Re: [Qemu-devel] [PATCH 07/12] savevm: split save_live_setup from save_live_state

[Orit Wasserman <owasserm@redhat.com>]

On 06/28/2012 10:22 PM, Juan Quintela wrote:
> This patch splits stage 1 to its own function for both save_live
> users, ram and block.  It is just a copy of the function, removing the
> parts of the other stages.  Optimizations would came later.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  arch_init.c       |   86 +++++++++++++++++++++++++++++++++++++++--------------
>  block-migration.c |   35 +++++++++++++++++-----
>  savevm.c          |    4 +--
>  vmstate.h         |    1 +
>  4 files changed, 95 insertions(+), 31 deletions(-)
> 
> diff --git a/arch_init.c b/arch_init.c
> index 36e19b0..b296e17 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -303,44 +303,85 @@ static void ram_migration_cancel(void *opaque)
> 
>  #define MAX_WAIT 50 /* ms, half buffered_file limit */
> 
> -static int ram_save_live(QEMUFile *f, int stage, void *opaque)
> +static int ram_save_setup(QEMUFile *f, void *opaque)
>  {
>      ram_addr_t addr;
> -    uint64_t bytes_transferred_last;
> +    RAMBlock *block;
>      double bwidth = 0;
>      int ret;
>      int i;
> 
>      memory_global_sync_dirty_bitmap(get_system_memory());
> 
> -    if (stage == 1) {
> -        RAMBlock *block;
> -        bytes_transferred = 0;
> -        last_block = NULL;
> -        last_offset = 0;
> -        sort_ram_list();
> -
> -        /* Make sure all dirty bits are set */
> -        QLIST_FOREACH(block, &ram_list.blocks, next) {
> -            for (addr = 0; addr < block->length; addr += TARGET_PAGE_SIZE) {
> -                if (!memory_region_get_dirty(block->mr, addr, TARGET_PAGE_SIZE,
> -                                             DIRTY_MEMORY_MIGRATION)) {
> -                    memory_region_set_dirty(block->mr, addr, TARGET_PAGE_SIZE);
> -                }
> +    bytes_transferred = 0;
> +    last_block = NULL;
> +    last_offset = 0;
> +    sort_ram_list();
> +
> +    /* Make sure all dirty bits are set */
> +    QLIST_FOREACH(block, &ram_list.blocks, next) {
> +        for (addr = 0; addr < block->length; addr += TARGET_PAGE_SIZE) {
> +            if (!memory_region_get_dirty(block->mr, addr, TARGET_PAGE_SIZE,
> +                                         DIRTY_MEMORY_MIGRATION)) {
> +                memory_region_set_dirty(block->mr, addr, TARGET_PAGE_SIZE);
>              }
>          }
> +    }
> 
> -        memory_global_dirty_log_start();
> +    memory_global_dirty_log_start();
> +
> +    qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE);
> +
> +    QLIST_FOREACH(block, &ram_list.blocks, next) {
> +        qemu_put_byte(f, strlen(block->idstr));
> +        qemu_put_buffer(f, (uint8_t *)block->idstr, strlen(block->idstr));
> +        qemu_put_be64(f, block->length);
> +    }
> +
> +    bwidth = qemu_get_clock_ns(rt_clock);
> 
> -        qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE);
> +    i = 0;
> +    while ((ret = qemu_file_rate_limit(f)) == 0) {
> +        int bytes_sent;
> 
> -        QLIST_FOREACH(block, &ram_list.blocks, next) {
> -            qemu_put_byte(f, strlen(block->idstr));
> -            qemu_put_buffer(f, (uint8_t *)block->idstr, strlen(block->idstr));
> -            qemu_put_be64(f, block->length);
> +        bytes_sent = ram_save_block(f);
> +        bytes_transferred += bytes_sent;
> +        if (bytes_sent == 0) { /* no more blocks */
> +            break;
>          }
> +        /* we want to check in the 1st loop, just in case it was the 1st time
> +           and we had to sync the dirty bitmap.
> +           qemu_get_clock_ns() is a bit expensive, so we only check each some
> +           iterations
> +        */
> +        if ((i & 63) == 0) {
> +            uint64_t t1 = (qemu_get_clock_ns(rt_clock) - bwidth) / 1000000;
> +            if (t1 > MAX_WAIT) {
> +                DPRINTF("big wait: %ld milliseconds, %d iterations\n", t1, i);
> +                break;
> +            }
