Messages in this thread | | | Subject | Re: What can OpenVZ do? | From | Dave Hansen <> | Date | Wed, 18 Feb 2009 13:27:27 -0800 |
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On Wed, 2009-02-18 at 19:16 +0100, Ingo Molnar wrote: > Nothing motivates more than app designers complaining about the > one-way flag. > > Furthermore, it's _far_ easier to make a one-way flag SMP-safe. > We just set it and that's it. When we unset it, what do we about > SMP races with other threads in the same MM installing another > non-linear vma, etc.
After looking at this for file descriptors, I have to really agree with Ingo on this one, at least as far as the flag is concerned. I want to propose one teeny change, though: I think the flag should be per-resource.
We should have one flag in mm_struct, one in files_struct, etc... The task_is_checkpointable() function can just query task->mm, task->files, etc... This gives us nice behavior at clone() *and* fork that just works.
I'll do this for files_struct and see how it comes out so you can take a peek.
-- Dave
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