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Tue, 23 Mar 2021 03:51:31 -0700 (PDT) Date: Tue, 23 Mar 2021 11:51:13 +0100 From: Jean-Philippe Brucker To: Lu Baolu Subject: Re: [PATCH v13 06/10] iommu: Add a page fault handler Message-ID: References: <20210302092644.2553014-1-jean-philippe@linaro.org> <20210302092644.2553014-7-jean-philippe@linaro.org> <15ff4704-0fbd-243f-8e49-a9523ae63ce6@linux.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <15ff4704-0fbd-243f-8e49-a9523ae63ce6@linux.intel.com> Cc: vivek.gautam@arm.com, guohanjun@huawei.com, will@kernel.org, Ashok Raj , linux-acpi@vger.kernel.org, zhangfei.gao@linaro.org, lenb@kernel.org, devicetree@vger.kernel.org, kevin.tian@intel.com, robh+dt@kernel.org, linux-arm-kernel@lists.infradead.org, rjw@rjwysocki.net, iommu@lists.linux-foundation.org, sudeep.holla@arm.com, robin.murphy@arm.com, linux-accelerators@lists.ozlabs.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Wed, Mar 03, 2021 at 01:27:34PM +0800, Lu Baolu wrote: > I have tested this framework with the Intel VT-d implementation. It > works as expected. Hence, > > Reviewed-by: Lu Baolu > Tested-by: Lu Baolu Thanks! > One possible future optimization is that we could allow the system > administrators to choose between handle PRQs in a workqueue or handle > them synchronously. One research discovered that most of the software > latency of handling a single page fault exists in the schedule part. > Hence, synchronous processing will get shorter software latency if PRQs > are rare and limited. Yes, the risk is that processing a fault synchronously will take too much time, leading to PRI queue overflow if the IOMMU keeps receiving page faults. That's why I opted for the workqueue initially, but it's definitely something we can tweak Thanks, Jean _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu