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[79.131.225.144]) by smtp.gmail.com with ESMTPSA id g14sm113417wro.11.2019.07.02.14.15.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 02 Jul 2019 14:15:39 -0700 (PDT) Date: Wed, 3 Jul 2019 00:15:36 +0300 From: Ilias Apalodimas To: Jesper Dangaard Brouer Cc: Ivan Khoronzhuk , netdev@vger.kernel.org, grygorii.strashko@ti.com, jakub.kicinski@netronome.com, daniel@iogearbox.net, john.fastabend@gmail.com, ast@kernel.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org Subject: Re: [PATCH] net: core: page_pool: add user refcnt and reintroduce page_pool_destroy Message-ID: <20190702211536.GA22618@apalos> References: <20190702153902.0e42b0b2@carbon> <156207778364.29180.5111562317930943530.stgit@firesoul> <20190702144426.GD4510@khorivan> <20190702165230.6caa36e3@carbon> <20190702145612.GF4510@khorivan> <20190702171029.76c60538@carbon> <20190702152112.GG4510@khorivan> <20190702202907.15fb30ce@carbon> <20190702185839.GH4510@khorivan> <20190702230241.3be6d787@carbon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190702230241.3be6d787@carbon> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jesper, Getting late here, i'll respond in detail tomorrow. One point though [...] > > This special use-case, seems confined to your driver. And Ilias told me > that XDP is not really a performance benefit for this driver as the HW > PPS-limit is hit before the XDP and netstack limit. I ask, does it > make sense to add XDP to this driver, if it complicates the code for > everybody else? I think yes. This is a widely used driver on TI embedded devices so having XDP to play along is a nice feature. It's also the first and only armv7 we have supporting this. Ivan already found a couple of issues due to the 32-bit architecture he is trying to fix, i think there's real benefit in having that, performance aside. I fully agree we should not impact the performance of the API to support a special hardware though. I'll have a look on the 2 solutions tomorrow, but the general approach on this one should be 'the simpler the better' Cheers /Ilias > > -- > Best regards, > Jesper Dangaard Brouer > MSc.CS, Principal Kernel Engineer at Red Hat > LinkedIn: http://www.linkedin.com/in/brouer