[PATCH v2] makedumpfile: exclude pages that are logically offline

David Hildenbrand david at redhat.com
Thu Mar 7 00:41:15 PST 2019

On 27.11.18 17:32, Kazuhito Hagio wrote:
>> Linux marks pages that are logically offline via a page flag (map count).
>> Such pages e.g. include pages infated as part of a balloon driver or
>> pages that were not actually onlined when onlining the whole section.
>> While the hypervisor usually allows to read such inflated memory, we
>> basically read and dump data that is completely irrelevant. Also, this
>> might result in quite some overhead in the hypervisor. In addition,
>> we saw some problems under Hyper-V, whereby we can crash the kernel by
>> dumping, when reading memory of a partially onlined memory segment
>> (for memory added by the Hyper-V balloon driver).
>> Therefore, don't read and dump pages that are marked as being logically
>> offline.
>> Signed-off-by: David Hildenbrand <david at redhat.com>
> Thanks for the v2 update.
> I'm going to merge this patch after the kernel patches are merged
> and it tests fine with the kernel.
> Kazu

Hi Kazu,

the patches are now upstream. Thanks!



David / dhildenb

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