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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9CA26E9D408 for ; Wed, 4 Feb 2026 16:09:33 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.1220964.1529359 (Exim 4.92) (envelope-from ) id 1vnfRB-0002Vt-Hc; Wed, 04 Feb 2026 16:09:05 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 1220964.1529359; Wed, 04 Feb 2026 16:09:05 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1vnfRB-0002Vm-Ey; Wed, 04 Feb 2026 16:09:05 +0000 Received: by outflank-mailman (input) for mailman id 1220964; Wed, 04 Feb 2026 16:09:04 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1vnfRA-0002Vg-2e for xen-devel@lists.xenproject.org; Wed, 04 Feb 2026 16:09:04 +0000 Received: from BL2PR02CU003.outbound.protection.outlook.com (mail-eastusazlp17011000f.outbound.protection.outlook.com [2a01:111:f403:c100::f]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id cecec5e2-01e3-11f1-9ccf-f158ae23cfc8; Wed, 04 Feb 2026 17:08:57 +0100 (CET) Received: from CH7PR03MB7860.namprd03.prod.outlook.com (2603:10b6:610:24e::14) by PH0PR03MB6591.namprd03.prod.outlook.com (2603:10b6:510:a8::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9587.12; Wed, 4 Feb 2026 16:08:53 +0000 Received: from CH7PR03MB7860.namprd03.prod.outlook.com ([fe80::f5ba:35df:1c9f:b343]) by CH7PR03MB7860.namprd03.prod.outlook.com ([fe80::f5ba:35df:1c9f:b343%4]) with mapi id 15.20.9587.013; Wed, 4 Feb 2026 16:08:53 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: cecec5e2-01e3-11f1-9ccf-f158ae23cfc8 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=pjE9sxM9AAAeAgfY2Gtze2YM1RQzMUtb06BSem8KmAO6W6BuuupbWZG152t6inE43hfFU5DeeaxkfVtoV78j+c6cGJWLUunYONc5LW6/R82n0yhyiw8q76+rw66ZxljZdytEsBcnXV8Gt1gv0d1jTnOveWOTSqh7UNEEog9szImQ8tD6lq2TtU1wiGQVEN/Cf9mHBB+3h98F7YSiLnmYO+xltiVZvSobos89LaQhXn1kuZAdQaH57FxTQN7TFpfn6W4vq63z/3P4WmClkKyCfDb4F3MCqsBy3URgbe4bjUm8ydWxwBfNXTSrTSWhInz70wMcm5FvsyNm0m9Em3AdSQ== 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=5rlL/QmA9PSmxfC2caP4vmCOdIWVGYrjz0Tbry7EOfc=; b=eBDPLt0X/s05DVKtKDsDVTGCMoKU26bEzHDOS8FVpSzunVyZ91CjHdA8XeOiz3ImnQR6d3YKMbxv/W/LZbK6t2iWQU4Rg5aplIHj4GWcM0qVo4Ud73cXVkHAJL4wB8UqLg+86BP7hRmOJ32gwkOo/GyazQobsAXCqSQrMa3oAF1+lMjz801cfB+Zw1bY25kLNtj0iU8fIZxv43ym0J0PIUPmprlpAC8SkgAipuCznWlGFm8fVbgTQ0brjyo7oqUUa+92mYqecoI5aTZxWX5Kq6cprk6+nrXQeTJJJK7t88u/Z+kLNTxCns9NqWIbqVc70uOv5JNo3UsBu6ADoOSEBQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=citrix.com; dmarc=pass action=none header.from=citrix.com; dkim=pass header.d=citrix.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=5rlL/QmA9PSmxfC2caP4vmCOdIWVGYrjz0Tbry7EOfc=; b=yzty6bfz7Jtb5kKoeUP75RkrxLMPSvk5Ajwyy4DF4l8F/xa2TTCGRzpZMyeKya1Nq/1FmhJoxYb6kb2Vkgtw28mfvitFXhKuVQvsgs/NEq3dWr4NDS6M5fI29X55TMHLAZMKaIMDY3DlXRMO9vY+voA8YLIRUpCQlEgFVHvblAQ= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=citrix.com; Date: Wed, 4 Feb 2026 17:08:50 +0100 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Jan Beulich Cc: Andrew Cooper , Anthony PERARD , Michal Orzel , Julien Grall , Stefano Stabellini , xen-devel@lists.xenproject.org Subject: Re: [PATCH v5 4/4] xen/mm: limit non-scrubbed allocations to a specific order Message-ID: References: <20260130145726.85907-1-roger.pau@citrix.com> <20260130145726.85907-5-roger.pau@citrix.com> <2c2b6189-9404-4378-a101-3a93cbadee43@suse.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <2c2b6189-9404-4378-a101-3a93cbadee43@suse.com> X-ClientProxiedBy: MA3P292CA0009.ESPP292.PROD.OUTLOOK.COM (2603:10a6:250:2c::10) To CH7PR03MB7860.namprd03.prod.outlook.com (2603:10b6:610:24e::14) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH7PR03MB7860:EE_|PH0PR03MB6591:EE_ X-MS-Office365-Filtering-Correlation-Id: 415b2ef1-9adc-4bb9-7785-08de6407b0fc X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|376014; X-Microsoft-Antispam-Message-Info: =?utf-8?B?SWdWc0xxVWI1L29GL2JVRGxZU1EzZjJXZEJmNFkrUWJLQVVvWDNLQjRzSEdy?= =?utf-8?B?bXVmcG9UbXdDOTNleGplSDlmYXNLdWNXM3I2WHphME5EakZZTU9MdlBBKzFN?= =?utf-8?B?ejJyZkxpQU1DTWFmUUdLUDh1NkZwQ1BRUTZIcmVha2hVVWxTUmZWdDlWNTBR?= =?utf-8?B?OERmVzh3bXZHUHZHN3ZXNyttSTNQeDhSbVZIM3FrbXBPVTBWNWR2MlNjaVZq?= =?utf-8?B?LzJGTEZLbEM1Ny9DTHlEUGRpUjhVOVF1cUJVWWcwd3h6UzVmVUJRcFloWmNi?= =?utf-8?B?TmVtYjFxaWlVTDZsVDZ0Y1Q0QXcrT2xoNWlOOFB5L0tMcWdQMjN2eVpQU0tE?= =?utf-8?B?UGJPZFNieTBTT3NpN3JOQkxoa0d3VkZDNDlNdUoxWVNjcHVsY2t1UmV0RTdx?= =?utf-8?B?WE9jMEZhOTFTVFY2WW9zT0NCNUZpd1NTTTh1UVduWGcxUkxQWTBFSmlCYmFp?= =?utf-8?B?N0hpb0VEOVAvWlk2WG1BcUpUSWRiamp1eFFDSkhReVZlbzhiWFphM21UTGcx?= =?utf-8?B?ZUFMYzlKb1VySDIwNmZSY1BjT1ZMUEFEZGh1c2ducFprcnN4MStteHJQcnVa?= =?utf-8?B?Z1cyUS9LOHRNU0NhT3VOZGVzR0dTWGRsbUY3T2I0M1pUMml6cHh5WW1yUEt4?= =?utf-8?B?czNNV3k2bEpjcjJqbEVoZUltMUl4T1htN1JkMkpnVEhYQkJWbjBlNHZBYVBs?= =?utf-8?B?NHNvdGEzK1hDUUpiTkZML2Y3TzJ4aS9TUUZTRklKV053dTArZ2JjYzlQTCtx?= =?utf-8?B?dDI2OVZmUm43Y2RvakFnSDlDOWZIaDB1ZW1HY2VZVHR2MFV6eGZ2MmZlMVJH?= =?utf-8?B?NmNyQUpSZUc0L0x1dlp0MU45a2o4NlIrQk9qQzhQeGFHdGdDbUFGV2ZVNVhC?= =?utf-8?B?cHNNQ1RCUXU3RHJtTU05czRSekhBc3N1ZU11VW9rMmpITGVxa05HQ1grUjg1?= =?utf-8?B?bE51d3ppdmJ1aTFMR3Z4eTV6YkxENEhCenVwZUJQVXUwbzZiNitaSndlZXNS?= =?utf-8?B?bVdZSjcxT3RRRGYrcEttVFhKTXpNanlUVm9vandMZ2huK1FBMi9qbXpleVdB?= =?utf-8?B?RlNGWXhqMGFQWG82VHI3UW9mc3ppMXdiU3FvSGpHamg4RUxpVW14cTZEdy9P?= =?utf-8?B?MTY3Y3dYVkpPRzBPQ3QrMHFsUThDSmZjOU81TWF0ckFFbnVDTkwyVDl4REVR?= =?utf-8?B?WWJZN1UrZVJ3V3h6UTVDeXNBbUlnYXhkWGgxbGFudVhDbXYwZTdLeXlZZ0ZJ?= =?utf-8?B?UFZQNXRkSER0QzlxVDd3dVkvVXZkK056SURVbE1UVEhHYlNPWWhnRjZFbmRZ?= =?utf-8?B?MU5oeDlQTmFyN1MvYmkxL0VINU1qam9kRUdvL2tHQXZrQ2RqbnRBSDRZRlUy?= =?utf-8?B?c1orV2d4OUhBVGpqdDJZZVlBRmdHVHBJL25MQVhHMFlxZi96VUF1LzE0L1lp?= =?utf-8?B?elM3RkN6NGdBM0xHMytBMitSWGFORVRwbmhoa0t1RUtkeVoxNU1pZFZ0RjY3?= =?utf-8?B?dHg0aFVnZmxRNG5EbHlPSEdrcVVRT2FoYmczaTJQckRXSndYRDdoUWRtYVVL?= =?utf-8?B?NU03V3FBQU9wUXRQanBqVG1BZ0VOdENOMjdoRUVDOHhNQUpSZklIRXpXamp5?= =?utf-8?B?VVA0QVJ4aklGVW8wMmhEeTUvd1ZsNkpldzNyd3o4ZTdnWEFzQ0hBd3g4SzEy?= =?utf-8?B?ZlBIay9xd01nWlo3Y24vVEdabzYyaDYxM0RpU2ZPa1lXRXh4bjhxZzNPSUpi?= =?utf-8?B?ODAzc1dRQXdLUHhCbmJOdGY5VWMrUW1BYU9rMUMvRVFNOXlBeVBvcFlHd0RX?= =?utf-8?B?dUdQcUdBM1czS3llaDgyUTNUVUI3UXV3Z3YyNGdHY3pDaUZQZ1N2L0MyVEpB?= =?utf-8?B?OHowTEpuUnBLeDB6L2JaaWpCM1hEZnBQQjBkZUhTMzh2K25NN1N6elpTRkNr?= =?utf-8?B?K2NVMkNySmpPUTJselZEQVpOWEQ2MTVUQ0NjRGNUbjlEY3lIRURmclVCS05n?= =?utf-8?B?QjN0bjNHODNDQzBUMkx1MzB2YlRRcjZHYmdMaDZydlRZdytSZXZ0a1ljM0RG?= =?utf-8?B?Qnp6ZHErZ0RuRkJRb2toNzdjS1JvSVJ4MWdyaEg1Y29sdStrdmhaS1o1bnZl?= =?utf-8?Q?lXvA=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH7PR03MB7860.namprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(1800799024)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?eW1keUNYYkN2RitTYlhaWWxrWDFLL3kreVA4UGsrUW5EZ1cyanZGaVR6Y1I5?= =?utf-8?B?R1g5cUdKeTFnajBCcmEwT1IzUDFRbDNNYjEwYXZ0cCtNOHBTOFVsdmV6Tlkw?= =?utf-8?B?b0hFd2ZFWUhsWGI5NVFOR3R4K3h2dVVESW9YN1NtRExMYnZjZGt1NVErM1gr?