http://bugzilla.kernel.org/show_bug.cgi?id=12222 ------- Comment #4 from grundler@xxxxxxxxxxxxxxxx 2008-12-15 13:40 ------- In 2.6.28-rc8 kernel, the BUG_ON is now at line 1276. The BUG_ON is just indicating the IOMMU page table entry is already (or still) in use. My guess is either the IOMMU space allocator is buggy *OR* the unmap code isn't clearing dma_pte_addr() (off by one?). Perhaps there needs to be a wmb() in intel_unmap_sg() between dma_pte_clear_range() and the later __free_iova() call. intel_iommu=off means no IOMMU will be used. For normal workloads with modern PCIe devices (which are all 64-bit, right?), there would be no perf impact. Not until you wanted to get better isolation for virtual guest OSs or used a device driver that only offers 32-bit DMA support, will it matter. -- Configure bugmail: http://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
