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Tue, 4 Aug 2026 09:04:32 -0700 Date: Tue, 4 Aug 2026 09:04:32 -0700 From: Nicolin Chen To: Jason Gunthorpe CC: Will Deacon , Kiryl Shutsemau , "Robin Murphy" , Joerg Roedel , "Pranjal Shrivastava" , Breno Leitao , "Kyle McMartin" , Usama Arif , , , Subject: Re: [PATCH v3] iommu/arm-smmu-v3: Shrink command/event/PRI queues in kdump kernel Message-ID: References: <20260706084708.8072-1-kas@kernel.org> <20260804141704.GB27883@nvidia.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20260804141704.GB27883@nvidia.com> X-NV-OnPremToCloud: ExternallySecured X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH1PEPF0000AD7A:EE_|PH8PR12MB6865:EE_ X-MS-Office365-Filtering-Correlation-Id: ec89bdbb-f939-4d94-eb74-08def2422013 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|36860700016|7416014|1800799024|376014|23010399003|6133799003|56012099006|4143699003|11063799006|22082099003|18002099003|10067099003; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: mbgP1TrCGHFwNEcwDt/7CwCD4OOBcfrEakJbU7PNTxLNvWBi9wyViSj1TfPAUG+cgu9jb6fsz33tFjhkmI5uSlMIOlG8OJA2VrsLb+rWDqcQ9NPRSo52M1omZsdcHWhYqTP2iht752NdRcDjOJF70IjvQ0qkiePDisl2cNe2C+zz+7JgdV8a06zaMZWagQhHu6vAy87MXnHhGAV8tmtGoiYt6FZFcYunBJliiTQ0nIoQknFjfWfD/t4ZH9NXlKqtYKQLGetSPjUJsBaqEOez3TWsRH9R/Apho41xbXjb9wqj7zQPlxlOfF3zj/G4bm8tLBlaKoa/fml4zj/M+NY+bg8LY2Ky3cVsELM1wZfZcAFgJeQFkiEp7ADvxzd+SsTSNQMCU1ztyamGgpvwg1u2/O9QnvgznrQNvrFi5Ebm0XRPtqzBRfaFswrkvu01LkAt X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Aug 2026 16:04:55.1671 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: ec89bdbb-f939-4d94-eb74-08def2422013 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.118.232];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: CH1PEPF0000AD7A.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR12MB6865 On Tue, Aug 04, 2026 at 11:17:04AM -0300, Jason Gunthorpe wrote: > On Tue, Aug 04, 2026 at 03:02:46PM +0100, Will Deacon wrote: > > > Would skipping their allocation when is_kdump_kernel() be acceptable on > > > its own, or would you rather see it done differently? > > > > With Nicolin's patch, we can just avoid allocating the priq and the evtq > > entirely in the kdump case. We can then add a cmdline option to control > > the maximum size of the cmdq, which is useful regardless of kdump. > > I would still prefer kdump do this re-sizing automatically, even if we > do add a commandline. It makes it easire to deploy than having to know > secret command lines :\ > > So functionally I still think this patch is fine, though yes it points > out more things in Nicolin's work too. I will send a v10 of mine, to skip the EVTQ/PRIQ allocations. Thanks Nicolin