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 74AF31B226 for ; Mon, 2 Oct 2017 16:26:45 +0200 (CEST) Received: from lfbn-lil-1-182-75.w90-45.abo.wanadoo.fr ([90.45.31.75] helo=droids-corp.org) by mail.droids-corp.org with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.84_2) (envelope-from ) id 1dz1ll-00042o-8u; Mon, 02 Oct 2017 16:32:30 +0200 Received: by droids-corp.org (sSMTP sendmail emulation); Mon, 02 Oct 2017 16:26:36 +0200 Date: Mon, 2 Oct 2017 16:26:36 +0200 From: Olivier MATZ To: Santosh Shukla Cc: dev@dpdk.org, thomas@monjalon.net, jerin.jacob@caviumnetworks.com, hemant.agrawal@nxp.com Message-ID: <20171002142635.hxoxgldphz6jcoa4@platinum> References: <20170907153042.30890-1-santosh.shukla@caviumnetworks.com> <20171001092902.10842-1-santosh.shukla@caviumnetworks.com> <20171001092902.10842-8-santosh.shukla@caviumnetworks.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171001092902.10842-8-santosh.shukla@caviumnetworks.com> User-Agent: NeoMutt/20170113 (1.7.2) Subject: Re: [dpdk-dev] [PATCH v7 7/8] mempool: introduce block size align flag X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Oct 2017 14:26:45 -0000 On Sun, Oct 01, 2017 at 02:59:01PM +0530, Santosh Shukla wrote: > Some mempool hw like octeontx/fpa block, demands block size > (/total_elem_sz) aligned object start address. > > Introducing an MEMPOOL_F_CAPA_BLK_ALIGNED_OBJECTS flag. > If this flag is set: > - Align object start address(vaddr) to a multiple of total_elt_sz. > - Allocate one additional object. Additional object is needed to make > sure that requested 'n' object gets correctly populated. > > Example: > - Let's say that we get 'x' size of memory chunk from memzone. > - And application has requested 'n' object from mempool. > - Ideally, we start using objects at start address 0 to...(x-block_sz) > for n obj. > - Not necessarily first object address i.e. 0 is aligned to block_sz. > - So we derive 'offset' value for block_sz alignment purpose i.e..'off'. > - That 'off' makes sure that start address of object is blk_sz aligned. > - Calculating 'off' may end up sacrificing first block_sz area of > memzone area x. So total number of the object which can fit in the > pool area is n-1, Which is incorrect behavior. > > Therefore we request one additional object (/block_sz area) from memzone > when MEMPOOL_F_CAPA_BLK_ALIGNED_OBJECTS flag is set. > > Signed-off-by: Santosh Shukla > Signed-off-by: Jerin Jacob > Tested-by: Hemant Agrawal Acked-by: Olivier Matz