From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BC4D3290DBB for ; Thu, 4 Jun 2026 21:16:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780607813; cv=none; b=rv1/BlxUzD9ov2Mt1RXVJPBH5kIiaHtSCXzblU/jXWc8RcI7SAJH9fxcsCBzURd53MhG/nEb/UGLQ/qQ20ABKOZRQ0XLc5tIYHNOh3xn2aIPgODx45nqOVcNBU4hXwGUkfidIVol62EgV8rLi2Q9NdpT4SHqR5pFMdtx1jQQqLo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780607813; c=relaxed/simple; bh=mYMvCc0A1MgnnOP5ER6SLTociqZv/ZRdkYxk3jZNUHY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=j1POEuNuQd2T07Lc/U8VQc81tzSBAyjkbbZ+yjmrQLjB0PqrPOW4MQ3dcGFrTTp/zGV1ISW0aUrF3qHl44kT9bQZd4BbTQkjfdsm5yTYd42PRIn1xsCImdU9GoQRdFpKfB8rpaM27MQLA2YnoRNhIbRzMSSclq3vtirCrY5S/uU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=kux9xOUw; arc=none smtp.client-ip=192.198.163.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="kux9xOUw" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1780607812; x=1812143812; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=mYMvCc0A1MgnnOP5ER6SLTociqZv/ZRdkYxk3jZNUHY=; b=kux9xOUwgFaQ/J4Ne9x6U1Qy3g43V/l/UzmrF8kZVHv3uD8G3u3vpCaa A0eYV1ZxhxgXx2QuVCe+MDYC5L8kTpLDjDR0gtVuDqzUWtGxukMFuvkpC zwRhm52Zl3lvuEgTw2DvTHg1I0165IFD6os3pGirIjPtOGhsZ8mGHH5o5 Wp2azllZMDte2NWF74piF3YCumE8kJzvRheN/nvSDnTt2uWuDUbhuCXOn BGBhfSh3rwatoLnfB/y35y6IQTHpGzzy5ix7mUebVOF63Xn5oSK437Hl4 E4rojFldJk9dXE5/F0OUY8+GteFq3jnYYSW6YoNcCIdOxFOEmpG3XbQLJ Q==; X-CSE-ConnectionGUID: fbxKG77mTcefhteyR7m4zQ== X-CSE-MsgGUID: 4Z+5RzlpQQS1E45+m9HHxw== X-IronPort-AV: E=McAfee;i="6800,10657,11807"; a="92818274" X-IronPort-AV: E=Sophos;i="6.24,187,1774335600"; d="scan'208";a="92818274" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jun 2026 14:16:50 -0700 X-CSE-ConnectionGUID: yZ6RUMwoTXehUIUFBpujvQ== X-CSE-MsgGUID: P5QaMJkuTtS9VFiRC4X5tw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,187,1774335600"; d="scan'208";a="274908986" Received: from ray2.jf.intel.com (HELO [10.24.81.183]) ([10.24.81.183]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jun 2026 14:16:50 -0700 Message-ID: <2d78085c-0d5f-4476-868e-23c763830fe3@intel.com> Date: Thu, 4 Jun 2026 14:16:41 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 10/12] x86/mm: Move flush_tlb_info back to the stack To: Nadav Amit Cc: Chuyi Zhou , tglx@kernel.org, mingo@redhat.com, luto@kernel.org, peterz@infradead.org, paulmck@kernel.org, muchun.song@linux.dev, bp@alien8.de, dave.hansen@linux.intel.com, pbonzini@redhat.com, bigeasy@linutronix.de, clrkwllms@kernel.org, rostedt@goodmis.org, linux-kernel@vger.kernel.org References: <20260528151338.617843-1-zhouchuyi@bytedance.com> <20260528151338.617843-11-zhouchuyi@bytedance.com> <7A89193C-45D6-4118-87D5-9DC08EBFC11D@gmail.