Re: [Qemu-devel] [PATCH 03/11] memory: Don't set migration bitmap when without migration

[Paolo Bonzini]

On 08/05/19 01:15, Peter Xu wrote:
> Similar to 9460dee4b2 ("memory: do not touch code dirty bitmap unless
> TCG is enabled", 2015-06-05) but for the migration bitmap - we can
> skip the MIGRATION bitmap update if migration not enabled.
> 
> Signed-off-by: Peter Xu <address@hidden>
> ---
>  include/exec/memory.h   |  2 ++
>  include/exec/ram_addr.h | 12 +++++++++++-
>  memory.c                |  2 +-
>  3 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index e6140e8a04..f29300c54d 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -46,6 +46,8 @@
>          OBJECT_GET_CLASS(IOMMUMemoryRegionClass, (obj), \
>                           TYPE_IOMMU_MEMORY_REGION)
>  
> +extern bool global_dirty_log;
> +
>  typedef struct MemoryRegionOps MemoryRegionOps;
>  typedef struct MemoryRegionMmio MemoryRegionMmio;
>  
> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
> index 993fb760f3..86bc8e1a4a 100644
> --- a/include/exec/ram_addr.h
> +++ b/include/exec/ram_addr.h
> @@ -348,8 +348,13 @@ static inline void 
> cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
>              if (bitmap[k]) {
>                  unsigned long temp = leul_to_cpu(bitmap[k]);
>  
> -                atomic_or(&blocks[DIRTY_MEMORY_MIGRATION][idx][offset], 
> temp);
>                  atomic_or(&blocks[DIRTY_MEMORY_VGA][idx][offset], temp);
> +
> +                if (global_dirty_log) {
> +                    atomic_or(&blocks[DIRTY_MEMORY_MIGRATION][idx][offset],
> +                              temp);
> +                }
> +
>                  if (tcg_enabled()) {
>                      atomic_or(&blocks[DIRTY_MEMORY_CODE][idx][offset], temp);
>                  }
> @@ -366,6 +371,11 @@ static inline void 
> cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
>          xen_hvm_modified_memory(start, pages << TARGET_PAGE_BITS);
>      } else {
>          uint8_t clients = tcg_enabled() ? DIRTY_CLIENTS_ALL : 
> DIRTY_CLIENTS_NOCODE;
> +
> +        if (!global_dirty_log) {
> +            clients &= ~(1 << DIRTY_MEMORY_MIGRATION);
> +        }
> +
>          /*
>           * bitmap-traveling is faster than memory-traveling (for addr...)
>           * especially when most of the memory is not dirty.
> diff --git a/memory.c b/memory.c
> index 0cce3a6fc5..1cc3531df5 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -38,7 +38,7 @@
>  static unsigned memory_region_transaction_depth;
>  static bool memory_region_update_pending;
>  static bool ioeventfd_update_pending;
> -static bool global_dirty_log = false;
> +bool global_dirty_log;
>  
>  static QTAILQ_HEAD(, MemoryListener) memory_listeners
>      = QTAILQ_HEAD_INITIALIZER(memory_listeners);
> 

Reviewed-by: Paolo Bonzini <address@hidden>