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 70F8CCCD1BF for ; Tue, 28 Oct 2025 18:53:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 45447801B2; Tue, 28 Oct 2025 14:52:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 42B9080199; Tue, 28 Oct 2025 14:52:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 31AD5801B2; Tue, 28 Oct 2025 14:52:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 215CD80199 for ; Tue, 28 Oct 2025 14:52:12 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id AAA4413B3EA for ; Tue, 28 Oct 2025 18:52:11 +0000 (UTC) X-FDA: 84048418062.06.EAA344D Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by imf21.hostedemail.com (Postfix) with ESMTP id 4ED171C0012 for ; Tue, 28 Oct 2025 18:52:08 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=n87PCZUy; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=b3mSEZ4Q; spf=pass (imf21.hostedemail.com: domain of ankur.a.arora@oracle.com designates 205.220.177.32 as permitted sender) smtp.mailfrom=ankur.a.arora@oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); dmarc=pass (policy=reject) header.from=oracle.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761677528; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=JT+/oOYpyq8SsRzuiae4g3fCj1jJqCHWAEtqeGZCOII=; b=gydyKmyZPVkBKMsSNXb64oflP3olSuOpwa15r1JNxQ4DzaG66ajtCO7iwaTg3s27MWT8HK r+lWlB/k1m4MVwXkXEyFTQh1wFoojixdpy9VilwTWPCnVTXrc9l/YpYzBm5WpZOIeAIiom rrj2W4xp+jZFXn5Q5QJ2LjPWdD0rX1Q= ARC-Authentication-Results: i=2; imf21.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=n87PCZUy; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=b3mSEZ4Q; spf=pass (imf21.hostedemail.com: domain of ankur.a.arora@oracle.com designates 205.220.177.32 as permitted sender) smtp.mailfrom=ankur.a.arora@oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); dmarc=pass (policy=reject) header.from=oracle.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1761677528; a=rsa-sha256; cv=pass; b=w+0aus6k+wR3fm802+IYswCjJhFTBMwpfoPZUH2oLl93V6G3Y3e8lgznZaCfSXV7y8JC6R lc7g2DudjPkOg7M8/dWxQEDUktgKYCjCGRWwjIDvelYNUsp8ejNNLSFzd9LPIBbo29htI3 nAW5NtX/gMCp3wOkOZ2Cz3c0qXQP9XM= Received: from pps.filterd (m0333520.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 59SHK1EK021838; Tue, 28 Oct 2025 18:51:50 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=corp-2025-04-25; bh=JT+/oOYpyq8SsRzuia e4g3fCj1jJqCHWAEtqeGZCOII=; b=n87PCZUyikcY9yXF048xM5HwNNttfgaHpm Wzqblw22vkmEz8JMt51oBLRXmwaASu6YgSrk3CQ+6adsQiT/SGJaqeWXpPkpPQHy eZnpKushbXxNOU/+CTpxevUNsS3jYqnAzM93CGqzsW1mL59iSHbvXUqogAAcxDLY wGInLReP4j1OBTjf8Wy9RGqdwraiqLPv6BI/UheiSE5hwH1n5ruDWxr3fDnf2hKu