On 18/06/2021 02:46, Lu Baolu wrote: Hi baolu,
I need to change that. How about this: bool print_warning = false; for_each_active_iommu(iommu, drhd) { /* * The flush queue implementation does not perform * page-selective invalidations that are required for efficient * TLB flushes in virtual environments. The benefit of batching * is likely to be much lower than the overhead of synchronizing * the virtual and physical IOMMU page-tables. */ if (!print_warning && cap_caching_mode(iommu->cap)) { pr_warn("IOMMU batching disallowed due to virtualization\n"); iommu_set_dma_strict(true); print_warning = true; } ... } or use pr_warn_once().From my p.o.v, pr_xxxx_once() is better. How about using a pr_info_once()? I don't think it's a warning, it's just a policy choice in VM environment.
ok, I can go with that, which Robin mostly agrees with. Thanks, John
