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From: Olivier MATZ <olivier.matz@6wind.com>
To: Bruce Richardson <bruce.richardson@intel.com>, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH 07/13] mbuf: use macros only to access the mbuf metadata
Date: Mon, 08 Sep 2014 14:05:41 +0200
Message-ID: <540D9B95.3020504@6wind.com> (raw)
In-Reply-To: <1409759378-10113-8-git-send-email-bruce.richardson@intel.com>

Hi Bruce,

On 09/03/2014 05:49 PM, Bruce Richardson wrote:
> Removed the explicit zero-sized metadata definition at the end of the
> mbuf data structure. Updated the metadata macros to take account of this
> change so that all existing code which uses those macros still works.
> 
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> ---
>  lib/librte_mbuf/rte_mbuf.h | 22 ++++++++--------------
>  1 file changed, 8 insertions(+), 14 deletions(-)
> 
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 5260001..ca66d9a 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -166,31 +166,25 @@ struct rte_mbuf {
>  	struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
>  	struct rte_mbuf *next;    /**< Next segment of scattered packet. */
>  
> -	union {
> -		uint8_t metadata[0];
> -		uint16_t metadata16[0];
> -		uint32_t metadata32[0];
> -		uint64_t metadata64[0];
> -	} __rte_cache_aligned;
>  } __rte_cache_aligned;
>  
>  #define RTE_MBUF_METADATA_UINT8(mbuf, offset)              \
> -	(mbuf->metadata[offset])
> +	(((uint8_t *)&(mbuf)[1])[offset])
>  #define RTE_MBUF_METADATA_UINT16(mbuf, offset)             \
> -	(mbuf->metadata16[offset/sizeof(uint16_t)])
> +	(((uint16_t *)&(mbuf)[1])[offset/sizeof(uint16_t)])
>  #define RTE_MBUF_METADATA_UINT32(mbuf, offset)             \
> -	(mbuf->metadata32[offset/sizeof(uint32_t)])
> +	(((uint32_t *)&(mbuf)[1])[offset/sizeof(uint32_t)])
>  #define RTE_MBUF_METADATA_UINT64(mbuf, offset)             \
> -	(mbuf->metadata64[offset/sizeof(uint64_t)])
> +	(((uint64_t *)&(mbuf)[1])[offset/sizeof(uint64_t)])
>  
>  #define RTE_MBUF_METADATA_UINT8_PTR(mbuf, offset)          \
> -	(&mbuf->metadata[offset])
> +	(&RTE_MBUF_METADATA_UINT8(mbuf, offset))
>  #define RTE_MBUF_METADATA_UINT16_PTR(mbuf, offset)         \
> -	(&mbuf->metadata16[offset/sizeof(uint16_t)])
> +	(&RTE_MBUF_METADATA_UINT16(mbuf, offset))
>  #define RTE_MBUF_METADATA_UINT32_PTR(mbuf, offset)         \
> -	(&mbuf->metadata32[offset/sizeof(uint32_t)])
> +	(&RTE_MBUF_METADATA_UINT32(mbuf, offset))
>  #define RTE_MBUF_METADATA_UINT64_PTR(mbuf, offset)         \
> -	(&mbuf->metadata64[offset/sizeof(uint64_t)])
> +	(&RTE_MBUF_METADATA_UINT64(mbuf, offset))
>  
>  /**
>   * Given the buf_addr returns the pointer to corresponding mbuf.
> 

I think it goes in the good direction. So:
Acked-by: Olivier Matz <olivier.matz@6wind.com>

Just one question: why not removing RTE_MBUF_METADATA*() macros?
I'd just provide one macro that gives a (void*) to the first byte
after the mbuf structure.

The format of the metadata is up to the application, that usually
casts (m + 1) into a private structure, making the macros not very
useful. I suggest to move these macros outside rte_mbuf.h, in the
application-specific or library-specific header, what do you think?

