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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60FE3C87FC3 for ; Thu, 29 Aug 2024 16:54:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C42C66B007B; Thu, 29 Aug 2024 12:54:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BF2726B0083; Thu, 29 Aug 2024 12:54:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A6D3B6B0085; Thu, 29 Aug 2024 12:54:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 8BD356B007B for ; Thu, 29 Aug 2024 12:54:30 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 18CDC1A0D9C for ; Thu, 29 Aug 2024 16:54:30 +0000 (UTC) X-FDA: 82505881500.08.ED2ABE6 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) by imf14.hostedemail.com (Postfix) with ESMTP id 2261F100004 for ; Thu, 29 Aug 2024 16:54:26 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=WT4LZFyd; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf14.hostedemail.com: domain of dave.hansen@intel.com designates 198.175.65.13 as permitted sender) smtp.mailfrom=dave.hansen@intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1724950447; a=rsa-sha256; cv=none; b=pwYOhgO+a9/yJJq9b+O2Rbr72Vl8Ok2Oa42SP55rGmk8hFQGKrqIjiiKnEc2dCWXYa2/v4 BW5AHlgjRJjfb1M+6+3u1AbqKHIcuPe9yUaiFCaOIfY5gW9/FzN9a/v1czzybOHI3+829z rg7u6ZpsPVvRmx7ecD5eOkXjHjyr3e8= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=WT4LZFyd; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf14.hostedemail.com: domain of dave.hansen@intel.com designates 198.175.65.13 as permitted sender) smtp.mailfrom=dave.hansen@intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1724950447; 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=p44OA7JFsgyeTtyzt/nlN43h3c/yeUSNVzwlj+9qeIo=; b=DPfSUT4Ic/YJK6aL/KgZ0V3XVW/n0lMDTxYGAzSgCtas7WWQzxf84DclERj7mr8jg3DfOi aD34GZZklmuSvNQ5ICMTwrfKAeSLqAv9UsBZuIQBVAXldLB7MqTQacTtsrWrSt1AuGmVjC QMlpIcJ/x3ybg42YYgWMTQ+TX18klgg= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1724950468; x=1756486468; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=ECTcIF0xxb8SZM8YCfmHs42MeG76z8YoRXRULe0ZOL0=; b=WT4LZFydtbblxDMMZIhuUpmzkJOlC4qO4+jMlZzj4Z+8snCH8/SZe1iy mBCXm0itm8tW3OuuiO80tAes6iJ89xYopPJJshBVTnUwXgBaEwZ8pvGH0 w5b2DiFII5gWiomsIKHURgeEqnf15WaHVPq1nugDLwaJLsTv0NZLqaWOt FNoKPHmry0Xm7YKuOKhHLxYxh9rP4jiIfuXkpPWXDCf81PmvgJaQwu4dC 2RwYSiO+cWKi/cqZ+DaA8GpFikZHlF1EIELgB7TAaHztseaxX6EcxDGUJ zVn/2GsfXutJe1qWrHgNrn1oUKGcI9sLTs2s/z5Uc1P6/AOx7IFWM5rwh Q==; X-CSE-ConnectionGUID: yDVsFHIEQpGgAL/hEgwpvw== X-CSE-MsgGUID: 4x5GQWQ8Rce/JCqY8BdHLA== X-IronPort-AV: E=McAfee;i="6700,10204,11179"; a="34724892" X-IronPort-AV: E=Sophos;i="6.10,186,1719903600"; d="scan'208";a="34724892" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Aug 2024 09:54:26 -0700 X-CSE-ConnectionGUID: P97BROI6SnmMUbj7R/2YUg== X-CSE-MsgGUID: Ykbtf9D6Se20V7CYNg9rEw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,186,1719903600"; d="scan'208";a="68308084" Received: from tfalcon-desk.amr.corp.intel.com (HELO [10.124.220.59]) ([10.124.220.59]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Aug 2024 09:54:23 -0700 Message-ID: <4219f619-4b32-40bc-85b8-cb11d76fde98@intel.com> Date: Thu, 29 Aug 2024 09:54:08 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 00/16] mm: Introduce MAP_BELOW_HINT To: Charlie Jenkins Cc: Arnd Bergmann , Paul Walmsley , Palmer Dabbelt , Albert Ou , Catalin Marinas , Will Deacon , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Naveen N Rao , Muchun Song , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Lorenzo Stoakes , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Huacai Chen , WANG Xuerui , Russell King , Thomas Bogendoerfer , "James E.J. Bottomley" , Helge Deller , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , "David S. Miller" , Andreas Larsson , Shuah Khan , Alexandre Ghiti , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Palmer Dabbelt , linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20240827-patches-below_hint_mmap-v1-0-46ff2eb9022d@rivosinc.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-Rspam-User: X-Rspamd-Queue-Id: 2261F100004 X-Rspamd-Server: rspam01 X-Stat-Signature: akzi75xyqd1rww15baot488aazj5yrd1 X-HE-Tag: 1724950466-749709 X-HE-Meta: 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 oQAhn2xx 8eP7oTV3XmYqbYZp3YPvEmo9Pqwu/lX33l2QerZne0/12/T5QHBV8fUIDU96Y2IPgb7/fTuqUcXGUZO5e+mN/uC48lPUa+rAaa4CddL6jvKz80WyQyt18dHO17vrAXiyBZYgD7ALNICis275KjWCjseBH8YOPQZu7eghIMqhy78qJthLDeE6brU+sqhn1y+r7aCA51QQua1oKBhchstHUfrEkWi10NohC/ejD9Or50DZBeawrfdLYSKaX/Q== 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 8/28/24 13:15, Charlie Jenkins wrote: > A way to restrict mmap() to return LAM compliant addresses in an entire > address space also doesn't have to be mutually exclusive with this flag. > This flag allows for the greatest degree of control from applications. > I don't believe there is additionally performance saving that could be > achieved by having this be on a per address space basis. I agree with you in general. The MAP_BELOW_HINT _is_ the most flexible. But it's also rather complicated. My _hope_ would be that a per-address-space property could share at least some infrastructure with what x86/LAM and arm/TBI do to the address space. Basically put the restrictions in place for purely software reasons instead of the mostly hardware reasons for LAM/TBI. Lorenzo also raised some very valid points about a having a generic address-restriction ABI. I'm certainly not discounting those concerns. It's not something that can be done lightly.