From nobody Sat Oct 4 17:30:18 2025 Received: from NAM12-MW2-obe.outbound.protection.outlook.com (mail-mw2nam12on2079.outbound.protection.outlook.com [40.107.244.79]) (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 A6027225A4F for ; Thu, 14 Aug 2025 15:36:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.244.79 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755185777; cv=fail; b=fvWp/Dl539nSqcJgwzxttxDZCbCUnM2cvWcWNKgaImGTtgyztAY0XzT8kh1CqQaeubc8gu3/ZJMvUiw+srrXROrpzPUopwlSKwM1bpK9YdXGcaCu4Ruv42N0UBrekXHWM9mAi8Z4Kf0F38vc7UNUFz7GjM4f92T99OlUQzzKWtI= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755185777; c=relaxed/simple; bh=ZrcXyqH0b8fwpD6YPmb020LxxuZBeGnP3WJBeg/Su8E=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=QkKv/mfl4yyNCPWaCv29dv8wpJzUSSJ/l6HqkgTBO7XTNrcRq7QVy7oc1zKneUWLL1xf1U6polYuJVlpaeSavPdZJG5J8C1frIBmLKS0MvXicaibFh0CHqPd1bgZcJ+hToqv0bRBN3e6xG9rItLbvKn3MY5OFZ9xTqYh7qI//90= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=RpCTePc+; arc=fail smtp.client-ip=40.107.244.79 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="RpCTePc+" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=ibiof957zINn5uoM5E9B/vDUdCdXXjjP4V9HuOPc8dT0WZXqXZrNaqvfziZj7rtwegIqfzufTP0ohbpdBhAPxyGs4cZY0wGjzpCoh2SNLOKj4liLiW+cWHNZKbhyrz4p5icBVbzCrqfOIqtZEYNSx00x5ObzGenYTyx5hVD5JFdQWzPCBlTWz5J2MysiyKza2US+Xqj/lwt80U7G1m8jbh+s/+S9WCHbgLyWFa/R4oVcCY2hV/NN7qLLJGNNHLrn8ObwpUuLeEs5o8KsFwEzVjPzo+51m55idTnklqrUea3nhF+AYyql240IAhsTaZkA1H22EAmxtl4Rsg8cDC2isA== 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=tH6WDjy9Gx73HB03x6/iHMIinsfhhhAxSTl2toAIzd0=; b=aqt2iCANuvtX234/Z407lYgGNrnS0ZBa+AgKGWbiMSmEYT4bGgWT+2SSKx0A1DBTUuVg8yU24nTVOaXR71xb4d73/mYANFeC50s1DFn10vaNBM1NTOcE6dmT2+dXWqAMtsoN0FGd3PzP3To8vs2+F/Z1v4zratn0rMx5XHRAtPpYTdclUtaQxNk3fiAANPMLzFMk0AMP5w6AL/NMoJJj/oDNPgTUt5MZVqLZ27dQO9/UhTKm19ki5m0Clx07gPWJdWllMBDYwAIZSlf4QxbTLD2uLdJbCvSbR8fjMZxLH0JR2UnZ4Z3H4nhVVSAwqw2jDyYlzWh5p15/G50ZTgx1Yg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=arm.com smtp.mailfrom=amd.com; dmarc=pass (p=quarantine sp=quarantine pct=100) action=none header.from=amd.com; dkim=none (message not signed); arc=none (0) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=tH6WDjy9Gx73HB03x6/iHMIinsfhhhAxSTl2toAIzd0=; b=RpCTePc+sCJ9y+6HCyWoZWQPDboHNowAkeihTLEJ0iYZEa+3GtM4Dw1oGabhSRGc8bjWBhrXkqva1AfjzuSNiDZr7p1qp/vt7lLJ+vgCrWf1Y19iOL22tTyP30BkhUscHj5Nyb6MGIxssbSK/ltrc6msn1mkcaRRuzLanBCNp9Q= Received: from DS7P220CA0011.NAMP220.PROD.OUTLOOK.COM (2603:10b6:8:1ca::16) by DM4PR12MB5820.namprd12.prod.outlook.com (2603:10b6:8:64::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9009.21; Thu, 14 Aug 2025 15:36:11 +0000 Received: from DS1PEPF00017097.namprd05.prod.outlook.com (2603:10b6:8:1ca:cafe::b) by DS7P220CA0011.outlook.office365.com (2603:10b6:8:1ca::16) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9031.18 via Frontend Transport; Thu, 14 Aug 2025 15:36:11 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 165.204.84.17) smtp.mailfrom=amd.