On Thu 19-07-18 23:17:53, Baoquan He wrote: > Kexec has been a formal feature in our distro, and customers owning > those kind of very large machine can make use of this feature to speed > up the reboot process. On uefi machine, the kexec_file loading will > search place to put kernel under 4G from top to down. As we know, the > 1st 4G space is DMA32 ZONE, dma, pci mmcfg, bios etc all try to consume > it. It may have possibility to not be able to find a usable space for > kernel/initrd. From the top down of the whole memory space, we don't > have this worry. I do not have the full context here but let me note that you should be careful when doing top-down reservation because you can easily get into hotplugable memory and break the hotremove usecase. We even warn when this is done. See memblock_find_in_range_node -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html