Quoting Sukadev Bhattiprolu (sukadev@xxxxxxxxxxxxxxxxxx): > Serge Hallyn [serge@xxxxxxxxxx] wrote: > | Quoting Matthieu Fertré (matthieu.fertre@xxxxxxxxxxx): > | > Hi, > | > > | > Here is a proposal for a C/R related feature already developed in > | > Kerrighed: file substitution at restart. > | > > | > The goal of this mail is to start a discussion about adding such feature > | > to Linux cr. Comments are welcome! > | > | Yup, AFAIK metacluster and zap do this too. I don't think there is > | any question about whether we want to support this, but rather > | what the user-kernel API should look like. Perhaps the easiest > | "API" is to have the userspace program rewrite the checkpoint image, > | but that probably isn't quite as simple as just substituting #s in > | the image, bc we'll have to also find the place where the source of > | the original fd was specified and tweak that. > | > | I assume this is one of the things Oren would have 'cradvise()' > | do, and at this point that sounds nice to me - might be worth > | seeing how the community reacts. Sentiments on such things change, > | after all. > > Yes, I had the same question about the kernel API. cradvise() would be > one option, but am not too clear on the details. For each process in > the checkpoint image that we want to substitute one or more fds, > do we call cradvise() *before* the call to sys_restart() ? This would No, I would rather think that we follow the Kerrighed example, and specify a checkpoint-wide id for the fd (the objhash id i guess). The first cr_advise() starts to create a restart context, which finally gets used at sys_restart by the coordinator (and of course all subsequent tasks). > require the kernel to save these substitution pairs in memory until > the following sys_restart() right ? > > Passing in a list of fd-substition pairs to sys_restart() might be one > option, but would require modifying the sys_restart() API. > > Sukadev _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