aaV6kP3ZEXemGxbc1J5ZE2eC1tXRlQSVTgWodnNdqJZTRKMiwaE1P+0UynZ6/LEj LgXWEn8E2hXnKMyzsvVqoUIqoALmSIH9jfp/U6AMMbtW8U3Wc0ig== Received: from phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta02.appoci.oracle.com [147.154.114.232]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 4a23gvmbx4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 28 Oct 2025 18:51:49 +0000 (GMT) Received: from pps.filterd (phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 59SIIQIh037422; Tue, 28 Oct 2025 18:51:48 GMT Received: from dm5pr21cu001.outbound.protection.outlook.com (mail-centralusazon11011037.outbound.protection.outlook.com [52.101.62.37]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 4a0n08mc1c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 28 Oct 2025 18:51:48 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=ayBe4DfGpXUWIIRfo+q2OsG5of3evlrxxz8cXOOvEvB6DFHC3f97ZsZ7IAhzHoT5GaNEhik+IHxxiLM501UHVFiMTnctQpHx2rTxK7KEraFkdPVxxXwCpQ3/MV21P0d4mnq2W2d2YJNHHzRx21rRySQhEaKmY8cMRUIGYnn42onFQPXnK/AsxKVSdWOcJp8hQpovAYGI16JjDDYT0Xe0p8+t+x/4hska8pYDQFboIUbIhxBShSPzkOVT72lgLIbT7IgufZZSlncSl1NmDpxb7MH2+4QamjQPK9I1Q+vTItthiB0EMYO0qGbNuJeaaKDNtasRqVAx4AeT4lWV20y5Mg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=JT+/oOYpyq8SsRzuiae4g3fCj1jJqCHWAEtqeGZCOII=; b=lqBC3Awo9fvBr4MMdYpBR0QKR5NRB1FMusxHglgnBiEL1VHSWUkJasg4FneG7L7eV6x14Dc2eWQHLIJM60Uxw2iY9hIeffJvlBMFvNgHZ1yKsVmlKqjBNSPxgvej+2OjbtxQ2xKpf0ZZFZfmCnZGVQdFxomRDEUdbJGd2Mu7NPjo4cZ7bdjuRXYUk5wVxrgJTDC4rttq3rrp9gBeniM1quR15I1PZShq08d+DpoVGbywtzAQ/nPVHwpORrPW+lNQpMeo3deb1hFF96d+73SEv2MuJmQ6xyyx3E0qXlegVHIeoIMUH3R8lxOMQPRO99M1fpMwR3GdT3mFGBX+zK0SYA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=JT+/oOYpyq8SsRzuiae4g3fCj1jJqCHWAEtqeGZCOII=; b=b3mSEZ4QazrhCiBy50qp/ALmj8Zaoa4Jnr8U8Sq3AErfYwBHzIXihc4jkI6lzF4HSFa67w9b6wksNUSQRugOWphP9wPPQLsz2Hvg2n9sEO+u4CWO4cHiXSyl2bLdhbzmwnLtgRUU+x4E9t6QZsXVHqHLavktBCC0mNXIgjlW2jg= Received: from CO6PR10MB5409.namprd10.prod.outlook.com (2603:10b6:5:357::14) by CY5PR10MB5940.namprd10.prod.outlook.com (2603:10b6:930:2b::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9253.19; Tue, 28 Oct 2025 18:51:41 +0000 Received: from CO6PR10MB5409.namprd10.prod.outlook.com ([fe80::3c92:21f3:96a:b574]) by CO6PR10MB5409.namprd10.prod.outlook.com ([fe80::3c92:21f3:96a:b574%4]) with mapi id 15.20.9275.011; Tue, 28 Oct 2025 18:51:40 +0000 References: <20251027202109.678022-1-ankur.a.arora@oracle.com> <20251027202109.678022-6-ankur.a.arora@oracle.com> <20251028135640.GBaQDLmHzCQDegBHd6@fat_crate.local> User-agent: mu4e 1.4.10; emacs 27.2 From: Ankur Arora To: Borislav Petkov Cc: Ankur Arora , linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, akpm@linux-foundation.org, david@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com, mjguzik@gmail.com, luto@kernel.org, peterz@infradead.org, acme@kernel.org, namhyung@kernel.org, tglx@linutronix.de, willy@infradead.org, raghavendra.kt@amd.