The kernel's kexec mechanism allows one kernel to directly boot a new one; it can be thought of as a sort of kernel equivalent to the execve() system call. Kexec has a number of uses, including booting a special kernel to perform dumps after a crash. Normally, one does not expect user-space processes to survive booting into a new kernel, but that has not stopped developers from trying to implement that ability. Mike Rapoport ran a memory-management-track session at the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit to discuss one piece of that problem: enabling the contents of memory to persist across a kexec handover so that the new kernel can pick up where the old one left off.
内核的 kexec 机制允许一个内核直接引导一个新的内核；它可以被看作是 execve() 系统调用的内核等价物。Kexec 有许多用途，包括在崩溃后引导一个特殊的内核来执行转储。通常，人们不会期望用户空间进程在引导到新内核后仍然存活，但这并没有阻止开发人员尝试实现这一能力。在 2025 年的 Linux 存储、文件系统、内存管理和 BPF 峰会上，Mike Rapoport 主持了一个关于内存管理的会议，讨论了这个问题的一个方面：如何使内存内容在 kexec 交接过程中保持不变，以便新内核可以从旧内核停止的地方继续运行。
The use case that is being worked on is to allow large cloud providers to update the kernel on a system hosting virtual machines without disturbing those machines in the process. The proposed new subsystem to enable this functionality is called Kexec HandOver, or KHO, but KHO needs layers on top to implement the persistence of memory contents, and how that will work is not yet entirely clear. There has to be some way for the system