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[213.41.151.210]) by smtp.gmail.com with ESMTPSA id ez4sm30586135wid.14.2015.07.30.09.07.36 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 30 Jul 2015 09:07:36 -0700 (PDT) Message-ID: <55BA4BC0.80800@6wind.com> Date: Thu, 30 Jul 2015 18:07:28 +0200 From: Olivier MATZ User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.7.0 MIME-Version: 1.0 To: "Zhang, Helin" , "dev@dpdk.org" References: <1682615.eOc1hvvtSx@xps13> <1438264561-18359-1-git-send-email-olivier.matz@6wind.com> In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH] mbuf: enforce alignment of mbuf private area X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Jul 2015 16:07:37 -0000 On 07/30/2015 05:33 PM, Zhang, Helin wrote: > > >> -----Original Message----- >> From: Olivier Matz [mailto:olivier.matz@6wind.com] >> Sent: Thursday, July 30, 2015 6:56 AM >> To: dev@dpdk.org >> Cc: Ananyev, Konstantin; olivier.matz@6wind.com; Zhang, Helin; >> martin.weiser@allegro-packets.com; thomas.monjalon@6wind.com >> Subject: [PATCH] mbuf: enforce alignment of mbuf private area >> >> It looks better to have a data buffer address that is aligned to >> 8 bytes. This is the case when there is no mbuf private area, but if there is one, >> the alignment depends on the size of this area that is located between the mbuf >> structure and the data buffer. >> >> Indeed, some drivers expects to have the buffer address aligned to an even >> address, and moreover an unaligned buffer may impact the performance when >> accessing to network headers. >> >> Add a check in rte_pktmbuf_pool_create() to verify the alignment constraint >> before creating the mempool. For applications that use the alternative way >> (direct call to rte_mempool_create), also add an assertion in rte_pktmbuf_init(). >> >> By the way, also add the MBUF log type. >> >> Signed-off-by: Olivier Matz >> --- >> lib/librte_eal/common/include/rte_log.h | 1 + >> lib/librte_mbuf/rte_mbuf.c | 8 +++++++- >> lib/librte_mbuf/rte_mbuf.h | 7 +++++-- >> 3 files changed, 13 insertions(+), 3 deletions(-) >> >> diff --git a/lib/librte_eal/common/include/rte_log.h >> b/lib/librte_eal/common/include/rte_log.h >> index 24a55cc..ede0dca 100644 >> --- a/lib/librte_eal/common/include/rte_log.h >> +++ b/lib/librte_eal/common/include/rte_log.h >> @@ -77,6 +77,7 @@ extern struct rte_logs rte_logs; >> #define RTE_LOGTYPE_PORT 0x00002000 /**< Log related to port. */ >> #define RTE_LOGTYPE_TABLE 0x00004000 /**< Log related to table. */ >> #define RTE_LOGTYPE_PIPELINE 0x00008000 /**< Log related to pipeline. */ >> +#define RTE_LOGTYPE_MBUF 0x00010000 /**< Log related to mbuf. */ >> >> /* these log types can be used in an application */ >> #define RTE_LOGTYPE_USER1 0x01000000 /**< User-defined log type 1. */ >> diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c index >> 4320dd4..a1ddbb3 100644 >> --- a/lib/librte_mbuf/rte_mbuf.c >> +++ b/lib/librte_mbuf/rte_mbuf.c >> @@ -125,6 +125,7 @@ rte_pktmbuf_init(struct rte_mempool *mp, >> mbuf_size = sizeof(struct rte_mbuf) + priv_size; >> buf_len = rte_pktmbuf_data_room_size(mp); >> >> + RTE_MBUF_ASSERT((priv_size & (RTE_MBUF_PRIV_ALIGN - 1)) == 0); > Using RTE_ALIGN() could be more readable? > >> RTE_MBUF_ASSERT(mp->elt_size >= mbuf_size); >> RTE_MBUF_ASSERT(buf_len <= UINT16_MAX); >> >> @@ -154,7 +155,12 @@ rte_pktmbuf_pool_create(const char *name, unsigned >> n, >> struct rte_pktmbuf_pool_private mbp_priv; >> unsigned elt_size; >> >> - >> + if ((priv_size & (RTE_MBUF_PRIV_ALIGN - 1)) != 0) { > Using RTE_ALIGN() could be more readable? Will do, thanks for commenting. > >> + RTE_LOG(ERR, MBUF, "mbuf priv_size=%u is not aligned\n", >> + priv_size); >> + rte_errno = EINVAL; >> + return NULL; >> + } >> elt_size = sizeof(struct rte_mbuf) + (unsigned)priv_size + >> (unsigned)data_room_size; >> mbp_priv.mbuf_data_room_size = data_room_size; diff --git >> a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h index >> 010b32d..c3b8c98 100644 >> --- a/lib/librte_mbuf/rte_mbuf.h >> +++ b/lib/librte_mbuf/rte_mbuf.h >> @@ -698,6 +698,9 @@ extern "C" { >> >> RTE_PTYPE_INNER_L4_MASK)) #endif /* RTE_NEXT_ABI */ >> >> +/** Alignment constraint of mbuf private area. */ #define >> +RTE_MBUF_PRIV_ALIGN 8 >> + >> /** >> * Get the name of a RX offload flag >> * >> @@ -1238,7 +1241,7 @@ void rte_pktmbuf_pool_init(struct rte_mempool *mp, >> void *opaque_arg); >> * details. >> * @param priv_size >> * Size of application private are between the rte_mbuf structure >> - * and the data buffer. >> + * and the data buffer. This value must be aligned to >> RTE_MBUF_PRIV_ALIGN. >> * @param data_room_size >> * Size of data buffer in each mbuf, including RTE_PKTMBUF_HEADROOM. >> * @param socket_id >> @@ -1250,7 +1253,7 @@ void rte_pktmbuf_pool_init(struct rte_mempool *mp, >> void *opaque_arg); >> * with rte_errno set appropriately. Possible rte_errno values include: >> * - E_RTE_NO_CONFIG - function could not get pointer to rte_config >> structure >> * - E_RTE_SECONDARY - function was called from a secondary process >> instance >> - * - EINVAL - cache size provided is too large >> + * - EINVAL - cache size provided is too large, or priv_size is not aligned. >> * - ENOSPC - the maximum number of memzones has already been >> allocated >> * - EEXIST - a memzone with the same name already exists >> * - ENOMEM - no appropriate memory area found in which to create >> memzone >> -- >> 2.1.4 >