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X-CSE-ConnectionGUID: sOFrQUMJRD+1yni9jcXVwQ== X-CSE-MsgGUID: fcd1+B63TIC5sD0tAJC+Jw== X-IronPort-AV: E=McAfee;i="6700,10204,11222"; a="47717870" X-IronPort-AV: E=Sophos;i="6.11,199,1725346800"; d="scan'208";a="47717870" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Nov 2024 12:39:24 -0700 X-CSE-ConnectionGUID: OHnYS5S6TcuNT3OY7OKdwA== X-CSE-MsgGUID: 2dJ9/DffSeuFoRFq5NBtZA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,250,1725346800"; d="scan'208";a="87583065" Received: from ccbilbre-mobl3.amr.corp.intel.com (HELO [10.124.220.146]) ([10.124.220.146]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Nov 2024 12:39:22 -0700 Message-ID: <4a015283-28e2-4459-825a-1fd542b81110@intel.com> Date: Fri, 1 Nov 2024 12:39:21 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v3 0/6] Direct Map Removal for guest_memfd To: "Manwaring, Derek" Cc: ackerleytng@google.com, agordeev@linux.ibm.com, aou@eecs.berkeley.edu, borntraeger@linux.ibm.com, bp@alien8.de, canellac@amazon.at, catalin.marinas@arm.com, chenhuacai@kernel.org, corbet@lwn.net, dave.hansen@linux.intel.com, david@redhat.com, elena.reshetova@intel.com, gerald.schaefer@linux.ibm.com, gor@linux.ibm.com, graf@amazon.com, hca@linux.ibm.com, hpa@zytor.com, jgowans@amazon.com, jthoughton@google.com, kalyazin@amazon.com, kernel@xen0n.name, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-trace-kernel@vger.kernel.org, loongarch@lists.linux.dev, luto@kernel.org, mathieu.desnoyers@efficios.com, mhiramat@kernel.org, mingo@redhat.com, mlipp@amazon.at, palmer@dabbelt.com, paul.walmsley@sifive.com, pbonzini@redhat.com, peterz@infradead.org, quic_eberman@quicinc.com, rostedt@goodmis.org, roypat@amazon.co.uk, rppt@kernel.org, seanjc@google.com, shuah@kernel.org, svens@linux.ibm.com, tabba@google.com, tglx@linutronix.de, vannapurve@google.com, will@kernel.org, x86@kernel.org, xmarcalx@amazon.com References: <71e9b2c8-0cc4-4646-88f0-7780e108e610@amazon.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: 9576980012 X-Rspamd-Server: rspam11 X-Stat-Signature: x8et3tesgegyzriwgn5iouwhjad8b1yc X-HE-Tag: 1730489912-909150 X-HE-Meta: U2FsdGVkX18VMrI/df12MMC2n4EthBAWKrjsvSyvN9Q9uvwS2mTXjyoSDoLdqXn98zwIAN79YBedfrQLBZwqWoxFy8aFN6ORxiLbOSNw/SZl0lkPvdDi9WjwtnTEXfGl2LaXC0ESw+d7e/0X87115OtCZUfj/DB8B9UDkkFTJopmkQtSJXlwqk9rQEDlK6yxaWjqf9e9cD1Pghc3/550fefqOD+coe4C5f2CXD3ThN7kL/Yrh7tg5CNdka5MWK/1+VBJUz0stz3ZLfmM9qnX8gScSFM6KmZrVOJZyu2tFLVp8WYXtnptno8tdo0A9WfHZYzAdIy4q7sB8W56+OXzqAIgo9L2vD8Q6AUTrybzrRUb/B2Z+J6IrNUnNcW+QC7o/1wxHWOYGE/PnpRoKDAxP7n4OH2ROGKkNxfVCXAmTL4ynTqAWTeG/h4VfBM9xey4q3pyp1aqPMQAR27eaKT3aCazfF04mcW6e4NqJuSx4UXXIao5MDVh27KlZwsniWJi/L/4hzAgp8A7LRFlIOQBcCP6wH8w4HYDRqYx8qxGRt1nnTMF+kgSU/wm5vY6LpI9U/twgs2b97pryWbsMh2mGCFBJZLeAPMIpzySQRUPQyWDOl51lWRMmEGuKTWSBi3S0ijV/Ug0eKksfeR+WRtvxzPpqPbOhJuW3TBClUb0B6e3y2j637izfsHKDzr/Rh2uZFcvncixi8+TGBGJJ98oKTaVsvnwXoIUgVTUwDQpk026azadSckijjw9kdbDkAwZwT57ZwepD6Zbwu7O957Y7Z6ZErq4/sPoXOLq75/S4fIbcPCv48ou7dbflbP5rwkMVaEqe/fhj10u+pMQZOPgnXxFHFJ8/GZfmzrQmMIG2VedMXr4Gfwvsi/nNSGGlqP7Gd0Ru4jmHgdTSEqnIeJu0QVdKEp/4iuYHlaxfGbVsoVt2p1l18UUlGpncXj6U5SN7lVCQzgcHdF5VVXEBGh HQk1Kzak Pq31zy2mrDegxYF6Cluc504CzFQaK6UqIjjP0B1iPHeVRd6qsVtzFM34kDCl9eTUV/65SkgVnGa/7zk7RyJoQH5+q+Ge+CPF/2NID7gsQgTazAW8v0qRH+NL4jtt7HEW9jTvaK8GGQArGaLj9o2wpaLy0Y0Sb82iFBNqnvJ7YJ9Yu2PIU0Z0zW7JUIVmbDexMrEIpFotQd6ndyz65jS2yeKnyUH3PKEipPp/iNYA5vrAh+QDokrEkAV3yWw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.002568, 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 11/1/24 12:29, Manwaring, Derek wrote: > As far as performance, are you talking about just the fracturing or > something beyond that? The data Mike brought to LSFMMBPF 2023 showed the > perf impact from direct map fragmentation for memfd_secret isn't "that > bad" [1]. Just the fracturing. Mike's data are interesting, but I still think we're pretty far away from saying that the kernel doesn't need large mappings.