Re: [Qemu-devel] [PATCH v2 3/3] migration: add bitmap for received page

[Peter Xu]

On Thu, Jun 15, 2017 at 07:36:15PM +0300, Alexey Perevalov wrote:

[...]

> +void init_receivedmap(void)
> +{
> +    RAMBlock *rb;
> +
> +    RAMBLOCK_FOREACH(rb) {
> +        unsigned long pages;
> +        pages = rb->max_length >> TARGET_PAGE_BITS;

Nit: I would assert(!rb->receivedmap) before new it in case for leak.

> +        rb->receivedmap = bitmap_new(pages);
> +    }
> +}
> +
> +static unsigned long int get_received_bit_offset(void *host_addr, RAMBlock 
> *rb)
> +{
> +    uint64_t host_addr_offset = (uint64_t)(uintptr_t)(host_addr
> +                                                      - (void *)rb->host);
> +    return host_addr_offset >> TARGET_PAGE_BITS;
> +}

Can we rename this function to ramblock_get_pfn() and export it in
ramblock API (exec/ram_addr.h)?

static inline uint64_t ramblock_get_pfn(RAMBlock *rb, void *host)
{
    return (host - rb->host) >> TARGET_PAGE_BITS;
}

> +
> +int test_receivedmap_by_addr(void *host_addr, RAMBlock *rb)
> +{
> +    return test_bit(get_received_bit_offset(host_addr, rb), rb->receivedmap);
> +}
> +
> +void set_receivedmap_by_addr(void *host_addr, RAMBlock *rb)
> +{
> +    set_bit_atomic(get_received_bit_offset(host_addr, rb), rb->receivedmap);
> +}
> +
>  /*
>   * An outstanding page request, on the source, having been received
>   * and queued
> @@ -2324,8 +2352,13 @@ static int ram_load_setup(QEMUFile *f, void *opaque)
>  
>  static int ram_load_cleanup(void *opaque)
>  {
> +    RAMBlock *rb;
>      xbzrle_load_cleanup();
>      compress_threads_load_cleanup();
> +
> +    RAMBLOCK_FOREACH(rb) {

Nit: I'd prefer: if (rb->receivedmap) {...}

> +        g_free(rb->receivedmap);

and: rb->receivedmap = NULL later.

> +    }
>      return 0;
>  }
>  
> diff --git a/migration/ram.h b/migration/ram.h
> index c081fde..7048ff9 100644
> --- a/migration/ram.h
> +++ b/migration/ram.h
> @@ -52,4 +52,9 @@ int ram_discard_range(const char *block_name, uint64_t 
> start, size_t length);
>  int ram_postcopy_incoming_init(MigrationIncomingState *mis);
>  
>  void ram_handle_compressed(void *host, uint8_t ch, uint64_t size);
> +
> +void init_receivedmap(void);
> +int test_receivedmap_by_addr(void *host_addr, RAMBlock *rb);
> +void set_receivedmap_by_addr(void *host_addr, RAMBlock *rb);

Nit: I would name these names as: ramblock_recv_map_*().

> +
>  #endif
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 31158da..668d3bb 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -1372,6 +1372,7 @@ static int 
> loadvm_postcopy_handle_advise(MigrationIncomingState *mis)
>          return -1;
>      }
>  
> +    init_receivedmap();
>      remote_pagesize_summary = qemu_get_be64(mis->from_src_file);
>      local_pagesize_summary = ram_pagesize_summary();
>  
> -- 
> 1.9.1
> 

Again, did you trap precopy?

Thanks,

-- 
Peter Xu