Re: [Qemu-devel] [PATCH 09/12] migration-local: implementation of outgoing part

[Lei Li <lilei@linux.vnet.ibm.com>]

On 08/03/2013 03:45 AM, Michael R. Hines wrote:
> On 07/25/2013 04:18 PM, Lei Li wrote:
>> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
>> ---
>>   Makefile.objs                 |    1 +
>>   include/migration/migration.h |   15 ++++
>>   migration-local.c             |  158 
>> +++++++++++++++++++++++++++++++++++++++++
>>   migration-unix.c              |   13 ++++
>>   qapi-schema.json              |   14 ++++
>>   qmp-commands.hx               |   22 ++++++
>>   6 files changed, 223 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 a821c80..a690e18 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);
>> @@ -88,6 +101,8 @@ void migrate_fd_error(MigrationState *s);
>>
>>   void migrate_fd_connect(MigrationState *s);
>>
>> +void local_migration_fd_connect(LocalMigState *s);
>> +
>>   int migrate_fd_close(MigrationState *s);
>>
>>   void add_migration_state_change_notifier(Notifier *notify);
>> diff --git a/migration-local.c b/migration-local.c
>> new file mode 100644
>> index 0000000..5bd1ed0
>> --- /dev/null
>> +++ b/migration-local.c
>> @@ -0,0 +1,158 @@
>> +/*
>> + * QEMU localhost 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.
>> + */
>> +
>> +#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 LocalMigState *local_migration_init(void)
>> +{
>> +    LocalMigState *s = g_malloc0(sizeof(*s));
>> +
>> +    s->state = MIG_STATE_SETUP;
>> +    trace_migrate_set_state(MIG_STATE_SETUP);
>> +    s->fd = -1;
>> +
>> +    return s;
>> +}
>> +
>> +static void local_migration_error(LocalMigState *s)
>> +{
>> +    assert(s->file == NULL);
>> +
>> +    s->state = MIG_STATE_ERROR;
>> +    trace_migrate_set_state(MIG_STATE_ERROR);
>> +}
>> +
>> +static void local_outgoing_completed(LocalMigState *s)
>> +{
>> +    s->state = MIG_STATE_COMPLETED;
>> +    trace_migrate_set_state(MIG_STATE_COMPLETED);
>> +}
>> +
>> +static void *migration_local_thread(void *opaque)
>> +{
>> +    LocalMigState *s = opaque;
>> +    int ret;
>> +
>> +    DPRINTF("Beginning savevm\n");
>> +
>> +    while (s->state == MIG_STATE_ACTIVE) {
>> +        qemu_mutex_lock_iothread();
>> +        ret = qemu_savevm_local(s->file);
>> +        qemu_mutex_unlock_iothread();
>> +
>> +        /* No need to send device states if ram pages fails to to 
>> sent. */
>> +        if (ret < 0) {
>> +            local_migration_error(s);
>> +            break;
>> +        }
>> +
>> +        qemu_save_device_state(s->file);
>> +        qemu_fclose(s->file);
>> +    }
>> +
>> +    ret = qemu_file_get_error(s->file);
>> +    if (ret < 0) {
>> +        local_migration_error(s);
>> +    } else {
>> +        local_outgoing_completed(s);
>> +    }
>> +
>> +    qemu_mutex_lock_iothread();
>> +
>> +    if (s->state == MIG_STATE_COMPLETED) {
>> +        runstate_set(RUN_STATE_POSTMIGRATE);
>> +    }
>> +
>> +    qemu_mutex_unlock_iothread();
>> +
>> +    return NULL;
>> +}
>> +
>> +void local_migration_fd_connect(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;
>> +
>> +    if (qemu_savevm_state_blocked(errp)) {
>> +        return;
>> +    }
>> +
>> +    s = local_migration_init();
>> +    bdrv_flush_all();
>> +
>> +    is_vm_running = runstate_is_running();
>> +
>> +    /* Stop the VM first */
>> +    if (is_vm_running) {
>> +        vm_stop(RUN_STATE_SAVE_VM);
>> +    }
>> +
>> +    /* 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..ec20c45 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");
>> +        local_migration_fd_connect(s);
>> +    }
>> +}
>> +
>>   static void unix_accept_incoming_migration(void *opaque)
>>   {
>>       struct sockaddr_un addr;
>> diff --git a/qapi-schema.json b/qapi-schema.json
>> index a80ee40..7431a41 100644
>> --- a/qapi-schema.json
>> +++ b/qapi-schema.json
>> @@ -2336,6 +2336,20 @@
>>   { 'command': 'migrate',
>>     'data': {'uri': 'str', '*blk': 'bool', '*inc': 'bool', '*detach': 
>> 'bool' } }
>>
>> +##
>> +# @localhost-migrate
>> +#
>> +# Migrates the current running guest to the localhost VM.
>> +#
>> +# @uri: the Uniform Resource Identifier of the destination VM
>> +#
>> +# Returns: nothing on success
>> +#
>> +# Since: 1.7
>> +##
>> +{ 'command': 'localhost-migrate',
>> +  'data': {'uri': 'str'} }
>> +
>>   # @xen-save-devices-state:
>>   #
>>   # Save the state of all devices to file. The RAM and the block devices
>> diff --git a/qmp-commands.hx b/qmp-commands.hx
>> index 8cea5e5..aba2327 100644
>> --- a/qmp-commands.hx
>> +++ b/qmp-commands.hx
>> @@ -640,6 +640,28 @@ Notes:
>>   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": 
>> "UNIX-SOCKET" }
>> +<- { "return": {} }
>> +
>> +EQMP
>> +
>> +    {
>>           .name       = "migrate_cancel",
>>           .args_type  = "",
>>           .mhandler.cmd_new = qmp_marshal_input_migrate_cancel,
>
> Why a separate thread? What's wrong with modifying the existing 
> migration_thread() ?

Well, as mentioned in the cover letter, it was implemented
separately to the current migration code just for a easier start..
I am looking for suggestions on the proper way to integrate it.

Yes, modify the existing migration_thread() is an option.

>
> - Michael
>
>


-- 
Lei