>>>>> "Oren" == Oren Laadan <orenl@xxxxxxxxxxxxxxx> writes: Oren> Daniel Lezcano wrote: >>> >>> The one exception (and it is a tedious one !) are states in which >>> the task is already frozen by definition: any ptrace blocking >>> point where the tracee waits for the tracer to grant permission to >>> proceed with its execution. Another example is in vfork(), waiting >>> for completion. >> I would say these are perfect places for "may be >> non-checkpointable" :) Oren> For now, yes. But we definitely want this capability in the long Oren> run; otherwise we won't be able to checkpoint a kernel compile Oren> ('make' uses vfork), or anything with 'gdb' running inside, or Oren> 'strace', and other goodies. The strace/gdb example is *really* hard; but for vfork, you just wait until it's over. The interval between vfork and exec/exit should be short enough not to affect the overall time for a checkpoint (and checkpoint can be fairly slow anyway --- on the HPC machines we used to do it on, writing half a terabyte of checkpoint image to disc could take many minutes. In hindsight, we should have multithreaded it). Waiting for a vforked process to exec is less than a millisecond. -- Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au http://www.ertos.nicta.com.au ERTOS within National ICT Australia _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers