xemu/migration.h
Glauber Costa a0a3fd60f6 add non-arbitrary migration stop condition
Currently, we're entering migration's stage 3 when
a treshold of 10 pages remain to be transferred in the system.

This has hurt some users. However, any proposed threshold is
arbitrary by nature, and would only shift the annoyance.

The proposal of this patch is to define a max_downtime variable,
which represents the maximum downtime a migration user is willing
to suffer. Then, based on the bandwidth of last iteration, we
calculate how much data we can transfer in such a window of time.

Whenever we reach that value (or lower), we know is safe to enter
stage3.

This has largely improved the situation for me.
On localhost migrations, where one would expect things to go as
quickly as me running away from the duty of writting software for
windows, a kernel compile was enough to get the migration stuck.

It takes 20 ~ 30 iterations now.

Signed-off-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-06-16 15:45:40 -05:00

104 lines
2.4 KiB
C

/*
* QEMU live migration
*
* Copyright IBM, Corp. 2008
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#ifndef QEMU_MIGRATION_H
#define QEMU_MIGRATION_H
#include "qemu-common.h"
#define MIG_STATE_ERROR -1
#define MIG_STATE_COMPLETED 0
#define MIG_STATE_CANCELLED 1
#define MIG_STATE_ACTIVE 2
typedef struct MigrationState MigrationState;
struct MigrationState
{
/* FIXME: add more accessors to print migration info */
void (*cancel)(MigrationState *s);
int (*get_status)(MigrationState *s);
void (*release)(MigrationState *s);
};
typedef struct FdMigrationState FdMigrationState;
struct FdMigrationState
{
MigrationState mig_state;
int64_t bandwidth_limit;
QEMUFile *file;
int fd;
Monitor *mon_resume;
int state;
int (*get_error)(struct FdMigrationState*);
int (*close)(struct FdMigrationState*);
int (*write)(struct FdMigrationState*, const void *, size_t);
void *opaque;
};
void qemu_start_incoming_migration(const char *uri);
void do_migrate(Monitor *mon, int detach, const char *uri);
void do_migrate_cancel(Monitor *mon);
void do_migrate_set_speed(Monitor *mon, const char *value);
uint64_t migrate_max_downtime(void);
void do_info_migrate(Monitor *mon);
int exec_start_incoming_migration(const char *host_port);
MigrationState *exec_start_outgoing_migration(const char *host_port,
int64_t bandwidth_limit,
int detach);
int tcp_start_incoming_migration(const char *host_port);
MigrationState *tcp_start_outgoing_migration(const char *host_port,
int64_t bandwidth_limit,
int detach);
void migrate_fd_monitor_suspend(FdMigrationState *s);
void migrate_fd_error(FdMigrationState *s);
void migrate_fd_cleanup(FdMigrationState *s);
void migrate_fd_put_notify(void *opaque);
ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size);
void migrate_fd_connect(FdMigrationState *s);
void migrate_fd_put_ready(void *opaque);
int migrate_fd_get_status(MigrationState *mig_state);
void migrate_fd_cancel(MigrationState *mig_state);
void migrate_fd_release(MigrationState *mig_state);
void migrate_fd_wait_for_unfreeze(void *opaque);
int migrate_fd_close(void *opaque);
static inline FdMigrationState *migrate_to_fms(MigrationState *mig_state)
{
return container_of(mig_state, FdMigrationState, mig_state);
}
#endif