* Dave Hansen <dave@xxxxxxxxxxxxxxxxxx> wrote: > 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. Yeah, per resource it should be. That's per task in the normal case - except for threaded workloads where it's shared by threads. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