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=amd.com; Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by DS1PEPF00017097.mail.protection.outlook.com (10.167.18.101) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.9031.11 via Frontend Transport; Thu, 14 Aug 2025 15:36:11 +0000 Received: from tunga.amd.com (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Thu, 14 Aug 2025 10:36:00 -0500 From: Raghavendra K T To: CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [RFC PATCH V3 15/17] prctl: Introduce new prctl to control scanning Date: Thu, 14 Aug 2025 15:33:05 +0000 Message-ID: <20250814153307.1553061-16-raghavendra.kt@amd.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250814153307.1553061-1-raghavendra.kt@amd.com> References: <20250814153307.1553061-1-raghavendra.kt@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: SATLEXMB03.amd.com (10.181.40.144) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS1PEPF00017097:EE_|DM4PR12MB5820:EE_ X-MS-Office365-Filtering-Correlation-Id: 0a9c6325-3791-4215-d5cc-08dddb484bb8 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|36860700013|1800799024|7416014|376014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?Dn3vY73JARjYDEzuJ3z93MctRJg3ikfy7I8wI+I22KL7Ji3rOHlpzbimW2X4?= =?us-ascii?Q?39nikR0jaBiJFUf4Rt7sRb0+DqujXnbiry/0pElvkxozX+CWhlOr7TkxlSNZ?= =?us-ascii?Q?4Y++zwkuhD5YMUbAJjWvGgLoAt8fZF2184HHErNdF9koBW8VuRguOkC3O+hz?= =?us-ascii?Q?rEnQWuW3vjfbycX6ZMRr4jYvdngku4rZR8e5MBMcIO5krMC393qvTzzpiwBX?= =?us-ascii?Q?SSXwUcJzBfCs6Jck2eU5+7gNyL7UDs8iB4mzCVzk2N47Fg5VU6JU6mlRHMs+?= =?us-ascii?Q?YRXGt7ntESGrj+tdLrCnG9hIEVFDMiQ2lSdEHK/WwGz7X0xOatRJyeCc6Sak?= =?us-ascii?Q?5XomUWRKprZL6yxryWuoVM89+O2h63jH0mET6X0vEJc9h0xwBS/ktY7IdlgJ?= =?us-ascii?Q?QeGPp7mOlrDmig2DccqoQwvRwjpulJHjHtzkwhIVvDpBfci0rI1owiMB3JRU?= =?us-ascii?Q?JF6mplAimzL9ea2LBVzDpPvxbwTpvBNmn40ya3LZCjdDscgErtsAvs1xRPnI?= =?us-ascii?Q?JHKx+X76eKFCj8yMpIrd7sWhtQA8U9a+iGEPj8hi2+3tAqRFxcwxMi3B3ZZg?= =?us-ascii?Q?RFk9WaTF5JptYK3+OIQqNiMKOT5FjfPgOnx/y7h3/mbb2781uzpm59SgeafR?= =?us-ascii?Q?PIi9jy2kPSCj8rqgT1tn2Qgnxxqf0OSS9Pj2FRvySSIv1bhfSqyzbtGwgzyJ?= =?us-ascii?Q?AjSnVkn6JhbOCUpgyGO3n6Proio9fr3OM9oPQnw90pwD3dj1Ukr3vhcg2TcT?= =?us-ascii?Q?z/3cLOTHBILSMNx9ZIQQzM9qyFgpwiK0QiF3mMh4ppMDnOz8IC+HGlmWeDgc?= =?us-ascii?Q?+K9e6R2GUdHpTY2BGWrhy1kT01EZvhaUOLO5YH1TkWWIwyfM2HgOespYN4OH?= =?us-ascii?Q?NeSrzQYByUYDF2I+mop/nbQFXMHcc2rhOVXTf6CmzKyqc2PlyJngtS+1ByZe?= =?us-ascii?Q?N5inoEo7ZCEh6UeEZjexQGUTKc7/tiMs6xjHZreGnIoBHGndJj2aEc7mJIPA?= =?us-ascii?Q?AkHtS8oKVrHtGYpzn8cLYk1IsUHnQ+re0SWUgCbyweYF5U5STa493pZ3AkRP?= =?us-ascii?Q?kCBeHJXH6dWuwyDlA/3v2lay3R6JBKWG8zlA96SP5VpzLdEnQsQZMlrtFmgG?= =?us-ascii?Q?jiAhJjvOLtw603ftkv1QgAZKYBXybZORTHk2VuudSp0u6ozXpm/L6H94m7o5?= =?us-ascii?Q?wD1EHAfLOf5giIyHjzRdlY1udGgbjoNjM1HxEdlvmjM4dAlT/ztf4e0MZiKZ?