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[142.162.113.129]) by smtp.gmail.com with ESMTPSA id 205sm7652317qkf.19.2021.10.04.06.27.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Oct 2021 06:28:00 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1mXO0d-00ATnh-F3; Mon, 04 Oct 2021 10:27:59 -0300 Date: Mon, 4 Oct 2021 10:27:59 -0300 From: Jason Gunthorpe To: Christian =?utf-8?B?S8O2bmln?= Cc: Logan Gunthorpe , Alistair Popple , Felix Kuehling , Christoph Hellwig , Dan Williams , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Stephen Bates , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Bjorn Helgaas , Ira Weiny , Robin Murphy , Martin Oliveira , Chaitanya Kulkarni Subject: Re: [PATCH v3 19/20] PCI/P2PDMA: introduce pci_mmap_p2pmem() Message-ID: <20211004132759.GX3544071@ziepe.ca> References: <32ce26d7-86e9-f8d5-f0cf-40497946efe9@deltatee.com> <20210929233540.GF3544071@ziepe.ca> <20210930003652.GH3544071@ziepe.ca> <20211001134856.GN3544071@ziepe.ca> <4fdd337b-fa35-a909-5eee-823bfd1e9dc4@deltatee.com> <20211001174511.GQ3544071@ziepe.ca> <809be72b-efb2-752c-31a6-702c8a307ce7@amd.com> <20211004131102.GU3544071@ziepe.ca> <1e219386-7547-4f42-d090-2afd62a268d7@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1e219386-7547-4f42-d090-2afd62a268d7@amd.com> X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 2C3D190009EF X-Stat-Signature: h4iwr5yuui1bb6jh43abqj5supt6hwcu Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=ziepe.ca header.s=google header.b=iDoHZmkG; spf=pass (imf28.hostedemail.com: domain of jgg@ziepe.ca designates 209.85.160.182 as permitted sender) smtp.mailfrom=jgg@ziepe.ca; dmarc=none X-HE-Tag: 1633354080-629317 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Oct 04, 2021 at 03:22:22PM +0200, Christian K=C3=B6nig wrote: > That use case is completely unrelated to GUP and when this doesn't work= we > have quite a problem. My read is that unmap_mapping_range() guarentees the physical TLB hardware is serialized across all CPUs upon return. It also guarentees GUP slow is serialized due to the page table spinlocks. Jason