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 352012040B6 for ; Mon, 25 Aug 2025 14:02:38 +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=1756130561; cv=none; b=Z14rXrViEi8IjCXiO7nK8+e4LPHLtixVAoYoqb5T5CF4h7C4d/L5taQwzBNrVSpFLGLBG7S3ddX3iMLqTAvc6kuGyuO17nATWfKBBW6iHRBdlxvLmhDZTwEU3LLJJ0Rl+UJ2tfpYfxPDyQwkmWVufhjKXie151HuZFTYEXtoW6s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756130561; c=relaxed/simple; bh=WIy7H5F4BIGIAuJoDRJa9Qm9GvHCfb9cAeB7Fcg9C4w=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=KdVTVp5rsfzI4i0UZ8AUx3KWypkebz/zul7oc34KqgZZz6WzzpId/TmfAvUbWrNxmPSG79kqHU3iG913fQwM9smrc4rF92y525Ke2313UMdCUvuNN2x99kiFev5sE8zWMWJtiA4nw6l02icsqPonxUg1NK3wvdKKKVqgckl8F0Q= 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=VT4tTxnE; 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="VT4tTxnE" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1756130560; x=1787666560; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=WIy7H5F4BIGIAuJoDRJa9Qm9GvHCfb9cAeB7Fcg9C4w=; b=VT4tTxnE+BIGiU0yod8vbta1+OoDZrZOQwJicFXAxlSxqELZIyGBLNKO UBHccwVOmiqQo56KWP/upN/yU5i+jSdgcsbKOYdxIca976t9p/ymWzOd2 yQwb2FU1AWIW1G3rG7KNsfJUJnJ3L9GjHi9Q/YlQ5C+3W21DPBRfudeRv YOcyhHkofBVrOB8n9bk92K6b3tOn5InRI9v0UuN01m3UR+t5v3SCz6Hn1 FRwa4LYoqLEcZDRoMvTSfssC3dBmYXcBwimS5vVGUFIjzs6oG8KAwakin /1Pj/hByeXxaEI2mMHT9Cfo0oZQjDyvV4Z4ChLzNePfqQgQ9wXR6mBAeP w==; X-CSE-ConnectionGUID: xWeQT1kmSsWSBjiRR6rAIA== X-CSE-MsgGUID: Q1VsM476TAam2yy3txN2oA== X-IronPort-AV: E=McAfee;i="6800,10657,11533"; a="69715686" X-IronPort-AV: E=Sophos;i="6.18,213,1751266800"; d="scan'208";a="69715686" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2025 07:02:39 -0700 X-CSE-ConnectionGUID: SQ3DV1HCQcy+vrAzWRTVsA== X-CSE-MsgGUID: rDYFGniDRPmNY07CXIQesw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,213,1751266800"; d="scan'208";a="169492202" Received: from cmdeoliv-mobl4.amr.corp.intel.com (HELO [10.125.108.213]) ([10.125.108.213]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2025 07:02:38 -0700 Message-ID: Date: Mon, 25 Aug 2025 07:02:37 -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] x86/mm: lower MAP_32BIT begin to reduce heap collisions To: Simon Liebold , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen Cc: x86@kernel.org, "H. Peter Anvin" , Andrew Morton , Mark Brown , Lorenzo Stoakes , Helge Deller , "Liam R. Howlett" , Simon Liebold , linux-kernel@vger.kernel.org References: <20250825104847.36669-1-simonlie@amazon.de> 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: <20250825104847.36669-1-simonlie@amazon.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/25/25 03:48, Simon Liebold wrote: > Commit 03475167fda5 ("x86: Increase brk randomness entropy for 64-bit > systems") increased the brk randomness from 32 MiB to 1 GiB. MAP_32BIT > looks between 1 GiB and 2 GiB for an unmapped area. Depending on the > randomization, a heap starting high enough and being big enough can use > up all the area that MAP_32BIT looks at, leading to allocation failures. Isn't that still a really unreasonably gigantic heap? Would you mind posting some actual /proc/$pid/maps output from one of the failure cases?