Re: [PATCH v8 2/6] memory: make global_dirty_tracking a bitmask

[Peter Xu]

On Fri, Jun 18, 2021 at 11:32:03PM +0800, huangy81@chinatelecom.cn wrote:
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index b114f54..dd2404f 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -55,7 +55,17 @@ static inline void fuzz_dma_read_cb(size_t addr,
>  }
>  #endif
>  
> -extern bool global_dirty_log;
> +/* Possible bits for global_dirty_log */

s/log/tracking/

[...]

> -static void memory_global_dirty_log_do_stop(void)
> +static void memory_global_dirty_log_do_stop(unsigned int flags)
>  {
> -    global_dirty_log = false;
> +    assert(flags && !(flags & (~GLOBAL_DIRTY_MASK)));
> +    assert((global_dirty_tracking & flags) == flags);
> +    global_dirty_tracking &= ~flags;
> +
> +    trace_global_dirty_changed(global_dirty_tracking);
>  
>      /* Refresh DIRTY_MEMORY_MIGRATION bit.  */
>      memory_region_transaction_begin();
> @@ -2691,8 +2699,9 @@ static void memory_global_dirty_log_do_stop(void)
>  static void memory_vm_change_state_handler(void *opaque, bool running,
>                                             RunState state)
>  {
> +    unsigned int *flags = (unsigned int *)opaque;

[1]

>      if (running) {
> -        memory_global_dirty_log_do_stop();
> +        memory_global_dirty_log_do_stop(*flags);
>  
>          if (vmstate_change) {
>              qemu_del_vm_change_state_handler(vmstate_change);
> @@ -2701,18 +2710,19 @@ static void memory_vm_change_state_handler(void 
> *opaque, bool running,
>      }
>  }
>  
> -void memory_global_dirty_log_stop(void)
> +void memory_global_dirty_log_stop(unsigned int flags)
>  {
>      if (!runstate_is_running()) {
>          if (vmstate_change) {
>              return;
>          }
>          vmstate_change = qemu_add_vm_change_state_handler(
> -                                memory_vm_change_state_handler, NULL);
> +                                memory_vm_change_state_handler,
> +                                (void *)&flags);

If to drop malloc/free, we need to cast it with (void *)flags.  &flags is the
address of the local var, which will lost its meaning after the function
returns..

Then at [1] it should be "unsigned int flags = (unsigned int)opaque;".

-- 
Peter Xu