Re: [Qemu-devel] [PATCH V7 RESEND 13/17] COLO: flush host dirty ram from cache

[Dr. David Alan Gilbert]

* Zhang Chen (address@hidden) wrote:
> From: zhanghailiang <address@hidden>
> 
> Don't need to flush all VM's ram from cache, only
> flush the dirty pages since last checkpoint
> 
> Signed-off-by: Li Zhijian <address@hidden>
> Signed-off-by: Zhang Chen <address@hidden>
> Signed-off-by: zhanghailiang <address@hidden>

Yes, I think that's right (although I wonder if it can actually be
merged in with the loop directly below it).



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

> ---
>  migration/ram.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index 4235a8f24d..21027c5b4d 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2786,6 +2786,7 @@ int colo_init_ram_cache(void)
>      }
>      ram_state = g_new0(RAMState, 1);
>      ram_state->migration_dirty_pages = 0;
> +    memory_global_dirty_log_start();
>  
>      return 0;
>  
> @@ -2806,10 +2807,12 @@ void colo_release_ram_cache(void)
>  {
>      RAMBlock *block;
>  
> +    memory_global_dirty_log_stop();
>      QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
>          g_free(block->bmap);
>          block->bmap = NULL;
>      }
> +
>      rcu_read_lock();
>      QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
>          if (block->colo_cache) {
> @@ -3042,6 +3045,15 @@ static void colo_flush_ram_cache(void)
>      void *src_host;
>      unsigned long offset = 0;
>  
> +    memory_global_dirty_log_sync();
> +    qemu_mutex_lock(&ram_state->bitmap_mutex);
> +    rcu_read_lock();
> +    RAMBLOCK_FOREACH(block) {
> +        migration_bitmap_sync_range(ram_state, block, 0, block->used_length);
> +    }
> +    rcu_read_unlock();
> +    qemu_mutex_unlock(&ram_state->bitmap_mutex);
> +
>      trace_colo_flush_ram_cache_begin(ram_state->migration_dirty_pages);
>      rcu_read_lock();
>      block = QLIST_FIRST_RCU(&ram_list.blocks);
> -- 
> 2.17.0
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK