On Mon, Jul 27, 2015 at 5:52 PM, Baoquan He <[email protected]> wrote: > On 07/22/15 at 04:47pm, Yinghai Lu wrote: > > Sorry for late reply. This problem is reported by customers. They usulay > don't like to make these things public. While for those systems with > good hard iommu support, it could also fail to initialize hw iommu and > then use swiotlb again, E.g in kdump kernel case. You can see in > intel_iommu_init() swiotlb is assigned to 0 only if intel iommu (namely vt-d) > is initialized successfully. There's possibility that hw iommu > initialization will fail, in this case kdump kernel will fail to boot > if no any low memory is given. So we can't make assumption that system > can boot always well without low memory.
When we had crashkernel=,high working with auto low=40M. all system with crashkernel=,high worked. Now come one model (assume it is 16 socket system), and it could use crashkernel=,high crashkernel=256M,low. So it forces all auto_low be 256M. That is ugly. If the customer does not want to make the log public to make us to find good solution, why should we care about it ? why not just let them carry the "crashkernel=256M,low" all the way? Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
