On Mon, May 06, 2024 at 12:57:46AM +0800, Yuan Liu wrote:
> Different compression methods may require different numbers of IOVs.
> Based on streaming compression of zlib and zstd, all pages will be
> compressed to a data block, so two IOVs are needed for packet header
> and compressed data block.
> 
> Signed-off-by: Yuan Liu <yuan1....@intel.com>
> Reviewed-by: Nanhai Zou <nanhai....@intel.com>
> ---
>  migration/multifd-zlib.c |  7 +++++++
>  migration/multifd-zstd.c |  8 +++++++-
>  migration/multifd.c      | 22 ++++++++++++----------
>  3 files changed, 26 insertions(+), 11 deletions(-)
> 
> diff --git a/migration/multifd-zlib.c b/migration/multifd-zlib.c
> index 737a9645d2..2ced69487e 100644
> --- a/migration/multifd-zlib.c
> +++ b/migration/multifd-zlib.c
> @@ -70,6 +70,10 @@ static int zlib_send_setup(MultiFDSendParams *p, Error 
> **errp)
>          goto err_free_zbuff;
>      }
>      p->compress_data = z;
> +
> +    /* Needs 2 IOVs, one for packet header and one for compressed data */
> +    p->iov = g_new0(struct iovec, 2);
> +
>      return 0;
>  
>  err_free_zbuff:
> @@ -101,6 +105,9 @@ static void zlib_send_cleanup(MultiFDSendParams *p, Error 
> **errp)
>      z->buf = NULL;
>      g_free(p->compress_data);
>      p->compress_data = NULL;
> +
> +    g_free(p->iov);
> +    p->iov = NULL;
>  }
>  
>  /**
> diff --git a/migration/multifd-zstd.c b/migration/multifd-zstd.c
> index 256858df0a..ca17b7e310 100644
> --- a/migration/multifd-zstd.c
> +++ b/migration/multifd-zstd.c
> @@ -52,7 +52,6 @@ static int zstd_send_setup(MultiFDSendParams *p, Error 
> **errp)
>      struct zstd_data *z = g_new0(struct zstd_data, 1);
>      int res;
>  
> -    p->compress_data = z;
>      z->zcs = ZSTD_createCStream();
>      if (!z->zcs) {
>          g_free(z);
> @@ -77,6 +76,10 @@ static int zstd_send_setup(MultiFDSendParams *p, Error 
> **errp)
>          error_setg(errp, "multifd %u: out of memory for zbuff", p->id);
>          return -1;
>      }
> +    p->compress_data = z;
> +
> +    /* Needs 2 IOVs, one for packet header and one for compressed data */
> +    p->iov = g_new0(struct iovec, 2);
>      return 0;
>  }
>  
> @@ -98,6 +101,9 @@ static void zstd_send_cleanup(MultiFDSendParams *p, Error 
> **errp)
>      z->zbuff = NULL;
>      g_free(p->compress_data);
>      p->compress_data = NULL;
> +
> +    g_free(p->iov);
> +    p->iov = NULL;
>  }
>  
>  /**
> diff --git a/migration/multifd.c b/migration/multifd.c
> index f317bff077..d82885fdbb 100644
> --- a/migration/multifd.c
> +++ b/migration/multifd.c
> @@ -137,6 +137,13 @@ static int nocomp_send_setup(MultiFDSendParams *p, Error 
> **errp)
>          p->write_flags |= QIO_CHANNEL_WRITE_FLAG_ZERO_COPY;
>      }
>  
> +    if (multifd_use_packets()) {
> +        /* We need one extra place for the packet header */
> +        p->iov = g_new0(struct iovec, p->page_count + 1);
> +    } else {
> +        p->iov = g_new0(struct iovec, p->page_count);
> +    }
> +
>      return 0;
>  }
>  
> @@ -150,6 +157,8 @@ static int nocomp_send_setup(MultiFDSendParams *p, Error 
> **errp)
>   */
>  static void nocomp_send_cleanup(MultiFDSendParams *p, Error **errp)
>  {
> +    g_free(p->iov);
> +    p->iov = NULL;
>      return;
>  }
>  
> @@ -228,6 +237,7 @@ static int nocomp_send_prepare(MultiFDSendParams *p, 
> Error **errp)
>   */
>  static int nocomp_recv_setup(MultiFDRecvParams *p, Error **errp)
>  {
> +    p->iov = g_new0(struct iovec, p->page_count);
>      return 0;
>  }
>  
> @@ -240,6 +250,8 @@ static int nocomp_recv_setup(MultiFDRecvParams *p, Error 
> **errp)
>   */
>  static void nocomp_recv_cleanup(MultiFDRecvParams *p)
>  {
> +    g_free(p->iov);
> +    p->iov = NULL;
>  }

Are recv_setup()/recv_cleanup() for zstd/zlib missing?

If the iov will be managed by the compressors, I'm wondering whether we
should start assert(p->iov) after send|recv_setup(), and assert(!p->iov)
after send|recv_cleanup().  That'll guard all these.

>  
>  /**
> @@ -783,8 +795,6 @@ static bool 
> multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp)
>      p->packet_len = 0;
>      g_free(p->packet);
>      p->packet = NULL;
> -    g_free(p->iov);
> -    p->iov = NULL;
>      multifd_send_state->ops->send_cleanup(p, errp);
>  
>      return *errp == NULL;
> @@ -1179,11 +1189,6 @@ bool multifd_send_setup(void)
>              p->packet = g_malloc0(p->packet_len);
>              p->packet->magic = cpu_to_be32(MULTIFD_MAGIC);
>              p->packet->version = cpu_to_be32(MULTIFD_VERSION);
> -
> -            /* We need one extra place for the packet header */
> -            p->iov = g_new0(struct iovec, page_count + 1);
> -        } else {
> -            p->iov = g_new0(struct iovec, page_count);
>          }
>          p->name = g_strdup_printf("multifdsend_%d", i);
>          p->page_size = qemu_target_page_size();
> @@ -1353,8 +1358,6 @@ static void 
> multifd_recv_cleanup_channel(MultiFDRecvParams *p)
>      p->packet_len = 0;
>      g_free(p->packet);
>      p->packet = NULL;
> -    g_free(p->iov);
> -    p->iov = NULL;
>      g_free(p->normal);
>      p->normal = NULL;
>      g_free(p->zero);
> @@ -1602,7 +1605,6 @@ int multifd_recv_setup(Error **errp)
>              p->packet = g_malloc0(p->packet_len);
>          }
>          p->name = g_strdup_printf("multifdrecv_%d", i);
> -        p->iov = g_new0(struct iovec, page_count);
>          p->normal = g_new0(ram_addr_t, page_count);
>          p->zero = g_new0(ram_addr_t, page_count);
>          p->page_count = page_count;
> -- 
> 2.39.3
> 

-- 
Peter Xu


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