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Thu, 21 Jan 2021 13:51:45 +0000 Date: Thu, 21 Jan 2021 09:51:43 -0400 From: Jason Gunthorpe To: liweihang CC: Leon Romanovsky , "dledford@redhat.com" , "linux-rdma@vger.kernel.org" , "linuxarm@openeuler.org" Subject: Re: [PATCH RFC 1/7] RDMA/hns: Introduce DCA for RC QP Message-ID: <20210121135143.GZ4147@nvidia.com> References: <1610706138-4219-1-git-send-email-liweihang@huawei.com> <1610706138-4219-2-git-send-email-liweihang@huawei.com> <20210120081025.GA225873@unreal> <8d255812177a4f53becd3c912d00c528@huawei.com> <20210121085325.GC320304@unreal> <96d7fb7db36e4bce8c556d0de5c8f961@huawei.com> <20210121133445.GY4147@nvidia.com> <14243f680ba6428789b878078f766967@huawei.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <14243f680ba6428789b878078f766967@huawei.com> X-ClientProxiedBy: BL1PR13CA0433.namprd13.prod.outlook.com (2603:10b6:208:2c3::18) 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 (206.223.160.26) by BL1PR13CA0433.namprd13.prod.outlook.com (2603:10b6:208:2c3::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3805.6 via Frontend Transport; Thu, 21 Jan 2021 13:51:45 +0000 Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1l2aND-0051l0-ON; Thu, 21 Jan 2021 09:51:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1611237107; bh=dAcLHAvcGKqXW9Mrf54v7UbYz/6agvxAw6vGWQcsmHE=; 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=oujH3TYwPLVl6APoRcRQ1+X1NdTWKukbN+mbUUs/VEBQnaiYUiG4RgtZIbXg6r+b0 w1ebPTa+WzpP419ZOBiPG9t3VrUfpdKccvdeLbGxJN73MYxQ2pmr1DNC+18IIMiKsN qtPMTpXCC7nYTcX8nZSkfgpQR5MWf54AlC/snBtXB3UyXlfy61Xj9tHCnpnRw9T1P0 PslVGgsE9EjCjYKbtlhZ1xsFuy3d22ECFAMj5I45tj5pQZnjAyppgrEiq0IcGw1G7T f/G5QbLhljpfACEaxIqpO3QA/60plqRuzqwlWm9KYPar6HpcQSsF8aVVLMFrA8xF23 hUcnsmG2/Szew== Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Thu, Jan 21, 2021 at 01:48:56PM +0000, liweihang wrote: > On 2021/1/21 21:36, Jason Gunthorpe wrote: > > On Thu, Jan 21, 2021 at 01:33:42PM +0000, liweihang wrote: > > > >> We need to allocate memory while spin_lock is hold, how about using GFP_KERNEL or > >> GFP_NOWAIT? > > > > You should try hard not to do that. Convert he spinlock to a mutex, > > for instance. > > > > Jason > > > > But what if some kernel users call ib_post_send() when holding a spinlock? I doubt extensions like this would be part of kernel verbs.. Does any ULP call ib_post_send under lock? I'm not sure that is valid. Jason