Re: [PATCH -v2] rmap: make anon_vma_prepare link in all the anon_vmasof a mergeable VMA

[Linus Torvalds]

On Thu, 8 Apr 2010, KOSAKI Motohiro wrote:
> 
> Now pagefault don't insert anon_vma anymore, right? if so, SIGBUS is better.
> Now SIGBUS and VM_FAULT_OOM make different result.
> 
> SIGBUS       -> kill current task
> VM_FAULT_OOM -> invoke oom-killer (see pagefault_out_of_memory())

Yeah, maybe VM_FAULT_SIGBUS works ok instead of VM_FAULT_OOM. But the 
cause of it is the system having been oom when themappign was created, so 
I think either is fine.

> If current task can't recover proper anon_vma. we should just kill current
> instead random highest badness process. otherwise !anon_vma process continue
> to randomly invoke oom-killer.

Yes, that is a good point.

Anyway, I think it might be interesting to test my anon_vma_prepare() 
locking change patch together with Rik's _first_ version of his "fix 
anon_vma_prepare" thing (the one without the spinlock). They should apply 
independently of each other, and maybe it all even works together.

		Linus
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