From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from SN4PR2101CU001.outbound.protection.outlook.com (mail-southcentralusazon11012014.outbound.protection.outlook.com [40.93.195.14]) (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 868EC33F8BE for ; Wed, 12 Nov 2025 15:53:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.195.14 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762962826; cv=fail; b=FeobKLsQfqyt8FdCAE8MVVcRHLX+HbySv1MF0T2GL3a831tfAUwttNqk0sFn29mcPQTsWoR880t44sHnEaTc0iKPoGBfeMPRiKOs/ggdI5QEnW/YJbE5PbVtHdvSyQMICxXeUDr2CHzj6Dqt6GzRzHswpux240MyEocEFgoT1Ng= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762962826; c=relaxed/simple; bh=xZxlDbSNqG0kH/d9apAqlmRNFmCdFY/V59Kcn24XUUo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=LMK+ORdRM0pwBkVYb6FEJoUEN7aXovtcbpRxHqUQIeN9etsHlnsG9bkHQEnG7wfe3nzOPXR8nKh1COH2FXFQbFfm9zLyLo7YFObWl84INtu0xnkbsmg/0Mn1N2mocZyfW/TRqaZXYOXTkJme29j4MmQl1aM+h7llKQRAN0HUpi0= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=Lo9GHNUY; arc=fail smtp.client-ip=40.93.195.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="Lo9GHNUY" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=OsKG5oZARTHHAZUIIpg/JfDE9q8e2VC7ABTrdiX1ci2KAPou1iPPS0mseW6o7kNdppZJJAP3tjezt5mXld3SOA1shgkDzYjL3j7RsYCSZFnd3ZREWivBKfukustPhQc7HnZwN+H4i5XSdhIrJaBDqoG+RHkG2kNvsa77GngbqfeI/ElAk1N7L2Rvur+CWJQOtL+RT8BojFTQzJUyveHkR0wmNMk9DHk0NBiY5zGfQiLwKe2psHGFIBLBzYr9KMFcpC2HFZKJ9sA+SBkrZRxKL/txAh69fkMUUcbyavLjQtwmlD3uzaAgfV9r76uftcjQFgHX1e0odblQ259/bkPa8A== 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=H3XzKmLPp3L9abWCAuN4QYo6hrdUgfg0ybrgeLmPa0Q=; b=xZD5Ss6juEG8DNllC+qP4lN8gRSf500rFPQblGTfSn3hhedZSUMSqmcSFzrupfSW1kVneD7vJM16FkGv8SXWHuFqtpkV3Agoey/NhdNv9nVPgHHfCuqSFl7ZdzSvwLMKxHjNJfJDs8rrRf1BXPyZPbMS3rS9T8dSNuU2WVvERAGlzCaWobd2gQH5hYfK4EwiYz+UKKRFz9tT25g9sTIkvoeKYnzlAow2dyzTBeh/1JQsxmy/VXyNpBzDbttkXXPKbMZ62mR+4yDEPwHwJ3Hw8BVcQzBUNT03PuHYrbistZljMoAUO4suwf/QLc9z8EuBl3iNsc1gelE1k7z2/M/RbQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=H3XzKmLPp3L9abWCAuN4QYo6hrdUgfg0ybrgeLmPa0Q=; b=Lo9GHNUY9QwOJQerRqD+8KfTW4zviQsKGKopa1i00e8s6TKMyBMlnenOIJ99rDvtrcxQOiMtFPy96obsbOoKwBjZ4FR8zeedwjdLI1U01GPaq4D/9NFtL2FjAxvtr7X+PKVdD4EWrNBZpQ9PgRFDhDqlaaSZ9k8EldZv2oa+qhCK9SULrjKr96W3dEqqJpgme5V1gM+ckSTIjxZM3fLb2Ny1gvfartrDm7+FoyYuAOzImoG1O8MbWbgPS0bUcK1DA8lKxQdK+fKfrViuGCoCDDPLDIensGK/odLhGcy0ylOPzodFuPiMz842EjMisrU4Qv5EoTrd9Mjirj820mm4og== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::5) by CH3PR12MB9315.namprd12.prod.outlook.com (2603:10b6:610:1cf::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9298.16; Wed, 