[PATCH v13 06/10] iommu: Add a page fault handler

Jean-Philippe Brucker jean-philippe at linaro.org
Tue Mar 23 21:51:13 AEDT 2021

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 <baolu.lu at linux.intel.com>
> Tested-by: Lu Baolu <baolu.lu at linux.intel.com>


> 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


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