_malloc0(sizeof(LocalMigState));
> +
> +    /* Start outgoing migration by unix socket. */
> +    if (strstart(uri, "unix:", &path)) {
> +        /* XXX. Creat a new unix_start_outgoing_migration_* is not necessary,
> +         * just for the first step. This will be replaced by vmsplice
> +         * mechanism. */
> +        unix_start_local_outgoing_migration(s, path, &local_err);
> +    } else {
> +        error_set(errp, QERR_INVALID_PARAMETER_VALUE, "uri", "a valid migration protocol");
> +        goto fail;
> +    }
> +
> +    if (local_err) {
> +        s->state = MIG_STATE_ERROR;
> +        error_propagate(errp, local_err);
> +        goto fail;
> +    }
> +
> +fail:
> +    if (!is_vm_running) {
> +        vm_start();
> +    }
> +}
> diff --git a/migration-unix.c b/migration-unix.c
> index 94b7022..a21262a 100644
> --- a/migration-unix.c
> +++ b/migration-unix.c
> @@ -49,6 +49,19 @@ void unix_start_outgoing_migration(MigrationState *s, const char *path, Error **
>      unix_nonblocking_connect(path, unix_wait_for_connect, s, errp);
>  }
>  
> +void unix_start_local_outgoing_migration(LocalMigState *s, const char *path, Error **errp)
> +{
> +    s->fd = unix_connect(path, errp);
> +    if (s->fd < 0) {
> +        s->file = NULL;
> +        /* There should be a fd_error_set function */
> +        s->state = MIG_STATE_ERROR;
> +    } else {
> +        s->file = qemu_fopen_socket(s->fd, "wb");
> +        migrate_fd_connect_local(s);
> +    }
> +}
> +

Skipping most of the above as it's a work-in-progress.

>  static void unix_accept_incoming_migration(void *opaque)
>  {
>      struct sockaddr_un addr;
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 5ad6894..2890f70 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -648,6 +648,20 @@
>  { 'command': 'query-migrate-capabilities', 'returns':   ['MigrationCapabilityStatus']}
>  
>  ##
> +# @localhost-migrate
> +#
> +# Migrates the current running guest to another localhost VM.
> +#
> +# @uri: the Uniform Resource Identifier of the destination VM
> +#
> +# Returns: nothing on success
> +#
> +# Since: 1.7
> +##
> +{ 'command': 'localhost-migrate',
> +  'data': {'uri': 'str'} }

I suspect we should just do this as a flag to the existing migration
command.  Perhaps we could even just use a capability.

Regards,

Anthony Liguori

> +
> +##
>  # @MouseInfo:
>  #
>  # Information about a mouse device.
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index 8cea5e5..bf6d042 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -787,6 +787,28 @@ Example:
>  EQMP
>  
>      {
> +        .name      = "localhost-migrate",
> +        .args_type = "uri:s",
> +        .mhandler.cmd_new = qmp_marshal_input_localhost_migrate,
> +    },
> +
> +SQMP
> +localhost-migrate
> +
> +Migrate VM in localhost.
> +
> +Arguments:
> +
> +- "uri": Destination URI (json-string)
> +
> +Example:
> +
> +-> { "execute": "localhost-migrate", "arguments": { "uri": "/tmp/foo" }
> +<- { "return": {} }
> +
> +EQMP
> +
> +    {
>          .name       = "dump-guest-memory",
>          .args_type  = "paging:b,protocol:s,begin:i?,end:i?",
>          .params     = "-p protocol [begin] [length]",
> -- 
> 1.7.7.6