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[67.165.232.89]) by smtp.gmail.com with ESMTPSA id 80-v6sm5220047itk.14.2018.09.18.13.21.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 Sep 2018 13:21:09 -0700 (PDT) Reply-To: ahs3@redhat.com Subject: Re: [PATCH] net: apm: xgene: force XGene enet driver to re-balance IRQ usage To: David Miller Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, isubramanian@apm.com, kchudgar@apm.com, qnguyen@apm.com References: <20180917233533.28626-1-ahs3@redhat.com> <20180917.193531.1424852853827678152.davem@davemloft.net> From: Al Stone Openpgp: preference=signencrypt Autocrypt: addr=ahs3@redhat.com; keydata= xsFNBE00uvkBEADX+CS2RClAYGscnc6960zOrin2cZ4F+p6WoabmLQOaesHN4Upztnbdb2nD hZeGM7zkMahFeArKixtSzoNzP0qbAVbD6hFDFk33YYlv+Bxp98TRbmQgKVmeuZ3a1FrQ7xy3 PpkR4jfob4v5mWFjbIfhCqglnkiS7sqdwjSP6zyfQ8rHh3eeUI77dacbdIdAjLjuZqeB7LW6 VNO+8hEWegKL1why2KUWGeMq3qVnc7CuJQicfVO4vmxY5XCu6H3XkGJrlGIUMJXYCW87Tvjt oceL4VmLu84nc7U1vf22FAW9ACiu86B2/Tjd8PFFdIkpEsXT5lyDEsQOFoZKXXWfeuab1MQR rQHHrbVd3j7dhijRRO9VI5wWea2+EvEC1hsrMcN8P9gaZtE2adZOVb26N1u7qnO7GR8sQJe8 Dp95qiqQdLQmUyhVCBCBZVuIQyM7p3gAb3W80wob9o6VHT8rQY5eZt/en3UetLvPaHO3DJkO ZNXBJFsrIm33fjqhs44bICJz1PzMj0qM7WgO7Nn4o4ZbhiDqQAUD0Gg1/8g4dDZgFOgv/CQw ix91nF32wC57BLp1NqtbeznXJ73QuAxiEeF9tW857vRXuAdU/qMbjQAPNux4PTTJqVS9zPwa hwzelqAwzLwM/DakHm9YEPUL7QahNHlft5yjjQx5fF5RN/SR+wARAQABzS9BbCBTdG9uZSAo QWxiZXJ0IEguIFN0b25lLCBJSUkpIDxhaHMzQGFoczMubmV0PsLBegQTAQgAJAIbAwULCQgH AwUVCgkICwUWAgMBAAIeAQIXgAUCTTS88QIZAQAKCRBTDLAC12GxbK/zD/sGIp3j8n+3LtXK XmYddHmCwhLh2p+qvmTXsn/gv29wDOkXdCwRKqLD/IhM3R1+to8Yowy+/TrEEr8+aSTTzBbE zqdXKEd7iSsfpU0KDApYbToj5SGMpLuBCBuPooMlTwOhiAYO3XfP1nQ3lkQZsGJij/e3N/Y/ eVHCEf6GP7BFaX7QiVItS1LTB7a88rIKWK+mzXTOJUZHZEgIY7OGYhyU0XlSgPE9TFyCiOBA ERBqP2ffgQ9J3e9eMOPqoKM7+fdYKtdPdGgSVTV69qMe2CDPO48gWWylkFnqBxEd7t4R2cfR JiaVRh+4Al784dOrFYjHJ03ZfFBuyszQ+mGMrzVAkwYHL4efbtjs4gSsvV12OyzNJ2xvcXCT rcu6xS4RwkUnZ2G7N2JHpQTE6dioBQVghnasuq8H+r5YnFFZ6gwJbxjLIazRQ3ckT485rf7p tVsiApZsk6N8kOvCq799dW42OizHBM4WghCIBp39K0H3AoEEb8CvsFEkLGdYrdi0VtCFbWhl jUkjcIlkqpg8SHgloEuJu1cnOGwlwlzoO6IDYEycr7Ca3UhH1IjuegGlpMNZXO+G0YMbdA7i IARWCT9+MP+3b6vYCkRqoIu7XVDXswxgMgNjYNZpTisjYfGnBwn5rUtXj1l/mZzqEKppgXYm zPL1kJjr2/6wYBnKOQ/UB87BTQRNNL0hARAAqj8oed+/8sAJfHXBMHEgXBJ9uEOrxxpfPEVS Avfb3I+L6atvEDgsPrldkT5JeX96tqZ6KeVyVGTBabBalmKqE5JLzfVM3H/ODYDmAwyl/hvh CDVuyzqvaRf8M8Nu/mvqOLNZtmAy6pD9sxmwwFTUbLXo8oV3ntscIyMjGiWLenAknz2zV8uz Nx4Jn1o39nh2Hd8LrD9DPklJiDD4Fi3ctAzq1bmaDhhGnqN0c9sHCFFU4gd7QeHue5cN1Cwm yR3/7DRFLolw23C2nWjkm2BbbXsEnp09GzeesXSjnSPJkvEsTfjrK02HIWtQE9nimgm8BTuL c587MdfHVDKNUtXksAuC4vAZToguteX8fRgoPRJAiig+SwOCZvABBepWVAzhe/3n6dZXMioa