Re: [Qemu-devel] [PATCH V7 RESEND 06/17] COLO: Remove colo_state migration struct

[Dr. David Alan Gilbert]

* Zhang Chen (address@hidden) wrote:
> We need to know if migration is going into COLO state for
> incoming side before start normal migration.
> 
> Instead by using the VMStateDescription to send colo_state
> from source side to destination side, we use MIG_CMD_ENABLE_COLO
> to indicate whether COLO is enabled or not.
> 
> Signed-off-by: zhanghailiang <address@hidden>
> Signed-off-by: Zhang Chen <address@hidden>

Yes, that simplifies it a bit.

Reviewed-by: Dr. David Alan Gilbert <address@hidden>

> ---
>  include/migration/colo.h |  5 +--
>  migration/Makefile.objs  |  2 +-
>  migration/colo-comm.c    | 76 ----------------------------------------
>  migration/colo.c         | 13 ++++++-
>  migration/migration.c    | 23 +++++++++++-
>  migration/savevm.c       | 20 +++++++++++
>  migration/savevm.h       |  1 +
>  migration/trace-events   |  1 +
>  vl.c                     |  2 --
>  9 files changed, 60 insertions(+), 83 deletions(-)
>  delete mode 100644 migration/colo-comm.c
> 
> diff --git a/include/migration/colo.h b/include/migration/colo.h
> index fefb2fcf4c..99ce17aca7 100644
> --- a/include/migration/colo.h
> +++ b/include/migration/colo.h
> @@ -28,8 +28,9 @@ void migrate_start_colo_process(MigrationState *s);
>  bool migration_in_colo_state(void);
>  
>  /* loadvm */
> -bool migration_incoming_enable_colo(void);
> -void migration_incoming_exit_colo(void);
> +void migration_incoming_enable_colo(void);
> +void migration_incoming_disable_colo(void);
> +bool migration_incoming_colo_enabled(void);
>  void *colo_process_incoming_thread(void *opaque);
>  bool migration_incoming_in_colo_state(void);
>  
> diff --git a/migration/Makefile.objs b/migration/Makefile.objs
> index c83ec47ba8..a4f3bafd86 100644
> --- a/migration/Makefile.objs
> +++ b/migration/Makefile.objs
> @@ -1,6 +1,6 @@
>  common-obj-y += migration.o socket.o fd.o exec.o
>  common-obj-y += tls.o channel.o savevm.o
> -common-obj-y += colo-comm.o colo.o colo-failover.o
> +common-obj-y += colo.o colo-failover.o
>  common-obj-y += vmstate.o vmstate-types.o page_cache.o
>  common-obj-y += qemu-file.o global_state.o
>  common-obj-y += qemu-file-channel.o
> diff --git a/migration/colo-comm.c b/migration/colo-comm.c
> deleted file mode 100644
> index df26e4dfe7..0000000000
> --- a/migration/colo-comm.c
> +++ /dev/null
> @@ -1,76 +0,0 @@
> -/*
> - * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
> - * (a.k.a. Fault Tolerance or Continuous Replication)
> - *
> - * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
> - * Copyright (c) 2016 FUJITSU LIMITED
> - * Copyright (c) 2016 Intel Corporation
> - *
> - * This work is licensed under the terms of the GNU GPL, version 2 or
> - * later. See the COPYING file in the top-level directory.
> - *
> - */
> -
> -#include "qemu/osdep.h"
> -#include "migration.h"
> -#include "migration/colo.h"
> -#include "migration/vmstate.h"
> -#include "trace.h"
> -
> -typedef struct {
> -     bool colo_requested;
> -} COLOInfo;
> -
> -static COLOInfo colo_info;
> -
> -COLOMode get_colo_mode(void)
> -{
> -    if (migration_in_colo_state()) {
> -        return COLO_MODE_PRIMARY;
> -    } else if (migration_incoming_in_colo_state()) {
