Quoting Oren Laadan ([email protected]): > > > Serge E. Hallyn wrote: > >Quoting Oren Laadan ([email protected]): > >> > >>Serge E. Hallyn wrote: > >>>Quoting Oren Laadan ([email protected]): > >>>>Serge E. Hallyn wrote: > >>>>>Quoting Oren Laadan ([email protected]): > >>>>>>Serge E. Hallyn wrote: > >>>>>>>Quoting Oren Laadan ([email protected]): > >>>>>>>>Cool ! > >>>>>>>> > >>>>>>>>So what do we have working now for 64 bit kernel (for 32 bit kernel > >>>>>>>>we know it works...): > >>>>>>>> > >>>>>>>> 'restart' checkpointed > >>>>>>>> program program > >>>>>>>> ---------------------------------------- > >>>>>>>> 64bit 64bit -> works > >>>>>>>> 32bit 32bit -> works > >>>>>>>> > >>>>>>>> 64bit 32bit -> ????? > >>>s/?????/Rejected/ > >>> > >>>CKPT_ARCH_ID is of course different for X86_32 than X86_64, so > >>>we refuse restart in restore_read_header(). > >>> > >>>-serge > >>> > >>lol ... that's actually funny ! > >> > >>Anyway, in light of the IRC discussions, here are the cases again: > >> > >> > >>original original restart target > >>program kernel program kernel > >>-------- --------- -------- -------- > >>64 bit 64 bit 64 bit 64 bit [0] works > >> > >>32 bit 32 bit 32 bit 32 bit [0] works > >>32 bit 64 bit 32 bit 64 bit [0] works > >> > >>32 bit 32 bit 32 bit 64 bit [1] > >>32 bit 64 bit 32 bit 32 bit [1] > >> > >>32 bit any 64 bit 64 bit [2] > >>64 bit 64 bit 32 bit 64 bit [2] > >> > >>[0] The first 3 cases are "homogeneous", with conditions equal at > >>checkpoint and restart. AFAIK, they work. > >> > >>[1] The next two cases consider 32 bit program, and vary only the > >>environment - the kernel may change from 32 to 64 or back. We want > >>them to work. > >> > >>IIUC, your comment above means that they don't work because the > >>CKPT_ARCH_ID is a mismatch. The fix should be trivial - either > >>make 'restart' modify it, or make the kernel tolerate it. > > > >Well, you'd think so, but we also check for uts->machine, and want > >to eventually check for kernel config, both of which are obviously > >different. > > Then we'll have to take that in account when we get to also > check those other fields. > > > > >After I comment out the obvious offending checks, it still fails to > >restart from x8632->x86-64. I can spend some time next week figuring > >out what we're not quite doing right as there shouldn't be a > >problem really. But do we definately want to go out of our way to try > > and mask out the differences in this case, while trying to detect > >cpu differences between two x86-32's for instance? > > I agree, there shouldn't be a problem really, and I expect this to > be a very useful feature for migration/fault-tolerance.
May be, but then perhaps this is the first case where we should be using a userspace checkpoing image rewriter to help us out. Otherwise we'll need to hardcode in the kernel that a task which was checkpointed on X86_32 should, on x86_64, have TIF_IA32 added to the thread_flags but may be restarted; etc. Should be doable, but kind of ugly... -serge _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
