From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CY3PR05CU001.outbound.protection.outlook.com (mail-westcentralusazon11013036.outbound.protection.outlook.com [40.93.201.36]) (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 CE0543BBFC5; Fri, 25 Sep 2026 19:05:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.201.36 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790363133; cv=fail; b=t+tHyzrN7us2Zw/mcoLe1X9j35Bvb8iF1WigxbDOpgHMAwsOXyz1BFyqio3CFQkTOdHjrGyc50npNoQpPziWUqB0H8RNCT/U/4haBamESM4qc+0LbY9iE7dvFYb7jYYDVxE0tlNiYaEmMgrmyCo0W4gxRFBz9WaT7k3G/Tl8cZc= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790363133; c=relaxed/simple; bh=AHzTHeQXHS3y1LJKGd6SPHWqs8qn/MMeeYMtQNKyVhc=; h=Date:From:To:CC:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ub5THqn/FFv69aLJpUe/BSmlWQqvKUHIQWmDENLxSRzTunWx2/fLJAvfdWokY7Y0U9p2a7dVoBzw0+jUSGvJYRcbQKdQ/3eo80kOMdbdO2GQ+X9RQzU2G0unS/T+PaBBadtFJj+v8eTMRe634bFOPyvx99aTTZ0YsnGq1s/h0hE= 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=sz/h3m13; arc=fail smtp.client-ip=40.93.201.36 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="sz/h3m13" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=R9KGlN8LFMaVy2ExnwG/I74Xym5krVWY+f6F5TLbXkaD4HgF2GBOoIMosgDYEG/yxiz0OBsFRG4+YquVUQVq9CIyUVAnUbuFyYKQq/nnk+4ArxWXVSYQicHeHoppZlcjR2LxbN5RMv51akfGEA+AJqZHxhbZACIpDVOFsa1t0AqoxEm3XPcHb4EyIiV+pDwkBDd7TXlOClAf+FU30K5Ybo20NJu/nUDTEH1L19ETJdPMYvvxZwAKYatd18VkQHyNVXS1msQ+S7CXE9V+VIfeu1RHRhrO89SJAxvxEl6y3RlLbUZx0qxJ6DnecgYnGBVwiG8zeZu6Gc8fKjmDq9m4Cg== 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=WJSuypaXynJqQikfcJPdhWO1iCIF7RzU05UW6qy9qew=; b=LPaaKZZbOg0zAxvwX/QsW2DrlzyZe7nr2Q/jBMkIGLeMKOcfaQQ85GclSuOme2PqyhUicVNQNQpE2V+IDCeac/6JvZH7sh0dbcx/e0QObhyvj+62ZH1ai82D/SzLcoGgEs9tymSLa8NMfnhTdkXtYSLg3R4Ux2xjatEQ374L2gElX8mx8rfaR8s3fdatMu9KbBw0bjvJJ1akYJMXGCRNw/eRFE4hc1A7TXHWbLFRq0i1mmF9ickPUQ+MKv9U6TMqmouDfXaXdarE6D3x6kfwth7tLBIqwJSEn7yO1u6Q3BfGARt2JJZWEmwfqDu66+TeCJSP0FeWUeiFA1yiDVqjbw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 216.228.117.160) smtp.rcpttodomain=shutemov.name smtp.mailfrom=nvidia.com; dmarc=pass (p=reject sp=reject pct=100) action=none header.from=nvidia.com; dkim=none (message not signed); arc=none (0) 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=WJSuypaXynJqQikfcJPdhWO1iCIF7RzU05UW6qy9qew=; b=sz/h3m13XggOhLI9bpM67zKch9BK9bh/znYc3y7eztJQriS0E22ucyRhm/i39TleWBnuqxFZkHVcN3TlkaZG5Val4hM2GX1A7hx2UyZ9ZzaU4mOJC8ClzX9yWwoTMeuyQz9UWnki9f0h4kvhr6q/vPESNDKY+2glzUJJKxGuFsIKxAGBxXSHxo1ctO/gCfgnRpSV1FHRFCshpJXRNp4vkXO/zVy0OFip5VqHsBXJkBVBNTcRIJSQ5FttfJP01H1jHFRo5Izq7H8TFyxOVuJW5lQKjnBNuE2cdxb3kJLgEMID/LD30avyQcpi9tmvgh/WssM4uF6V/WqGvbub30ML1w== Received: from BN9P222CA0012.NAMP222.PROD.OUTLOOK.COM (2603:10b6:408:10c::17) by DM4PR12MB5916.namprd12.prod.outlook.com (2603:10b6:8:69::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.451.18; Fri, 25 Sep 2026 19:05:23 +0000 Received: from BN3PEPF0000B06C.namprd21.prod.outlook.com (2603:10b6:408:10c:cafe::5e) by BN9P222CA0012.outlook.office365.com (2603:10b6:408:10c::17) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.21.451.19 via Frontend Transport; Fri, 25 Sep 2026 19:05:22 +0000 X-MS-Exchange-Authentication-Results: mx.microsoft.com 1; spf=pass (sender IP is 216.228.117.160) smtp.mailfrom=nvidia.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=nvidia.com; Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates 216.228.117.160 as permitted sender) receiver=protection.outlook.com; client-ip=216.228.117.160; helo=mail.nvidia.com; pr=C Received: from mail.nvidia.com (216.228.117.160) by BN3PEPF0000B06C.mail.protection.outlook.com (10.167.243.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.451.0 via Frontend Transport; Fri, 25 Sep 2026 19:05:22 +0000 Received: from rnnvmail204.nvidia.com (10.129.68.6) by mail.nvidia.com (10.129.200.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.49; Fri, 25 Sep 2026 12:05:03 -0700 Received: from rnnvmail202.nvidia.com (10.129.68.7) by rnnvmail204.nvidia.com (10.129.68.6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.49; Fri, 25 Sep 2026 12:05:03 -0700 Received: from nvidia.com (10.127.8.12) by mail.nvidia.com (10.129.68.7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.49 via Frontend Transport; Fri, 25 Sep 2026 12:05:01 -0700 Date: Fri, 25 Sep 2026 12:04:59 -0700 From: Nicolin Chen To: Kiryl Shutsemau CC: Will Deacon , Robin Murphy , "Joerg Roedel" , Thierry Reding , Jonathan Hunter , Jason Gunthorpe , Breno Leitao , "Kiryl Shutsemau (Meta)" , Krishna Reddy , Pranjal Shrivastava , Mostafa Saleh , Ashish Mhetre , Shameer Kolothum , Yuanhe Shu , Kyle McMartin , Usama Arif , , , , , Subject: Re: [PATCH v7 2/2] iommu/arm-smmu-v3: Default queue depths to one page in a kdump kernel Message-ID: References: <20260925141532.1274962-1-kirill@shutemov.name> <20260925141532.1274962-3-kirill@shutemov.name> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20260925141532.1274962-3-kirill@shutemov.name> X-NV-OnPremToCloud: ExternallySecured X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN3PEPF0000B06C:EE_|DM4PR12MB5916:EE_ X-MS-Office365-Filtering-Correlation-Id: c5ef0bda-4df3-4eae-3287-08df1b37f30d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|36860700016|23010399003|376014|7416014|1800799024|10067099003|56012099006|3023799007|6133799003|22082099003|18002099003|4143699003|11063799006; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:216.228.117.160;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge1.nvidia.com;CAT:NONE;SFS:(13230040)(82310400026)(36860700016)(23010399003)(376014)(7416014)(1800799024)(10067099003)(56012099006)(3023799007)(6133799003)(22082099003)(18002099003)(4143699003)(11063799006);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 3FV7EEf+YRFK/1ftbRkEOmoS4pW5cbP4/4dPKXqyvkDIURnZFzMj4xVJERPwkxYF4HBwkJr/xzHFOQLMorFxMiwZSSMau7CYwr0B2s87eNw+hg9O/vtK+MsKOt75BjqEAnFMIarXmHcLAhSmnu8+s1sxkgQ4jK2ivEmXVoQ36uMMJtss7Rx75oyZgu3lQHiFXS8+YqZDUJhVfr1kMeuWs5NRm+vRK/ZxPTrVOJ1w11TyhN7rMoS/W2P1dNVtQWDFCSrKc87TjcuuBgvrjy6+f3MUsjFNeWVeN3+m/t2dAwPhjVx6UuDWi4AO3fF7v5IjBOPR81CUvCH4mqFVIZTz4zRmRObUY9tMR79MM/ke9uM+Ydg/0g2deaYKDsiVLjGk1iK1kRG2ETGrq9wQJuQP4lCg3iiaq7spc0qp8dB0UQl6l4m+V3hJmBkGEt/CI4dq X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Sep 2026 19:05:22.2976 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: c5ef0bda-4df3-4eae-3287-08df1b37f30d X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN3PEPF0000B06C.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB5916 On Fri, Sep 25, 2026 at 03:15:30PM +0100, Kiryl Shutsemau wrote: > From: "Kiryl Shutsemau (Meta)" > > All three queues are sized from the maxima the hardware advertises in IDR1 > and allocated at probe, up to 4 MB each on a 4K-page kernel. The capture > kernel already disables two of them: arm_smmu_device_reset() drops > CR0_EVTQEN and CR0_PRIQEN. It still allocates both at full size. > > A kdump capture kernel runs from a small crashkernel reservation, and every > SMMUv3 instance pays that cost again, up to 12 MB apiece. It goes to queues > that either serve the handful of devices used to save the dump or are > switched off outright, and it is memory the dump itself needs. > > Size all three queues at one page worth of entries when is_kdump_kernel(). > The queues carry commands and fault records rather than DMA data, so dump > throughput is unaffected. A shallower command queue only bounds how many > commands may be in flight before a sync, which does not matter for the few > devices that save the dump. The cmdq_max_n_shift parameter therefore does > not apply in a capture kernel. > > Suggested-by: Kyle McMartin > Assisted-by: LLM > Reviewed-by: Jason Gunthorpe > Tested-by: Yuanhe Shu > Signed-off-by: Kiryl Shutsemau (Meta) Reviewed-by: Nicolin Chen Tested-by: Nicolin Chen