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[97.113.8.179]) by smtp.googlemail.com with ESMTPSA id 71-v6sm2362342pfx.182.2018.09.12.08.08.02 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 Sep 2018 08:08:02 -0700 (PDT) Subject: Re: [PATCH 0/2] Use named address spaces for percpu data To: Matthew Wilcox , Ingo Molnar Cc: Waiman Long , x86@kernel.org, linux-kernel@vger.kernel.org References: <20180912144442.29271-1-willy@infradead.org> From: Richard Henderson Openpgp: preference=signencrypt Autocrypt: addr=rth@twiddle.net; prefer-encrypt=mutual; keydata= xsBNBFGuLC8BCADcAoWcnW9lTsDMzbO3MBU+KbiGaj5JPatEUscRDkQYM2fyNjJp2tIWDK5a n4yngeXB3eX61WbYR3QraRK8mlYLGxyAdHMEQfPipbqf3TmN043fssT2bc82ApJcs1zvLYgI rhMht7Dck7A0wNC1jo+ZjVVFig5gDTN7gOzaAdBtV8tVNUddwkLzzaGpfihhSD6U46NdqKOG Wlnn6TrkMy0QGdQ5NaXHkRlUjnnUTSW/nKfoxD+EI+A9V4sYOd8mc/TL4aJh/i/AiU57eLbo n17uQI6/VTWDUWl8USiz4x9c8vmqlywLx00tAFxxoRWqk4KVJlj+Sh0up/D/sJ+vPpgBABEB AAHNI1JpY2hhcmQgSGVuZGVyc29uIDxydGhAdHdpZGRsZS5uZXQ+wsCBBBMBAgArAhsDBgsJ CAcDAgYVCAIJCgsEFgIDAQIeAQIXgAUJC7UHogUCWaDNVgIZAQAKCRCtEnDMTdAnm9N5CADO cB8F/SudJ72IupxQf40hbJdBK176+gb3sHMsixyLtrU59lee+lIM1OZmlNjsnCYmiSnbA5ks Q7p0HfO7DgdmfLzcK6xsHZukqSZy5LByw348Y913ZyjOrJZFdPP7kDg1MnqRqH4+3ZdzxV4y eYBWFU9GYMIF06JbUubossOOO4ArNVZbnIPu8Vn2tDZVVqsCBqkoCSBMj519xrvyOu5z4mHS LkCglXmVDOXMbqLuNAC3rfNXSnyM4hYkLUyfALJlAAy1Ro+jUqYhu7XUFV/MiwRuFMh5GbtY Urkx7tqsWQXLT3GeDk/LqvpWJQwk4cHHckYjRih+70CHIenm81PVzsBNBFGuLC8BCACyEx3x 94HIkTX0CHu2sA0w75+h9wuoA8ggJ7+S4ri0y2YsijWad5TTt6z6MMiqxk9kSA5bppaj4HXh 86hBF/dWCtMpNr3Rb8FNOKyeA/qkYHVD6HiAiw9c6D8Dr9hWmOk3/HSmGrNURxeUFOckDXsv I+yGGKBNshj59j7QZr7ZiuIi2rWlBL8dFN/OWa/o3x7HKsE4k6K8ngwvCKP/QbDLwLLBOWH+ VEUtpyeyxTr3OJ47ECTxdYvXoAV2iJaKr+6doVQiiR5eVFiMYrUPUECJeolOCwqc/JlWE18L +PCAFaW1H+/mpPVfSpN4wnkJ5cQiQVB41IaCM4p20iRzx7ZJABEBAAHCwGUEGAECAA8CGwwF AlmgzYEFCQu1CEoACgkQrRJwzE3QJ5s7rggAwABzDAGrZ6uWsMxg5PeiiAYPy6LBnCBJSpB5 Tfy5jH8QTmLfXW+u4Ib4sWXG7PYNR7sIrtqUHjRqXLVXrSnBX9ASGcYw/Xil45khW6LsRpO1 prHv9gkwQfa6fTiWXVfSfm2Nant6u02q+MaYtQpCVTiz/9ki4FfftUwUHFLU0MhIQogjd11y /E08RJsqBwaHQdt14PwU1HphDOzSkhOXRXQLSd3ysyeGUXvL+gqQoXl5XYdvk8IId4PoJRo4 jcyJ4VbnldvXh5gdGhFA/f9JgkLk9tPW+C3wNtNWyRUq8azR9hF2fg2HJUf4IXQlIu8OOgh1 VcROBqvtH3ecaIL9iw== Message-ID: <988cf77c-e0cc-25fb-dcd6-945e6f2ba65e@twiddle.net> Date: Wed, 12 Sep 2018 08:08:01 -0700 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: <20180912144442.29271-1-willy@infradead.org> 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 09/12/2018 07:44 AM, Matthew Wilcox wrote: > rth wrote a patch back in 2016 that uses gcc's address space machinery > to improve code generation for percpu accesses. Ingo asked for some > minor changes to be made, but Richard didn't respond. While looking at > something related, I came across them, and asked Richard's permission > to resurrect and resend the patch, with the changes Ingo asked for at > the time. > > The important information about why we want these patch is in 1/2. > > Richard Henderson (2): > x86: Use named address spaces in asm/percpu.h > x86: Enable named address spaces for percpu data > > arch/x86/include/asm/percpu.h | 147 ++++++++++++++++++++-------------- > 1 file changed, 88 insertions(+), 59 deletions(-) Thanks for resurrecting this, Willy. I'd totally forgotten about it. The adjustments you made look fine. r~