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com Subject: Re: [PATCH v8 5/7] x86/clear_page: Introduce clear_pages() In-reply-to: <20251028135640.GBaQDLmHzCQDegBHd6@fat_crate.local> Date: Tue, 28 Oct 2025 11:51:39 -0700 Message-ID: <874iriq2pw.fsf@oracle.com> Content-Type: text/plain X-ClientProxiedBy: MW4P221CA0016.NAMP221.PROD.OUTLOOK.COM (2603:10b6:303:8b::21) To CO6PR10MB5409.namprd10.prod.outlook.com (2603:10b6:5:357::14) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CO6PR10MB5409:EE_|CY5PR10MB5940:EE_ X-MS-Office365-Filtering-Correlation-Id: fe0cb080-2415-4f1a-11a3-08de165307e1 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|366016|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?kqy4xmvNJaini4ih9VMrQUSliL3LIITMqyibTJ/pbJV+DJafKKPlhHSorcl6?= =?us-ascii?Q?rAk2K/cj/YHgYO2vCcdvmIrDSpDTE+6UCpM/gRA1AUIIoWwFqpiYPaGv94gp?= =?us-ascii?Q?y/raQ44QZBD7iuiyCkt6UoYKQvuZdiFf+Y3lAwBQVbhJHonHuUGF5L7jfWm9?= =?us-ascii?Q?ttwTd8V6ID8I/2SIWkBNJzXN2Ck8IUZnJ/bB0poiAkY/vDsr/xEFcPVh9JJt?= =?us-ascii?Q?bYnB9T2Tf5CpeNVffks3RXQEfqttKdvhrHufIJWNqmp8xZXraLlGaPd1N5gX?= =?us-ascii?Q?AEodAtYMJeWfHcsHKVZaR6dklwsDGBobI0ZWhUmsekEl4gXGRPhhLZEPua73?= =?us-ascii?Q?dGP70sTd1NxdyAWCb1B7Q8Lb4Spr215PDmkkFjO73LnSJHx78GiDQ4NX2cL4?= =?us-ascii?Q?wadnh0uW9rO+zDbrjofojga/rJj//kXjaA2/ySB9X6H6PHTzxq7qGiTUHbVd?= =?us-ascii?Q?kGWtHSV2VyD6gob8Y26JSI45cbTsiYQH8e6y/V6V1XQ8qTgC2iSUMNLbnTqj?= =?us-ascii?Q?We/7LtybVw7tDEcjl0dbprb+BWfAes7TD1lg9d6uwEiivQ9oHkEeSSHDL9e1?= =?us-ascii?Q?F0n+jvHRBjA23nI2j+VFh8cS7Pa5AmJReGY7BFHjtndUTbNnLgEpS68+48bO?= =?us-ascii?Q?L+8HFYifQ//e6idHTT0/XqSTTUJw9yBUMq7Sy67lLl/oimti1rTVzfkS6X4B?= =?us-ascii?Q?aUNeQ4CncF3/OlLxUBwwHZCtBf8/VR7CpiDLJTP3cyQee6/kSToX64ABNV6r?= =?us-ascii?Q?kSiRg2Qlvqm88tJ2C9IseJiQEDe87REX5VDWEs2fQJ0Rtvz6lHCkzRa+KpyM?= =?us-ascii?Q?CJfZsxo4xTITVlxXf016Xd1x6qgpd9cmdNmNf3gcgf2aSHM2+SS77CXRUbaV?= =?us-ascii?Q?CRvKvOiGy5iUaFcPTQet8944atqX3MfGAr+xECxXGiD0LbTZDjqeWRbK37qm?= =?us-ascii?Q?VwgCle79aOV4FRJcw2+mHX7zbV5/Wf+J2McTjMzD45b7aSvI1G7ZICB5gKVQ?= =?us-ascii?Q?c1mHOqU4UYXFVaOwmk/QUWyuwb5sM2z2J3nxizoG//6ViMSZNy94C2XDorHe?= =?us-ascii?Q?AM6Ug+sy5E8AnzdeSBHYY20yJ/FsXUvkPd9TxxvSNcp+muwJrl/RbXJuYxpb?= =?us-ascii?Q?0RGTYxRPNV3T9ilm64iFe9LMHxyOIvyuhyzWWl1fF4bUr4JP/8pAfuuVYaFl?