Regards,
Olivier

  reply	other threads:[~2014-09-08 12:00 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-03 15:49 [dpdk-dev] [PATCH 00/13] Mbuf Structure Rework, part 2 Bruce Richardson
2014-09-03 15:49 ` [dpdk-dev] [PATCH 01/13] mbuf: replace data pointer by an offset Bruce Richardson
2014-09-08  9:52   ` Olivier MATZ
2014-09-08  9:55     ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 02/13] mbuf: reorder fields by time of use Bruce Richardson
2014-09-08 10:17   ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 03/13] mbuf: add packet_type field Bruce Richardson
2014-09-08 10:17   ` Olivier MATZ
2014-09-08 10:33     ` Yerden Zhumabekov
2014-09-08 11:17       ` Olivier MATZ
2014-09-09  3:59         ` Zhang, Helin
     [not found]           ` <540EB428.9060706@6wind.com>
2014-09-09  8:45             ` Zhang, Helin
2014-09-09  9:47             ` Richardson, Bruce
2014-09-09 15:05         ` Jim Thompson
2014-09-03 15:49 ` [dpdk-dev] [PATCH 04/13] mbuf: expand ol_flags field to 64-bits Bruce Richardson
2014-09-08 10:25   ` Olivier MATZ
2014-09-09  9:00     ` Richardson, Bruce
2014-09-03 15:49 ` [dpdk-dev] [PATCH 05/13] mbuf: introduce a flag to indicate a control mbuf Bruce Richardson
2014-09-08 11:53   ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 06/13] mbuf: minor changes for readability Bruce Richardson
2014-09-08 12:03   ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 07/13] mbuf: use macros only to access the mbuf metadata Bruce Richardson
2014-09-08 12:05   ` Olivier MATZ [this message]
2014-09-09  9:01     ` Richardson, Bruce
2014-09-12 16:56       ` Dumitrescu, Cristian
2014-09-12 21:02         ` Olivier MATZ
2014-09-16 20:07           ` Dumitrescu, Cristian
2014-09-16 22:06             ` Ramia, Kannan Babu
2014-09-17 10:31               ` Richardson, Bruce
2014-09-17 14:01                 ` Thomas Monjalon
2014-09-10 15:09     ` Bruce Richardson
2014-09-10 15:31       ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 08/13] mbuf: add named points inside the mbuf structure Bruce Richardson
2014-09-08 12:08   ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 09/13] ixgbe: rework vector pmd following mbuf changes Bruce Richardson
2014-09-03 15:49 ` [dpdk-dev] [PATCH 10/13] mbuf: split mbuf across two cache lines Bruce Richardson
2014-09-08 12:10   ` Olivier MATZ
2014-09-03 15:49 ` [dpdk-dev] [PATCH 11/13] mbuf: move l2_len and l3_len to second cache line Bruce Richardson
2014-09-04  5:08   ` Yerden Zhumabekov
2014-09-04 10:27     ` Bruce Richardson
2014-09-04 11:00       ` Yerden Zhumabekov
2014-09-04 11:55         ` Bruce Richardson
2014-09-03 15:49 ` [dpdk-dev] [PATCH 12/13] ixgbe: Fix perf regression due to moved pool ptr Bruce Richardson
2014-09-03 15:49 ` [dpdk-dev] [PATCH 13/13] ixgbe: Improve slow-path perf: vector scattered RX Bruce Richardson
2014-09-11 13:15 ` [dpdk-dev] [PATCH v2 00/13] Mbuf Structure Rework, part 2 Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 01/13] mbuf: replace data pointer by an offset Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 02/13] mbuf: reorder fields by time of use Bruce Richardson
2014-09-15  7:11     ` Liu, Jijiang
2014-09-15  8:19       ` Richardson, Bruce
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 03/13] mbuf: expand ol_flags field to 64-bits Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 04/13] mbuf: introduce a flag to indicate a control mbuf Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 05/13] mbuf: minor changes for readability Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 06/13] mbuf: use macros only to access the mbuf metadata Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 07/13] mbuf: move metadata macros to rte_port library Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 08/13] mbuf: add named points inside the mbuf structure Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 09/13] ixgbe: rework vector pmd following mbuf changes Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 10/13] mbuf: split mbuf across two cache lines Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 11/13] mbuf: move l2_len and l3_len to second cache line Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 12/13] ixgbe: Fix perf regression due to moved pool ptr Bruce Richardson
2014-09-15 16:20     ` [dpdk-dev] [PATCH v3 " Bruce Richardson
2014-09-11 13:15   ` [dpdk-dev] [PATCH v2 13/13] ixgbe: Improve slow-path perf: vector scattered RX Bruce Richardson
2014-09-17 22:35   ` [dpdk-dev] [PATCH v2 00/13] Mbuf Structure Rework, part 2 Thomas Monjalon

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