> +        }
> +        i++;
>      }
> 
> +    if (ret < 0) {
> +        return ret;
> +    }
> +
> +    qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
> +
> +    return 0;
> +}
> +
> +static int ram_save_live(QEMUFile *f, int stage, void *opaque)
> +{
> +    uint64_t bytes_transferred_last;
> +    double bwidth = 0;
> +    int ret;
> +    int i;
> +
> +    memory_global_sync_dirty_bitmap(get_system_memory());
> +
>      bytes_transferred_last = bytes_transferred;
>      bwidth = qemu_get_clock_ns(rt_clock);
> 
> @@ -534,6 +575,7 @@ done:
>  }
> 
>  SaveVMHandlers savevm_ram_handlers = {
> +    .save_live_setup = ram_save_setup,
>      .save_live_state = ram_save_live,
>      .load_state = ram_load,
>      .cancel = ram_migration_cancel,
> diff --git a/block-migration.c b/block-migration.c
> index 6d37dc1..fc3d1f4 100644
> --- a/block-migration.c
> +++ b/block-migration.c
> @@ -541,20 +541,40 @@ static void block_migration_cancel(void *opaque)
>      blk_mig_cleanup();
>  }
> 
> -static int block_save_live(QEMUFile *f, int stage, void *opaque)
> +static int block_save_setup(QEMUFile *f, void *opaque)
>  {
>      int ret;
> 
> -    DPRINTF("Enter save live stage %d submitted %d transferred %d\n",
> -            stage, block_mig_state.submitted, block_mig_state.transferred);
> +    DPRINTF("Enter save live setup submitted %d transferred %d\n",
> +            block_mig_state.submitted, block_mig_state.transferred);
> 
> -    if (stage == 1) {
> -        init_blk_migration(f);
> +    init_blk_migration(f);
> +
> +    /* start track dirty blocks */
> +    set_dirty_tracking(1);
> +
> +    flush_blks(f);
> 
> -        /* start track dirty blocks */
> -        set_dirty_tracking(1);
> +    ret = qemu_file_get_error(f);
> +    if (ret) {
> +        blk_mig_cleanup();
> +        return ret;
>      }
> 
> +    blk_mig_reset_dirty_cursor();
> +
> +    qemu_put_be64(f, BLK_MIG_FLAG_EOS);
> +
> +    return 0;
> +}
> +
> +static int block_save_live(QEMUFile *f, int stage, void *opaque)
> +{
> +    int ret;
> +
> +    DPRINTF("Enter save live stage %d submitted %d transferred %d\n",
> +            stage, block_mig_state.submitted, block_mig_state.transferred);
> +
>      flush_blks(f);
> 
>      ret = qemu_file_get_error(f);
> @@ -710,6 +730,7 @@ static bool block_is_active(void *opaque)
> 
>  SaveVMHandlers savevm_block_handlers = {
>      .set_params = block_set_params,
> +    .save_live_setup = block_save_setup,
>      .save_live_state = block_save_live,
>      .load_state = block_load,
>      .cancel = block_migration_cancel,
> diff --git a/savevm.c b/savevm.c
> index afa0c9e..0b80a94 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -1573,7 +1573,7 @@ int qemu_savevm_state_begin(QEMUFile *f,
>      QTAILQ_FOREACH(se, &savevm_handlers, entry) {
>          int len;
> 
> -        if (!se->ops || !se->ops->save_live_state) {
> +        if (!se->ops || !se->ops->save_live_setup) {
>              continue;
>          }
>          if (se->ops && se->ops->is_active) {
> @@ -1593,7 +1593,7 @@ int qemu_savevm_state_begin(QEMUFile *f,
>          qemu_put_be32(f, se->instance_id);
>          qemu_put_be32(f, se->version_id);
> 
> -        ret = se->ops->save_live_state(f, QEMU_VM_SECTION_START, se->opaque);
> +        ret = se->ops->save_live_setup(f, se->opaque);
>          if (ret < 0) {
>              qemu_savevm_state_cancel(f);
>              return ret;
> diff --git a/vmstate.h b/vmstate.h
> index 96651a5..049f2b7 100644
> --- a/vmstate.h
> +++ b/vmstate.h
> @@ -32,6 +32,7 @@ typedef int LoadStateHandler(QEMUFile *f, void *opaque, int version_id);
>  typedef struct SaveVMHandlers {
>      void (*set_params)(const MigrationParams *params, void * opaque);
>      SaveStateHandler *save_state;
> +    int (*save_live_setup)(QEMUFile *f, void *opaque);
>      int (*save_live_state)(QEMUFile *f, int stage, void *opaque);
>      void (*cancel)(void *opaque);
>      LoadStateHandler *load_state;
> 

Reviewed-by: Orit Wasserman <owasserm@redhat.com>