= =?us-ascii?Q?YqicsArL9IXEmLIY1ZcXm+DM+1IbRNthvDcA5uIGprHv5UZ0qGgOF0/RNZ6h?= =?us-ascii?Q?tQ1X4F5S6sKj/uHrlvXSZyVx8zp+rAT3w+hIaSGnT3XYBD5gY1d9XwFdpn8H?= =?us-ascii?Q?13CShF8iJzBuVHmCYnOmF5PQfM3+ydPKQYq3se7bmssT8k+V+2PpcFw3Xa9F?= =?us-ascii?Q?y3Z1FC6Y163CpokF/SGbfdWuHqx3F+qJbHoF79K5hGn1o6cuA92AbeYEJQY8?= =?us-ascii?Q?tko9fWNtwvZQ2Mk5FNLfIxIkKUPymXQu?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CO6PR10MB5409.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(1800799024)(366016)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?jmO1mg7c8RLzuvYL/2YAWOllnHFyuI9BhqkM/BREgh22LjYDEn2BAggLWmQP?= =?us-ascii?Q?ZKP4Kx8wxrdCkePf/BVqO3wh/beKnDP2K5knt8PNHGzPOTPtX3QDBNrSsPna?= =?us-ascii?Q?bSBwRQuyvUhSn9NTP+fVGrUa+/hf2uXWvyR6laj9Bd7DYkNMi1JZ8FsZvWZO?= =?us-ascii?Q?QibRQz+en2+J12vYxf9HsQWAd1i5ciVyeKegonu7ijd22LYeevDxm0OBaYrP?= =?us-ascii?Q?7qjDpB8qpM8cma72nQlGlty94LnQlcud4/JdljwiN43GiJlzVUN/bCPb9YiJ?= =?us-ascii?Q?PESarFNrFcZY9/e3vTDtmuLdyOObLE0OTAt4F3Rtup2FyQKKTKrSwUnTM2y7?= =?us-ascii?Q?C0nkgtbQjC/yDZZkZ4CDKicNMpWl6TNKF59DulIkaBz1oD4X1VhQTnJ1llld?= =?us-ascii?Q?uqexvf55npBhVqamaXl3mwgB+2jmmZRqL9Br/DoYp+B4ipXU170WR9U4QZV0?= =?us-ascii?Q?Z7+Fv2wfs9+5ak6wmfAV7cIpmUz91xbOE4sYITHalUko53W9uo+mmUnyEmbb?= =?us-ascii?Q?zT9BOfrzO4Zk9YypAC9TLQ+QgVaeIv4SciWixyhUv+hs3q0NPBFnIEp464dF?= =?us-ascii?Q?fbxhijTKmfdCdVdxLI9jA9CPqVYZf8csdH3e2Mm0VtD5vdrGBBVcWqhVeuuY?= =?us-ascii?Q?0Wg9kpvxEBygkj5ugxulz4/MNfqFwS6IfyMdfjHaosmXs1IMukZ9g8KmWrte?= =?us-ascii?Q?/xv5h85CqYznw8nkFSqFMlblSedDkTiLRiTYhIclRkMZ9/bQGVMHPQN0nW3L?= =?us-ascii?Q?KQo+hrXWaMr1oG6Wu6WAi8xL3KvHvIFh34m8kKQjPpKHG7ILwzMA7o2yuMj9?= =?us-ascii?Q?Ikn0oEQ/Uskyl0VAU42rfJ92U/2QPFUYRhcE3Rh4RwXsVAXaqIz9lqPM4UuQ?= =?us-ascii?Q?vYr5jOI7c1i8g3ca0JnDAu/cUYDqNTJCjdtPsAzTOdT6qCdLI0nYwvDGcTpy?= =?us-ascii?Q?DEXJjxUL08jVH1b30Qh69PdXCeCABJyJT3MjWAysQbEcte9eU7s41Qq9QuNW?= =?us-ascii?Q?uZg6R0QpawM9ivbREdVI0ymvBfLp2jOigx3cTVtP/VSlPh21NWuaSGB9WrPa?= =?us-ascii?Q?xDBEaWXRVs4YblyzTFQjXfuC647aDeqNYPACS5xsXQwopK0PRqJdl/lzIZl6?= =?us-ascii?Q?kLhrN1IJMVPUhtbkR4gN7oKSaFcUnzcAEfiMyc0rdJeaQgPW3au4cbmxeHok?= =?us-ascii?Q?0vXS60KEG0OxCPNOJRFzULobrUDMuM1G7B3UW3mC7hOk1zFAJdJHQlCTDoNM?= =?us-ascii?Q?F7ups30lQxUCm7xfpjSWGyQZ1RVUe8OUddcBMuQRpA0RQ4N8R/p+bN40mUId?= =?us-ascii?Q?MFv1Wo/EYH6E2Kbo0mNTNOkZ7Swmv45zmvHtN3dlC9QLoreByb3Vx7M3Hm8S?= =?us-ascii?Q?FwiEOBKIIjKmKhiaGQ2TtazTAEccB7qNKf+t+wrupjFjz+UbGnqGgjW3MSdt?= =?us-ascii?Q?BECRP2QWIboXbVBSyPN5/uaIU2ZaOhux1MS4Ig0LE/htv3sHEXDLiiBvaXmR?= =?us-ascii?Q?ipjKZ/pxzUKpE1rVG0un8bvPSDs9dhSaUzJbQ55AmWErOBfLLnQeyuAIDxXG?= =?us-ascii?Q?/8mSg1PudShQoFeGSyjhm8jf5YByP0ZYVNyVsmP75AoD0+Qiz22tFLv9DCh8?= =?us-ascii?Q?rg=3D=3D?