Re: [Qemu-devel] [PATCH 23/30] exec: move listener from AddressSpaceDispatch to AddressSpace

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2013-06-28 20:26, Paolo Bonzini wrote:
> This will help having two copies of AddressSpaceDispatch during the
> recreation of the radix tree (one being built, and one that is complete
> and accessed under RCU).  We do not want to have to unregister and
> re-register the listener.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  exec.c                | 17 +++++++++--------
>  include/exec/memory.h |  2 ++
>  2 files changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/exec.c b/exec.c
> index f138e56..dffdf23 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -99,7 +99,6 @@ struct AddressSpaceDispatch {
>       * The bottom level has pointers to MemoryRegionSections.
>       */
>      PhysPageEntry phys_map;
> -    MemoryListener listener;
>      AddressSpace *as;
>  };
>  
> @@ -855,7 +854,8 @@ static void register_multipage(AddressSpaceDispatch *d,
>  
>  static void mem_add(MemoryListener *listener, MemoryRegionSection *section)
>  {
> -    AddressSpaceDispatch *d = container_of(listener, AddressSpaceDispatch, listener);
> +    AddressSpace *as = container_of(listener, AddressSpace, dispatch_listener);
> +    AddressSpaceDispatch *d = as->dispatch;
>      MemoryRegionSection now = *section, remain = *section;
>      Int128 page_size = int128_make64(TARGET_PAGE_SIZE);
>  
> @@ -1717,7 +1717,8 @@ static void io_mem_init(void)
>  
>  static void mem_begin(MemoryListener *listener)
>  {
> -    AddressSpaceDispatch *d = container_of(listener, AddressSpaceDispatch, listener);
> +    AddressSpace *as = container_of(listener, AddressSpace, dispatch_listener);
> +    AddressSpaceDispatch *d = as->dispatch;
>  
>      d->phys_map.ptr = PHYS_MAP_NODE_NIL;
>  }
> @@ -1786,22 +1787,22 @@ void address_space_init_dispatch(AddressSpace *as)
>      AddressSpaceDispatch *d = g_new(AddressSpaceDispatch, 1);
>  
>      d->phys_map  = (PhysPageEntry) { .ptr = PHYS_MAP_NODE_NIL, .is_leaf = 0 };
> -    d->listener = (MemoryListener) {
> +    d->as = as;
> +    as->dispatch = d;
> +    as->dispatch_listener = (MemoryListener) {
>          .begin = mem_begin,
>          .region_add = mem_add,
>          .region_nop = mem_add,
>          .priority = 0,
>      };
> -    d->as = as;
> -    as->dispatch = d;
> -    memory_listener_register(&d->listener, as);
> +    memory_listener_register(&as->dispatch_listener, as);
>  }
>  
>  void address_space_destroy_dispatch(AddressSpace *as)
>  {
>      AddressSpaceDispatch *d = as->dispatch;

You could save this line, but only if you need to touch the patch for
some other reason.

>  
> -    memory_listener_unregister(&d->listener);
> +    memory_listener_unregister(&as->dispatch_listener);
>      g_free(d);
>      as->dispatch = NULL;
>  }
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index 913ac45..1cd1f50 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -212,6 +212,8 @@ struct AddressSpace {
>      int ioeventfd_nb;
>      struct MemoryRegionIoeventfd *ioeventfds;
>      struct AddressSpaceDispatch *dispatch;
> +    MemoryListener dispatch_listener;
> +
>      QTAILQ_ENTRY(AddressSpace) address_spaces_link;
>  };
>  
> 

Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>

Jan

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