From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.droids-corp.org (zoll.droids-corp.org [94.23.50.67]) by dpdk.org (Postfix) with ESMTP id E76AD4CE6 for ; Thu, 21 Jul 2016 16:25:53 +0200 (CEST) Received: from alille-653-1-293-182.w90-1.abo.wanadoo.fr ([90.1.53.182] helo=[192.168.1.13]) by mail.droids-corp.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84_2) (envelope-from ) id 1bQExb-0007gC-HF; Thu, 21 Jul 2016 16:28:27 +0200 To: Zoltan Kiss , Zoltan Kiss , dev@dpdk.org References: <1469034999-2732-1-git-send-email-zoltan.kiss@schaman.hu> <34eb5f3b-307a-3072-d262-e46a6437eea7@linaro.org> Cc: Bruce Richardson From: Olivier Matz Message-ID: <1e8aa5d1-b83e-5e35-e382-b0cc685ffb56@6wind.com> Date: Thu, 21 Jul 2016 16:25:41 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.1.0 MIME-Version: 1.0 In-Reply-To: <34eb5f3b-307a-3072-d262-e46a6437eea7@linaro.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH v2] mempool: adjust name string size in related data types 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, 21 Jul 2016 14:25:54 -0000 On 07/21/2016 03:47 PM, Zoltan Kiss wrote: > > > On 21/07/16 14:40, Olivier Matz wrote: >> Hi Zoltan, >> >> >> On 07/20/2016 07:16 PM, Zoltan Kiss wrote: >>> A recent patch brought up an issue about the size of the 'name' fields: >>> >>> 85cf0079 mem: avoid memzone/mempool/ring name truncation >>> >>> These relations should be observed: >>> >>> 1. Each ring creates a memzone with a prefixed name: >>> RTE_RING_NAMESIZE <= RTE_MEMZONE_NAMESIZE - strlen(RTE_RING_MZ_PREFIX) >>> >>> 2. There are some mempool handlers which create a ring with a prefixed >>> name: >>> RTE_MEMPOOL_NAMESIZE <= RTE_RING_NAMESIZE - >>> strlen(RTE_MEMPOOL_MZ_PREFIX) >>> >>> 3. A mempool can create up to RTE_MAX_MEMZONE pre and postfixed >>> memzones: >>> sprintf(postfix, "_%d", RTE_MAX_MEMZONE) >>> RTE_MEMPOOL_NAMESIZE <= RTE_MEMZONE_NAMESIZE - >>> strlen(RTE_MEMPOOL_MZ_PREFIX) - strlen(postfix) >>> >>> Setting all of them to 32 hides this restriction from the application. >>> This patch decreases the mempool and ring string size to accommodate for >>> these prefixes, but it doesn't apply the 3rd constraint. Applications >>> relying on these constants need to be recompiled, otherwise they'll run >>> into ENAMETOOLONG issues. >>> The size of the arrays are kept 32 for ABI compatibility, it can be >>> decreased next time the ABI changes. >>> >>> Signed-off-by: Zoltan Kiss >> >> Looks like to be a good compromise for the 16.07 release. One question >> however: why not taking in account the 3rd constraint? Because it may >> not completly fix the issue if the mempool is fragmented. >> >> We could define RTE_MEMPOOL_NAMESIZE to 24 >> = 32 - len('mp_') - len('_0123')) > > I was trying to figure out a compile time macro for strlen(postfix), but > I could not. Your suggestion would work only until someone increases > RTE_MAX_MEMZONE above 9999. As the likelihood of fragmenting a pool over > 99 memzones seems small, I did not bother to fix this with an ugly hack, > but if you think we should include it, let me know! Ok, looks fair, thanks for the clarification. Acked-by: Olivier Matz