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s=arc-20220608; d=hostedemail.com; t=1710785856; a=rsa-sha256; cv=none; b=dfntx3l+EYblKbckstZ84GrS28d3y+8+VYLfQEjCSkzyr74cfBuDrRsmJjboUdxfN3PBEj Wnd7OJdcScxm6zwK+M1X1kEM1fP58dmCMw6idFMdEcibUqq6OSPBzw4sA7H9pkSF45Inmj 8ebv4mqKZ2+eX0IPkyM89Xi/drgGKv0= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=none; spf=pass (imf16.hostedemail.com: domain of cmarinas@kernel.org designates 145.40.73.55 as permitted sender) smtp.mailfrom=cmarinas@kernel.org; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id A9E7ECE0B26; Mon, 18 Mar 2024 18:17:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E9D78C433C7; Mon, 18 Mar 2024 18:17:24 +0000 (UTC) Date: Mon, 18 Mar 2024 18:17:22 +0000 From: Catalin Marinas To: Mark Rutland , "Christoph Lameter (Ampere)" Cc: Will Deacon , Jonathan.Cameron@huawei.com, Matteo.Carlini@arm.com, akpm@linux-foundation.org, anshuman.khandual@arm.com, Eric Mackay , dave.kleikamp@oracle.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux@armlinux.org.uk, robin.murphy@arm.com, vanshikonda@os.amperecomputing.com, yang@os.amperecomputing.com, Valentin Schneider Subject: Re: [PATCH v3] ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512 Message-ID: References: <37099a57-b655-3b3a-56d0-5f7fbd49d7db@gentwo.org> <170983839495.1825460.8461454086733296317.b4-ty@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <170983839495.1825460.8461454086733296317.b4-ty@arm.com> X-Rspamd-Queue-Id: 8CD38180012 X-Rspam-User: X-Stat-Signature: o18kcm3p8jkc6onx1sai88t69k8wdhas X-Rspamd-Server: rspam03 X-HE-Tag: 1710785855-383407 X-HE-Meta: U2FsdGVkX18RGBVgvWpmmcipmL/Zqu85TPdT1NR1jKc9E98ynarn4uhHw/bfBgak8W+1dxFgkUVtU0Ej8F/ZHEAAOk2IR28QhxqD3Shd2WWLpDPpYSVmggERFUMZ03+XK6osr09F1vLc0eRHSiclPRKC7ayTo86yBXUHF76ael/MDcAr6fVzRqDgPnokHgilY+otsBg//edQiW+8P9rbNBXBG5/sjftaUrgGMcqgFlhV/Q5XTb8VSIyxrB0qLQkIwYUfm1KhyN8kDLQOlNK7IHPqj7gana1OEocPO6qCiEuezDpJlKtj370JL/AVFowQw5/TEust9CiDd3a9uM+aGw19GSVEG1emKUQDgOjGWE5PD7cHtD4Ur+p2pwh6UWrsT4IRfybK9l35QRYWyHPdB1Q8XgSiEjHIY7m18IP2wdXWEqkhv0oAb9sg5xOdJz2OGciXIsJjWHkzl7hscT+wevWzXDbZMs6PZlVB5t5C0ZMVv7NRmB/wuwTZRSE7DzKRJbvpeUNFHQcq6V9jhWM+ZpgapjLUT/cqeId3/Tr/Ebz0ZEnvzz+9+K9EEmc3TfWYJB0pv9t3W/tTNWRpldXaM5DkYfW1BUw2xvnIaYIJ/vWY/2LwCbh9EFO9BaXvqZUxNF4Gm52tI2bXN5REntTno/XoWf9EvOajaYODeOYdy+lRpo1nFP+2FJMbLKGvVlF7DLS29gY8lV/ypuE6ld4ZjRbTrnt2Rqzjeai3vF1LuNQHE4ZrQuxhdthJHsRjszaujjFhm1bD3dB3/bcT2TxN1YGK6RT2K5La5SrkYUesHoRgTPOd+cATOu2r92VZK3lNiXuBl3ttRGFTjbfwGT5LZ3f70dTDBNgX04pd9eCZqKVDpTtB2fJXWJime3B/Rpti4D9BewHjw2F8erXZ0ONOmWwNLdDpDU9P2Ykf1JzZRRco1P4/4VpTPKFAgRJ3+xUyl6FWyREJaHS25Ctvou1 q4WGWkpg cAVBdgUCdf0OQBqohicEnNqyAr2ZZOPs+NbIRSicsK3Lz/xM= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Mar 07, 2024 at 07:07:07PM +0000, Catalin Marinas wrote: > On Wed, 06 Mar 2024 17:45:04 -0800, Christoph Lameter (Ampere) wrote: > > Currently defconfig selects NR_CPUS=256, but some vendors (e.g. Ampere > > Computing) are planning to ship systems with 512 CPUs. So that all CPUs on > > these systems can be used with defconfig, we'd like to bump NR_CPUS to 512. > > Therefore this patch increases the default NR_CPUS from 256 to 512. > > > > As increasing NR_CPUS will increase the size of cpumasks, there's a fear that > > this might have a significant impact on stack usage due to code which places > > cpumasks on the stack. To mitigate that concern, we can select > > CPUMASK_OFFSTACK. As that doesn't seem to be a problem today with > > NR_CPUS=256, we only select this when NR_CPUS > 256. > > > > [...] > > Applied to arm64 (for-next/misc), thanks! > > I dropped the config entry and comment, replaced it with a select as per > Mark's suggestion. > > [1/1] ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512 > https://git.kernel.org/arm64/c/0499a78369ad I re-instated this patch in arm64 for-next/core as: https://git.kernel.org/arm64/c/3fbd56f0e7c1 -- Catalin