Messages in this thread | | | From | (Eric W. Biederman) | Date | Thu, 10 Jul 2008 11:55:34 -0700 | Subject | Re: Checkpoint/restart (was Re: [PATCH 0/4] - v2 - Object creation with a specified id) |
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"Serge E. Hallyn" <serue@us.ibm.com> writes:
>> So, the checkpoint-as-a-corefile idea sounds good to me, but it >> definitely leaves a lot of questions about exactly how we'll need to do >> the restore. > > Talking with Dave over irc, I kind of liked the idea of creating a new > fs/binfmt_cr.c that executes a checkpoint-as-a-coredump file. > > One thing I do not like about the checkpoint-as-coredump is that it begs > us to dump all memory out into the file. Our plan/hope was to save > ourselves from writing out most memory by: > > 1. associating a separate swapfile with each container > 2. doing a swapfile snapshot at each checkpoint > 3. dumping the pte entries (/proc/self/) > > If we do checkpoint-as-a-coredump, then we need userspace to coordinate > a kernel-generated coredump with a user-generated (?) swapfile snapshot. > But I guess we figure that out later.
Well it is a matter of which VMAs you dump. For things that are file backed you need to dump them.
I don't know that even a binfmt for per process level checkpoints is sufficient but I do know having something of that granularity looks much easier. Otherwise it takes a bazillian little syscalls to do things no one else is interested in doing.
Eric
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