On Mon, Feb 18, 2019 at 9:48 AM Dave Young <dyoung@xxxxxxxxxx> wrote: > > On 02/15/19 at 11:24am, Borislav Petkov wrote: > > On Tue, Feb 12, 2019 at 04:48:16AM +0800, Dave Young wrote: > > > Even we make it automatic in kernel, but we have to have some default > > > value for swiotlb in case crashkernel can not find a free region under 4G. > > > So this default value can not work for every use cases, people need > > > manually use crashkernel=,low and crashkernel=,high in case > > > crashkernel=X does not work. > > > > Why would the user need to find swiotlb range? The kernel has all the > > information it requires at its finger tips in order to decide properly. > > > > The user wants a crashkernel range, the kernel tries the low range => > > no workie, then it tries the next range => workie but needs to allocate > > swiotlb range so that DMA can happen too. Doh, then the kernel does > > allocate that too. > > It is ideal if kernel can do it automatically, but I'm not sure if > kernel can predict the swiotlb reserved size automatically. > Agreed, I think it is hard to decide the reserved size automatically. We do not know the requirement for memory of ZONE_DMA32 at boot time. The requirement depends on how many DMA32 devices, and the dynamic payload of them. > Let's add more people to seek for comments. > > > > > Why would the user need to do anything here?! > > > > -- > > Regards/Gruss, > > Boris. > > > > Good mailing practices for 400: avoid top-posting and trim the reply. _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
