From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ale.deltatee.com (ale.deltatee.com [207.54.116.67]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 7C78D21106F13 for ; Mon, 3 Sep 2018 15:26:54 -0700 (PDT) References: <20180830185352.3369-1-logang@deltatee.com> <20180830185352.3369-8-logang@deltatee.com> <20180901082812.GB670@lst.de> From: Logan Gunthorpe Message-ID: <5f79c012-c6e1-56bb-62fd-0689181fb2c9@deltatee.com> Date: Mon, 3 Sep 2018 16:26:27 -0600 MIME-Version: 1.0 In-Reply-To: <20180901082812.GB670@lst.de> Content-Language: en-US Subject: Re: [PATCH v5 07/13] block: Add PCI P2P flag for request queue and check support for requests List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Christoph Hellwig , Jens Axboe Cc: Alex Williamson , linux-nvdimm@lists.01.org, linux-rdma@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Jason Gunthorpe , Benjamin Herrenschmidt , Bjorn Helgaas , Max Gurtovoy , =?UTF-8?Q?Christian_K=c3=b6nig?= List-ID: On 01/09/18 02:28 AM, Christoph Hellwig wrote: > On Thu, Aug 30, 2018 at 01:11:18PM -0600, Jens Axboe wrote: >> I think this belongs in the caller - both the validity check, and >> passing in NOMERGE for this type of request. I don't want to impose >> this overhead on everything, for a pretty niche case. > > It is just a single branch, which will be predicted as not taken > for non-P2P users. The benefit is that we get proper error checking > by doing it in the block code. I personally agree with Christoph. But if there's consensus in the other direction or this is a real blocker moving this forward, I can remove it for the next version. Logan _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: To: Christoph Hellwig , Jens Axboe Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org, linux-nvdimm@lists.01.org, linux-block@vger.kernel.org, Stephen Bates , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Jason Gunthorpe , Max Gurtovoy , Dan Williams , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt , Alex Williamson , =?UTF-8?Q?Christian_K=c3=b6nig?= References: <20180830185352.3369-1-logang@deltatee.com> <20180830185352.3369-8-logang@deltatee.com> <20180901082812.GB670@lst.de> From: Logan Gunthorpe Message-ID: <5f79c012-c6e1-56bb-62fd-0689181fb2c9@deltatee.com> Date: Mon, 3 Sep 2018 16:26:27 -0600 MIME-Version: 1.0 In-Reply-To: <20180901082812.GB670@lst.de> Content-Type: text/plain; charset=utf-8 Subject: Re: [PATCH v5 07/13] block: Add PCI P2P flag for request queue and check support for requests List-ID: On 01/09/18 02:28 AM, Christoph Hellwig wrote: > On Thu, Aug 30, 2018 at 01:11:18PM -0600, Jens Axboe wrote: >> I think this belongs in the caller - both the validity check, and >> passing in NOMERGE for this type of request. I don't want to impose >> this overhead on everything, for a pretty niche case. > > It is just a single branch, which will be predicted as not taken > for non-P2P users. The benefit is that we get proper error checking > by doing it in the block code. I personally agree with Christoph. But if there's consensus in the other direction or this is a real blocker moving this forward, I can remove it for the next version. Logan From mboxrd@z Thu Jan 1 00:00:00 1970 From: Logan Gunthorpe Subject: Re: [PATCH v5 07/13] block: Add PCI P2P flag for request queue and check support for requests Date: Mon, 3 Sep 2018 16:26:27 -0600 Message-ID: <5f79c012-c6e1-56bb-62fd-0689181fb2c9@deltatee.com> References: <20180830185352.3369-1-logang@deltatee.com> <20180830185352.3369-8-logang@deltatee.com> <20180901082812.GB670@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180901082812.GB670-jcswGhMUV9g@public.gmane.org> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: Christoph Hellwig , Jens Axboe Cc: Alex Williamson , linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-nvme-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Jason Gunthorpe , Benjamin Herrenschmidt , Bjorn Helgaas , Max Gurtovoy , =?UTF-8?Q?Christian_K=c3=b6nig?= List-Id: linux-rdma@vger.kernel.org On 01/09/18 02:28 AM, Christoph Hellwig wrote: > On Thu, Aug 30, 2018 at 01:11:18PM -0600, Jens Axboe wrote: >> I think this belongs in the caller - both the validity check, and >> passing in NOMERGE for this type of request. I don't want to impose >> this overhead on everything, for a pretty niche case. > > It is just a single branch, which will be predicted as not taken > for non-P2P users. The benefit is that we get proper error checking > by doing it in the block code. I personally agree with Christoph. But if there's consensus in the other direction or this is a real blocker moving this forward, I can remove it for the next version. Logan From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: To: Christoph Hellwig , Jens Axboe References: <20180830185352.3369-1-logang@deltatee.com> <20180830185352.3369-8-logang@deltatee.com> <20180901082812.GB670@lst.de> From: Logan Gunthorpe Message-ID: <5f79c012-c6e1-56bb-62fd-0689181fb2c9@deltatee.com> Date: Mon, 3 Sep 2018 16:26:27 -0600 MIME-Version: 1.0 In-Reply-To: <20180901082812.GB670@lst.de> Subject: Re: [PATCH v5 07/13] block: Add PCI P2P flag for request queue and check support for requests List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Keith Busch , Alex Williamson , Sagi Grimberg , linux-nvdimm@lists.01.org, linux-rdma@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Stephen Bates , linux-block@vger.kernel.org, =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Jason Gunthorpe , Benjamin Herrenschmidt , Bjorn Helgaas , Max Gurtovoy , Dan Williams , =?UTF-8?Q?Christian_K=c3=b6nig?= Content-Type: text/plain; charset="us-ascii" Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+bjorn=helgaas.com@lists.infradead.org List-ID: On 01/09/18 02:28 AM, Christoph Hellwig wrote: > On Thu, Aug 30, 2018 at 01:11:18PM -0600, Jens Axboe wrote: >> I think this belongs in the caller - both the validity check, and >> passing in NOMERGE for this type of request. I don't want to impose >> this overhead on everything, for a pretty niche case. > > It is just a single branch, which will be predicted as not taken > for non-P2P users. The benefit is that we get proper error checking > by doing it in the block code. I personally agree with Christoph. But if there's consensus in the other direction or this is a real blocker moving this forward, I can remove it for the next version. Logan _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme From mboxrd@z Thu Jan 1 00:00:00 1970 From: logang@deltatee.com (Logan Gunthorpe) Date: Mon, 3 Sep 2018 16:26:27 -0600 Subject: [PATCH v5 07/13] block: Add PCI P2P flag for request queue and check support for requests In-Reply-To: <20180901082812.GB670@lst.de> References: <20180830185352.3369-1-logang@deltatee.com> <20180830185352.3369-8-logang@deltatee.com> <20180901082812.GB670@lst.de> Message-ID: <5f79c012-c6e1-56bb-62fd-0689181fb2c9@deltatee.com> On 01/09/18 02:28 AM, Christoph Hellwig wrote: > On Thu, Aug 30, 2018@01:11:18PM -0600, Jens Axboe wrote: >> I think this belongs in the caller - both the validity check, and >> passing in NOMERGE for this type of request. I don't want to impose >> this overhead on everything, for a pretty niche case. > > It is just a single branch, which will be predicted as not taken > for non-P2P users. The benefit is that we get proper error checking > by doing it in the block code. I personally agree with Christoph. But if there's consensus in the other direction or this is a real blocker moving this forward, I can remove it for the next version. Logan