= =?utf-8?B?R3VwMzl5aFBWakNCYTRlTXU2bVlYY1BpWEE0ZHVBZkVGWEdYTFVrbHJkb3Nx?= =?utf-8?B?Nyt5aC9Yc1JDcW93SkxESU9QQ213TDRDcHpsaTdYcUpNeHhFMjdJcWp2MzhT?= =?utf-8?B?d3hGZ1dvQ29idklYQ1h3WE9CTFFka0RWUXN1UElMUXMyYUMyUzVKelhyc2l2?= =?utf-8?B?dmFSakRKNGdVZjN1Y2k4VyszRlNSdE4yUlJBNWNuQUkxU3NrcFRuanBEeHFH?= =?utf-8?B?Mm1aQ2hWaG5NTWJ4U2grdVlveUFpdnpkSHY3K3BMNEZyN0FDMEhxUFpSbGF3?= =?utf-8?B?M2FibjRXQ01nZXRtc3VncnJWNTBkNWg4bkllRjlibDBxQzBZQWNGM1VrZHZn?= =?utf-8?B?c1ZsMjNHQ0hiQ3lackdIQWNrTlQzSUJtNVlXOTNPMmZ6bE5udWN4V1lETkZ5?= =?utf-8?B?T09qVUFBUk9QTE4wRUFicDIvdmF6R2FJZzRFUGg4b0l0VUNmdm1CK2VuZEJS?= =?utf-8?B?N3pjRHdVTDJ4S0xKWjJ0WXJBOGZ0eFNDZVp3L0hFbFBFUXlsTmFYTlpDZzd0?= =?utf-8?B?NzdURnN1bVozbUVuRC9oSEdqWkhZY2dVK081UGpweUpmY3VGM2ZyREZnZzFI?= =?utf-8?B?R05YYVlpWDFaWjFTcHJ1VXI5N3Fzb3lNcnRRYSsvc1llQ1VtSWo3R013bFF5?= =?utf-8?B?VHNwNVNsNVp2cFhQekRFOVR3aVZkYmNQakc4UFV3RXFsTGVvQ2dsdENQVmpw?= =?utf-8?B?QXdZU2huc3YvaHV1M2RtTzBYRFd5YzZmV1FzSWV0ZzlGeTV1aEQwMkZEQ1R1?= =?utf-8?B?OEYxbFU2YzBzVWZOL1NmcFJ4QnF3VW4zWXQ1VUxxazlzUVB2RzFaemlHczVB?= =?utf-8?B?MEY5VUlvanBDNFpuUGpkaldwQyt4UkZkbmxETVcyQmZsQUdtb1k3VENMVS9F?= =?utf-8?B?VncwNGRHeEwxbjRTS010allweFZndnBSeEVtVStqN1p0WE1WbVFGSnF6Z01j?= =?utf-8?B?azh1SW8xbTk4OFVVeHJGc3FRbWk5TmNGOHBraXZtSmhERjRGczhoZHNZdHJ6?= =?utf-8?B?ZXd5ak9nZGs2b2poVjVKWEN4dXNDVStIbGtwNjRnTWN1TXNQL2hPbmwvMW1H?= =?utf-8?B?S2RYR3VYcG9UdkxIV0tCeWR2SmNZbFltRmpVUTNMUFd4ZUpkSXVheE45bkN4?= =?utf-8?B?d0RLVnZlTjMyaFRVY01hRnYvNVppTU1hZktQQ0ZrMHRKVWpmRFQrZzRramlL?= =?utf-8?B?Wk13a3BTNEEzdklKSjRwUUNmMS9BUTl0d0ZpalIrbEl5Y1B6b3h0UTAyZzRD?= =?utf-8?B?SlNJb0ZkRTg3Z0FEWFVpSytmb3NpdVEzR0MyRkZlYno0YS8rVmtvbzhtcWtG?= =?utf-8?B?NlVCSW4xMy82Wmc4N3o1aUJDSWtTRTViYXJyeWRGdlZtSjBzZHhvbHM3QUJK?= =?utf-8?B?aDQwOXRUTUF5YVNia0xxVTFOZDZxSDRONXBLK3JEczFZRjhBd01MVTZMTWhS?= =?utf-8?B?QXQwQWVLQkpSRm40ZHJIYXNmd3E3VDNOdzhrRWJtd2hDMXpjQkovbnZYWE13?= =?utf-8?B?dmI4WWFaWVhZS2xRNWh1QXNnZThQVTd5Y1RIejdDTW1tcVh2bmZtMjFLSE40?= =?utf-8?B?Yis5c1Rob1NGaElqVXFwYXA2L3BpQ3FHNTF6YXorWmlkc1ZFcFk0cWcwQ0JX?= =?utf-8?B?U3hRdHlIdjZJRjl3aWR4L1diREJDTzFEM05haHNjWW0rVDgxT3lSZmNSdlNh?= =?utf-8?B?VHlma2RFMU9wNUc0c1BIdG11bEl6M243d3IyRitXOUQ2ZWRtaWljZ1dES1FW?= =?utf-8?B?QzJqVlF5ZjBaSlZYTmh1cXB5QU5XMnEwSnZJS3FPS1Z5TmFSek5yVG1BTHha?= =?utf-8?B?dVcxR1hOdExjMllvZVduU1U4dGRRTkdwS1RLQ3RWOE1Jajl6T0pKRTNIVldC?= =?utf-8?B?Z2taNHJmU2VhaitSTktTcmsraXJwK2JFdEIrSURYN3FKTFI4d3FJbHRhYVJ4?= =?utf-8?B?dGozUDdyWmtzUWxiRVAySFFGKzFDVUNyQTN1dkNEQXErMjRMdkxjSFd2VlVR?= =?utf-8?B?Rng0aW1QMnFybnhMS3JyNmRBRzV4aVpSNlNhbXU3K3JDN3pJVjB4dWtra3Vr?= =?utf-8?B?My9sczlwR2RnazJBNWlEb0Z0U3ZsTTRHaWR4anZMb0Y3R1BMMmlKQVpzN1Ny?= =?utf-8?B?d3A0c1g2SVArRHhSNHgxdSswM0pPWmhoUm9rT28xSEp1bVlLbUNadz09?= X-OriginatorOrg: citrix.com X-MS-Exchange-CrossTenant-Network-Message-Id: 415b2ef1-9adc-4bb9-7785-08de6407b0fc X-MS-Exchange-CrossTenant-AuthSource: CH7PR03MB7860.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Feb 2026 16:08:53.2190 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: b2d5nJPjbumR9AW9zhlt9ZmGynP3jbN5eluQe9pdaj/bAmdV+n8e6hZlAFlCdYvDKx1d3tqifM0cL1K0lR0+mA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR03MB6591 On Tue, Feb 03, 2026 at 04:00:09PM +0100, Jan Beulich wrote: > On 30.01.2026 15:57, Roger Pau Monne wrote: > > @@ -1117,6 +1130,14 @@ static struct page_info *alloc_heap_pages( > > scrub_one_page(&pg[i], cold); > > > > dirty_cnt++; > > + > > + /* > > + * Use SYS_STATE_smp_boot explicitly; ahead of that state > > + * interrupts are disabled. > > + */ > > + if ( system_state == SYS_STATE_smp_boot && > > + !(dirty_cnt & 0xff) ) > > + process_pending_softirqs(); > > } > > else > > check_one_page(&pg[i]); > > Coming back to this, I see two possible issues. One is that on x86 enabling > of IRQs happens a bit earlier than setting of SYS_STATE_smp_boot. Maybe this > isn't really a problem right now, but it could become one if the "wrong" > thing is inserted into that window in __start_xen(). Even if IRQs are enabled a bit earlier, the watchdog is only setup after SYS_STATE_smp_boot state is set. > The other is that only x86 actually ever sets that state. TBH we have never seen the watchdog triggering during initial domain creation, so the workaround added here was out of caution. There's a certain amount of contention required for the watchdog to trigger, and that scenario doesn't happen during boot, as domain creation is serialized. I could maybe gate the softirq processing as: if ( system_state < SYS_STATE_active && local_irq_enabled() && !(dirty_cnt & 0xff) ) process_pending_softirqs(); Or completely avoid softirq processing in alloc_heap_pages(). Thanks, Roger.