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: fY5B23n/opXSfO2NGFmnb4im3OQF8d36HW3DcyAh+hZPukRtg9X09A3ZvfKHuevl1P1QY9tRxWom667MeU2ZVo/T7FxqTBOL0c21yvowDwPbwizw/qTpirtMi2oLAjUg9cz8bPirmgFTdK4i8qARHeAnVlSC2FAnhN4v0NoLt1I6is2+O0hUrgi3nV19al2W5Uwwz6LJCkF2oWfNEPWqKjMhZstdxkPvuG9NDQoZhWvHxgpgoHsO/6WJ+yUN41DYbh5OjhOZIUunM+h7ye8sSpEbw6nFS8BkAd0zcNxvPKV3sxZwxoSR7+HO4QTIpaKMvOhEJ4CdJFTnH39D8HLxAyRGVNh1TqteMbbM4p+ELK6tJzFOJ8hAlR10l/DHy2dWStxDjRUdwmNv9wnL7ju30cjWjnmKkA0PPlbiQrsr3g8/7kt8gsPWPploFH1dp+AmaYvszAJ98/ZGDhQvaspjllNkhOFyDmc3zygSvBEWOK4Hhm0fbS7kOV/OMeQx7VkYtiogpp5CxT7GTGLKHLp+4elJFxuCkSgDUfZgXfUL1KKd4oQlc83rXCUTIcgPhGoJZ7/mSet9F8jXEONeLN2gnpjBla8FuOkZ3nkSNPfMswY= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: fe0cb080-2415-4f1a-11a3-08de165307e1 X-MS-Exchange-CrossTenant-AuthSource: CO6PR10MB5409.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 Oct 2025 18:51:40.5770 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: XKJ9bRvo4onlXW2Vqq/cK9zk7rMJ3fZWPy5rJZdRf+6GVKd4FN7uTNipmXt8quuBzkAnT30TvmjLucFkDYT1rovaVtho51DQNDipskXQRt4= X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY5PR10MB5940 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-10-28_07,2025-10-22_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 phishscore=0 suspectscore=0 malwarescore=0 adultscore=0 mlxscore=0 mlxlogscore=999 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2510020000 definitions=main-2510280159 X-Proofpoint-GUID: JY-jpoAqnY1KJ-9fvs1rut1KiQdZoy8h X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMDI3MDA1OCBTYWx0ZWRfX4YXhpIjBDmIF O4Uyg0dvXgcRDD4ilUmq3byjLmhmpe3Qmm7ih7qEdDTKoBuIuFi6DrehDiRDT5ZRbRC+5d76GpX PJ8QBIfgecYpMffzBbkSCecAf2A/B0t0k7CVwGj7PC7FqrfVjwXbcdm8daiQSqekdgRBuGkDPa8 x1mn5Cx61UZyZ/AwhWgxyOCfxjb95WNT2EOdf/5GuVCtvGHKRLAJnVw+WjyPa1biMmtNL5WfE31 0K7GS7FHVdMCgPqTlS33JztkQrRS4DNeG5dWxDMXCqXmXUiDG+lJusbpfaV/3Wkccdys8RH+mhC PKDQlkvmcoMSV94NCHmytoR8qpOfWb5MfEV9IQoCo24Gcn0LA1NBLaSovhwDt9FfapV8/lQ6Jgb +l7k9F2eIeTsrLM7fBcwEXad1TzQ7A== X-Authority-Analysis: v=2.4 cv=HsN72kTS c=1 sm=1 tr=0 ts=690110c5 cx=c_pps a=OOZaFjgC48PWsiFpTAqLcw==:117 a=OOZaFjgC48PWsiFpTAqLcw==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=xqWC_Br6kY4A:10 a=x6icFKpwvdMA:10 a=GoEa3M9JfhUA:10 a=VkNPw1HP01LnGYTKEx00:22 a=N5MSUnm-BLtD-S_oZroA:9 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-ORIG-GUID: JY-jpoAqnY1KJ-9fvs1rut1KiQdZoy8h X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 4ED171C0012 X-Stat-Signature: xg1pkrdxu7gy6ke118qrq6z4uarjcgps X-Rspam-User: X-HE-Tag: 1761677528-514989 X-HE-Meta: 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 lOn5BKvj 