Re: [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code

[Ingo Molnar]

* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Thu, Jun 11, 2015 at 1:37 PM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Don't use "for_each_process_thread(g, p)". You only care about each mm, and 
> > threads all share the same mm, so just do
> >
> >     for_each_process(p)
> >
> > instead of iterating over all threads too.
> 
> Hmm. I may be wrong. It strikes me that one of the group leaders might have 
> exited but the subthreads live on. We'd see p->mm being NULL, even though the mm 
> was originally in use.
> 
> Ugh. So maybe the code really does need to iterate over all threads.

Yeah, for_each_process() is indeed no guarantee that we iterate over all mm's.

We might make it so: but that would mean restricting certain clone_flags variants 
- not sure that's possible with our current ABI usage?

Thanks,

	Ingo
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