Re: [Qemu-devel] [PATCH 2/7] cutils: Export only buffer_is_zero

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Richard Henderson (rth@twiddle.net) wrote:
> Since the two users don't make use of the returned offset,
> beyond ensuring that the entire buffer is zero, consider the
> can_use_buffer_find_nonzero_offset and buffer_find_nonzero_offset
> functions internal.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>

Thanks, I've wanted to kill that off for a while.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  include/qemu/cutils.h | 2 --
>  migration/ram.c       | 2 +-
>  migration/rdma.c      | 5 +----
>  util/cutils.c         | 8 ++++----
>  4 files changed, 6 insertions(+), 11 deletions(-)
> 
> diff --git a/include/qemu/cutils.h b/include/qemu/cutils.h
> index 3e4ea23..ca58577 100644
> --- a/include/qemu/cutils.h
> +++ b/include/qemu/cutils.h
> @@ -168,8 +168,6 @@ int64_t qemu_strtosz_suffix_unit(const char *nptr, char **end,
>  /* used to print char* safely */
>  #define STR_OR_NULL(str) ((str) ? (str) : "null")
>  
> -bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len);
> -size_t buffer_find_nonzero_offset(const void *buf, size_t len);
>  bool buffer_is_zero(const void *buf, size_t len);
>  
>  /*
> diff --git a/migration/ram.c b/migration/ram.c
> index a3d70c4..a6e1c63 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -73,7 +73,7 @@ static const uint8_t ZERO_TARGET_PAGE[TARGET_PAGE_SIZE];
>  
>  static inline bool is_zero_range(uint8_t *p, uint64_t size)
>  {
> -    return buffer_find_nonzero_offset(p, size) == size;
> +    return buffer_is_zero(p, size);
>  }
>  
>  /* struct contains XBZRLE cache and a static page
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 5110ec8..88bdb64 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -1934,10 +1934,7 @@ retry:
>               * memset() + madvise() the entire chunk without RDMA.
>               */
>  
> -            if (can_use_buffer_find_nonzero_offset((void *)(uintptr_t)sge.addr,
> -                                                   length)
> -                   && buffer_find_nonzero_offset((void *)(uintptr_t)sge.addr,
> -                                                    length) == length) {
> +            if (buffer_is_zero((void *)(uintptr_t)sge.addr, length)) {
>                  RDMACompress comp = {
>                                          .offset = current_addr,
>                                          .value = 0,
> diff --git a/util/cutils.c b/util/cutils.c
> index 1c8635c..621ca67 100644
> --- a/util/cutils.c
> +++ b/util/cutils.c
> @@ -327,9 +327,9 @@ static bool avx2_support(void)
>      return b & bit_AVX2;
>  }
>  
> -bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len) \
> +static bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len) \
>           __attribute__ ((ifunc("can_use_buffer_find_nonzero_offset_ifunc")));
> -size_t buffer_find_nonzero_offset(const void *buf, size_t len) \
> +static size_t buffer_find_nonzero_offset(const void *buf, size_t len) \
>           __attribute__ ((ifunc("buffer_find_nonzero_offset_ifunc")));
>  
>  static void *buffer_find_nonzero_offset_ifunc(void)
> @@ -350,12 +350,12 @@ static void *can_use_buffer_find_nonzero_offset_ifunc(void)
>  }
>  #pragma GCC pop_options
>  #else
> -bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len)
> +static bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len)
>  {
>      return can_use_buffer_find_nonzero_offset_inner(buf, len);
>  }
>  
> -size_t buffer_find_nonzero_offset(const void *buf, size_t len)
> +static size_t buffer_find_nonzero_offset(const void *buf, size_t len)
>  {
>      return buffer_find_nonzero_offset_inner(buf, len);
>  }
> -- 
> 2.7.4
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK