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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0A66BC87FC8 for ; Thu, 29 Aug 2024 16:54:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=hbEVdDk8Xzt097YPBS+xXItE5UyyltWwygfqV9IwXYA=; b=uShSOY8bc5jFRb glv9YxH7e7wzmmAUqRHUeinqQxs4D1JIZdVG+/r2nv3AtA8zXPYPuM73aYLLpq9J182OK5grqC3kE WS4/fQFCEmMG3qhwOYQ3OLOW6+bPKgE9HX9MHjYkhkp+w9VshicTnK3aLTdPNRor6keb+T1Ab54w1 /FCzwb1noMGkNogVv5ILSXv3kdJDSxaSbYFEiToMTJbY3nldZJcIH+1SWqV1S43yGYQnBdCya/Fmn uvZimadBQYhwq1902cUKveNoIFn95Hurctv4t5gi1Vvcm57SanHgwP540a0VLESLiBOVV+zx/Wn2Y sRsRsR2+hN4zou+S+pMg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sjiQ2-00000002uql-099N; Thu, 29 Aug 2024 16:54:46 +0000 Received: from mgamail.intel.com ([198.175.65.13]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sjiPj-00000002ukq-3DTc; Thu, 29 Aug 2024 16:54:29 +0000 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: XopDvlezTI+s47Eo5sCWTQ== X-CSE-MsgGUID: om7GkX8uSKW6n2N3A2a3fQ== X-IronPort-AV: E=McAfee;i="6700,10204,11179"; a="34724898" X-IronPort-AV: E=Sophos;i="6.10,186,1719903600"; d="scan'208";a="34724898" 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: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240829_095427_884415_0B5E08BD X-CRM114-Status: GOOD ( 12.82 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv