Matt Helsley wrote: > On Mon, May 18, 2009 at 06:21:22PM -0500, Nathan Lynch wrote: >> Matt Helsley <matthltc@xxxxxxxxxx> writes: >> >>> On Mon, May 18, 2009 at 04:36:11PM -0500, Nathan Lynch wrote: >>>> [1] Should CONFIG_CHECKPOINT depend on CONFIG_CGROUPS and/or >>>> CONFIG_CGROUPS_FREEZER? We require tasks to be put in frozen state >>>> before checkpoint, is there any mechanism apart from >>>> cgroup/freezer.state to do this? >>> Have you tried sending all of the tasks SIGSTOP? It won't 100% freeze >>> the tasks -- they'd still be capable of responding to some signals >>> (CONT, TERM..). Also they'd presumably be placed in the stopped state >>> upon restart so a SIGCONT will be needed. In the case of bash, at >>> least, that will technically change what happens upon restart. My >>> guess is that in many cases it won't matter but there are some where >>> it will. >> Hmm, I'm having trouble understanding your suggestion. The current >> checkpoint implementation requires non-self tasks to be frozen (p->flags >> & PF_FROZEN), which is not equivalent to stopped state (task->state & >> __TASK_STOPPED). That is, it would refuse to checkpoint tasks in >> stopped state. See may_checkpoint_task(). > > Oops. You're right. That would require changing may_checkpoint_task() to include > __TASK_STOPPED -- not something we'd want in the final code. I had assumed > you wanted to try a different mechanism for debugging purposes. > Allowing checkpoint of stopped tasks is actually not such a bad idea, IMHO. Oren. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