12 Nov 2025 15:53:27 +0000 Received: from DS7PR12MB9473.namprd12.prod.outlook.com ([fe80::5189:ecec:d84a:133a]) by DS7PR12MB9473.namprd12.prod.outlook.com ([fe80::5189:ecec:d84a:133a%5]) with mapi id 15.20.9320.013; Wed, 12 Nov 2025 15:53:25 +0000 From: Zi Yan To: Huang Ying Cc: Catalin Marinas , Will Deacon , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Vlastimil Babka , Baolin Wang , Ryan Roberts , Yang Shi , "Christoph Lameter (Ampere)" , Dev Jain , Barry Song , Anshuman Khandual , Kefeng Wang , Kevin Brodsky , Yin Fengwei , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH -v5 1/2] mm: add spurious fault fixing support for huge pmd Date: Wed, 12 Nov 2025 10:53:21 -0500 X-Mailer: MailMate (2.0r6283) Message-ID: <409ECE2A-166D-4C16-BC41-E327572E6376@nvidia.com> In-Reply-To: <20251112013822.54334-2-ying.huang@linux.alibaba.com> References: <20251112013822.54334-1-ying.huang@linux.alibaba.com> <20251112013822.54334-2-ying.huang@linux.alibaba.com> Content-Type: text/plain X-ClientProxiedBy: BL1PR13CA0191.namprd13.prod.outlook.com (2603:10b6:208:2be::16) To DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::5) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS7PR12MB9473:EE_|CH3PR12MB9315:EE_ X-MS-Office365-Filtering-Correlation-Id: 1644ca61-47a8-4767-8b61-08de22039d0a 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?WoXvNbmZkfBj7Zca9QwD06gq2bEfUJKYlTIJLg/JXFkNBzdC4sveYkijBsmh?= =?us-ascii?Q?r13DFb1JlmE5xm7E++A7k5/GDURV0sx5zQPs1DbjJo2zBxl2VL6FINijd8Zh?= =?us-ascii?Q?XRM2Ix5AcXoPhxK+PbZzr+qsxy4l1w5o12Dy1C0bngO4RWPfVaMWJQuHpfw7?= =?us-ascii?Q?y18HRqkZGPQVl/M2vMCZ2zI6vydWS8xX1dCWnEa+4UFrDL+C83BTSuUeI1EH?= =?us-ascii?Q?rJ2cUUPwL9ohtovtbyF2ItRr+b1KlLMia5ODL10Ua9JCkcI1h1sE9SVn+H/H?= =?us-ascii?Q?jMfIr7jaO8IGbCYIe1XpvRwlKijlE9Q01bVZgp+474cYRrC5lKDiiOny9PIe?= =?us-ascii?Q?xRB3raBor9x90AehPAvKZDmMBfdKS5FOktZ+zmzczKDDB7Hu/C++hq/gnU9V?= =?us-ascii?Q?A9WVohD1LU0tXBD1aI1JKFOZomyW1WUFNh//ntm8F4q2dFsN2AF01YbhU+iL?= =?us-ascii?Q?kP87SlMeqALf5sxLtqr7upVdvSSfwH+ptUEkflVRtocnB/i0NTNPEFrNJorq?= =?us-ascii?Q?ehcHUX8LSs1hVxmnb0laKnoHbjtBCNcIiaGP7hZNKt24hiY5+RvHdipaU+0g?= =?us-ascii?Q?xnur5aF6kOEbtSuO97rlrGmuPOoN/ksT6wSspv6zSRVsahFM/wiEYrk027yH?= =?us-ascii?Q?r3Fw6lKZq2XAapPrGL+YXLdYUErkTlt+3YWUmhjwLRSU4iWALAFPoW/SRZkn?= =?us-ascii?Q?wKmbsDPMcsaoxt6zSjTAMBKKcdaE7XBqcTgqWh6n1myIM5US+UcvF7lOygTS?= =?us-ascii?Q?mzYj2GK7TV3xhGcPvSBf11GCkGqGF/Poa4y1DFJ08ssxq8DFXi91W4mvm7Rp?= =?us-ascii?Q?jVf4QMcCb+feKLAhRQtJOo57bX4FmVZvhgLEAc7akLEN/pt9bJpgRUR2kEwY?= =?us-ascii?Q?Pps9UvL4CiPZn+GGB53Wi4splM/3SzfDQLaokc9V984uO0OKvrnYbH3ISxmI?