On Thu 07-12-23 12:23:13, Baoquan He wrote: [...] > We can't guarantee how swift the DMA transfer could be in the cma, case, > it will be a venture. We can't guarantee this of course but AFAIK the DMA shouldn't take minutes, right? While not perfect, waiting for some time before jumping into the crash kernel should be acceptable from user POV and it should work around most of those potential lingering programmed DMA transfers. So I guess what we would like to hear from you as kdump maintainers is this. Is it absolutely imperative that these issue must be proven impossible or is a best effort approach something worth investing time into? Because if the requirement is an absolute guarantee then I simply do not see any feasible way to achieve the goal of reusable memory. Let me reiterate that the existing reservation mechanism is showing its limits for production systems and I strongly believe this is something that needs addressing because crash dumps are very often the only tool to investigate complex issues. -- Michal Hocko SUSE Labs _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
