On Fri, Jun 22, 2012 at 03:28:14PM +0400, Alexandra N. Kossovsky wrote: > Hello. > > It is not clear from the documentation if iommu_map()/iommu_unmap() > functions may be called from atomic context. > In case of Intel IOMMU, it works; in case of AMD IOMMU, it does not. > > Was it done by purpose? May I propose a patch for AMD IOMMU replacing > GFP_KERNEL by GFP_ATOMIC to make things better?
Well, a better option would be to have an iommu_map_atomic() alongside the current iommu_map API call. > We use IOMMU API in OpenOnload project http://www.openonload.org/, > and we get better latency with Intel IOMMU because we are not > forced to use threaded IRQ. Yes, the IRQ for the AMD IOMMU is threaded. But I don't understand how that is relevant for your latency. Can you give more details here? Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