= =?us-ascii?Q?MayxOSgc0lZBD9XUUC2RIY8BgdgZlyQZ1VX43FrhQ9HyRTV3gFkgyDpULBWD?= =?us-ascii?Q?BHDryFkGDpC5jNvf2+EfKAVjKy/bYW2wq8G/WsuqjT+W48nP45EGEtCMNTFy?= =?us-ascii?Q?MG6o1xWM4OlQY3x5cGDUC/Im1NVpDyhF/3sk1yvETKWXDRp987OTqLePFLyh?= =?us-ascii?Q?RggSVoGR/UqAawOd/dfdpBRiwrbqfaq4U604h6RghXjMwKlkDkbIgpGJsCan?= =?us-ascii?Q?Ncpstt4bLMK84q+23NiLcp+UGE/IGHxs1ugd1hfAbqDPdVDCjV9sec0JsNS1?= =?us-ascii?Q?/5mKXPmi0daeWwC3e9hrWb/oCRtZh+qubjeBOFv/yZ6ECKkKSA4SHKxVJJ21?= =?us-ascii?Q?W5oE/WFaYoozXteO5N2WDt0urKWunbkHvQQTH7ztdYZBI+GSln9hYXwNXvZl?= =?us-ascii?Q?qmIk2TC7F57AFt/KKD/hq/CxlosEX8RCZnGKGaVh2H6vpyFoepc9Xo8O9I9r?= =?us-ascii?Q?ls+TBzVrf7xbEUGtM2XZuv0P5Ykpd0Li?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DS7PR12MB9473.namprd12.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?w+OP02A/y9/uD9bauY63HqyWD5nsL/rCYL7nbS32kUKJ+R4eKPpuj9/OfGQt?= =?us-ascii?Q?7cfOmhHGgCI8ebAVDCSqhjM0L2EQybqQAk+DdVR1IaCVQz0DiKjAHv/5286C?= =?us-ascii?Q?8ePbu22PxT1mE0rQTJr5T1BGpeM8OA/JwRQv28lCW5KrWoKNrEyL92nQ7Zh1?= =?us-ascii?Q?Gt+Jlh7jMfxWN+D2os82wm3gbV5eFaxlJ+Ez4lMkoyDMu5homdKvZ/PY9R+Z?= =?us-ascii?Q?6AVLWqcBOsTS78aJoX7u9wIsF+mxvuU3b6fUJBckAgshxuZ7itDBlpJb3rUP?= =?us-ascii?Q?WhIsqXcvjG5p7YI6rW3JywUV8mmE63O4Q5YyronaZlPMfL2P4HeHZUoV9twO?= =?us-ascii?Q?Uoe6taf1UJ9/AcfaKjaoSpbm2Cnu5gm47xF6LO0Y9TAcIGrGkx1yeUs/R6n0?= =?us-ascii?Q?vsEyba9TT0/5PUzeEc4PzVzh6h7W6RrdQ9u1GuKytWbWOrgK77aoWMZj+J7r?= =?us-ascii?Q?hLKFw1hze6ODyxtGZ6/lcWXPLTovX3hSv16D0S6XRUdRkxhPeCiLgNS365X1?= =?us-ascii?Q?7iDxjhFaDWvXPtE3ywySqr5RLL1tW+yrUklh4vxfM3Ib56trdnN848A+s+Dv?= =?us-ascii?Q?BDoobDRlQNsC/xIiZkO86B4N3OY+yOBg10wkSBgbrKozQzpef4MjGHz6hf6j?= =?us-ascii?Q?QaODdhHUaOlbx8JGzqIoVbOxX3K++hCx0z32DDJ507kHvoDgdeaakTHfhYgm?= =?us-ascii?Q?yqcsuK6xJB/8jTCwUnmUDWZNBtJJPiDuuZ+OAyXfvdH+l4UIYYmuZqIif5D7?= =?us-ascii?Q?oBzYQbQmQW9VIuBk9G6To/mnr6/ok3Qn5hrTrn1WJloMMI4eB++v+wrylT+j?= =?us-ascii?Q?DeJ7LS+vDPvyZOC6z2DAyPItMdaKQz6SaCMqm32atqXZVQ3M/0wqUEy9/8m4?= =?us-ascii?Q?0XD9q2hFJyK2DbhUXiy70qwOpDs5whkSC+H0CRmwQvkbH2E2jj0CBJxy6Udq?= =?us-ascii?Q?BpaGilN3WQDpGahB8/dECdLHFRobw3awRdTg7GnSzvjqYvcvcjk3HduCa+Qd?= =?us-ascii?Q?EZRFCIoRDbJduohBmu8dgslrh6nZsL4D7fUDEYKuq8OBeSxKDI22AYG8oGVf?= =?us-ascii?Q?HDgrjOASOOzco0DgdobuJ2PhNXEhEc4QX+o4i4kKbH6vsVqOTLqe/ipkCavE?= =?us-ascii?Q?jdlbhWul4mbKV9p2e+su7s56uXNCiP9yNWwTWhHRzOZTkBF+X+Lbr2mYOWPw?= =?us-ascii?Q?vdFdAPDKQyFTMmzMhAKavR5XsQFWQRvBVvOqJ203F8m1LSZBAYh7mIL4jEr+?= =?us-ascii?Q?6QkR/aXlxid5rlIQyUs2DGv2HbXXFkvkMyfNJy9tuZfgSrj7BZzzo5fyYqUc?= =?us-ascii?Q?+UpSiUusAuOOXM+Ok/1GNsd1Tl7Sge4SNOIWzHJzwLD0mQ84L+VvAzN9aZTd?