= =?us-ascii?Q?tcSg2+cHhibGRREmaPDrER0oIuEkBCr49mfmi4HWPMpmU2JxEAILeQdY4q5q?= =?us-ascii?Q?rdRoUtgNsud5+tTxCSc+PGINBwETT9T7bBTZ23K5CSz0fFa03kN5EcN3sId7?= =?us-ascii?Q?BjFcAycoJp0DScuaYXXH6CuuIN4cON/cMFFAHEr7VR3SWP1cNaAJ02SP316X?= =?us-ascii?Q?8xhRScxMs0PXlO0lxWwdP4uhhplBKvkbUb6xmBH8jYpP2cMWou+jxxciQubg?= =?us-ascii?Q?dxHoTWv01Fpm1opEsKNEFthzfqfS68Pe5wb2?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(36860700013)(1800799024)(7416014)(376014);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Aug 2025 15:36:11.0205 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 0a9c6325-3791-4215-d5cc-08dddb484bb8 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: DS1PEPF00017097.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB5820 Content-Type: text/plain; charset="utf-8" A new scalar value (PTEAScanScale) to control per task PTE A bit scanning is introduced. 0 : scanning disabled 1-10 : scanning enabled. In future PTEAScanScale could be used to control aggressiveness of scanning. CC: linux-doc@vger.kernel.org CC: Jonathan Corbet CC: linux-fsdevel@vger.kernel.org Suggested-by: David Rientjes Signed-off-by: Raghavendra K T --- Documentation/filesystems/proc.rst | 2 ++ fs/proc/task_mmu.c | 4 ++++ include/linux/mm_types.h | 3 +++ include/uapi/linux/prctl.h | 7 +++++++ kernel/fork.c | 4 ++++ kernel/sys.c | 25 +++++++++++++++++++++++++ mm/kscand.c | 5 +++++ 7 files changed, 50 insertions(+) diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems= /proc.rst index 5236cb52e357..0e99d1ca229a 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -205,6 +205,7 @@ read the file /proc/PID/status:: VmLib: 1412 kB VmPTE: 20 kb VmSwap: 0 kB + PTEAScanScale: 0 HugetlbPages: 0 kB CoreDumping: 0 THP_enabled: 1 @@ -288,6 +289,7 @@ It's slow but very precise. VmPTE size of page table entries VmSwap amount of swap used by anonymous private data (shmem swap usage is not included) + PTEAScanScale Integer representing async PTE A bit scan agr= ression HugetlbPages size of hugetlb memory portions CoreDumping process's memory is currently being dumped (killing the process may lead to a corrupted = core) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 751479eb128f..05be24e4bc4f 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -79,6 +79,10 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) " kB\nVmPTE:\t", mm_pgtables_bytes(mm) >> 10, 8); SEQ_PUT_DEC(" kB\nVmSwap:\t", swap); seq_puts(m, " kB\n"); +#ifdef CONFIG_KSCAND + seq_put_decimal_ull_width(m, "PTEAScanScale:\t", mm->pte_scan_scale, 8); + seq_puts(m, "\n"); +#endif hugetlb_report_usage(m, mm); } #undef SEQ_PUT_DEC diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index e3d8f11a5a04..798e6053eebe 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1151,6 +1151,9 @@ struct mm_struct { #ifdef CONFIG_KSCAND /* Tracks promotion node. XXX: use nodemask */ int target_node; + + /* Integer representing PTE A bit scan aggression (0-10) */ + unsigned int pte_scan_scale; #endif /* * An operation with batched TLB flushing is going on. Anything diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 43dec6eed559..6b5877865e08 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -371,4 +371,11 @@ struct prctl_mm_map { # define PR_FUTEX_HASH_GET_SLOTS 2 # define PR_FUTEX_HASH_GET_IMMUTABLE 3 =20 +/* Set/get PTE A bit scan scale */ +#define PR_SET_PTE_A_SCAN_SCALE 79 +#define PR_GET_PTE_A_SCAN_SCALE 80 +# define PR_PTE_A_SCAN_SCALE_MIN 0 +# define PR_PTE_A_SCAN_SCALE_MAX 10 +# define PR_PTE_A_SCAN_SCALE_DEFAULT 8 + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/fork.c b/kernel/fork.c index a13043de91b0..bb780215024c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -106,6 +106,7 @@ #include #include #include +#include =20 #include #include @@ -1050,6 +1051,9 @@ static struct mm_struct *mm_init(struct mm_struct *mm= , struct task_struct *p, futex_mm_init(mm); #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_SPLIT_PMD_PTLO= CKS) mm->pmd_huge_pte =3D NULL; +#endif +#ifdef CONFIG_KSCAND + mm->pte_scan_scale =3D PR_PTE_A_SCAN_SCALE_DEFAULT; #endif mm_init_uprobes_state(mm); hugetlb_count_init(mm); diff --git a/kernel/sys.c b/kernel/sys.c index adc0de0aa364..f6c893b22bc6 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2147,6 +2147,19 @@ static int prctl_set_auxv(struct mm_struct *mm, unsi= gned long addr, =20 return 0; } +#ifdef CONFIG_KSCAND +static int prctl_pte_scan_scale_write(unsigned int scale) +{ + scale =3D clamp(scale, PR_PTE_A_SCAN_SCALE_MIN, PR_PTE_A_SCAN_SCALE_MAX); + current->mm->pte_scan_scale =3D scale; + return 0; +} + +static unsigned int prctl_pte_scan_scale_read(void) +{ + return current->mm->pte_scan_scale; +} +#endif =20 static int prctl_set_mm(int opt, unsigned long addr, unsigned long arg4, unsigned long arg5) @@ -2824,6 +2837,18 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, a= rg2, unsigned long, arg3, case PR_FUTEX_HASH: error =3D futex_hash_prctl(arg2, arg3, arg4); break; +#ifdef CONFIG_KSCAND + case PR_SET_PTE_A_SCAN_SCALE: + if (arg3 || arg4 || arg5) + return -EINVAL; + error =3D prctl_pte_scan_scale_write((unsigned int) arg2); + break; + case PR_GET_PTE_A_SCAN_SCALE: + if (arg2 || arg3 || arg4 || arg5) + return -EINVAL; + error =3D prctl_pte_scan_scale_read(); + break; +#endif default: trace_task_prctl_unknown(option, arg2, arg3, arg4, arg5); error =3D -EINVAL; diff --git a/mm/kscand.c b/mm/kscand.c index 273306f47553..8aef6021c6ba 100644 --- a/mm/kscand.c +++ b/mm/kscand.c @@ -1306,6 +1306,11 @@ static unsigned long kscand_scan_mm_slot(void) goto outerloop; } =20 + if (!mm->pte_scan_scale) { + next_mm =3D true; + goto outerloop; + } + mm_target_node =3D READ_ONCE(mm->target_node); if (mm_target_node !=3D mm_slot_target_node) WRITE_ONCE(mm->target_node, mm_slot_target_node); --=20 2.34.1