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Fri, 30 Oct 2020 11:47:34 +0000 Date: Fri, 30 Oct 2020 08:47:32 -0300 From: Jason Gunthorpe To: Bob Pearson CC: "linux-rdma@vger.kernel.org" Subject: Re: another change breaks rxe Message-ID: <20201030114732.GC2620339@nvidia.com> References: <32fa9c9f-5816-7474-b821-ccccd4cb5af0@gmail.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <32fa9c9f-5816-7474-b821-ccccd4cb5af0@gmail.com> X-ClientProxiedBy: MN2PR10CA0013.namprd10.prod.outlook.com (2603:10b6:208:120::26) To DM6PR12MB3834.namprd12.prod.outlook.com (2603:10b6:5:14a::12) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from mlx.ziepe.ca (156.34.48.30) by MN2PR10CA0013.namprd10.prod.outlook.com (2603:10b6:208:120::26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3499.18 via Frontend Transport; Fri, 30 Oct 2020 11:47:33 +0000 Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1kYSsW-00CwHt-OG; Fri, 30 Oct 2020 08:47:32 -0300 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1604058457; bh=yEj98RiKUedCvIJLRq5PRwXY4N+xgposVn0nq8rSQRE=; h=ARC-Seal:ARC-Message-Signature:ARC-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; b=gaHMJz3fodpzMlqvVq4QdOvcJHrPa7FbsfYg8ooQmY+/6sxsjFDKTnvfhB2i/xjS3 knYvNko2TJeNdJBasy9ATYZZUcw892j4PlDcMl/VdJfovA9C9a7pJKglBF3TrbgeCe pmp2YM+ekOwVxywXNjXlJFDfrqalOjZhoYrKjPPPI73ov9CDNFiq0noM3+4ow2qgev rmqNIsIKKT4E0szqes2XWhA7Olz3c8WGRR0xfUQlZhK7j62FjFkSb44SCQkWXIK1yY Xdege3NNwWJJIMApOJZ/CRryZRxbsxq5qKkkWVnLU+3UoBVXSjN3wRCyrJt+w9E74A cGzlblMldwWug== Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Fri, Oct 30, 2020 at 12:41:12AM -0500, Bob Pearson wrote: > breaks rxe because it does use IB_USER_VERBS_CMD_POST_SEND. rxe > posts wqes to a work queue in shared memory and then calls > ibv_post_send with zero wqes as a doorbell to the kernel which uses > this as a hint to go read the shared memory. Gah, siw and rxe are open coding this stuff (wrongly!) in rdma-core This would be a lot better to use an eventfd Jason