Re: [Qemu-devel] [PATCH 21/41] migration: run setup callbacks out of big lock

[Orit Wasserman]

On 02/15/2013 07:46 PM, Paolo Bonzini wrote:
> Only the migration_bitmap_sync() call needs the iothread lock.
> 
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
>  arch_init.c                 |   10 ++++++----
>  block-migration.c           |    2 ++
>  include/migration/vmstate.h |    2 +-
>  migration.c                 |    2 --
>  savevm.c                    |    3 +++
>  5 files changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/arch_init.c b/arch_init.c
> index adca555..6f0e389 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -569,10 +569,6 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
>      bitmap_set(migration_bitmap, 0, ram_pages);
>      migration_dirty_pages = ram_pages;
>  
> -    qemu_mutex_lock_ramlist();
> -    bytes_transferred = 0;
> -    reset_ram_globals();
> -
>      if (migrate_use_xbzrle()) {
>          XBZRLE.cache = cache_init(migrate_xbzrle_cache_size() /
>                                    TARGET_PAGE_SIZE,
> @@ -586,8 +582,14 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
>          acct_clear();
>      }
>  
> +    qemu_mutex_lock_iothread();
> +    qemu_mutex_lock_ramlist();
> +    bytes_transferred = 0;
> +    reset_ram_globals();
> +
>      memory_global_dirty_log_start();
>      migration_bitmap_sync();
> +    qemu_mutex_unlock_iothread();
>  
>      qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE);
>  
> diff --git a/block-migration.c b/block-migration.c
> index 143180c..d673658 100644
> --- a/block-migration.c
> +++ b/block-migration.c
> @@ -583,10 +583,12 @@ static int block_save_setup(QEMUFile *f, void *opaque)
>      DPRINTF("Enter save live setup submitted %d transferred %d\n",
>              block_mig_state.submitted, block_mig_state.transferred);
>  
> +    qemu_mutex_lock_iothread();
>      init_blk_migration(f);
>  
>      /* start track dirty blocks */
>      set_dirty_tracking(1);
> +    qemu_mutex_unlock_iothread();
>  
>      ret = flush_blks(f);
>      blk_mig_reset_dirty_cursor();
> diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
> index 5f803f5..abc3b47 100644
> --- a/include/migration/vmstate.h
> +++ b/include/migration/vmstate.h
> @@ -34,7 +34,6 @@ typedef struct SaveVMHandlers {
>      void (*set_params)(const MigrationParams *params, void * opaque);
>      SaveStateHandler *save_state;
>  
> -    int (*save_live_setup)(QEMUFile *f, void *opaque);
>      void (*cancel)(void *opaque);
>      int (*save_live_complete)(QEMUFile *f, void *opaque);
>  
> @@ -49,6 +48,7 @@ typedef struct SaveVMHandlers {
>      int (*save_live_iterate)(QEMUFile *f, void *opaque);
>  
>      /* This runs outside the iothread lock!  */
> +    int (*save_live_setup)(QEMUFile *f, void *opaque);
>      uint64_t (*save_live_pending)(QEMUFile *f, void *opaque, uint64_t 
> max_size);
>  
>      LoadStateHandler *load_state;
> diff --git a/migration.c b/migration.c
> index cb7f7b4..d6a7dff 100644
> --- a/migration.c
> +++ b/migration.c
> @@ -648,10 +648,8 @@ static void *buffered_file_thread(void *opaque)
>      bool old_vm_running = false;
>      bool last_round = false;
>  
> -    qemu_mutex_lock_iothread();
>      DPRINTF("beginning savevm\n");
>      qemu_savevm_state_begin(s->file, &s->params);
> -    qemu_mutex_unlock_iothread();
>  
>      while (s->state == MIG_STATE_ACTIVE) {
>          int64_t current_time = qemu_get_clock_ms(rt_clock);
> diff --git a/savevm.c b/savevm.c
> index e10a045..7c7774e 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -1768,7 +1768,10 @@ static int qemu_savevm_state(QEMUFile *f)
>          return -EINVAL;
>      }
>  
> +    qemu_mutex_unlock_iothread();
>      qemu_savevm_state_begin(f, &params);
> +    qemu_mutex_lock_iothread();
> +
>      while (qemu_file_get_error(f) == 0) {
>          if (qemu_savevm_state_iterate(f) > 0) {
>              break;
> 
Reviewed-by: Orit Wasserman <address@hidden>