From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8975EC4453A for ; Wed, 22 Jul 2026 20:20:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4DB0E6B00A2; Wed, 22 Jul 2026 16:20:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 464EF6B00A4; Wed, 22 Jul 2026 16:20:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 308696B00A6; Wed, 22 Jul 2026 16:20:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id F275F6B00A2 for ; Wed, 22 Jul 2026 16:20:45 -0400 (EDT) Received: from smtpin26.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 6F1A7C0285 for ; Wed, 22 Jul 2026 20:20:45 +0000 (UTC) X-FDA: 85017530850.26.52113BA Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) by imf09.hostedemail.com (Postfix) with ESMTP id BCAF9140008 for ; Wed, 22 Jul 2026 20:20:42 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=SNxsNMiZ; spf=pass (imf09.hostedemail.com: domain of dave.hansen@intel.com designates 198.175.65.18 as permitted sender) smtp.mailfrom=dave.hansen@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1784751643; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=CPvnSwlo/21AAoFc/5ntGQLtjYyWcNx4/mbJQiNHpGA=; b=mHiLCsBMnjEWwTY6nG5dq4xQWQXcZ1mEQ9Uqx//Z2z8nqO83fy7Cb860WELcOR5HNCn52X a7tnNtqK/psiZhf+acX5kAB6C0ylfab0j3rootRfIGmPFxIl+8DaXtzhxP0ptfSTcXGLxy XJqmpGEvq4oUhR7HG9UZ4jbTacFhAhU= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1784751643; b=J4vuXalkiOIL+mjfA3eKYK6DvYdeLDV4UjERQVAS+ZtjZZIYClPoYuMP6l7uSOX5Uybxns 3Ez0xx35b2ESMU8X3ETxUx5XxMFDYzM6WVd7keyEXxgzPaPU1JrooNjjDt40ay23ezzUV4 uKgDO7h35Enf1SpLo9qZ0inM/wQP0/o= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=SNxsNMiZ; spf=pass (imf09.hostedemail.com: domain of dave.hansen@intel.com designates 198.175.65.18 as permitted sender) smtp.mailfrom=dave.hansen@intel.com; dmarc=pass (policy=none) header.from=intel.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1784751643; x=1816287643; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=JGaQKmk/1f26nF/+nvxjfYdWz6Jdt3Ok7POmfjc1hRA=; b=SNxsNMiZ12kdonZvE2/+Fw4LOLDyYJZM73fXZzPgezWjT60DKg79Omqj 1f04tz9jSOiKpD0uCUdF+2VUsv0sAlEZ8JVPaQpAC/rOw4NuR/cBzdmBL +L4OenTcKaCe3xoKKSAr5t+QTbAqQsA7btoVyBvQcPKTYRz+SDYf49rt2 nfYI9Hj8fO+LFi5qFWdjsCC95PiM3jgE8DRzoCMMAmn3pjSJQYjb4j+/g VvxJVABsvndSFyfrek1qX7U1hv/qYXg5ZDNdxLilIm03pQ2cOo/lCrpSM 1JvJNY16eMECO3QTS9eiL+FoNYIuulJp/MQOq2AqpVgqasJpO9jAZP2zX w==; X-CSE-ConnectionGUID: YAWBcs2qT12OR/fddm+ecw== X-CSE-MsgGUID: hE2iZherT3GnG9XcQ0UulQ== X-IronPort-AV: E=McAfee;i="6800,10657,11854"; a="85488984" X-IronPort-AV: E=Sophos;i="6.25,179,1779174000"; d="scan'208";a="85488984" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jul 2026 13:20:41 -0700 X-CSE-ConnectionGUID: R4FecRX6TXioPL2/MbQm4Q== X-CSE-MsgGUID: Hfdmu0XVToqbSJhXxxcGdg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,179,1779174000"; d="scan'208";a="296397967" Received: from sghuge-mobl2.amr.corp.intel.com (HELO [10.125.110.58]) ([10.125.110.58]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jul 2026 13:20:40 -0700 Message-ID: <33c774f6-2750-4831-8eee-e43dc471da32@intel.com> Date: Wed, 22 Jul 2026 13:20:39 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v2 13/20] x86: mm: carve out the generic compile-time folded pgtable case in effective_prot() To: Yeoreum Yun Cc: Russell King , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Catalin Marinas , Will Deacon , Arnd Bergmann , Andrew Morton , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Johannes Weiner , David Hildenbrand , Michal Hocko , Lorenzo Stoakes , Tianrui Zhao , Bibo Mao , Anup Patel , Atish Patra , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonas Bonn , Stefan Kristiansson , Stafford Horne , linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-openrisc@vger.kernel.org References: <20260722-dummy_ptxp3-v2-0-d9e4bad31e0a@arm.com> <20260722-dummy_ptxp3-v2-13-d9e4bad31e0a@arm.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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: BCAF9140008 X-Stat-Signature: jwg3bneys8u8hmu9r34db9s9j6wzo1e1 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1784751642-973016 X-HE-Meta: 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 eH3AIytt YarHc4z82ublnjTVeAiJmteFNYCLKRSn9ReizQfZg3a0L5AnIEW1leMqohvsLjOrG2/ybax/gt4pPKHPKyn1vATe9pDux3G6LDVLQgmnHgzf8xbP4ZpBg2+fGKQMHERleENV5WQteIgskc8QzppoPuORwA9iyLVLsmof/2zyCXzRSev7X9I6BfWbpPRUg2apShlVq+Z5ondj6fqtvetWZHC1NFJMuJAABiMq98aYCCgZaYYASvZeGXxMnPg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 7/22/26 10:37, Yeoreum Yun wrote: >> On 7/22/26 08:30, Yeoreum Yun wrote: >>> struct pg_state { >>> struct ptdump_state ptdump; >>> + int first_level; >>> int level; >>> pgprotval_t current_prot; >>> pgprotval_t effective_prot; >> There is zero reason on x86 to hold this value in a data structure. It >> is 100% determined at boot time or earlier. Pre-5-level-paging it's a >> compile-time constant. >> >> On x86, it never varies per-mm. > However, mm_pXd_folded() requires to mm for other architecture like > s390. might save the mm instead of first_level and calls the > ptdump_pt_level_first() with static inline version would make the > constant comparison. So it requires to save *mm* structure in here. I'm having a really hard time parsing that. I think you're trying to say that the effective_prot_p*() functions need to know the first level but they don't (today) need the mm_struct. If they don't get the (calculated) first_level passed in, they need the mm_struct instead. I think you're arguing 'pg_state' needs a ->first_level or a ->mm. Having a pg_state->mm doesn't seem bad to me at all. But, it's also a little bit silly. It would not be rocket science to pass an mm_struct down to the effective_prot_p*() functions. It makes a whole lot of sense to me for a page table walking function to need metadata from the mm_struct to walk correctly.