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Groups > linux.kernel > #1164435
| From | Oleg Nesterov <oleg@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code |
| Date | 2015-06-13 01:40 +0200 |
| Message-ID | <pAGIi-3SR-1@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <pAsci-7Wu-27@gated-at.bofh.it> <pAsci-7Wu-25@gated-at.bofh.it> <pADU5-87c-9@gated-at.bofh.it> <pAEds-8uK-13@gated-at.bofh.it> <pAFMd-2pg-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 06/12, Boris Ostrovsky wrote:
>
> On 06/12/2015 04:53 PM, Oleg Nesterov wrote:
>>>
>>> for_each_process(p) {
>>>
>>> for_each_thread(p, t) {
>>> if (t->mm) {
>>> do_something(t->mm);
>>> break;
>>> }
>>> }
>>> }
>>>
>>> But either way I don't understand what protects this ->mm. Perhaps this needs
>>> find_lock_task_mm().
>>
>> And, I don't understand this code, probably this doesn't matter, but.
>>
>> unpin_all() is probably fine, but xen_mm_pin_all() can race with fork()
>> and miss the new child. Is it OK?
>
>
> Currently xen_mm_pin_all() is only called in the suspend path, out of
> stop_machine(), so presumably at that time fork is not possible.
OK, thanks, this also means that this code shouldn't worry about ->mm,
it should be stable.
But for_each_process() in sync_global_pgds() should, afaics.
Oleg.
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Re: [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code Linus Torvalds <torvalds@linux-foundation.org> - 2015-06-11 22:40 +0200
Re: [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code Linus Torvalds <torvalds@linux-foundation.org> - 2015-06-11 22:50 +0200
Re: [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code Oleg Nesterov <oleg@redhat.com> - 2015-06-13 01:40 +0200
Re: [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code Ingo Molnar <mingo@kernel.org> - 2015-06-13 09:30 +0200
Re: [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code Oleg Nesterov <oleg@redhat.com> - 2015-06-13 20:10 +0200
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