> -        return COLO_MODE_SECONDARY;
> -    } else {
> -        return COLO_MODE_UNKNOWN;
> -    }
> -}
> -
> -static int colo_info_pre_save(void *opaque)
> -{
> -    COLOInfo *s = opaque;
> -
> -    s->colo_requested = migrate_colo_enabled();
> -
> -    return 0;
> -}
> -
> -static bool colo_info_need(void *opaque)
> -{
> -   return migrate_colo_enabled();
> -}
> -
> -static const VMStateDescription colo_state = {
> -    .name = "COLOState",
> -    .version_id = 1,
> -    .minimum_version_id = 1,
> -    .pre_save = colo_info_pre_save,
> -    .needed = colo_info_need,
> -    .fields = (VMStateField[]) {
> -        VMSTATE_BOOL(colo_requested, COLOInfo),
> -        VMSTATE_END_OF_LIST()
> -    },
> -};
> -
> -void colo_info_init(void)
> -{
> -    vmstate_register(NULL, 0, &colo_state, &colo_info);
> -}
> -
> -bool migration_incoming_enable_colo(void)
> -{
> -    return colo_info.colo_requested;
> -}
> -
> -void migration_incoming_exit_colo(void)
> -{
> -    colo_info.colo_requested = false;
> -}
> diff --git a/migration/colo.c b/migration/colo.c
> index e06640c3d6..c083d3696f 100644
> --- a/migration/colo.c
> +++ b/migration/colo.c
> @@ -152,6 +152,17 @@ static void primary_vm_do_failover(void)
>      qemu_sem_post(&s->colo_exit_sem);
>  }
>  
> +COLOMode get_colo_mode(void)
> +{
> +    if (migration_in_colo_state()) {
> +        return COLO_MODE_PRIMARY;
> +    } else if (migration_incoming_in_colo_state()) {
> +        return COLO_MODE_SECONDARY;
> +    } else {
> +        return COLO_MODE_UNKNOWN;
> +    }
> +}
> +
>  void colo_do_failover(MigrationState *s)
>  {
>      /* Make sure VM stopped while failover happened. */
> @@ -745,7 +756,7 @@ out:
>      if (mis->to_src_file) {
>          qemu_fclose(mis->to_src_file);
>      }
> -    migration_incoming_exit_colo();
> +    migration_incoming_disable_colo();
>  
>      return NULL;
>  }
> diff --git a/migration/migration.c b/migration/migration.c
> index ddd0c4b988..8dee7dd309 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -277,6 +277,22 @@ int migrate_send_rp_req_pages(MigrationIncomingState 
> *mis, const char *rbname,
>      return migrate_send_rp_message(mis, msg_type, msglen, bufc);
>  }
>  
> +static bool migration_colo_enabled;
> +bool migration_incoming_colo_enabled(void)
> +{
> +    return migration_colo_enabled;
> +}
> +
> +void migration_incoming_disable_colo(void)
> +{
> +    migration_colo_enabled = false;
> +}
> +
> +void migration_incoming_enable_colo(void)
> +{
> +    migration_colo_enabled = true;
> +}
> +
>  void qemu_start_incoming_migration(const char *uri, Error **errp)
>  {
>      const char *p;
> @@ -388,7 +404,7 @@ static void process_incoming_migration_co(void *opaque)
>      }
>  
>      /* we get COLO info, and know if we are in COLO mode */
> -    if (!ret && migration_incoming_enable_colo()) {
> +    if (!ret && migration_incoming_colo_enabled()) {
>          /* Make sure all file formats flush their mutable metadata */
>          bdrv_invalidate_cache_all(&local_err);
>          if (local_err) {
> @@ -2431,6 +2447,11 @@ static void *migration_thread(void *opaque)
>          qemu_savevm_send_postcopy_advise(s->to_dst_file);
>      }
>  
> +    if (migrate_colo_enabled()) {
> +        /* Notify migration destination that we enable COLO */