w8zDBHRa9vroHfW28Pb4OULV4Ckm+xDdx/O7R9oogZEvOf+hi/zbMhbFnhg0aENU6Xx960g8 WstUNiiQ/CKAA/LzjrdEvLPKFqhu2W3HCUMtUTcPh65wK5fpaKDjmdeGha7SulroId6G0thP 6ldRDeq/qDEIlE9RLY7UHuiPdgSaGIFHkIiV9spemEF5zbFyKH5YIpdKlLUBxroeDOg26bXK QEXFUnt3/I/Rlrq6GGSy74N9vVtbRnWGXfjMi9yM/tJgnRb1als/icmx4aaqh4QkBE4GgA0A EQEAAcLBXwQYAQgACQUCTTS9IQIbDAAKCRBTDLAC12GxbORUEACKZW3kToE8eiYK5lIGaCPQ +wIMIVxBXghMTLeszXTkuhUaysLk7gveUz8q6OTnUE2iXAQQ3CAfsHLKMHwZWp1UBnTOXA16 uxsRcTL+YOBwuHBZKtt22VbIuDzFQonwoDQZ5kxycptKem61rxwTdLU2xppdplGARyWAY/RJ tj7ptWDsOQJDxNBQywUxVxo982kSs+P7QEm1RqiqKq5RfZue6Z4rvU+O2lLgnWxodYq+V6he UYYefFwVS2AOVBIwAo55Oo25wacLcdKoN2rqCCEsePWdeQ/CCODThUIPNWXL6NdyXkpZTy6Z 2DmnNwYOFcN/Oc5t/EhCxd6gWPTDymqn7N1x4o74WIh20ynPbX6gxCK1Q2NywRDBEbh9DQ/n 4wFK3jUmHGvA05LlRIzuq51AR5WaGU2sNmlWhbYRautMzCVLhsOLHlFw9fxLpMQm5lgbloDd X43U6SQES/LpEp642swYeEHngt2wUbtQnx99L0zedrc6yIb30uYoD0sqXLTXK9yetosnyEXV QKG2t/fxNPce6rdWVXuq79nrwfko/xQ+wAYAycbTBbCMZ2czy//XK7uYv2M/dB0QCv7mobHP Rjn8ZXVjntXp8Oed0GCBmPI4GPF5bDS+Xzrba24QLr39b/PCWYYb9GdV30jUAhlLu2UFuree AeZZwq9vgjZvBA== Organization: Red Hat, Inc. Message-ID: <9594b4ee-f5bb-7d6e-f7e4-452091150dd6@redhat.com> Date: Tue, 18 Sep 2018 14:21:08 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180917.193531.1424852853827678152.davem@davemloft.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/17/2018 08:35 PM, David Miller wrote: > From: Al Stone > Date: Mon, 17 Sep 2018 17:35:33 -0600 > >> @@ -866,8 +866,11 @@ static int xgene_enet_napi(struct napi_struct *napi, const int budget) >> processed = xgene_enet_process_ring(ring, budget); >> >> if (processed != budget) { >> + struct irq_desc *desc = irq_to_desc(ring->irq); >> + >> napi_complete_done(napi, processed); >> - enable_irq(ring->irq); >> + if (desc && desc->depth > 0) >> + enable_irq(ring->irq); > > I really can't accept a patch that grovels into IRQ layer internals > to work around a driver's IRQ enable/disable usage problem. > > Sorry. No worries. I hesitated even sending it, actually. The rewrite of the driver that is needed is just something no one seems to have any interest in, or any time for, but it really needs it to fix this properly (a colleague has found at least one other issue in the structure of this driver, for example). The cost of doing that rewrite/restructure, though, far outweighs the benefit for this device -- especially when the workaround is "don't run tuned". I'll put a proper fix back on the list of Interesting Things to Work On When Time Allows, for now. Thanks for the quick -- and kind :) -- response. I really appreciate it. -- ciao, al ----------------------------------- Al Stone Software Engineer Red Hat, Inc. ahs3@redhat.com -----------------------------------