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzUVEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gKEludGVsIFdvcmsgQWRkcmVzcykgPGRhdmUuaGFuc2VuQGludGVs LmNvbT7CwXgEEwECACIFAlQ+9J0CGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEGg1 lTBwyZKwLZUP/0dnbhDc229u2u6WtK1s1cSd9WsflGXGagkR6liJ4um3XCfYWDHvIdkHYC1t MNcVHFBwmQkawxsYvgO8kXT3SaFZe4ISfB4K4CL2qp4JO+nJdlFUbZI7cz/Td9z8nHjMcWYF IQuTsWOLs/LBMTs+ANumibtw6UkiGVD3dfHJAOPNApjVr+M0P/lVmTeP8w0uVcd2syiaU5jB aht9CYATn+ytFGWZnBEEQFnqcibIaOrmoBLu2b3fKJEd8Jp7NHDSIdrvrMjYynmc6sZKUqH2 I1qOevaa8jUg7wlLJAWGfIqnu85kkqrVOkbNbk4TPub7VOqA6qG5GCNEIv6ZY7HLYd/vAkVY E8Plzq/NwLAuOWxvGrOl7OPuwVeR4hBDfcrNb990MFPpjGgACzAZyjdmYoMu8j3/MAEW4P0z F5+EYJAOZ+z212y1pchNNauehORXgjrNKsZwxwKpPY9qb84E3O9KYpwfATsqOoQ6tTgr+1BR CCwP712H+E9U5HJ0iibN/CDZFVPL1bRerHziuwuQuvE0qWg0+0SChFe9oq0KAwEkVs6ZDMB2 P16MieEEQ6StQRlvy2YBv80L1TMl3T90Bo1UUn6ARXEpcbFE0/aORH/jEXcRteb+vuik5UGY 5TsyLYdPur3TXm7XDBdmmyQVJjnJKYK9AQxj95KlXLVO38lczsFNBFRjzmoBEACyAxbvUEhd GDGNg0JhDdezyTdN8C9BFsdxyTLnSH31NRiyp1QtuxvcqGZjb2trDVuCbIzRrgMZLVgo3upr MIOx1CXEgmn23Zhh0EpdVHM8IKx9Z7V0r+rrpRWFE8/wQZngKYVi49PGoZj50ZEifEJ5qn/H Nsp2+Y+bTUjDdgWMATg9DiFMyv8fvoqgNsNyrrZTnSgoLzdxr89FGHZCoSoAK8gfgFHuO54B lI8QOfPDG9WDPJ66HCodjTlBEr/Cwq6GruxS5i2Y33YVqxvFvDa1tUtl+iJ2SWKS9kCai2DR 3BwVONJEYSDQaven/EHMlY1q8Vln3lGPsS11vSUK3QcNJjmrgYxH5KsVsf6PNRj9mp8Z1kIG qjRx08+nnyStWC0gZH6NrYyS9rpqH3j+hA2WcI7De51L4Rv9pFwzp161mvtc6eC/GxaiUGuH BNAVP0PY0fqvIC68p3rLIAW3f97uv4ce2RSQ7LbsPsimOeCo/5vgS6YQsj83E+AipPr09Caj 0hloj+hFoqiticNpmsxdWKoOsV0PftcQvBCCYuhKbZV9s5hjt9qn8CE86A5g5KqDf83Fxqm/ vXKgHNFHE5zgXGZnrmaf6resQzbvJHO0Fb0CcIohzrpPaL3YepcLDoCCgElGMGQjdCcSQ+Ci FCRl0Bvyj1YZUql+ZkptgGjikQARAQABwsFfBBgBAgAJBQJUY85qAhsMAAoJEGg1lTBwyZKw l4IQAIKHs/9po4spZDFyfDjunimEhVHqlUt7ggR1Hsl/tkvTSze8pI1P6dGp2XW6AnH1iayn yRcoyT0ZJ+Zmm4xAH1zqKjWplzqdb/dO28qk0bPso8+1oPO8oDhLm1+tY+cOvufXkBTm+whm +AyNTjaCRt6aSMnA/QHVGSJ8grrTJCoACVNhnXg/R0g90g8iV8Q+IBZyDkG0tBThaDdw1B2l asInUTeb9EiVfL/Zjdg5VWiF9LL7iS+9hTeVdR09vThQ/DhVbCNxVk+DtyBHsjOKifrVsYep WpRGBIAu3bK8eXtyvrw1igWTNs2wazJ71+0z2jMzbclKAyRHKU9JdN6Hkkgr2nPb561yjcB8 sIq1pFXKyO+nKy6SZYxOvHxCcjk2fkw6UmPU6/j/nQlj2lfOAgNVKuDLothIxzi8pndB8Jju KktE5HJqUUMXePkAYIxEQ0mMc8Po7tuXdejgPMwgP7x65xtfEqI0RuzbUioFltsp1jUaRwQZ MTsCeQDdjpgHsj+P2ZDeEKCbma4m6Ez/YWs4+zDm1X8uZDkZcfQlD9NldbKDJEXLIjYWo1PH hYepSffIWPyvBMBTW2W5FRjJ4vLRrJSUoEfJuPQ3vW9Y73foyo/qFoURHO48AinGPZ7PC7TF vUaNOTjKedrqHkaOcqB185ahG2had0xnFsDPlx5y In-Reply-To: <7A89193C-45D6-4118-87D5-9DC08EBFC11D@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 6/4/26 14:11, Nadav Amit wrote: > > That's what led us to move flush_tlb_info into a per-cpu struct (preemption > was disabled at that time, so there was no trade-off). Now that Zhou claims > that disabling the preemption is a pain-point, and therefore does not want > to set flush_tlb_info per-cpu, the solution we've landed on is to put it back > on the stack - avoiding the need for a single flush_tlb_info that depends on > preemption being disabled — while limiting the alignment to 64 bytes so the > stack doesn't grow out of control. OK, cool. That's great info for a Link: tag. It also seems like you're happy with this, so would a ack/review tag be appropriate to provide?