5/D15IpGVORUIt+5bcdRvcKqsigWQX9+B4rn+SSwAfG2s2wcSSfgckfCEeavybww6lNHSRQmJe6+xl8ksPThffYOHLrlJv0uuEYo2YQQwQwxxqrBflNo3qq0o1YVm5dFB8s7ZjW10O+hZgTbiMXkS/k0pi+8/30rjD6+u+4xyBuzwNJ95ZPUWqny1whq/0i18HWVQlaQd1SZSYIYjIdT/Xlo7hhHCTScchN8bfBOge+yOYcgCSzfuBldp54MflYEkGRyUxBjMrvaHIZ+URMzAjbi41SnbeoF03V1dCmiDNuIkelpNkYcSzUh3ogBEpJ+CtUzjMzxfIeyCIPxLN8cgxUU6679I8gatMovw3y+gKlgFxn591bWQTZrRocNfXLaXpR6TygQY/O+S0TnpucrV4vrpAyxRAl2y3QeVz1iGDQ43BXI+6GcdrYLpQg4quEqpt95iyJlVle9tX3tBNQvqKa5Fh+X//MtMOI5yXQngn2W5e/v/moTOcZeGC4WbtrAuziD/Wmrcd+gUYLARbERCYmvrKXLmequaHkZu7tg86BzSzvctXjYZvY17Cc401POh5nsA2a44xNFcdNGn45OHDzyTpA== 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: Borislav Petkov writes: > On Mon, Oct 27, 2025 at 01:21:07PM -0700, Ankur Arora wrote: >> Also define ARCH_PAGE_CONTIG_NR to specify the maximum contiguous page >> range that can be zeroed when running under cooperative preemption >> models. This limits the worst case preemption latency. > > Please do not explain what the patch does in the commit message - that should > be clear from the diff itself. Rather, concentrate on why this patch exists. Ack. >> +/* >> + * When running under cooperatively scheduled preemption models limit the >> + * maximum contiguous extent that can be cleared to pages worth 8MB. > > Why? Will mention that the point is to minimize worst case preemption latency. >> + * >> + * With a clearing BW of ~10GBps, this should result in worst case scheduling > > This sounds like you have this bandwidth (please write it out - we have more > than enough silly abbreviations) on *everything* x86 the kernel runs on. Which > simply ain't true. > >> + * latency of ~1ms. >> + */ >> +#define ARCH_PAGE_CONTIG_NR (8 << (20 - PAGE_SHIFT)) > > And so this looks like some magic number which makes sense only on some > uarches but most likely it doesn't on others. The intent was to use a large enough value that enables uarchs which do 'REP; STOS' optimizations, but not too large so we end up with high preemption latency. > Why isn't this thing determined dynamically during boot or so, instead of > hardcoding it this way and then having to change it again later when bandwidth > increases? I thought of doing that but given that the precise value doesn't matter very much (and there's enough slack in it in either direction) it seemed unnecessary to do at this point. Also, I'm not sure that a boot determined value would really help given that the 'REP; STOS' bandwidth could be high or low based on how saturated the bus is. Clearly some of this detail should have been in my commit message. Let me add it there. Thanks -- ankur