= =?us-ascii?Q?AUqEM7A2tlE9RVWK+H9AlnPEFCJLBmR/VdjgEFRj0J/BPSSs6tuAasFaTyYt?= =?us-ascii?Q?8vBHw3GzagozaW0G9y9aT5bY4SZ7s+wL/Fk1qA6Zgx4g6kbStot9dPS9xZlx?= =?us-ascii?Q?nwJm+y7e1MqyUO+vglGtn6EjJYoQkKcr+k1doTxdF1EUYBYAnhrvZtpIZbrL?= =?us-ascii?Q?XsDm541fx20CmtpFdCQj/dxvvm8ghL4a+RP91EJG?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 1644ca61-47a8-4767-8b61-08de22039d0a X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB9473.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Nov 2025 15:53:24.9656 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: SG6QvUpBNs51sjREPWyMCKZkRrQfOhiLn5yy5K5BjzkA+tWT+EUQplUjugNZHLlE X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR12MB9315 On 11 Nov 2025, at 20:38, Huang Ying wrote: > The page faults may be spurious because of the racy access to the page > table. For example, a non-populated virtual page is accessed on 2 > CPUs simultaneously, thus the page faults are triggered on both CPUs. > However, it's possible that one CPU (say CPU A) cannot find the reason > for the page fault if the other CPU (say CPU B) has changed the page > table before the PTE is checked on CPU A. Most of the time, the > spurious page faults can be ignored safely. However, if the page > fault is for the write access, it's possible that a stale read-only > TLB entry exists in the local CPU and needs to be flushed on some > architectures. This is called the spurious page fault fixing. > > In the current kernel, there is spurious fault fixing support for pte, > but not for huge pmd because no architectures need it. But in the > next patch in the series, we will change the write protection fault > handling logic on arm64, so that some stale huge pmd entries may > remain in the TLB. These entries need to be flushed via the huge pmd > spurious fault fixing mechanism. > > Signed-off-by: Huang Ying > Reviewed-by: Lorenzo Stoakes > Acked-by: David Hildenbrand > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Andrew Morton > Cc: Vlastimil Babka > Cc: Zi Yan > Cc: Baolin Wang > Cc: Ryan Roberts > Cc: Yang Shi > Cc: "Christoph Lameter (Ampere)" > Cc: Dev Jain > Cc: Barry Song > Cc: Anshuman Khandual > Cc: Kefeng Wang > Cc: Kevin Brodsky > Cc: Yin Fengwei > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Cc: linux-mm@kvack.org > --- > include/linux/huge_mm.h | 2 +- > include/linux/pgtable.h | 4 +++ > mm/huge_memory.c | 33 ++++++++++++++-------- > mm/internal.h | 2 +- > mm/memory.c | 62 ++++++++++++++++++++++++++++++----------- > 5 files changed, 73 insertions(+), 30 deletions(-) > LGTM. Acked-by: Zi Yan Best Regards, Yan, Zi