> +        qemu_savevm_send_colo_enable(s->to_dst_file);
> +    }
> +
>      qemu_savevm_state_setup(s->to_dst_file);
>  
>      s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
> diff --git a/migration/savevm.c b/migration/savevm.c
> index e2be02afe4..c43d220220 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -55,6 +55,8 @@
>  #include "io/channel-buffer.h"
>  #include "io/channel-file.h"
>  #include "sysemu/replay.h"
> +#include "migration/colo.h"
> +
>  
>  #ifndef ETH_P_RARP
>  #define ETH_P_RARP 0x8035
> @@ -81,6 +83,9 @@ enum qemu_vm_cmd {
>                                        were previously sent during
>                                        precopy but are dirty. */
>      MIG_CMD_PACKAGED,          /* Send a wrapped stream within this stream */
> +
> +    MIG_CMD_ENABLE_COLO, /* Enable COLO */
> +
>      MIG_CMD_MAX
>  };
>  
> @@ -836,6 +841,12 @@ static void qemu_savevm_command_send(QEMUFile *f,
>      qemu_fflush(f);
>  }
>  
> +void qemu_savevm_send_colo_enable(QEMUFile *f)
> +{
> +    trace_savevm_send_colo_enable();
> +    qemu_savevm_command_send(f, MIG_CMD_ENABLE_COLO, 0, NULL);
> +}
> +
>  void qemu_savevm_send_ping(QEMUFile *f, uint32_t value)
>  {
>      uint32_t buf;
> @@ -1793,6 +1804,12 @@ static int 
> loadvm_handle_cmd_packaged(MigrationIncomingState *mis)
>      return ret;
>  }
>  
> +static int loadvm_process_enable_colo(MigrationIncomingState *mis)
> +{
> +    migration_incoming_enable_colo();
> +    return 0;
> +}
> +
>  /*
>   * Process an incoming 'QEMU_VM_COMMAND'
>   * 0           just a normal return
> @@ -1866,6 +1883,9 @@ static int loadvm_process_command(QEMUFile *f)
>  
>      case MIG_CMD_POSTCOPY_RAM_DISCARD:
>          return loadvm_postcopy_ram_handle_discard(mis, len);
> +
> +    case MIG_CMD_ENABLE_COLO:
> +        return loadvm_process_enable_colo(mis);
>      }
>  
>      return 0;
> diff --git a/migration/savevm.h b/migration/savevm.h
> index cf4f0d37ca..c6d46b37a2 100644
> --- a/migration/savevm.h
> +++ b/migration/savevm.h
> @@ -52,6 +52,7 @@ void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, 
> const char *name,
>                                             uint16_t len,
>                                             uint64_t *start_list,
>                                             uint64_t *length_list);
> +void qemu_savevm_send_colo_enable(QEMUFile *f);
>  
>  int qemu_loadvm_state(QEMUFile *f);
>  void qemu_loadvm_state_cleanup(void);
> diff --git a/migration/trace-events b/migration/trace-events
> index d6be74b7a7..9295b4cf40 100644
> --- a/migration/trace-events
> +++ b/migration/trace-events
> @@ -34,6 +34,7 @@ savevm_send_open_return_path(void) ""
>  savevm_send_ping(uint32_t val) "0x%x"
>  savevm_send_postcopy_listen(void) ""
>  savevm_send_postcopy_run(void) ""
> +savevm_send_colo_enable(void) ""
>  savevm_state_setup(void) ""
>  savevm_state_header(void) ""
>  savevm_state_iterate(void) ""
> diff --git a/vl.c b/vl.c
> index 12e31d1aa9..a1576d2045 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -4437,8 +4437,6 @@ int main(int argc, char **argv, char **envp)
>  #endif
>      }
>  
> -    colo_info_init();
> -
>      if (net_init_clients(&err) < 0) {
>          error_report_err(err);
>          exit(1);
> -- 
> 2.17.0
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK