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a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1600342349; bh=AMloEs2OJvzqHjkveAYpZ03oJ0AdBGCE4ZSSuMFW35E=; h=X-PGP-Universal:ARC-Seal:ARC-Message-Signature: ARC-Authentication-Results:Authentication-Results:Date:From:To:CC: Subject:Message-ID:References:Content-Type:Content-Disposition: In-Reply-To:X-ClientProxiedBy:MIME-Version: X-MS-Exchange-MessageSentRepresentingType:X-Originating-IP: X-MS-PublicTrafficType:X-MS-Office365-Filtering-Correlation-Id: X-MS-TrafficTypeDiagnostic:X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers:X-MS-Exchange-SenderADCheck: X-Microsoft-Antispam:X-Microsoft-Antispam-Message-Info: X-Forefront-Antispam-Report:X-MS-Exchange-AntiSpam-MessageData: X-MS-Exchange-CrossTenant-Network-Message-Id: X-MS-Exchange-CrossTenant-AuthSource: X-MS-Exchange-CrossTenant-AuthAs: X-MS-Exchange-CrossTenant-OriginalArrivalTime: X-MS-Exchange-CrossTenant-FromEntityHeader: X-MS-Exchange-CrossTenant-Id:X-MS-Exchange-CrossTenant-MailboxType: X-MS-Exchange-CrossTenant-UserPrincipalName: X-MS-Exchange-Transport-CrossTenantHeadersStamped:X-OriginatorOrg; b=Dpeimn7TXOjjg21KX/KAwJlUBXDTGEniy3g+08+81ZqpjE8m2sHZC8s4PiO3D72YP nbAxFXOyK+IX62GQoJj1a6ApROF5XxeXnbECiyALkPL1YtOkpj3XJAFU4Y0eJjuEi4 KPMLid/+OzbhmOvXaGYbG+f2bkrFov8b3gKuDV3rUV1lxG4Ur1zKe2Ntc6wr++eqQF zqx/E84Q3BQT+fQDezoYdwf56UJpdtDZu9c12shZe58/CP5tgQtZ/p+UXAB6RJgbUm c9NZsEynaoOHY7RPUj7fEYRPAbGXnn9iG5owd47wkPIqjqqIBqqCg6EVmDahrNh5MT NEmz38AK1GmwA== Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Sep 17, 2020 at 11:28:19AM +0100, Lorenzo Pieralisi wrote: > Unfortunately if we merge this patch we _do_ know from this thread > that userspace will suffer from a perf regression on TX2. > > Either we ignore it or we write some code to prevent it > (ie first step make arch_can_pci_mmap_wc() return 0 on TX2 - > possibly using the arm64 errata detection mechanism). If anyone complains they can send the change to arch_can_pci_mmap_wc() - I'm pretty sure nobody will complain due to mlx5 Jason